Animal health and welfare in fattening pigs. in relation to housing and husbandry 1. Scientific Opinion of the Panel on Animal Health and Welfare

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1 The EFSA Journal (2007) 564, 1-14 Animal health and welfare in fattening pigs in relation to housing and husbandry 1 Scientific Opinion of the Panel on Animal Health and Welfare (Question No EFSA-Q ) Adopted on 6 September For citation purposes: Scientific Opinion of the Panel on Animal Health and Welfare on a request from the Commission on Animal health and welfare in fattening pigs in relation to housing and husbandry. The EFSA Journal (2007) 564, 1-14 European Food Safety Authority, 2007

2 PANEL MEMBERS The Scientific Panel for Animal Health and Welfare (AHAW) of the European Food Safety Authority adopted the current Scientific Opinion on 6 September The Members of the AHAW Scientific Panel were: Bo Algers, Harry J. Blokhuis, Donald M. Broom, Patrizia Costa, Mariano Domingo, Mathias Greiner, Daniel Guemene, Jörg Hartung, Frank Koenen, Christine Muller-Graf, David B. Morton, Albert Osterhaus, Dirk U. Pfeiffer, Ron Roberts, Moez Sanaa, Mo Salman, J. Michael Sharp, Philippe Vannier, Martin Wierup, Marion Wooldridge. SUMMARY Council Directive 91/630/EEC 2, as amended, laying down minimum standards for the protection of pigs, requires the Commission to submit to the Council a report, based on a scientific opinion of the European Food Safety Authority (EFSA), concerning the welfare various aspects of housing and husbandry systems for farmed pigs. EFSA has therefore been required to provide a Scientific Opinion on several aspects of this, one concerning fattening pigs. The opinion should include: the effects of stocking density, including group size and grouping methods, space requirements and the impact of stall design and different flooring types taking into account different climatic conditions. The Scientific Opinion was adopted by the Panel on Animal Health and Welfare (AHAW) on 6 September Based on the scientific data presented in the Scientific Report and risk assessment, conclusions and recommendations were drawn. In relation to disease, respiratory and gastrointestinal infections and production-related diseases can have a major impact on the welfare of fattening pigs. Management, inspection and other disease prevention measures, handling, hygiene, floor type and the manure system have major effects on disease risk and significant importance for ensuring good welfare. At post-mortem slaughter inspection, pigs kept outdoors usually have a lower prevalence of lesions due to respiratory infections than indoor pigs but higher risk of some internal parasites. Leg disorders, which are caused by a complex of factors including genetic selection and high energy and high protein diet, are a major problem. Interactions between many aspects of the biological functioning of pigs and effects of housing and management on welfare are described. Without suitable rooting and manipulation materials, pigs are likely to direct tactile behaviour towards companions using aggression or other causes of poor welfare. Manipulable material makes any floor more attractive for exploration and pigs prefer the presence of straw to an unbedded floor. The provision of appropriate foraging material is difficult in pens with fully slatted floors unless there is automatic shredding in the waste disposal system. If the ambient temperatures are too high, adequate space to separate from other pigs, sufficient contact with a cool floor, access to outdoors, air-flow rates to help evaporation, water on the skin, or more drinking water help to avoid over-heating. In the case of too low a temperature, better insulation of the floor lowers the risk of hypothermia. When there is too little sensory input, because of social isolation, a barren environment or too little light intensity, pigs are likely to show abnormal behavioural and physiological responses. Flashing lights can be disturbing to pigs and poor welfare is also associated with light of a wavelength or intensity that does not allow the pig to discriminate the behaviour of other pigs or materials. 2 E.C.O.J. n L340 of 11/12/1991. p. 33. The EFSA Journal (2007) 564, 2-14

3 The genetic selection for rapid growth and lean meat without enough consideration of other factors has led to some widespread and serious problems. However, selective breeding to eliminate the halothane gene has improved pig welfare. Poor quality pen design can cause poor welfare in pigs because of parts that cause injury, or disturbance and aggression. If pigs do not have sufficient exercise, there can be adverse effects on bone and muscle development. Dunging behaviour (urination and defecation) is facilitated by design of the housing system and good management. Mixing unacquainted pigs leads to a substantial risk of fighting, injury and production loss. Recommendations presented in the Scientific Opinion include the need to provide an environment and management so that the negative consequences of poor welfare such as injurious behaviours, physiological problems and immunosuppression, caused in barren environments, are avoided. In this sense, it is recommended that pigs should be provided with manipulable, destructible materials, wallows, lighting of appropriate wavelength and intensity, water of a quality and quantity sufficient for their needs, and a balanced diet with no harmful contaminants. In order to minimise disease in pigs, and hence poor welfare, effective disease preventive and management procedures should be in place. The design of accommodation for pigs should be such that the pigs have sufficient exercise for normal bone and muscle development. There should be further efforts to select and breed so that problems of pig welfare, including cardiovascular malfunction, risk of early death and leg disorders are maintained at a low level. The recommendations for further research are mainly focused on the evaluation of the effects of the exposure to several factors (i.e. barren environment, light intensity, noise, respiratory disorders) on the welfare of fattening pigs. Recommendations for further research in relation to the heavy pig production are also provided. The methodology and the results of this scientific report and opinion should be developed to identify welfare outcomes (indicators) that are valid and can be used in an animal welfare monitoring system. Key words: Pig Welfare, pig disease, fattening pigs, weaner, grower, finisher, husbandry, pen design, housing system. The EFSA Journal (2007) 564, 3-14

4 TABLE OF CONTENTS Panel Members... 2 Summary Background Terms of Reference Acknowledgements Scope and Objectives Introduction Statement of purpose of the Risk Assessment Exercise The chosen approach Conclusions and Recommendations Conclusions concerning the welfare of fattening pigs Recommendations Recommendations for further research (in order of priority) References The EFSA Journal (2007) 564, 4-14

5 1. BACKGROUND Council Directive 91/630/EEC 3, as amended, laying down minimum standards for the protection of pigs and requires the Commission to submit to the Council a report, based on a scientific opinion of the European Food Safety Authority (EFSA), concerning various aspects of housing and husbandry systems for farmed pigs. In this context and upon requests from the Commission, EFSA has already issued opinions 4 on welfare aspects of the castration of pigs and the welfare of weaners and rearing pigs: effects of different space allowances and floor types. Council Directive 91/630/EEC, as amended, also provides for the Commission to report to Council, on the basis of an EFSA scientific opinion, on the effects on welfare of numerous other aspects of housing and husbandry systems for farmed pigs, such as the effects of stocking density, including group size and methods of grouping the animals; the implications of different space requirements, including the service area for individually housed adult breeding boars; the impact of stall design and different flooring types; the risk factors associated with tail-biting and possible means to reduce the need for tail-docking; the latest developments of group-housing systems for pregnant sows and also loose-house systems for sows in the service area and for farrowing sows which meet the needs of the sow without compromising piglet survival. It should be noted that for weaners and rearing pigs EFSA has already issued a scientific opinion on the impact of different space allowances and flooring types, and so in respect of these two issues the new EFSA opinions should consider other categories of pigs (e.g. sows including farrowing sows, boars, pigs recruited for breeding programmes etc.). The Commission s report to Council will be drawn up also taking into account socio-economic consequences, consumers attitudes and behaviour, sanitary consequences, environmental effects and different climatic conditions concerning this issue. 2. TERMS OF REFERENCE Mandate 1: Request for a scientific opinion concerning animal health and welfare aspects of different housing and husbandry systems for adult breeding boars, farrowing and pregnant sows The opinion should consider, inter alia, the following specific issues: The effects of stocking density, including the group size and methods of grouping the animals, in different farming systems on the health and welfare of adult breeding boars, farrowing and pregnant sows The animal health and welfare implications of space requirements; including the service area for individually housed adult breeding boars. The impact of stall design and different flooring types on the health and welfare of breeding boars, pregnant and farrowing sows with piglets through weaning taking into account different climatic conditions. The latest developments of group housing systems for pregnant and farrowing sows with piglets through weaning, taking account both of pathological, zootechnical, physiological and ethological aspects of the various inside/outside -systems and of their health and environmental impact and of different climatic conditions. 3 E.C.O.J. n L340 of 11/12/1991. p The EFSA Journal (2007) 564, 5-14

6 The latest developments of loose-house systems for sows in the service area and for farrowing sows with piglets through weaning, which meet the needs of the sow without compromising piglet survival. Mandate 2: Request for a scientific opinion concerning animal health and welfare aspects of different housing and husbandry systems for farmed fattening pigs The opinion should consider, inter alia, the following specific issues: The effects of stocking density, including the group size and methods of grouping the animals, in different farming systems on the health and welfare The animal health and welfare implications of space requirements The impact of stall design and different flooring types on the health and welfare of fattening pigs taking into account different climatic conditions. Mandate 3: Request for a scientific opinion concerning the risks associated with pig tail biting and possible means to reduce the need for tail docking considering the different housing and husbandry systems This report will refer only to Mandate 2 as referenced above. 3. ACKNOWLEDGEMENTS The European Food Safety Authority and the AHAW Panel wishes to thank the members of the working group chaired by the panel member D. M. Broom: B. Algers, T. Nunes Pina and M. Sanaa (Risk Assessors), M. Bonde, S. Edwards, J. Hartung, I. de Jong, X. Manteca Vilanova, G. Martelli, G. P. Martineau, for the preparation of the Scientific Report, which has been used as the basis of this Scientific Opinion. The scientific co-ordination for this Scientific Report has been undertaken by the EFSA AHAW Panel Scientific Officers Elisa Aiassa and Oriol Ribó. 4. SCOPE AND OBJECTIVES 4.1. Introduction In 1997, the Scientific Veterinary Committee of the European Commission published the report The Welfare of Intensively Kept Pigs. The SVC (1997) Report contains information on the biology and behaviour of pigs in natural and semi-natural conditions, an overview of production systems, a production systems comparison, specific husbandry factors and pig welfare. Further, chapters covered socio-economic aspects. In that report conclusions and recommendations were made. The Scientific Report on animal health and welfare in fattening pigs, in relation to housing and husbandry contains an update of the scientific information presented in the previous SVC Report, excluding economic aspects which are not in the mandate for this report but including a risk assessment. This Report is one of five EFSA Reports on the welfare of pigs: Welfare aspects of the castration of piglets (July 2004); The welfare of weaners and rearing pigs: effects of different space allowances and floor types (EFSA, 2005); Animal health and welfare aspects of different housing and husbandry systems for adult breeding boars, pregnant, farrowing sows and unweaned piglets (EFSA, 2007); and concerning the risks associated with tail-biting in pigs and possible means to reduce the need for tail-docking considering the different housing and husbandry systems (EFSA, 2007 under adoption procedure at the time of writing). The EFSA Journal (2007) 564, 6-14

7 Factors which are important for pig welfare include housing (space and pen design, flooring and bedding material, temperature, ventilation and air hygiene), feeding (liquid feed, concentrates, roughage) other management of the animals (grouping, weaning, human-animal relations) and their health (disease prevention, health control and health service). Where the welfare of fattening pigs has been described in The welfare of weaners and rearing pigs: effects of different space allowances and floor types (March 2005), this information is not repeated in the Report unless new information is available, in which case an up-date is included Statement of purpose of the Risk Assessment Exercise The working group set out to systematically determine whether various factors potentially affecting pig welfare are beneficial or constitute a potential hazard or risk. To the latter end their severity and likelihood of occurrence in animal (sub) populations were evaluated using a qualitative (i.e. using expert opinion to classify magnitude and exposure) and a quantitative (estimating percentages of magnitude and exposure) approach. This allowed an estimation of associated risks to pig welfare, hence providing the basis for decision makers to decide which measures could reduce or eliminate such risks. It should be noted, however, that this does not imply that a hazard that has a serious effect on just a few animals should not be dealt with by managers on farm level as the suffering imposed on some animals constitutes a major welfare problem for those individuals The chosen approach In line with the terms of reference, the working group carried out a qualitative risk assessment. A quantitative risk assessment approach was followed, which constitutes a development of the one produced in earlier welfare reports such as the one in the Calf Welfare Report and the methods for the qualitative and quantitative risk assessment are described in chapter 8 of the Scientific Report. The objectives of the scientific assessment are: to review and report recent scientific literature on the animal health and welfare of fattening pigs, to report on recent findings as an update to the Scientific Veterinary Committee s previous report, to make a qualitative risk assessment concerning the welfare of fattening pigs. Where relevant, food safety implications of different farming systems are also considered. 5. CONCLUSIONS AND RECOMMENDATIONS Some conclusions and recommendations in this list are of a general nature and refer to all pigs including fattening pigs. Some of these are also used in other reports prepared in 2007 on: Animal health and welfare aspects of different housing and husbandry systems for adult breeding boars, pregnant, farrowing sows and unweaned piglets (EFSA, 2007); and The risks associated with tail-biting in pigs and possible means to reduce the need for tail-docking considering the different housing and husbandry systems (EFSA, 2007 under adoption procedure at the time of writing). Conclusions and recommendations from the Report The welfare of weaners and rearing pigs: effects of different space allowances and floor types (EFSA, 2005), whose subject matter overlaps substantially with this Opinion, are also relevant. These are not replicated here. In a few cases, new information requires some update in the previous recommendation, and these The EFSA Journal (2007) 564, 7-14

8 are marked with *+. Data presented in the space allowance and floor types Report are not repeated in the Report unless an update is required. Hence, some of the Conclusions and Recommendations of the current Scientific Opinion depend in part on data from the previous Report. Some of the conclusions below were produced following the reports on fattening pigs, sows and boars, tail-biting, welfare aspects of castration and effects of space and flooring on pig welfare. As a consequence they appear in more than one scientific opinion. Except where otherwise stated, the conclusions and recommendations of the 1997 SVC Report and the EFSA Reports on space allowance and flooring and castration are supported Conclusions concerning the welfare of fattening pigs The risk assessment tables and the histograms focusing on the welfare of individual pigs and welfare in populations of pigs are an integral part of the conclusions to this Report 1) Leg disorders, which are caused by a complex of factors including genetic selection and ad libitum feeding of high energy and high protein diet, are a major problem in fattening pigs. These cause poor welfare because of pain, reduced ability to move around and increased risk of victimisation. 2) Respiratory and gastrointestinal infections and production-related diseases can have a major impact on the welfare of fattening pigs. Whilst there is much published information on these subjects, there are also substantial gaps in scientific knowledge about them and their influence on animal welfare. 3) Pigs have good diurnal vision, hearing and olfaction and use all of these senses when exploring their environment. They learn rapidly and have substantial cognitive ability and a complex social life. 4) In common with other domestic animal species, when there is too little sensory input, because of social isolation, a barren environment or too little light intensity, pigs show abnormal behavioural and physiological responses. 5) Grooming in pigs, a means of caring for the skin and alleviating irritation, involves rubbing the body on posts and walls, occasionally scratching the head and body with the feet, and wallowing. At lower temperatures, below 14C for pigs over 50 Kg, wallowing serves only a grooming purpose, but at higher temperatures it also helps in thermoregulation. 6) Pigs show strong preferences to root with the nose and manipulate material with the mouth. These behaviours may be part of foraging but both are also shown when potential food is not ingested and at times when the pig is satiated with food, so they can also have an exploratory or other function that is not directly food-related. Appropriate substrates are earth for rooting and destructible materials such as straw or twigs for manipulation. When suitable rooting and manipulation materials are not available, pigs are likely to direct tactile behaviour towards companions, e.g. anal massage or tail-biting, or to show increased aggression. These are among the major causes of poor welfare in pigs. 7) Material for rooting and manipulation could be bedding material but the quantities needed are much smaller than those needed as bedding. Studies on preferences for such materials and on the adverse effects of its absence carried out since 2005 have further emphasised its importance for weaned pigs, older fattening pigs and sows. Substantial quantities of straw or similar material are the most preferred but smaller quantities receive much usage. 8) The prevention of disease is of significant importance for ensuring good welfare. One key action is regular inspection of the pigs by farm staff and veterinary checks where necessary followed by prompt treatment of problems. Another is the maintenance of good hygiene by The EFSA Journal (2007) 564, 8-14

9 the use of proper biosecurity precautions. A further action, which is of importance in relation to enteric diseases, is to minimise the exposure of the pigs to their faeces and urine. Management, handling, hygiene, floor type and the manure system have major effects on disease risk. 9) *+In the case of an outbreak of a highly contagious disease, the use of a set of biosecurity precautions reduces the risk of its transmission. These include various aspects of decontamination. Liquid slurry is easier to decontaminate chemically than solid manure. 10) *+If the ambient temperatures are too high for pigs, their welfare will be poor and they are at risk of dying. They cool themselves in several ways. Firstly by wallowing in water or mud, an especially favoured method at temperatures above 19C in pigs of over 50 Kg. Secondly by reducing activity level so that there is less body heat production. This occurs at temperatures above 19C in larger pigs and above 25C in pigs of more than 20 Kg. Thirdly, pigs will seek areas where there is greater air-flow. Fourthly, when lying the posture adopted is to stretch out the legs at 25C or above for smaller weaned pigs and at 19C and above for larger pigs. The building in which pigs are kept may provide heating or ventilation systems that compensate for outside temperatures. At higher temperatures, adequate space to separate from other pigs when standing or lying, sufficient contact with a cool floor, or access to outdoors, or evaporative cooling aided by higher air-flow rates, or water on the skin or more drinking water help to avoid over-heating. 11) High humidity is generally better for pig skin condition but it impairs cooling by evaporation at temperatures near or above 19C for larger pigs (more than 50 Kg) and at 25C for smaller pigs (more than 20 Kg). 12) If the ambient temperature is too low, better insulation of the floor, for example from a substantial layer of bedding, lowers the risk of hypothermia. Pigs in groups huddle at low temperatures. Rest is likely to be disrupted if huddling is necessary because of the disturbance caused by neighbouring pigs. 13) If pigs cannot be inspected individually in such a way that sick, injured or frequently attacked or belly-nosed animals can be identified, there is a potential for very poor welfare in some animals. 14) Flashing lights can be disturbing to pigs and poor welfare is also associated with light of a wavelength or intensity that does not allow the pig to discriminate the behaviour of other pigs or of materials such as straw. The major periods of activity by pigs are in the light period. The minimum duration of the dark period for there to be sufficient rest is 6 hours. It is indicated from one study that a light level of 450 lux during the light period is required in order that a normal diurnal endocrine rhythm is established. Adequate inspection of animals is not possible unless there is a sufficient light level. In some circumstances, pigs find very high light intensity aversive, but this may be affected by the social situation. Pigs are not able to discriminate cues adequately at light levels of less than 10 lux. 15) With the exception of recently born piglets, when unacquainted pigs are mixed there is a substantial risk of fighting, injury, production loss and poor welfare. There will be some fear, injury and pain in attacked animals, and other severe physiological effects as is evident from the carcasses of animals slaughtered after mixing. A consequence of the associated poor welfare is often increased risk of disease. The interchange of pathogens amongst pigs mixed from different buildings can also increase disease prevalence, especially in younger pigs whose immune system is not fully developed. 16) When the welfare of pigs in large groups is studied, the number of sources is a key factor affecting disease and whilst there are some results indicating that there are few welfare The EFSA Journal (2007) 564, 9-14

10 problems in large groups, other results indicate that disease incidence is increased so welfare can be poorer than in small groups. 17) If animals are sick or injured in a severe or prolonged way, or if they are frequently subjected to attack or belly-nosing, their welfare can be very poor. 18) Poor quality pen design can cause poor welfare in pigs because of parts that cause injury or open sides between adjacent pens so that there is disturbance and aggression. If pigs have pens that allow the opportunity to hide their heads or bodies from other pigs, aggression and belly-nosing may be reduced. 19) If pigs do not have sufficient exercise, there can be adverse effects on bone and muscle development. 20) *+Many aspects of the behaviour of modern pigs have a common genetic basis with those of the wild boar ancestors. However, generations of selective breeding have resulted in changes in morphology, growth and temperament. Some of these changes have helped the animals to adapt to modern housing and management conditions; however others can cause problems for pigs. The genetic selection of pigs for rapid growth and lean meat without enough consideration of other factors has led to some widespread and serious problems, in particular leg disorders, cardiovascular malfunction when high levels of activity are needed or stressful conditions are encountered, and inadequate maternal behaviour. 21) *+Pigs use separate areas for lying and for urination and defecation (dunging behaviour), except (i) when stressed by heat, disease, etc.; (ii) when the space allowance in a housing system is not sufficient, or (iii) when the system is poorly designed or managed. Adequate management and design of the housing system: position of drinkers, floor quality in the lying area, position of open pen partitions, possibility for visual contact with pigs in neighbouring pens, and lack of draught in the lying area facilitate this dunging behaviour. Where some individual pigs dung and urinate in the lying area, a change in design or space allowance is usually necessary. 22) The actions of stockpersons have a substantial effect on pig welfare. During the development of young pigs, relatively brief contact with non-aggressive humans can improve the welfare of the pigs, growth rates and ease of later handling. 23) Pigs need water of good quality. This is often still necessary even if they are provided with wet feed. If water supply systems are not well maintained, pigs can be deprived of water. Where pigs have high concentrations of blood toxins, their requirement for water is increased. 24) Pigs need an adequate quantity of a balanced diet in order to reduce the risk of disease and abnormal behaviours, as well as to decrease pollutants spreading with manure. If there is insufficient care taken in selecting and keeping feed, pigs can be subjected to harmful contaminants such as mycotoxins and man-made toxic substances and these can cause pathology and have severe effects on welfare. Unbalanced diet can significantly increase nitrogen losses and ammonia production. 25) Rest in pigs is impaired in over-crowded conditions because other individuals step on or otherwise disturb the pigs. Rest can also be impaired when there is huddling due to low temperature, human disturbance, too much noise, or an insufficiently long dark period during each 24 hours. 26) Where straw, or other manipulable materials of plant origin, are provided for pigs, provided that the materials are used when fresh or stored in good conditions, any risk of mycotoxin presence can be reduced to a low level. The EFSA Journal (2007) 564, 10-14

11 27) Additional cooling devices, such as water sprinklers, showers, increased air speed, and shaded areas in outdoor management systems help to reduce heat stress during summer. If sprinklers for cooling are used in housing systems with bedding, wetting of the litter can lead to bacterial growth and increased release of noxious gases. 28) *+In outdoor rearing systems, the substratum for pigs can be good. Pigs kept outdoors usually have a lower prevalence of lesions due to respiratory infections at post-mortem slaughter inspection compared with indoor pigs but the risk of some internal parasites may be higher. There is a risk that pigs may be infected by, or in turn infect, wild birds and mammals, for example wild boar with classical swine fever or brucellosis. 29) *+Compost or straw-based deep-litter bedding can provide thermal comfort in cold conditions, but their heat production potential can result in heat stress at higher ambient temperatures. Pigs in warmer conditions indoors need access to an additional area with a different floor quality to cool down. 30) *+Manipulable material makes any floor more attractive for exploration and, in choice tests, the presence of straw is preferred to an unbedded floor. Straw may be used by pigs when lying, but only when they are not over-heated. The extent of the use of straw and other bedding materials (sawdust, wood chips, peat, etc.) is influenced by different climatic conditions and the availability of such material and also by the type of housing chosen in various European regions. Straw-based housing systems in buildings often kept at cooler temperatures are typically found more frequently in Northern Europe. 31) *+The use of bedding materials in combination with a fully-slatted floor creates problems in handling the manure. However, small quantities of straw from racks, if sufficient for rooting behaviour to be possible, can be used as environmental enrichment on any slatted floors. The use of straw or other materials, in small quantities for manipulation by the pigs in order to fulfil their needs, can be combined with slatted floors provided that an adequate waste disposal system, perhaps involving automatic shredding is used. Shredding systems are not commonly in use at present. If the straw is chopped before giving it to the pigs, larger quantities can be used but manipulation possibilities are reduced. The materials may fall through the gaps so that they are not available to the pigs but can easily be replaced. In practice, at present few farmers using fully-slatted floors provide particulate materials for manipulation. 32) *+The provision of appropriate foraging material is difficult in pens with fully slatted floors so housing systems with partly-slatted or solid floors with bedding lead to fewer problems with manipulative behaviour directed at pen mates such as tail-biting. The occurrence of tail-biting can be reduced dramatically by the provision of straw as well as by other measures (see the Scientific Report on the risks associated with tail-biting in pigs and possible means to reduce the need for tail-docking considering the different housing and husbandry systems; EFSA, 2007). 33) Selective breeding to eliminate the halothane gene is a good example of the technology to improve pig health and welfare. Demonstrated differences in some genetic lines indicated the potential for further improvements arising from this approach Recommendations Since space allowance and flooring are key issues affecting fattening pig welfare, the recommendations from the EFSA Scientific Opinion (EFSA Space Allowance) (not listed here) are also important and relevant to this report. The EFSA Journal (2007) 564, 11-14

12 1) Pigs should be provided with such an environment and management that the negative consequences of poor welfare such as injurious behaviours, physiological problems and immunosuppression, caused in barren environments are avoided. 2) In order to provide for the need to root with the nose and manipulate destructible materials, each pig should have access to manipulable destructible material such as straw or other fibrous material that does not harm the pigs if ingested to such an extent that negative effects do not occur. 3) Since indestructible objects such as chains or tyres are not sufficient to provide for the manipulatory need of pigs, they may be used as a supplement to destructible and rooting materials but not as a substitute for them. 4) Pen surfaces suitable for body-rubbing, and wherever possible wallows, should be provided for pigs for grooming purposes. 5) Where the ambient temperature around the pigs is below the lower critical temperature, shelter for outdoor pigs and an insulated lying area should be available to the pigs. At such temperatures inside the building, insulating bedding should be provided. Since huddling behaviour disrupts sleep in pigs, the necessity for huddling should be minimised by bedding provision or ambient temperature control. 6) Where the ambient temperature around the pigs is above 19C in pigs of over 50Kgs and above 25C in weaned pigs, once established on solid feed, measures should be taken to facilitate heat loss in the pigs. This is best achieved by allowing the pigs to take action to cool themselves by visiting a wallow or other place where they can cool themselves such as a cool floor, shower, or place of greater air flow. Above these temperatures, each pig should be able to lie so that it is not in contact with any other pigs. 7) In order to minimise disease in pigs, and hence poor welfare, effective disease preventive and management procedures should be in place. In addition to health control and health service these procedures include e.g avoiding mixing of animals, daily inspection of all the pigs so that sick or injured animals can be identified and more intensive inspections when infectious diseases, injury due to aggression, belly-nosing or tail-biting is occurring. 8) The lighting in pig houses should not be flashing and should be of a wavelength and intensity during the light period that allows pigs to discriminate the behaviour of other pigs and materials such as straw and to show normal diurnal rhythms. The light level and distribution at times of inspection should be sufficient to allow each pig to be seen. 9) The design of accommodation for pigs should be such that the pigs have sufficient exercise for normal bone and muscle development and opportunities to avoid or hide from other pigs that may show aggression, belly-nosing or tail-biting to them. 10) Breeding of pigs in order to eradicate halothane gene has significantly improved pig welfare. There should be further efforts in selection and breeding methods so that the likelihood of problems of pig welfare, including cardiovascular malfunction, risk of early death and leg disorders is maintained at a low level. Welfare outcomes concerning the frequency of cardiovascular malfunction, mortality rate and prevalence leg disorders should be defined. 11) Pigs should be exposed to appropriate human contact early in their lives so that later they are less fearful and negative effects on their welfare during the handling of the animals are minimised and there are associated benefits for production. 12) All pigs should be provided with water of good quality sufficient for their needs. Water supply systems should be well-maintained and their efficiency regularly checked. The EFSA Journal (2007) 564, 12-14

13 13) Pigs should be provided with a diet whose components are balanced so that the pig is not harmed and which do not contain harmful contaminants such as mycotoxins. 14) Although outdoor pig units usually have less respiratory disorders than indoor units, however, care should be taken to minimise exposure to infectious agents. 15) Liquid feeding methods have benefits for pigs, including benefits for welfare, but should be accurately managed so as to minimise the risk of contamination by pathogens. 16) Dietary fibre provision should be managed in order to reduce both abnormal behaviour and ammonia production from excreta. 17) Indoor housing systems should be modified so that the occurrence of pressure bursae on leg joints is minimised. A threshold level for the occurrence of pressure bursae could be used as a welfare outcome. 18) The diets fed to pigs should be quantitatively and qualitatively adjusted so that the incidence of leg disorders is minimised. 19) The methodology and the results (Conclusions and Recommendations) of this opinion as well as the previous opinions on Pig Welfare, should be further analysed identifying welfare outcomes or indicators (in particular animal-based) suitable for the development of an animal welfare monitoring system Recommendations for further research (in order of priority) 1) The effects of barren environments on the welfare of young pigs and their future coping abilities. 2) 2.a. How to provide for the needs of pigs to root and to manipulate materials in practical farm situations. 2.b. A comparison of systems for removal of rooting or manipulable materials where slatted floors or partly slatted floors are used. 3) The effects on animal welfare of respiratory diseases. 4) The effects of light intensity, duration of light period and type of lighting on the welfare of pigs. 5) Methods for minimising the adverse effects of social mixing in pigs. 6) Methods of genetic selection of pigs to minimise negative side effects of selection for productivity such as cardiovascular and leg disorders and to maximise disease resistance. 7) The effects of housing system design on leg disorders in fattening pigs. 8) The causation of respiratory and gut disorders in pigs in relation to management system. 9) The effects of weaning at different ages on the welfare of piglets and sows and its relation to disease prevention methods and the need for antibiotic treatment measures. 10) Systems for preventing over-heating in pigs on farm. 11) The management of pig food so as to minimise mycotoxins, other toxins and pathogens that could lead to poor welfare in pigs. 12) The effect of housing and management system on disease resistance in growing pigs. 13) The effect of noise on the welfare of growing pigs. 14) The effect of housing system on skin care and grooming behaviour. The EFSA Journal (2007) 564, 13-14

14 With respect to Italian heavy pigs in particular, it would be worthwhile investigating topics related to: 1. The quality of meat from heavy pigs reared in different conditions as to availability of space, floor type and/or provision of litter; 2. The consequences of drinking water deprivation on the welfare of pigs fed liquid diets; 3. Elements of environmental enrichment especially suited to heavy pigs kept on fully slatted floors. 6. REFERENCES References used in this Scientific Opinion are available and listed in the Scientific Report published at the EFSA web ( The EFSA Journal (2007) 564, 14-14

15 Annex to the EFSA Journal (2007) 564, 1-14 Scientific Report on animal health and welfare in fattening pigs in relation to housing and husbandry (Question No EFSA-Q ) European Food Safety Authority, 2007

16 WORKING GROUP MEMBERS The members of the Working Group which authored the Scientific Report were: Donald Maurice Broom (Chairman) Centre for Animal Welfare and Anthrozoology Department of Veterinary Medicine University of Cambridge Cambridge, United Kingdom Bo Algers Department of Animal Environment and Health Swedish University of Agricultural Science Skara, Sweden Telmo Nunes Pina (Risk Assessor) Faculty of Veterinary Medicine University of Lisbon Lisbon, Portugal Moez Sanaa (Risk Assessor) Veterinary School Maisons Alfort Maisons Alfort, France Marianne Bonde Department of Animal Health, Welfare and Nutrition Faculty of Agricultural Sciences University of Aarhus Tjele, Denmark Sandra Edwards School of Agriculture, Food and Rural Development Newcastle University Newcastle, United Kingdom Joerg Hartung Institute of Animal Hygiene, Animal Welfare and Behaviour of Farm Animals University of Veterinary Medicine Hannover Hannover, Germany Ingrid de Jong Animal Sciences Group of Wageningen UR Animal Production Division Lelystad, The Netherlands Xavier Manteca Vilanova School of Veterinary Science Universitat Autònoma de Barcelona Barcelona, Spain Giovanna Martelli Dip. Morfofisiologia Veterinaria e Produzioni Animali (DIMORFIPA) Alma Mater Studiorum - Università di Bologna Bologna, Italy Guy Pierre Martineau Ecole Nationale Veterinaire de Toulouse Toulouse, France 1

17 AHAW SCIENTIFIC PANEL MEMBERS This Scientific Report was peer-reviewed by the Members of the Scientific Panel for Animal Health and Welfare (AHAW) of the European Food Safety Authority. The Scientific Report was used as the basis for a Scientific Opinion adopted on 6 September The Members of the AHAW Scientific Panel were: Bo Algers, Harry J. Blokhuis, Donald M. Broom, Patrizia Costa, Mariano Domingo, Mathias Greiner, Daniel Guemene, Jörg Hartung, Frank Koenen, Christine Muller-Graf, David B. Morton, Albert Osterhaus, Dirk U. Pfeiffer, Ron Roberts, Moez Sanaa, Mo Salman, J. Michael Sharp, Philippe Vannier, Martin Wierup, Marion Wooldridge. 2

18 SUMMARY Council Directive 91/630/EEC 1, as amended, laying down minimum standards for the protection of pigs, requires the Commission to submit to the Council a report, based on a scientific opinion of the European Food Safety Authority (EFSA), concerning the welfare various aspects of housing and husbandry systems for farmed pigs. EFSA has therefore been required to provide a Scientific Opinion on several aspects of this, one concerning fattening pigs. The opinion should include: the effects of stocking density, including group size and grouping methods, space requirements and the impact of stall design and different flooring types taking into account different climatic conditions. The Scientific Opinion was adopted by the Panel on Animal Health and Welfare (AHAW) on 6 September Based on the scientific data presented in the Scientific Report and risk assessment, conclusions and recommendations were drawn. In relation to disease, respiratory and gastrointestinal infections and production-related diseases can have a major impact on the welfare of fattening pigs. Management, inspection and other disease prevention measures, handling, hygiene, floor type and the manure system have major effects on disease risk and significant importance for ensuring good welfare. At post-mortem slaughter inspection, pigs kept outdoors usually have a lower prevalence of lesions due to respiratory infections than indoor pigs but higher risk of some internal parasites. Leg disorders, which are caused by a complex of factors including genetic selection and high energy and high protein diet, are a major problem. Interactions between many aspects of the biological functioning of pigs and effects of housing and management on welfare are described. Without suitable rooting and manipulation materials, pigs are likely to direct tactile behaviour towards companions using aggression or other causes of poor welfare. Manipulable material makes any floor more attractive for exploration and pigs prefer the presence of straw to an unbedded floor. The provision of appropriate foraging material is difficult in pens with fully slatted floors unless there is automatic shredding in the waste disposal system. If the ambient temperatures are too high, adequate space to separate from other pigs, sufficient contact with a cool floor, access to outdoors, air-flow rates to help evaporation, water on the skin, or more drinking water help to avoid over-heating. In the case of too low a temperature, better insulation of the floor lowers the risk of hypothermia. When there is too little sensory input, because of social isolation, a barren environment or too little light intensity, pigs are likely to show abnormal behavioural and physiological responses. Flashing lights can be disturbing to pigs and poor welfare is also associated with light of a wavelength or intensity that does not allow the pig to discriminate the behaviour of other pigs or materials. The genetic selection for rapid growth and lean meat without enough consideration of other factors has led to some widespread and serious problems. However, selective breeding to eliminate the halothane gene has improved pig welfare. Poor quality pen design can cause poor welfare in pigs because of parts that cause injury, or disturbance and aggression. If pigs do not have sufficient exercise, there can be adverse effects on bone and muscle development. Dunging behaviour (urination and defecation) is facilitated by design of the housing system and good management. Mixing unacquainted pigs leads to a substantial risk of fighting, injury and production loss. Recommendations presented in the Scientific Opinion include the need to provide an environment and management so that the negative consequences of poor welfare such as 1 E.C.O.J. n L340 of 11/12/1991. p

19 injurious behaviours, physiological problems and immunosuppression, caused in barren environments, are avoided. In this sense, it is recommended that pigs should be provided with manipulable, destructible materials, wallows, lighting of appropriate wavelength and intensity, water of a quality and quantity sufficient for their needs, and a balanced diet with no harmful contaminants. In order to minimise disease in pigs, and hence poor welfare, effective disease preventive and management procedures should be in place. The design of accommodation for pigs should be such that the pigs have sufficient exercise for normal bone and muscle development. There should be further efforts to select and breed so that problems of pig welfare, including cardiovascular malfunction, risk of early death and leg disorders are maintained at a low level. The recommendations for further research are mainly focused on the evaluation of the effects of the exposure to several factors (i.e. barren environment, light intensity, noise, respiratory disorders) on the welfare of fattening pigs. Recommendations for further research in relation to the heavy pig production are also provided. The methodology and the results of this scientific report and opinion should be developed to identify welfare outcomes (indicators) that are valid and can be used in an animal welfare monitoring system. Key words: Pig Welfare, pig disease, fattening pigs, weaner, grower, finisher, husbandry, pen design, housing system. 4

20 Table of Contents Working Group Members... 1 AHAW Scientific Panel Members... 2 Summary Background Terms of Reference Acknowledgements Scope and Objectives of the Report Introduction Statement of purpose of the Risk Assessment Exercise The chosen approach Identification of factors affecting risks or benefits Current production systems for fattening pigs in the EU European Pig Production Current systems Weaners Grower/ Finisher pigs Fully-slatted floor Partly-slatted floor Solid floor, no bedding Solid floor, some bedding (sloped-floor/straw-flow system) Deep litter system Outdoor / semi-outdoor rearing on earth or concrete Mediterranean silvopastoral systems Pigs reared to organic standards Field rearing Paddock systems (free-range production) Tents and deep-litter paddocks Hut-and-run systems Factors affecting pig welfare Pig genetics in relation to welfare Leg problems Cardiovascular problems Social behaviour and fearfulness Disease resistance Light inadequacy Ability to rest and sleep Ability to exercise Food and water in relation to pig welfare Effects of water supply Liquid feeding Lack of food and food restriction Lack or excess of specific nutrients Undesirable compounds in feedstuffs Benefits of specific foods Ability to explore Ability to have proper social interaction Lack of maternal contact Contact with other pigs Mixing of unacquainted pigs Group size Space allowance and access to resources Ability to avoid fear Ability to groom Thermal inadequacy

21 7.11. Humidity Respiratory disorders Air quality Gut disorders Postweaning diarrhoea Diarrhoea during finishing period Gastric ulcers Production - related and other diseases Injuries Risk Assessment Approach Introduction Steps of Risk Assessment ) Definition of the target populations ) Hazard identification ) Hazard Characterization (HC) ) Exposure assessment (EA) ) Risk characterization (RC) Graphical presentation of the Risk Characterisation Food Safety Considerations References Appendix 1. Welfare and its assessment Appendix 2. The needs of Pigs Glossary Abbreviations Index of Tables and Figures

22 1. BACKGROUND Council Directive 91/630/EEC 2, as amended, laying down minimum standards for the protection of pigs and requires the Commission to submit to the Council a report, based on a scientific opinion of the European Food Safety Authority (EFSA), concerning various aspects of housing and husbandry systems for farmed pigs. In this context and upon requests from the Commission, EFSA has already issued opinions 3 on welfare aspects of the castration of pigs and the welfare of weaners and rearing pigs: effects of different space allowances and floor types. Council Directive 91/630/EEC, as amended, also provides for the Commission to report to Council, on the basis of an EFSA scientific opinion, on the effects on welfare of numerous other aspects of housing and husbandry systems for farmed pigs, such as the effects of stocking density, including group size and methods of grouping the animals; the implications of different space requirements, including the service area for individually housed adult breeding boars; the impact of stall design and different flooring types; the risk factors associated with tail-biting and possible means to reduce the need for tail-docking; the latest developments of group-housing systems for pregnant sows and also loose-house systems for sows in the service area and for farrowing sows which meet the needs of the sow without compromising piglet survival. It should be noted that for weaners and rearing pigs EFSA has already issued a scientific opinion on the impact of different space allowances and flooring types, and so in respect of these two issues the new EFSA opinions should consider other categories of pigs (e.g. sows including farrowing sows, boars, pigs recruited for breeding programmes etc.). The Commission s report to Council will be drawn up also taking into account socio-economic consequences, consumers attitudes and behaviour, sanitary consequences, environmental effects and different climatic conditions concerning this issue. 2. TERMS OF REFERENCE Mandate 1: Request for a scientific opinion concerning animal health and welfare aspects of different housing and husbandry systems for adult breeding boars, farrowing and pregnant sows The opinion should consider, inter alia, the following specific issues: The effects of stocking density, including the group size and methods of grouping the animals, in different farming systems on the health and welfare of adult breeding boars, farrowing and pregnant sows The animal health and welfare implications of space requirements; including the service area for individually housed adult breeding boars. The impact of stall design and different flooring types on the health and welfare of breeding boars, pregnant and farrowing sows with piglets through weaning taking into account different climatic conditions. The latest developments of group housing systems for pregnant and farrowing sows with piglets through weaning, taking account both of pathological, zootechnical, physiological and ethological aspects of the various inside/outside -systems and of their health and environmental impact and of different climatic conditions. 2 E.C.O.J. n L340 of 11/12/1991. p

23 The latest developments of loose-house systems for sows in the service area and for farrowing sows with piglets through weaning, which meet the needs of the sow without compromising piglet survival. Mandate 2: Request for a scientific opinion concerning animal health and welfare aspects of different housing and husbandry systems for farmed fattening pigs The opinion should consider, inter alia, the following specific issues: The effects of stocking density, including the group size and methods of grouping the animals, in different farming systems on the health and welfare The animal health and welfare implications of space requirements The impact of stall design and different flooring types on the health and welfare of fattening pigs taking into account different climatic conditions. Mandate 3: Request for a scientific opinion concerning the risks associated with pig tail biting and possible means to reduce the need for tail docking considering the different housing and husbandry systems This report will refer only to Mandate 2 as referenced above. 3. ACKNOWLEDGEMENTS The scientific co-ordination for this Scientific Report has been undertaken by the EFSA AHAW Panel Scientific Officers Elisa Aiassa and Oriol Ribó. 4. SCOPE AND OBJECTIVES OF THE REPORT 4.1. Introduction In 1997, the Scientific Veterinary Committee of the European Commission published the report The Welfare of Intensively Kept Pigs. The SVC (1997) Report contains information on the biology and behaviour of pigs in natural and semi-natural conditions, an overview of production systems, a production systems comparison, specific husbandry factors and pig welfare. Further, chapters covered socio-economic aspects. In that report conclusions and recommendations were made. The present Scientific Report on animal health and welfare in fattening pigs, in relation to housing and husbandry contains an update of the scientific information presented in the previous SVC Report, excluding economic aspects which are not in the mandate for this report but including a risk assessment. This Report is one of five EFSA Reports on the welfare of pigs: Welfare aspects of the castration of piglets (July 2004); The welfare of weaners and rearing pigs: effects of different space allowances and floor types (March 2005); Animal health and welfare aspects of different housing and husbandry systems for adult breeding boars, pregnant, farrowing sows and unweaned piglets (EFSA, 2007 under adoption procedure at the time of writing); and concerning the risks associated with tail-biting in pigs and possible means to reduce the need for tail-docking considering the different housing and husbandry systems (EFSA, 2007 under adoption procedure at the time of writing). Factors which are important for pig welfare include housing (space and pen design, flooring and bedding material, temperature, ventilation and air hygiene), feeding (liquid feed, concentrates, roughage) other management of the animals (grouping, weaning, human-animal relations) and their health (disease prevention, health control and health service). Where the welfare of fattening pigs has been described in The welfare of weaners and rearing pigs: effects of different space allowances and floor types (March 2005), this information is 8

24 not repeated in the current Report unless new information is available, in which case an up-date is included. The measures used to assess welfare include behavioural and physiological measures, pathophysiological measures and clinical signs as well as production measures (Appendix 1) Statement of purpose of the Risk Assessment Exercise The working group set out to systematically determine whether various factors potentially affecting pig welfare are beneficial or constitute a potential hazard or risk. To the latter end their severity and likelihood of occurrence in animal (sub) populations were evaluated using a qualitative (i.e. using expert opinion to classify magnitude and exposure) and a quantitative (estimating percentages of magnitude and exposure) approach. This allowed an estimation of associated risks to pig welfare, hence providing the basis for decision makers to decide which measures could reduce or eliminate such risks. It should be noted, however, that this does not imply that a hazard that has a serious effect on just a few animals should not be dealt with by managers on farm level as the suffering imposed on some animals constitutes a major welfare problem for those individuals The chosen approach In line with the terms of reference, the working group carried out a qualitative risk assessment. A quantitative risk assessment approach was followed, which constitutes a development of the one produced in earlier welfare reports such as the one in the Calf Welfare Report and the methods for the qualitative and quantitative risk assessment are described in Chapter 8. The objectives of this report are: to review and report recent scientific literature on the animal health and welfare of fattening pigs, to report on recent findings as an update to the Scientific Veterinary Committee s previous report, to make a qualitative risk assessment concerning the welfare of fattening pigs. Where relevant, food safety implications of different farming systems are also considered. The Report includes, as Appendix 1, an explanation of welfare and its assessment and, as Appendix 2, the physiological and other needs of pigs. The current housing and husbandry systems for fattening pigs are briefly described. The scientific literature on the factors affecting fattening pigs welfare is then reviewed under headings related to pig genetics and the various needs of pigs. Food safety consequences of different pig rearing systems are discussed in a chapter approved by the EFSA Biohazards Panel. A risk assessment, including detailed tables, then follows. 5. IDENTIFICATION OF FACTORS AFFECTING RISKS OR BENEFITS Certain factors or hazards may result in the needs of pigs not being met and hence may lead to poorer welfare. The needs of pigs are briefly explained in Appendix 2. As explained in Chapter 8, some factors lead to benefits and the absence of some of these can constitute a risk. The factors or hazards affecting pig welfare were identified and related to each relevant need (Table 1). This forms the basis for the hazard description and the exposure intensity. 9

25 Table 1. Factors or hazards with their related needs Factors or hazards Needs (as numbered in Appendix 2) Absence of wallow 9,10 Enrichment material (absence, too little, low quality) 2,5,6, Lack of space 3,4,6,7,9,10,12,14 Too short period of low light intensity per day 3 Environmental temperature outside the thermo neutral zone 10 No comfortable lying place 3 Inappropriate pen design 3,4,7,8,9,12 Poor hygiene 9,12,13 Noise 2,3,7,8,14 Poor stockmanship 4,5,7,8,9,1012,13,14 Poor flooring 3,4,9,12,14 Mixing of unacquainted animals 5,6,7,8,12,14 Large group size >40 an./group (management difficulties) 5,7,12 Genotype problems 12,14 Inadequate quantity, poor quality or no water 5,10 Food: inadequate hygienic conditions 5,12 Inadequate quantity or quality of food, unbalanced diets 5,12 Inappropriate materials in feed 5,12,13 Early weaning before 28 days 2,5,6,7 Inadequate air quality: ammonia, dust 1,12 Parasitism (internal) 5,12 Predation 8,14 Sunburn 14 10

26 6. CURRENT PRODUCTION SYSTEMS FOR FATTENING PIGS IN THE EU This Report concerns fattening pigs, i.e. weaned piglets and older pigs kept for the production of pork, bacon and ham European Pig Production The enlargement of the European Union from 15 to 25 Member States, which occurred in 2004, influenced the European pig production figures. This chapter aims to provide a general overview of the main statistical data currently available and to analyse the trend of the European pig production, which has a great importance in a world context. In the 25 member countries of the European Union in 2005, the production jumped to more than 150 million pigs (data refer to the number of pigs processed in the slaughterhouses), approximately 30 million more than the EU 15 (Figure 1). 170,000, ,000, ,000, ,000, ,000,000 EU 25 EU ,000, ,000, ,000, Figure 1. The number of pigs, whose meat is certified for human consumption, from 1995 to 2005 (in red, the provisional value) in the European Union (Source: Eurostat, 2007) Germany, Spain, Poland, France, Denmark and the Netherlands are the major producers at EU level (Table 1). 11

27 Table 2. The number of pigs, whose meat is certified for human consumption, from 2004 to 2006 in the European Countries (Source: Eurostat, 2007) Austria 3,125,204 3,169,541 3,139,438 Belgium 6,318,734 6,252,988 n.a. Bulgaria* 942, ,699 1,010,789 Cyprus 470, , ,644 Czech Republic 2,915,000 2,719,000 2,741,300 Denmark 13,407,000 12,604,000 13,613,000 Estonia 353, , ,200 Finland 1,435,000 14,40,000 1,435,400 France 15,150,000 15,123,000 15,009,000 Germany 26,334,800 26,989,054 26,602,000 Greece 994,000 1,042,000 n.a. Hungary 4,059,000 3,853,000 3,987,000 Ireland 1,757,600 1,678,000 n.a. Italy 8,971,762 9,200,000 9,281,083 Latvia 435, , ,750 Lithuania 1,073,300 1,114,700 1,127,100 Luxembourg 77,133 84,547 86,954 Malta 76,853 73,025 73,683 Netherlands 11,140,000 11,000,000 11,220,000 Poland 17,395,570 18,711,290 18,812,975 Portugal 2,347,852 2,344,064 2,295,451 Romania* 6,494,700 6,603,800 6,905,000 Slovakia 1,149,282 1,108,265 1,104,829 Slovenia 533, , ,116 Spain 24,894,960 24,888,882 n.a. Sweden 1,920,420 1,797,400 1,661,520 United Kingdom 4,787,379 4,726,207 4,691,245 * Joined the EU in 2007 n.a.: data not available Productive levels in the EU were almost stable during the last 2 years. The self-sufficiency is stable too and the per capita consumption of pig meat was 42.9 kg in 2006 (Table 2). Table 3. Consumption of pork and self-sufficiency for the pig meat in the European Union in the last four years (Source: modified, 2007) Consumption (kg/per capita) (EU 15) Self- sufficiency (%) (EU 15) 12

28 6.2. Current systems Animal Health and Welfare in Fattening Pigs The remainder of this chapter is taken from the Scientific Report on the impact on pig welfare of different space allowances and flooring types (EFSA, 2005) with some small additions. The 25 EU countries have approximately 152 million pigs (Eurostat, 2003). Weights at slaughter differ markedly according to countries. Italy has a tradition of high carcass weights, in connection with the production of dry meat products. On the contrary, UK, Ireland, Denmark, Greece and Portugal slaughter much lighter pigs. In the remaining countries, including most of the new EU member countries, carcass weights are in the range of kg, corresponding to a live weight of kg. Over the last 15 years, there has been a general tendency for increasing carcass weights in most countries, including those slaughtering light pigs. This elevation in slaughter weight is likely to result in increased incidence of boar taint in entire males (EFSA, 2004). Slaughter weights in the new member countries tend to converge towards the average slaughter weight in the 15 EU countries. The mean litter size in the EU is approximately 11 piglets. Weaning most commonly takes place at about 4 weeks of age. After weaning, piglets are generally moved to, and mixed with members of other litters in specially designed housing systems for weaners. When the piglets reach kg live-weight they are often moved on to further accommodation to finish their growth prior to slaughter at approximately months of age. Weights at slaughter differ markedly according to countries. In most countries the live-weight at slaughter is kg, but is lower in countries like Denmark and UK and is higher when special products such as Italian PDO hams are produced. Hence, in Italy, weights at slaughter may reach 170kg. Although some pigs are reared in extensive outdoor facilities, particularly when neonates, most pigs in the EU are now raised indoors under intensive farming conditions, which itself has implications for the local environment of intensive pig farms and also raises concerns for control of diseases in such units. Only small numbers of pigs in the post-weaning and fattening phase of pig meat production are in outdoor facilities in fields or in indoor housing with access to an outdoor area. In intensive systems, three separate phases of production (farrowing, birth and neonatal period; weaning; and, growing and finishing) are recognised, and in many instances necessitate different feeding and housing conditions. The gestation length of the sow is approximately 112 to 115 days. The average litter size in the EU is 11. After birth, piglets are nursed by their dams for approximately 21 to 28 (in some MS up to 35) days. During this phase of production in most Member States, male piglets that will not be used for breeding are surgically castrated. In some countries this phase of life is spent outdoors. After weaning, piglets are generally moved to - and mixed with - members of other litters in specially designed housing systems for weaners. This phase presents the greatest management challenge as dietetic changes are frequently associated with disease outbreaks. After about 5 weeks, when the piglets reach approximately 30 kg live weight the weaned pigs are moved on to further accommodation to finish their growth prior to slaughter. It is now rare that the weaning and fattening phases of a pig s life take place in outdoor facilities in the EU. As selection of individuals to fill pens in the fattening sheds is based on live weight, members of different litters may become penmates in the fattening pens. This mixing will provoke the establishment of new social hierarchies resulting in dominating and submissive behaviour. If entire (not castrated) males are becoming sexually mature at this stage, aggressive behaviour may be prolonged. There are a few incidences where pigs are housed together during the entire rearing period from weaning to slaughter. Ekkel et al. (1996) reported that health, production and welfare in general of pigs are improved when kept in these housing systems without being mixed or transported. However, due to economic reasons, different management and environmental requirements during the production phases, these systems are mostly found in some, mainly straw-based, housing systems in Scandinavia (Martinsson and Olsson, 1994). On 13

29 a more large scale basis it has become increasingly common during the last decade to practice farrowing of groups of sows (e.g ) so that their offspring following weaning are continuously housed together until slaughter, a system that leads to reduced disease and better growth rates and welfare. Housing system designs are affected by a number of factors including, climate, legislation, economics, farm structure and ownership, research and traditions. Recent EU legislation, combined with certain socio-economic issues, has had a great impact on pig housing systems in Member States. For example Council Directive 91/630 (EEC, 1991), as amended by Council Directives 2001/88/EC (EC, 2001a) and 2001/93/EC (EC, 2001), dealing with animal welfare and Council Directives 1996/61/EC (EC, 1996) and 2003/87/EC (EC, 2003), covering environmental concerns. And, added to the legislation, changes have also come about because of retailing standards applied in certain Member States that have had a major effect on the production methods used by some producers. Weaner pigs and fattening pigs are typically housed indoors, although there are housing systems that provide indoor housing with access to an outside area. In few cases, these pigs are also kept outdoors during the whole rearing period. Different climatic conditions and the availability of bedding material in various European regions also greatly influence the type of housing chosen. Deep-litter housing systems using straw or peat in buildings often kept at cooler temperatures are found more in Northern Europe, but are rare. The length of time that pigs spend in the fattening sheds will be determined by their growth rate as in most systems live weight determines time of slaughter. The weight of carcasses will depend on the demand for meat cuts. Indoor systems can be divided into 3 categories based on the manure-handling system adopted: deep-litter systems, scraped systems or slatted systems. Some of these systems provide different climatic zones where the pig can choose its microclimate for various activities (i.e. for resting in kennels or under thermo-boards). The latter systems may provide supplemented heating only in the lying area which reduces the overall energy input for the building. In deep litter systems, the total area occupied by the animal has to be maintained in a clean and dry condition through regular provision and removal of absorbent bedding material. In such systems the animals will often subdivide the pen area into separate lying and dunging area, choosing to lie in the most thermally comfortable and undisturbed areas and excreting in areas of the pen which are cold, wet or draughty. Space requirements are therefore greater in these systems compared with fully or partly-slatted pens. In scraped systems, the lying and dunging areas are made structurally distinct and the manure is removed at frequent intervals from the dunging area, often daily. Such systems require little or no bedding and make a lower space allowance for the animal. There have been no very recent studies of the distribution of housing systems for weaners and for growers and finishers but Tables 3 and 4 show data from a 1999 publication. Housing systems with slatted floors are the most widely used throughout the EU. In these systems hygiene is maintained, usually in the absence of any bedding, by installation of slatted floors through which the excreta can fall and be stored in a physically separate place from that occupied by the animals. Floors may be fully-slatted over the entire pen area, or have a solid floored lying area combined with a slatted dunging area. Pens with partly-slatted floors may require more space allowance than fully-slatted floors. Partly-slatted floor systems need to provide enough space for pigs to be able to maintain separate and distinct lying and dunging areas, so that the solid portion of the floor and the pigs can be kept clean. Some pens are therefore equipped with two floor types that differ in the degree of perforation (i.e. 40% vs. 10 %; the area with lower perforation intended for lying) in order to reduce the risk for reduced 14

30 cleanliness. More recently, slatted systems designed especially to reduce ammonia emissions have been developed. Table 4. Distribution of housing systems for weaned pigs (weaning to kg) in European countries (pigs x 1000; after Hendriks and van de Weerdhof, 1999, on the basis of data from a questionnaire collected between 1996 and 1998, EAAP working group Future Housing and Management for Pigs ). NB. The remaining 5% of piglets remain in lactation pen Without/restricted straw With straw Partly-slatted Fully-slatted Fully solid concrete Countries piglets % tr.* piglets % tr.* piglets % tr.* Belgium Denmark France Germany Greece Hungary Ireland Italy Netherlands Portugal Spain UK Total *tr.: trend in 1999 Increasing Steady Decreasing 15

31 Countries Animal Health and Welfare in Fattening Pigs Table 5. Distribution of housing systems for growers and finishers in European countries (pigs x 1000; after Hendriks and van de Weerdhof., 1999, on the basis of data from a questionnaire collected between 1996 and 1998, EAAP working group Future Housing and Management for Pigs ) Without/restricted straw With straw Partly-slatted Fully-slatted Solid concrete Solid concrete Deep litter finisher finishers finishers finishers % tr.* % tr. s % tr. % tr. finishers % tr. Belgium Denmark Finland??? France Germany Greece Hungary Ireland Italy Netherlan ds Portugal Spain Switzerla nd UK Total Systems without/restricted straw Systems with straw *tr.: trend in 1999 Increasing Steady Decreasing The following sections briefly review the design of typical commercial pig housing systems in the European Union with emphasis on floor design and space allowance Weaners After weaning, the sow is returned to service accommodation and the piglets are either left in the farrowing pen (not very common) or more commonly, moved immediately to the weaner accommodation. The technology of segregated early weaning has been established primarily in large pig farm enterprises across North America. Segregated early weaning is characterised by weaning piglets at days 7-21 of age (mostly between days 12-16) and isolated housing in nurseries and growing / finishing units (multi-site production with all-in all-out pig flow). The goal of this technology is to break the infection chain by utilising acquired maternal (passive) immunity from the dam before piglets develop their own active immunity in response to pathogens (Borell, 2000). A variety of housing systems is used for weaned piglets. Piglets are typically housed in highly controlled environments with supplementary heating in partly or fully-slatted pens, or raised in flat decks, in groups of varying sizes (10-40). They may be moved from the first stage weaner accommodation to larger, second stage accommodation after 2-4 weeks or remain in the same pen until the age of 10 weeks (30-40 kg) or, in a few instances, until slaughter. The pen area 16

32 per pig varies from 0.2 (< 20 kg) to 0.3 m2 per pig (< 30 kg). Weaner pigs are typically fed ad libitum (dry) or restricted (liquid) with an animal: feeder space ratio of 1: 1 to 12:1, depending on the feeding system. Within nursery accommodation, the ambient temperature recommended by, e.g. Close and Le Dividich (1984) and Madec et al. (2003) and generally used (non bedded, perforated floors) is in the range 26-30C e.g. a temperature of 28C for piglets weaned at days of age. The following figures 3 to 8 are selected examples of housing systems taken from the IPPC- BAT Reference Document on the Intensive Rearing of Poultry and Pigs dated October 2000 (IPPC, 2000; 2003). Figure 2. Partly-slatted and convex floor with iron or plastic slats (Hendriks and van de Weerdhof, 1999) Figure 3. Example of flat decks with fully-slatted plastic flooring and sloped concrete floor underneath to separate faeces and urine (CRPA, 2003) Figure 4. Rearing unit with partly-slatted floor and two-climate zones (IPPC, 2000) 17

33 6.4. Grower/ Finisher pigs Animal Health and Welfare in Fattening Pigs Accommodation for fattening pigs may be fully-slatted, partly-slatted, minimally bedded with scraped dunging area or deep bedded with straw or strawdust. Although there are national differences, housing with fully or partly-slatted flooring (typically on concrete slats with mm slot spacing) with a pen floor area of 0.7 m2 at the end of the finishing period predominates within the EU. The recommended common range of temperature for buildings with non-bedded perforated floors is at 20-26C (McFarlane and Cunningham, 1993). Feed might be provided either wet or dry. Feed is increasingly distributed automatically to sensor controlled liquid feeders or slop feeders (semi-liquid) with an animal feeding place ratio of max. 12:1. Dry feed is often given ad libitum from one or more hoppers, although feed may be restricted in the later stages to prevent excessive fatness of unimproved genotypes or with very heavy slaughter weights (>120 kg). Liquid feed is also restricted in Italian heavy pig production for animals weighing more than kg. In controlled environment housing, it is common to use two or three housing stages with larger pens at each stage in the growing/finishing period, to make most efficient use of space (single-phase from kg to kg, two-phase with a grower period from kg to kg and a finisher period from kg to kg; Italy: kg). Slaughter weights may be much lower (i.e. in the UK: 90 kg) in countries where boars are not castrated after birth. Feeding may be adjusted to the respective growing phase of the pigs. Traditionally, fattening pigs are housed in groups of 10-15, but recently the number of fattening units with large group sizes (24 pigs up to 40 and more) on perforated floors is increasing. Large group sizes are also typical for deep litter systems. Kennels, intended to provide a separate resting area, can be included in all housing conditions. They are typically used in cold non-insulated buildings or outdoors. Combinations of kennels with the following floor types may require additional space per pig depending on the specific pen design features Fully-slatted floor Slatted housing systems are widely used throughout the EU and in all other significant pig producing countries in the industrialised world. In these systems, slats cover the entire pen area, usually to maintain hygiene. Foraging material, if used, is small in quantity. From a technical point of view, flooring in unbedded systems should have sufficient perforation or slot-width to keep the pen clean from manure and urine. Studies have been carried out as laboratory tests as well as case studies (Seufert et al., 1980; Svennerstedt and Praks, 1997; Rantzer and Svendsen, 2001a). The importance of designing slatted floors for avoiding emissions has been emphasised (Brok and Voerman, 1995). The construction and design requirements for concrete slats are that of highest exposure class. Recommendations about design are to be found mainly for concrete and metal slatted floor constructions with less information for other (mainly plastic compound) constructions. The use of polymer and composite materials is increasing. One vital component for the successful use of slatted flooring is the proportions of the floor solid and slot dimensions in relation to the dimensions of the feet of the pig at any given age. However, even the construction profile is critical: sharp edges may cause cut injuries as well as a compressive stress when the loading force will exceed the strength of the digits (Webb and Nilsson, 1983; Webb, 1984; Udesen, 1997). The lack of elasticity, besides softness, of hard flooring material such as metal constructions, is another critical characteristic and may explain the increased level of lesions (Fritschen, 1979). Slatted flooring can contribute substantially to the cleanliness and health of an animal by allowing for the speedy removal of faecal and urinary products from the immediate 18

34 environment of the animal, and thus assisting the provision of a dry lying area. Slatted systems generally give lower airborne endotoxin concentrations than litter based systems, due to bacterial contamination of straw and other litter materials (Seedorf and Hartung, 2002). The possible use of straw is strictly limited with fully-slatted floors. Usual characteristics: Pen floor area per pig: 0.4 m 2 (growing), m 2 (finishing). Concrete slats with 17 mm slot spacing. Pig: feeder place ratio 1:1 up to 12:1 depending on the feeding system. Figure 5. Example of growing-finishing unit with a fully-slatted floor (CRPA, 2003) 6.6. Partly-slatted floor Partly-slatted flooring may reduce emission of ammonia and other gases released from the excreta, and if correctly designed and well-drained, can lower emissions considerably. Partlyslatted floor systems, preferably with a raised level of the slatted part, allow for a fairly good supply of straw. Usual characteristics: Pen floor area per pig: 0.4 m 2 (growing), m 2 (finishing). Concrete slats with 17 mm slot spacing. Pig: feeder place ratio 1:1 up to 12:1 depending on the feeding system. a) b) Figure 6. Example of a) Partly-slatted floor with deep slurry pit b) Partly-slatted floor with fast removal of slurry and littered external alley (CRPA, 2003). 19

35 Figure 7. Growing-finishing unit with a partly-slatted floor (IPPC, 2000) 6.7. Solid floor, no bedding Solid floors (concrete constructions) are used with all pigs from weaning to slaughter as the only floor type, or in combination with other constructions, where the resting area is of solid construction. The solid floor is characterised by a non-perforated surface where different properties may differ according to the choice of surface treatment and materials in the concrete. The construction and design requirements for concrete are that it be of the highest exposure class to resist feed residues, faeces, urine, chemicals and high pressure cleaning (Nilsson, 1988; Jakobsen and Nielsen, 2001; Olsson et al., 1993). Traditionally, solid concrete floors are used for both the resting and defecating areas. The manure is scraped, manually or by mechanical scrapers at frequent intervals and the urine usually drained separately. The slope towards the dunging area is about 3% (Jakobsen and Nielsen, 2001). A dry concrete floor can easily be warmed and it will retain heat quite well, but it will worsen the harmful effects of low temperatures if floors or bedding are cold or damp. Therefore, solid floors are found to need either insulation, or support from a floor heating system (warm water pipes or electric cables), whether used with or without small amounts of bedding materials (Nilsson, 1988). Usual characteristics: Solid pen floor area per pig: 0.5 m 2 (growing), m 2 (finishing). Flat or sloped (with 3% gradient) solid floor, typically combined with an internal or external alley with a scraped manure canal. Pig: feeder place ratio 1:1 up to 12:1 depending on the feeding system Solid floor, some bedding (sloped-floor/straw-flow system) The straw-flow system is used for growing pigs from 10 weeks (20 30 kg) to slaughter ( kg). The straw-flow pen system is characterised by sloping concrete floors, where the laying area has a curved surface, gradually increased sloping, or an equal slope of about 5-7% towards the dunging area. The resting area is sometimes levelled about 5 cm above the manure area, which has a slope for allowing the manure to flow down into a manure channel or pit. The total depth of the straw-flow pen has to be limited to about 6 m. Contrary to deep-straw systems, the group-size in straw-flow systems will be about the size of a litter and is not recommended for more than 30 individuals (Brogaard-Petersen and Jensen, 1996; Jackisch et al., 1996; Andersson et al., 1998). For the flow function of the pen, the amount of 50 grams of straw per pig / day is satisfactory; the amount may not exceed 100 grams for avoiding clogging or a flow malfunction. Uninsulated floors, however, need a bedding depth of at least about 75 mm for the weaned pig to achieve a thermal resistance to the floor above at about 0.5 (Bruce, 1990; Kelly, 1996; Brogaard-Petersen and Jensen, 1996). 20

36 Usual characteristics: Pen floor area per pig: 0.5 m 2 (growing), m 2 (finishing). Sloped solid floor with 8-10% gradient with some bedding (straw from rack). Pig: feeder place ratio 1:1 up to 12:1 depending on the feeding system Deep litter system Deep bedding (> cm bedding) with bedding materials such as straw, saw dust, wood chips, peat etc. usually have a solid concrete floor underneath, although even a slatted floor may be used for drainage purposes of the litter bedding. The use of a deep bedding system demands good facilities for removing the bedding and cleaning/disinfecting in a strict batch system. Provision of straw, especially straw of poor quality, and the use of wood chips and saw dust, will increase the production of airborne particles such as dust, moulds and fungi associated with respiratory disturbances in pigs and humans (Boon and Wray, 1989; Jensen, 2003). The deep litter system has disadvantages in increased emissions of, among other things, ammonia, nitrous oxide (N 2 O), nitrogen and methane (Groenestein and Van Faassen, 1996). The amount of nitrogen excreted by the pigs will emit to the atmosphere up to % depending upon type of bedding, temperature and other storage conditions (Jeppsson, 1998; Nicks et al., 2004). In insulated buildings (and during summer periods in uninsulated ones) the UCT (upper critical temperature) of the deep bedding systems, especially when the bedding is fermenting and producing a large amount of heat, may be critical in creating thermoregulatory problems, resulting in heat stress and decreased performance; the heat production will also lead to an increased evaporation of water (van den Weghe et al., 1999; De Oliviera et al., 1999). Deep straw bedding for pigs from weaning to 10 weeks (20-30 kg) and from 10 weeks (20 30 kg) to slaughter ( kg) may take place with a wide variation of pen designs, feeding and management systems. The group size is usually more than 30 pigs with an area of at least 0.5 m 2 and 1.0 m 2 per weaner and grower, respectively. The use of straw is approximately 1 kg per kg live weight gain (Jensen and Nielsen, 2004; Brogaard-Petersen and Jensen, 2003; 2004). Usual characteristics: Pen floor area per pig: 0.5 m 2 (growing), m 2 (finishing). Straw bedded deep litter pen with elevated feeding area. Pig: feeder place ratio 1:1 up to 12:1 depending on the feeding system Outdoor / semi-outdoor rearing on earth or concrete Outdoor rearing systems are much less common than indoor rearing, and come in many forms (Edwards, 1999). Floor design and pen dimension greatly depend on soil characteristics, management and environmental conditions. Resting areas (indoors or kennels/huts) are typically insulated or bedded and protect pigs from adverse climatic conditions Mediterranean silvopastoral systems This traditional Mediterranean system involves indigenous breeds that are extensively pastured in natural forests for the production of high-value dry-cured hams (Dobao et al., 1988). Typically, all phases of production take place outdoors, sometimes in extreme conditions in mountain zones. The finishing takes place during autumn in forests of oak or chestnut. 21

37 Pigs reared to organic standards Animal Health and Welfare in Fattening Pigs Whilst accounting for a small minority of pigs in the EU, this category includes most outdoor growing pigs since it is a requirement of the European Community standards for organic livestock and livestock products (Council Regulation EC 1804/1999 supplementing Directive EEC 2092/91) that pigs be maintained with outdoor access for the majority of their life. In some certification schemes (e.g. the UK Soil Association) it is also a requirement that finishing pigs be kept at pasture, although this is not universal and in many countries growing and finishing pigs are housed with an outdoor run area which may be of concrete (Olsen, 2001; Kelly et al., 2007). Minimum space allowances are specified by the Directive for both indoor and outdoor areas, and are greater than those required for other commercial pigs (see Table 6). Table 6. Minimum space requirements for organic pigs (EC Regulation 1804/99) Indoor area (m 2 /head) Outdoor exercise area (m 2 /head) Piglets Up to 30 kg Fattening pigs Up to 50 kg Up to 85 kg Up to 110 kg Field rearing Outdoor rearing in fields can be divided into two types. In the first, free-range pigs are provided with a large paddock and simple shelter, whilst in the second they are confined within an outdoor hut-and-run system Paddock systems (free-range production) In true paddock systems, pigs have the free run of a fenced paddock area. The stocking rate suggested has been approximately 4,000 kg/ha (Brownlow et al., 1995), giving finishing pigs/ha, although this will depend on soil type and climatic conditions. Housing for free-range pigs depends on climate and group size and typically comprises corrugated iron arcs or wooden sheds, although tents have more recently been adopted on a few farms.. Housing is generally moveable, so that each new batch of pigs can begin in a clean paddock with a newly resited house Tents and deep-litter paddocks This system has been developed in Denmark (Jensen, 1994) but is not seen widely in the EU. The objective has been to provide outdoor housing on a semi-permanent site whilst controlling pollution risk. The tents have roofs of 16-guage double skin transparent polyethylene film supported by a 10m central pole and shorter poles around the circumference. The walls are made of 2 layers of straw bales, protected by wire mesh. The inside area of 40 m 2 houses 100 pigs from weaning to slaughter. The outdoor area provides 1.8 m 2 per pig and is bounded by an electric fence. To prevent leaching of nitrate, the topsoil is removed from this area and banked around it. A 1mm density polyethylene membrane is placed at the bottom, with 10cm layers of sand on both sides. An 80cm drainage layer of crushed shells is then covered by a top layer of 10 kg straw per m Hut-and-run systems In these systems, the pigs are provided with a hut and small outdoor run area bounded by solid fencing and bedded with straw to maintain hygiene. One common type features a wooden hut of 2.4 x 6.1 m with an insulated steel roof, and an outdoor run of ~33 m 2 to house 25 pigs from 30 to 90 kg (Figure 8). The hut has an adjustable ventilator and contains and integral feed 22

38 hopper with large capacity and water tank holding a one day reserve supply. It is moved to fresh ground for each new batch of pigs. Figure 8. Outdoor growing hut for fattening pigs (drawing E.v.Borrell) 7. FACTORS AFFECTING PIG WELFARE The factors referred to in the risk assessment tables have been related to the needs of pigs in Appendix 2. The risk assessment tables are based on data from this chapter and on data in the EFSA Report The welfare of weaners and rearing pigs: effects of different space allowances and floor types (EFSA, 2005) Pig genetics in relation to welfare Genetic selection focuses on increasing productivity with pig breeding programmes traditionally favouring high growth rates, high levels of lean meat in the carcass and high feed conversion efficiency. However, negative side effects of this selection could be higher risks of welfare problems as reviewed by e.g. Rauw et al. (1998). Increasingly other factors related to health have also been considered and one positive effect of breeding has been the dramatic reduction of the incidence of the ryanodine receptor gene (halothane gene) in most of the EU Leg problems A welfare problem specifically relevant to growing pigs is leg weakness, in part caused by osteochondrosis. Leg weakness and osteochondrosis have low to moderate heritabilities, and the prevalence of the lesions varies between breeds (Jørgensen and Andersen, 2000, Kadarmideen et al., 2004). Most studies have found a positive correlation between osteochondrosis and growth rate indicating a negative side effect of selecting for high growth rate (Jørgensen and Andersen, 2000, Kadarmideen et al., 2004, Busch et al., 2006). Busch et al. (2006) reported a higher risk of osteochondrosis associated with increased growth rate in the weaner and finisher period (+ 100 grams ADG increases risk of osteochondrosis by 20 %), and associated to lean meat percentage (+1% lean meat increases risk by 3-5 %), with a heritability of osteochondrosis of approximately 0,20 in 9696 pigs from four herds. Contrary to this, a negative correlation has been found between elbow joint osteochondrosis and growth rate 23

39 (Kadarmideen et al., 2004, Jørgensen and Nielsen, 2005). There is some complexity in the relationship between growth rate and osteochondrosis. Leg weakness and osteochondrosis are genetically correlated with lean meat content and this points to a negative effect of selecting for lean meat content in the carcass (Jørgensen and Andersen, 2000, Kadarmideen et al., 2004, Jørgensen and Nielsen, 2005, Busch et al., 2006). Heavier, older pigs tend to be more susceptible to osteochondrosis in the elbow and carpal joints (Kadarmideen et al., 2004, Jørgensen and Nielsen, 2005) Cardiovascular problems The size of the heart in relation to body mass is 0.21 % in a 160 kg German landrace pig compared with 0.38 % in a wild boar of similar age weighing 57 kg (Dämmrich, 1987). Further the thickness of muscle fibres is enlarged in modern pig breeds; especially as regards type II muscle fibres, which have a size of 7335 μm 2 compared with 2500 μm 2 in wild boars. Additionally, the percentage of type IIb fibres characterised by the functioning by anaerobic glycolysis have increased in modern pigs. This leads to myopathies caused by an increased production and accumulation of lactic acid during locomotor activity in the pig (Dämmrich, 1987; Fabrega et al., 2002). Cardiovascular problems are also part of the porcine stress syndrome (Ratcliffe et al., 1969) which is linked to the halothane gene. Halothane sensitivity potentially leads to severe welfare problems if the pig is subjected to a stressful situation. Fabrega et al. (2002) estimated the mortality during transport and lairage for homozygous (nn 2.29%) and heterozygous (Nn 0.09%) pigs compared with the normal type (NN 0.02%) by examining the genotype of 107 dead pigs. This showed increased mortality rates in halothane homozygous and heterozygous animals. How is the information in this section relevant to currently used breeds of pigs? We know that modern pigs can die during handling on farm or when loaded into vehicles (Fabrega et al., 2002; EFSA, 2004). We also know that the mortality of pigs during transport was high in the early 1990s but, with the elimination of the halothane gene, it has been reduced to one tenth of that high level. However, pig mortality during handling and transport is still much higher than sheep mortality during handling and transport. Hence it seems that further genetic change to reduce the risk of poor welfare, PSE meat and high mortality during handling on farm and transport to slaughter might be possible to achieve Social behaviour and fearfulness Other aspects relevant to fattening pig welfare also have a genetic component and may be influenced by genetic selection, and thus manipulated by the focus of breeding programmes. For example, Hemsworth et al. (1990) found a heritability of 0.38 for fear of humans in 425 gilts, measured by the latency to interact with the experimenter in a human approach test; and Lund and Simonsen (2000) observed breed differences between Duroc and Danish Landrace in aggressive and stimulus-directed behaviour. Breuer et al. (2003) found similar breed differences between Duroc, Landrace and Large White in social behaviours of weaned pigs. Further Breuer et al. (2005) found a genetic component of tail-biting behaviour in Landrace pigs, and they observed a genetic correlation between leanness and tail-biting. A genetic variation in post-mixing aggressiveness has also been described by Turner et al. (2006), using skin lesion scores as an indicator of aggression. Furthermore, according to this study the lesion scores were not significantly genetically correlated with growth rate or back-fat depth. Therefore selection programmes aiming at reducing post-mixing aggressiveness may be applied without compromising productivity. 24

40 Disease resistance Animal Health and Welfare in Fattening Pigs Henryon et al. (2001) found genetic variation as well as breed differences in disease resistance in a survival analysis recording days to diagnosis of diseases in rearing pigs, including lameness, diarrhoea, respiratory diseases, and other diseases. Disease resistance might be mediated through varying levels of immune responses. Genetic variation, as well as breed differences (Duroc, Landrace and Yorkshire), have been reported in several immunological traits in growing pigs: total and differential numbers of leucocytes, expression levels of swine leucocyte antigens (SLA) I and II, and serum concentrations of IgG and haptoglobin (Henryon et al., 2006). In accordance with this Clapperton et al. (2005) found differences between Meishan and Large White pigs in differential numbers of leucocytes, and in the function of neutrophils. Also levels of acute phase proteins differed between the breeds. Sutherland et al. (2005) reported that different pig breeds varied in baseline immune measures and plasma cortisol. However, there were no pig breed differences in physiological responses to chronic concurrent stressors such as mixing, heat and crowding (Sutherland et al., 2006). In large white pigs genetic lines selected for high or low lean growth under restricted feeding have been shown to differ in innate immune response measured by white blood cell numbers, in particular lymphocytes (Clapperton et al., 2006). This suggests a genetic correlation between certain immune traits and performance, but further research is needed to investigate if this affects the health of the pigs and their ability to resist or cope with infections Light inadequacy In general, it can be assumed that the mainly nocturnal habits of wild boar are a consequence of being hunted by predators (Hafez and Signoret, 1969). The diurnal rhythm of captive breeds is probably not changed from that of their wild ancestors, and we can observe that pigs are mainly diurnal or crepuscular animals. Simonsen (1990) recorded that fattening pigs in multi-activity pens restricted most of their activities to diurnal hours, with a bimodal distribution during the morning and the late afternoon. Similarly, the light-darkness rhythm with 16 hours of light (5:00 to 21:00) and 8 hours of darkness affects feeding, causing two peaks of feeding activity: one when the light turns on and another one just before it turns off. The dimensions of the pig s eye are comparable with those of humans, having the same hypermetropia value, i.e. the same ability to see at a distance. Consequently, pigs have good visual capabilities (Piggins, 1992). Using operant discrimination Tanida et al. (1991) found that weaned piglets are able to detect only blue among the three primary colours, and may not be able to discriminate all wavelengths. According to some investigations, light intensity does not seem to be of great importance to the welfare of pigs. Van Putten (1980) could not prove experimentally that the behavioural repertoire of pigs, and indirectly their welfare, is affected by the presence or absence of light. However, van Putten (1968) found tail-biting to decrease greatly when, apart from other variables, pigs were maintained in a warm environment and in low light. Also aggression among unfamiliar, recently grouped individuals is greatly reduced when they are in darkness (Barnett et al., 1994). However, van Putten and Elshof (1983) stated their opinion that the welfare of pigs is poor if they are kept at a very low level of illumination (less than 0.2 lux). Some pig interactions would inevitably be altered if the animals were kept in darkness. Zonderland et al. (2007) demonstrated that increasing the illuminance level between lux has no effect on the ability to distinguish visual cues, only at an illuminance level lower than 10 lux the number of incorrect choices of pigs increased; the size of the symbol had an effect on the number of incorrect choices: more incorrect choices were seen for the small symbols; the visual acuity of pigs is much lower as compared to humans (Zonderland et al., 2007). 25

41 Engmann (2004) investigated the melatonin rhythm of pigs, using light-phase intensities of 250 lux or 470 lux and setting scotophase light intensities below 1.0 lux. The results of the study show a lack of suppression of the pineal melatonin secretion during the light-phase at 250 lux. This indicates that differences in hormone concentrations driven by day to night-changeovers did not vary between day and night. At 450 lux the light-phase melatonin concentrations were significantly lower, indicating stronger light-reduced melatonin suppression. Still, as synchronisation with the light regimen was incomplete the light intensity may be insufficient for the animals. Baldwin and Meese (1977) trained young pigs to perform an operant response to obtain brief periods of illumination of their pen. Surprisingly, the pigs kept the light on for only 0.5% of the available time. In another study, young pigs of 8 to 12 weeks, kept in light-proof pens, were trained to break an infrared beam switch with their snout to obtain periods of 40s of illumination (Baldwin and Start, 1985). They turned the light on for hours during the 24 hour period. In addition, the rewarding properties of light onset did not wane during a ten dayperiod, showing that the operant interruption of the beam was not caused by novelty. Light was mainly turned on at feeding times but very rarely during the night (22:00 to 7:00). In contrast, pigs kept in continuous light were not motivated at all to operate the beam switch to obtain 40s of darkness, because the total time of darkness over the 24 hours amounted to a mean duration of about 30 minutes. Since 40 s of darkness is not usable for rest by the pigs, this result does not show lack of need for darkness. Pigs allowed to move freely between two light-proof pens, one of them illuminated only by 0.1 lux (i.e. virtual darkness), the other one by 60 lux, no difference between the time spent in either pen could be found over a period of 8 days (van Rooijen, 1985). There also was no evident circadian rhythm of illumination preference; during the night the pigs stayed in the twilight pen for almost the same time as in the light pen (Baldwin and Meese, 1977; van Rooijen, 1985). It seems that pigs do not like intense light. When pigs were kept in darkness and trained to operate an infrared beam to obtain 40 seconds of illumination, they spent 54% of their time over the 24-hour period activating a lamp with 110 lux, while they did so for 63% of time when the light was much less intense (10 lux). Hence the contrast between darkness and 110 lux may have been somewhat aversive. Some behavioural responses can only occur when the pigs are able to see the object of the response Ability to rest and sleep Sleeping in groups simultaneously is usual in pigs and they may be recumbent in rest or sleep for as much as 19 h per day. The amount of time young pigs (up to 5 weeks of age) are resting or sleeping was estimated to be between 40 and 60% of each day (Kuipers and Whatson, 1979). For pigs up to 12 weeks of age it was 60% per day (Blackshaw, 1981), whereas pigs of 10 weeks or older spent about 80% of the time resting (Ekkel et al., 2003). Since all of those pigs were in pens with relatively small space allowance and little diversity in the environment, the result reflects the response of the pigs to these conditions. In the study of Ekkel et al. (2003) it was shown that the fully recumbent position was predominant with more than 60% of the pigs lying in this position. This percentage increased with age and was higher during the night period (Ekkel et al., 2003). Pigs also drowse and about 5 h are spent in this state daily. Pigs are characterised by complete muscle relaxation during sleep (Fraser and Broom, 1990). Pigs adopt two postures when resting or sleeping, i.e. sternally lying with at least two legs folded under the body and lateral lying with all four legs stretched out (e.g., Ekkel et al., 2003). The floor area required for resting is dependent on the posture adapted; laterally lying pigs need more space as compared with sternally lying pigs. In addition, the space needed for lying 26

42 is dependent on the actual number of pigs lying down at a given time and space sharing. At thermoneutral conditions space sharing percentages were only 20-40% for lying pigs with more space sharing during the dark period as compared with the light period (Ekkel et al., 2003). Petherick (1983) estimated the minimum area required for lying at thermoneutral conditions, based on the estimated floor area for half recumbent pigs, as A (m2) = x W0.66. This was confirmed by Ekkel et al. (2003). Pigs with more restricted space, i.e. using a constant of in the equation, spent less time lying recumbent as compared with pigs provided with the amount of space needed for minimal normal movement (i.e. a constant of in the equation) (Pearce and Paterson, 1993). The space allowance needed for different lying postures was described in detail in a previous EFSA report (EFSA, 2005). Pigs use separate areas for different activities, i.e. for resting, feeding and dunging (Stolba and Wood Gush, 1989). This implies that if the available space is not sufficient to separate the different activities it may lead to poor welfare. In addition, the pen lay-out plays an important role in the selection of these areas and is thus important for the ability to separate the different areas. For example, solid floors and closed pen partitions promote lying whereas open pen partitions appear to promote dunging behaviour (Blackshaw, 1981; EFSA, 2005). With inadequate design of the housing system (e.g., position of feeders, drinkers, floor quality) there is a risk that different activity areas can not be separated and that for example the dunging area and lying area overlap or that lying pigs are frequently disturbed by active pigs. Other factors that play a role in the space necessary for resting and lying is that functional areas may overlap and that group size may play a role. When many of the pigs in a group are lying, other activities cannot occur in that area. Overlap of the resting or lying area with areas for other activities is not preferred with respect to pig welfare (disturbance by other pigs). In small groups (less than 10 pigs) the usable space in a pen is less as compared with larger groups. Hence, in these small groups, more space per pig is required for different activities like resting and lying. It has been estimated that for 4-10 pigs the space required per pig is 30% greater than in groups of more than 10 pigs (EFSA, 2005). Thermal conditions play an important role in the choice of the lying places by pigs. Under cold conditions pigs show huddling behaviour when lying whereas under high environmental temperatures pigs choose to lie down so that they are not touching one another, or even to lie in the dunging area (e.g., Hillmann et al., 2004a, b; Hyunh et al., 2005). Under cold conditions pigs prefer to lie on bedding like straw as compared with bare floors (Tuyttens et al., 2005). Huddling behaviour leads to a disturbance of resting behaviour in pigs of more than 50 kg (Hillmann et al., 2004a, b). Thus, thermal conditions are important with respect to undisturbed resting and lying behaviour. Pigs prefer a low light intensity for rest and sleep. In a recent experiment it has been shown that pigs prefer to rest and sleep in a dark compartment with 2.4 lux as compared with compartments with 4, 40 and 400 lux (Taylor et al., 2006). Besides a low light intensity, an appropriate continuous period of darkness should be provided for resting and sleeping. In the study of Taylor et al. (2006) pigs spent on average about 7 h per 24 h in the darkest compartment. It was therefore suggested that a low light intensity should be provided for at least 6 h a day. Spatial provision of the minimal illuminance needed could potentially improve pig welfare by providing a preferred light environment for resting (Taylor et al., 2006). From this study it is not clear whether pigs prefer complete darkness to rest and sleep or the lowest light intensity provided in the experiment. 27

43 7.4. Ability to exercise Animal Health and Welfare in Fattening Pigs The effects of space allowance and flooring on the ability to carry out locomotor behaviour have been reviewed in detail in the previous EFSA-report The Welfare of Weaners and Rearing Pigs: Effects of Different Space Allowances and Floor Types (EFSA, 2005). Apart from these environmental factors, animal-related factors such as the physical condition of the pigs also affect their ability to exercise. Leg weakness, in particular osteochondrosis, is affected by genetics (see section 12.1 above). However, the housing system and on-farm management may additionally influence the occurrence of leg problems. Sather (1987) observed an improvement, however not substantial, in clinical leg weakness, especially in the rear legs and hips, when transferring 90 kg boars from confinement to outdoor housing, while there was hardly any effect on 75 kg gilts. Grøndalen (1974) described a positive effect on gait score in pigs that were exercised 3 times a week throughout the fattening period. On the other hand Enfält et al. (1993) did not observe any effects of moderate indoor exercise on the prevalence of osteochondrosis, or musculo-skeletal development in growing pigs. Jørgensen (2003) compared fully-slatted-floor, bare solid floor and solid floor with straw bedding and reported that pigs on slatted floor showed more clinical leg weakness than pigs on bedded floors, while claw disorders were more prevalent on bare solid floors. High stocking density (0.65 m2 per pig) resulted in higher prevalence of some claw lesions than observed in pigs housed with a density of 1.2 m2 per pig. Marchant and Broom (1996) have reported a detrimental effect of long-term restrictive housing on bone strength and locomotor muscle weights in dry sows. Weiler et al. (2006) studied the effect of two-weeks confinement on bone growth in 40 kg growing pigs, and found reduced tibial growth, cortical area and caudal thickness, in confined as opposed to group-housed or exercised pigs. Longitudinal growth was also affected by the short-term confinement. Petersen et al. (1998b) found changes in muscle fibres and hypertrophy induced by spontaneous as well as forced activity in fattening pigs. Spontaneous activity induced by group-housing increased muscle weight and total carcass bone mass, and forced activity by treadmill training induced cardiac hypertrophy (Petersen et al., 1998a). Further, Jørgensen (1995) found that slaughter pigs fed ad libitum showed more leg weakness than pigs on a restricted diet. Similar results were reported by Grøndalen (1974) Food and water in relation to pig welfare Effects of water supply Water accounts for over 82% of the body weight of a piglet, excluding gut content, and approximately 53% in a 90 kg pig (Shields et al., 1983). Irrespective of the numerous physiological and metabolic functions water must perform, e.g. tissue maintenance and growth, adjustment of body temperature, maintenance of mineral homeostasis, excretion of end products of digestion, excretion of anti-nutritional factors ingested, excretion of drug residues, achievement of satiety and satisfaction of behavioural drives, pigs obtain water from the following sources: water that is consumed by drinking, water added to feeds provided in liquid form, moisture naturally present in feedstuffs and water formed by processes of oxidative metabolism (metabolic water). The latter two sources are of marginal importance compared with the former two. Pigs display diurnal drinking behaviour. Growing-finishing pigs given ad libitum access to nipple drinkers drink for approximately 6 to 8 min during the light phase and a total of 10 min over the 24-h period (Li et al., 2005). Systems able to reveal alterations in the circadian rhythm of drinking behaviour can provide early indications of health impairment in young pigs (Madsen and Kristensen, 2005). 28

44 A consumption-based approach to the quantitative water requirements of pigs may not be precise due to inevitable waste. As regards efforts aimed at better defining quantitative water requirements, an initially promising model, open to further development, for predicting the water intake of pigs growing in a known environment on a known diet, was recently described by Schiavon and Emmans (2000). As a rule, young pigs require relatively larger quantities of water per unit of live weight than older pigs, and this reflects the respective body composition of these two categories. Water availability is of particular importance for newly-weaned piglets, that must suddenly consume water as their major fluid source, and it is generally recognised that water restriction can impair piglets growth rate (Barber et al., 1989). During the first 48 h after weaning, drinker design affects piglet behaviour. Piglets with bowls spend less time at the drinker and more time at the feeder and eat more than piglets with nipple drinkers do. They also belly-nose less over the nursery period (Torrey and Widowski, 2004). The mixing of litters at weaning changes drinking behaviour. Mixed piglets drink for a shorter time immediately after weaning and drink earlier in the morning (Dybkjaer et al., 2006). Considering both the numerous physiological and metabolic functions performed by water and the numerous factors, mainly tied to the animal s physiological stage, rearing environment and diet, that may cause water requirements to change, it is clear that availability of drinking water is important, in particular to dry-fed pigs. At a group level, water intake influences dry matter intake and hence pig growth performance. The issue of water deprivation and its effects on animal welfare concerns three main types of deprivation that have different implications: accidental water deprivations; water deprivations resulting from management errors and voluntary water restrictions. Accidental water deprivations occur when the water distribution system fails or performs inefficiently. They may affect a large number of animals and may be either of limited duration, as in the case of complete failures of the water supply and distribution systems, or of prolonged duration, as in the case of operating inefficiencies within the systems themselves, e.g. insufficient pressure in the water supply lines, or silting up of pipes or drinker valves. Inspection of animals and water provision systems at least once daily, should serve as a guarantee against the negative effects of complete system failures. It shall be noted, however, that there is also a need for appropriate back-up water and feed distribution With regard to management errors, these may be due mainly to an insufficient availability of drinkers in relation to the number of animals, incorrect positioning or inadequate maintenance of drinkers, precluding a correct flow of water, unpalatable or excessively cold water and feeding errors which increase water requirements and excess of protein or minerals. Management errors may affect a large number of animals and their duration may be limited or long). As a rule, water flow rates vary from 500 ml/min for weaned pigs to 1000 ml/min and more for finisher pigs. Pigs usually adapt to a slow flow rate by increasing drinking time. On the other hand, when drinker flow-rate is higher than the recommended level, pigs increase water spillage. The effects of incorrect positioning of drinkers e.g. low height, and increased flow rate are additive with incorrect positioning showing the more marked effect on water wastage (Li et al., 2005). With respect to drinker number, providing one drinker per 20 animals kept at 14-18C with adequate water flow-rate, even in a large group, does not affect diurnal spread of drinking and social behaviours and production parameters of pigs weighing on average 36 kg (Turner et al., 1999 and 2000). The most serious consequence of water deprivation is so-called salt poisoning (indirect sodium ion toxicosis). This disease may cause death in 50% of affected pigs. In a Brazilian study (Brito et al., 2001) piglet mortality was found to be 100% in the 29

45 presence of concomitant conditions that favoured poisoning (feeding factors such as the use of salty milk whey and elevated ambient temperatures). However, it is also worth stressing that, according to Livesey (1994), salt poisoning accounted for over 2/3 of the total cases of feed intoxication recorded in pigs in the 1980s in the United Kingdom, a country that is hardly known for temperatures conducive to development of the condition. Furthermore a high urinary ph, small abnormalities in the mineral composition of the feed and the inadequate provision of drinking water are the most important identified risk factors for urolithiasis in finishing pigs (Maes et al., 2004). Voluntary water restrictions primarily regard pigs on wet feeding systems and are aimed at saving water and reducing the final volume of animal waste. From the standpoint of water quality, the pig might appear to be a fairly adaptable animal. However, preference tests conducted by Carpenter and Brooks (1989), cited by Brooks and Carpenter, 1990) reveal that pigs clearly prefer clean water to water containing food residues. Another study showed that the presence of 1.5 g/l of faeces in drinking water can depress water consumption in pigs over 9 weeks of age (Sørensen et al., 1994) and impair growth without, however, negatively affecting the frequency of diarrhoea or blood haemoglobin and methaemoglobin levels. The same study also provided evidence that pigs have a high level of tolerance to the presence of additional nitrates in water. Total Dissolved Solids (TDS) may provide a rough estimate of water quality (< 1000 ppm safe water - > 7000 ppm unfit water ; NRC, 1998), an assessment of which should also take into account the presence of potentially toxic elements. Adding acidifying substances to water is an approach that has some benefits for the animals but which warrants careful scrutiny, not only because of the effects it may have on water palatability, but also because of the risk that the acidifying substances might cause materials inside the supply system to come dislodged and obstruct the flow of water into the drinkers. This could lead to various degrees of water starvation which may be difficult to perceive and have a negative impact on numerous animals, even over extended periods of time. Among the other elements to be considered when assessing water quality are the presence of pollutants, such as pesticides, and the possible colonisation by toxic algae when water is stored in light-exposed containers. According to Robertson et al. (2002) the higher prevalence of gastric ulcers in pigs given dam water compared with those receiving water from rivers or bores could be related to proliferations of algae or bacteria Liquid feeding Liquid feeding is a technique which can have an impact on the productive parameters and health of pigs and the quality and safety of meat. There are three types of liquid feeding that are practised: (i) meal mixed in water; ph neutral; (ii) meal mixed in water and with addition of by-products from the human food industry that usually have a ph < 7 and (iii) fermented liquid feed produced by the addition of bacterial culture, i.e. selected lactobacilli fermented under controlled conditions resulting in ph < 4. The clinical effects and effects on welfare and performance should therefore carefully be related to the type of liquid feed used and the epidemiological situation of the pathogens involved. Vermeer et al. (2007) showed that, compared with dry-fed pigs with a drinker in the feeder and provided with an additional drinker, wet-fed pigs do not make more effort to obtain water from an additional drinker when asked to work for it. The elasticity of the demand is equal to that of dry-fed pigs. Moreover, wet-fed pigs consume significantly less water from an additional water drinker compared with the amount that dry-fed pigs drink from an additional water drinker. In common practice, the ratios of water to meal may vary from 2.5 to 1 to 6 to 1, the highest ratio being reached when milk serum is used as the diluent. This latter case, besides being 30

46 subject to the availability of milk serum, represents a traditional practice expressly advocated for certain products such as Parma ham. Several investigations have shown that liquid feed improves feed intake and growth performance in pigs. In general liquid feed, especially fermented liquid feed, stimulates the growth of piglets, while in slaughter pigs it improves the efficiency of feed utilisation as extensively reviewed by Jensen and Mikkelsen (2001). Liquid feeding can also have some behavioural effects: pigs on liquid diets spent more time sleeping and less time standing and investigating (nosing, chewing, rooting and biting any available substrate) as compared with dry-fed pigs (Scott et al., 2007). The use of fermented liquid feeds has been shown to reduce the level of enterobacteria and the ph along the gastro-intestinal tract of weaned piglets (Mikkelsen and Jensen, 1997); however, such effects are not always accompanied by an improvement in growth (Canibe and Jensen, 2003). Fermented liquid feeds decrease both the incidence and severity of the symptoms caused by Brachyspira hyodysenteriae infections (Lindecrona et al., 2000). Furthermore, the use of fermented liquid feeds has recently been associated with lower levels of plasma urea nitrogen in growing fattening pigs (Dung et al., 2005) indicating a reduced urea synthesis and more efficient use of amino acids for body tissue growth. An aspect that is very important for risk assessment purposes is the relationship between the physical form of feed (dry or wet) and the epidemiology of Salmonella infections. Such importance arises from the fact that these infections may affect both pigs and the people who handle them; plus the meat may be contaminated during slaughtering. A recent French epidemiological study (Fablet et al., 2003) investigating the risk factors of Salmonella shedding at the end of the fattening period pointed to a significant role for the physical form of feed (dry or wet, but without any specification as to how wet feed was administered). Wet feeding during the fattening period acts as a protecting factor against Salmonella shedding at the end of the finishing phase (BPEX, 2004a, b). A Dutch epidemiological study (van der Woolf et al., 1999) highlighted the fact that a lower Salmonella prevalence was associated with the use of liquid feeds containing fermented or acidified byproducts administered by means of an automated system, but was not associated with the unhygienic practice of preparing feed mixtures by adding water to pellets, mixtures that are then fed to the pigs hours later. This finding is in agreement with the results of a survey conducted in England by Pearce (1999), who places wet feeding among the factors associated with scour problems in growing fattening pigs, due to the poor overall conditions of hygiene in farms that used liquid feeds However, in addition to the epidemiological situation, the prevalence of salmonella in pigs also depends on other feed and non-feed related factors as can be seen from Table 7. 31

47 Table 7. Risk factors influencing Salmonella infection in swine from herds in Denmark, Germany, Greece, Sweden and The Netherlands (Lo Fo Wong et al., 2004). Risk factors Odds Ratio Feed Pelleted dry feed 8,2 Pelleted liquid feed 10,4 Non pelleted dry feed 4,2 Non pelleted liquid feed 1,0 Whey No use of whey 5,6 Whey is used 1,0 Production system Continuous production 2,0 Batch- production 1,0 The use of pelleted feed is of special importance a practice that primarily was introduced to improve feed conversion due to the fact that it decreases the passage time of ingested feed through stomach and in the small intestine. However, this feeding practice also decreases the acidifying effect in the stomach and thereby the decontamination effects of orally ingested microbial pathogens like salmonella (Mikkelsen et al., 2004). In case of herd problem with salmonella, a recommendation is to replace part of the pelleted feed with roughly grounded meal which increases passage time in stomach and small intestine (Borg- Jensen et al., 2006; Wierup 2006). Listeria (Listeria monocytogenes in particular) is another zoonotic agent whose prevalence in feed intended for pigs can be influenced by the physical form of the feed itself. In a survey of 47 Breton farms, Beloeil et al. (2003) found that the percentage of feed samples positive for Listeria spp. was higher in liquid than in dry feeds. This circumstance may be related both to the fact that dry feed (pellets) is submitted to thermal treatments while meal used to prepare liquid feed usually are made on the farm without equipment for heat treatment, and to inadequate hygienic management of the liquid feed distribution system. The effects of Salmonella and Listeria on pigs and humans are discussed further in Chapter 9. Judging from the literature, few trials have been conducted to investigate the effects of restricting the water intake of pigs fed wet feed. In an Italian study (Faeti et al., 1998) conducted on heavy pigs, slaughtered at 170 kg body weight, that had been fed a liquid diet with a water/feed ratio of 2 to 1 and 2.5 to l and given or denied the possibility of consuming additional water, no differences were observed in growth parameters, slaughter weight or meat quality. Similar findings were reported by Smolders and Hoofs (2000) who did not observe any differences with respect to growth, carcass lean percentage, mortality or number of veterinary treatments in pigs that received a liquid diet with a water/feed ratio of 2.6 to 1 and had or did not have access to an unlimited supply of drinking water. Especially during hot months, pigs may require additional drinking water despite being wet-fed Lack of food and food restriction With the exception of pre-slaughter deprivation, a total lack of feed accessible to growingfattening pigs is an occurrence tied mainly to failures in the automatic distribution system. Partial quantitative deficiencies of feed may be due to accidental or deliberate causes. In the former case their duration will vary and they can also affect all the animals in the unit. Adequate access to food for all group members is a prerequisite for good welfare. Welfare problems of pigs arising from poor feeder space availability, leading to feed deficiencies or to competition for feed, have been discussed by SVC (1997). 32

48 With respect to recent literature in ad libitum-fed pigs, Spoolder et al. (1999) did not find an interactive effect of group size (20, 40 or 80 pigs per pen) and feeder space allowance (either one or two single space feeders per 20 pigs) on indicators of welfare in finishing pigs. However, feeder space availability by itself influenced aggression at the trough suggesting that from a welfare point of view the number of pigs per feeder space should be lower than 20. To avoid a depression in growth rate, a minimum feeder space allowance of 42.5 mm per pig is recommended by Turner et al. (2002) for pigs weighing more than 40 kg and having ad libitum access to dry pelleted diets. Accidental quantitative deficiencies in feed are chiefly ascribable to the unmixing (sedimentation) of liquid feeds and the occurrence of ingredient weighing errors in automated systems for the preparation of complete feed. To limit the risk of sedimentation, the ingredients having a higher specific weight should be finely ground. To maintain a uniform water-feed suspension, specific feed additives may also be introduced. The quantity of feed is deliberately limited in restricted-fed pigs. Feed restrictions are imposed on fattening pigs with the aim of improving feed efficiency, limiting carcass adiposity and, in the case of some typical products, obtaining carcasses and meat with specific technological characteristics. From a behavioural standpoint, pigs that are submitted to complete feed withdrawal even for a short time or are given access to feed only for limited periods of time will display a series of negative behavioural changes, consisting primarily in a reduction in lateral lying down time and an increase in oral activities, including those directed toward other pigs (Fernandez et al., 1994; Day et al., 1995; Lewis et al., 1999; Bornett et al., 2000). With respect to the effects of fasting, Fernandez et al. (1994) did not observe any differences in respect of plasma cortisol concentration between pigs submitted to a 24-hour feed withdrawal and ad libitum fed pigs in situations of rest or competition. However, this is not surprising as cortisol concentrations do not necessarily change when animals are fed or are deprived of food. In young pigs, an 18-hour fast leads to an increase in the lesions incurred by pigs of a lower social status at the time when feed is again made available. Enriching the environment with straw serves to limit the plasma cortisol increase caused in pigs of lower social status both as a result of fasting and the competitions that take place when feed is again made available (O Connell et al., 2004). Pigs show diurnal feeding behaviour: a 12-hour overnight feed withdrawal does not influence the time pigs spend at the feeder when feed availability is restored (Beattie et al., 2002). Feed restrictions achieved by limiting access to feeders to 2 hours a day have been shown to induce a flexible feeding behaviour in individually housed pigs, which spend more time at the feeder during the times of day when feed is available (Bornett et al., 2000). Feed restrictions are associated with an increase in active rooting and non-rooting behaviours (Beattie and O Connell, 2002). As recently suggested by Tuyttens (2005), enriching the environment with fibrous rootable material, particularly where fibre sources of good nutritional value are used, may reduce the abnormal behaviour induced in pigs as a result of feed restrictions. In the case of wet-restricted-fed pigs an increase in the number of meals (9 vs. 3) may not be advisable since it causes an increase in aggressive behaviour, lesion scores and belly-nosing and such effects are especially evident in animals with higher initial body weights (Hessel et al., 2006). 33

49 Lack or excess of specific nutrients Animal Health and Welfare in Fattening Pigs In intensive farming the problems associated with nutrient deficiencies should be rare, provided that pigs are fed correctly balanced diets supplemented with minerals and vitamins. Any problems that do occur could derive from accidental dosing errors or incorrect mixing of premixes. Paradoxically, in the case of trace elements and vitamins the main problems are generally due to accidental excesses rather than deficiencies. The most important aspects contributing to proper mixing of a feed are: the physical characteristics of the particles, the order of mixing, the mixing time, and the use of binders, as reviewed by Axe (1995). In consideration of the fact that some modern pig genetic types are characterised by a high protein deposition rate and reduced appetite (Van Lunen and Cole, 2001), for these animals close attention should be paid to ensure that no imbalances are created in the energy/protein ratio. Such imbalances may at most result in an impairment of carcass quality (higher adiposity), rather than affecting animal welfare in the strict sense. With respect to dietary protein, adult pigs can tolerate relatively high intakes of protein. Protein excess, however, is wasteful and contributes to environmental pollution whilst protein excesses, leading to the production of harmful by-products, may predispose piglets to postweaning colibacillosis (Pluske et al., 2002; Wellock et al., 2006). Given that post-weaning digestive disorders have a multi-factorial origin, decreasing the level of dietary crude protein may help to prevent and minimise the effects of post-weaning colibacillosis especially in earlier weaned animals and particularly in environments that are challenging to the health of pigs (Wellock et al., 2005, 2006) Undesirable compounds in feedstuffs The presence in feeds of undesirable substances, including microbial contamination, that may be harmful to pigs, and possibly humans as well, is a subject of concern in animal nutrition. Feed contaminants may be of anthropogenic origin (heavy metals, pesticides, dioxins, PCBs etc ) or intrinsic to the raw materials themselves (toxins of plant origin, anti-nutritional factors, by-products of amino acid degradation and lipid oxidation, etc.). In addition, contaminations of microbial pathogens like salmonella and other microbes (e.g. due to bad harvest conditions) which during storage can result in abnormal bacterial and fungal growth and the production of mycotoxins). Without overlooking the importance that toxins of anthropogenic origin have for animal and human health or the negative effects of anti-nutritional factors on animal health, it may be affirmed that mycotoxins are the feed contaminants of greatest concern in the case of intensively-reared pigs fed conventional industrial diets. Also bedding material of bad hygienic quality as well as from deep litter when eaten can be a carrier of mycotoxins as demonstrated in an Australian survey by Moore (2005). Examples of mycotoxins include aflatoxins (AF), ochratoxins (OT), trichothecenes, zearalenone (ZEN), fumonisin (F), tremorgenic toxins and ergot alkaloids. The impacts of mycotoxin ingestion on pig health, the severity of which varies according to the type of compound, length of exposure, age and gender, have been broadly recently reviewed by Hussein and Brasel (2001) and Meissonnier et al. (2005). Such effects are mainly ascribable to growth rate impairment (AF and OT), liver toxicity (AF, OT), carcinogenesis (AF, OT), pulmonary oedema (F), nephropathy (OT), negative effects on reproductive function (ZEN), rectal prolapse (OT) and potential immunodepression (AF). Within the realm of mycotoxins, there may be some ability of oral-administrated ochratoxin A (OTA) to contaminate pork products and persist even after storage and seasoning (Malagutti et al., 2005). 34

50 Although several nutritional strategies (e.g. the use of antioxidants or adsorbents) have shown their effectiveness in reducing the detrimental effects of mycotoxins on animal health, the first line of defence is to decrease mould contamination of feeds to the minimum (Adams, 2006). This goal can by achieved by improving the method of cultivation, harvest and storage of raw materials and feeds Benefits of specific foods The use of low protein diets supplemented with synthetic amino acids represents, together with phase-feeding, the most effective technique for reducing nitrogenous emissions from faeces, as amply illustrated by Henry (1996). From a theoretical point of view, phase-feeding improves efficiency of nitrogen retention through adjustment of daily nutrient supply over time to meet the requirement according to production potential by means of prediction modelling. In the case of low-protein diets supplemented with synthetic amino acids, nitrogenous emissions are reduced through dietary changes such as to achieve an ideal protein profile and a correct energy/protein ratio. Generally speaking the application of targeted feed and nutritional strategies can reduce nitrogenous excretion from pigs by 30% or more compared to what may be observed in pigs receiving conventional diets. If correctly applied, the use of low-protein diets supplemented with amino acids neither determine a decline in production nor affect the quality of carcasses and meat of growing-finishing pigs. However, there may be some doubts as far as weaning piglets are concerned; if dietary crude protein is reduced by 4 or more percentage units from 23%, growth may be impaired (Nyachoti et al., 2006) even in the presence of adequate supplementation with synthetic amino acids. In terms of animal welfare, the most immediate effect of low-protein diets supplemented with amino acids is a reduction in the production of ammonia, due both to the decrease in nitrogenous excretions and a reduction in the ph of slurry. It may generally be affirmed that for each 1% unit reduction in dietary protein combined with amino acid supplementation, the estimated ammonia losses are reduced by 10% in pigs and poultry, as recently reported by Le et al. (2005). Among essential amino acids a special role on animal welfare is played by tryptophan. It is the precursor of serotonin, which in turn is involved in a variety of adaptive responses. Piglets have shown to reject diets low in tryptophan (0.11%) and prefer diets containing adequate levels of this amino acid (Ettle and Roth, 2004). As regards behaviour, tryptophan supplementation (via feed or drinking water) has been reported to reduce the duration of fighting among unfamiliar pigs (Li et al., 2006) and increase the time spent lying in pigs submitted to a transport simulation (Peeters et al., 2004). Dietary supplementation with tryptophan induces a reduction in the plasma concentrations of noradrenaline (Koopmans et al., 2005) and there are various possible effects on cortisol production (Meunier-Salaün et al., 1991; Peeters et al., 2004; Koopmans et al., 2005 and 2006). Such inconsistency of findings may depend on the different age of the pigs used in the various trials and on the different doses of tryptophan used. Dietary fibre may be defined as the sum of polysaccharides and lignin that are not digested by the endogenous secretion of the GI (gastrointestinal) tract (Trowell et al., 1976). The digestibility of fibrous feeds varies according to the physicochemical characteristics of the fibre they contain and digestive utilisation of dietary fibre improves with body weight with the highest values obtained in adult sows (Noblet and Le Goff, 2001). Dietary fibre is recognised to exert positive effects on the behaviour of restricted-fed gestating sows (consisting mainly in a reduction of non feeding activities including stereotypies - and increase in lying time). In the short term, the greater volume of feed is responsible for the 35

51 decrease in feeding motivation whilst, in the longer term, both bulk and energy have significant effects (Meunier-Salaün, 2001; Meunier-Salaün et al., 2001). Highly fermentable fibre (i.e. sugarbeet pulp) is capable of maintaining satiety and of stabilising the glucose and insulin blood levels for many hours after feeding (Whittaker et al., 1998; Leeuw et al., 2004). With respect to the effects of dietary fibre on piglet health (incidence and severity of diarrhoea, trophic state of the mucosa), as recently reported by Mosenthin et al. (2001) and Montagne et al. (2003), they vary radically from positive to negative depending on the source used and its physicochemical properties (solubility, fermentation rate). In order to reduce the risk of enteric disorders of weaners special attention should be paid to the NSP (Non-Starch-Polysaccharides) fractions soluble NSP (snsp), leading to an increased digesta viscosity. The use of materials containing soluble NSP should be minimised, whereas moderate levels of insoluble NSP (insp) can be included, especially when the diet contains a high level of crude protein (Wellock et al., 2007, in press).with respect to the effects on the behaviour of growingfinishing pigs induced by the inclusion of fibrous feeds in the diet, the findings are in some cases inconsistent. Schrama et al. (1998) reported a reduction in physical activity (measured with an ultrasonic device) in pigs weighing around 55 kg when increasing percentages of sugar-beet pulp were introduced into the diet, whereas Rijnen et al. (2003) did not observe any differences in behaviour (assessed by scan sampling of video recordings) as regards the time spent in physical activity (standing + sitting) in pigs who received increasing quantities of different fibrous sources (coconut meal and soybean hulls). The discrepancies between these findings may be ascribed to the different types of vegetable sources (and hence dietary fibre sources) used in the various trials. Again with regard to the behaviour of growing pigs, the ability of the fibre to be fermented appears to play a more determinant role than its bulkiness in causing a reduction in physical activity (Schrama and Bakker, 1999). Fibrous sources of good quality (e.g. pressed beet pulp) may contribute significantly to satisfying the maintenance requirements of fattening heavy pigs and be used in dietary formulations as a replacement for significant percentages of cereals without negatively impacting growth and slaughter performances or the characteristics of meat and cured products (Martelli et al., 1999). However, it is worth pointing out that the use of substantial quantities of fibrous feeds may result in an increase in the volume of faeces produced (Meunier-Salaün, 2001; Meunier-Salaün et al., 2001; Scipioni and Martelli, 2001). Some fermentable fibrous sources (e.g. pressed beet pulp, soybean hulls) also represent a further opportunity for reducing the production of ammonia by dietary means. In fact, fermentable carbohydrates in the gastrointestinal tract shift urinary N excretion to faecal N excretion in the form of bacterial protein which is less susceptible to rapid hydroxylation (Morgan and Whittemore, 1988; Canh et al., 1997; Scipioni and Martelli, 2001). The use of several fermentable fibres is moreover associated with an increase in the production of volatile fatty acids (VFA), a reduction in the ph of faeces and consequent reduction in ammonia production (Canh et al., 1998). Finally, a combination of low-protein diets supplemented with amino acids and fermentable fibres may act synergically in reducing the urinary excretion of urea in finishing pigs (Shriver et al., 2003). The recent EC ban on the use of antibiotic feed additives, restrictions on the maximum levels of feed supplementation with several microelements exhibiting an antimicrobial action (Zn and Cu) and the diffusion in some countries of the practice of early weaning have, as of late, stimulated interest in studying the effectiveness of a wide array of alternative additives (i.e. having no pharmacological action) for piglets and nutritional strategies apt to prevent the occurrence of diarrhoea at weaning. Deserving special attention in this context are prebiotics, probiotics, yeasts, organic acids, enzymes, plant extracts, specific clay minerals, appetizing substances, oral-administered antibodies and feeding strategies aimed at increasing the plasma 36

52 levels of antisecretory factors, etc., topics that have been broadly addressed by numerous authors in recent times (Göransson, 2001; Varley, 2004; Dirkzwageret al., 2005; Fairbrother et al., 2005; Roselli et al., 2005). Generally speaking it may be affirmed that the effectiveness of these feeding and nutritional strategies largely depends on the interaction among intrinsic characteristics of the diet (application of suitable technological treatments, digestibility, protein source and level, presence of any antinutritional factors) and farm health and hygiene standards Ability to explore Pigs have a high level of curiosity and have well developed exploratory behaviour (Wood- Gush and Vestergaard, 1991). Much of the general activity of pigs appears to stem from their exploratory behaviour. This behaviour is mainly directed at objects at floor level that are investigated by nosing, nibbling, chewing and rooting (Fraser and Broom, 1990). In a seminatural environment pigs spent the greatest proportion of time active (up to 75%) in exploratory behaviour to examine the environment and collect and manipulate food items (Newberry and Wood-Gush, 1988; Stolba and Wood-Gush, 1989). It is difficult to distinguish exploratory behaviour and foraging behaviour. Exploration may be part of foraging behaviour to search possible locations for food but it is also performed to gather general information on the surroundings (Studnitz et al., 2006). Day et al. (1996) found that growing pigs can gather nutritional information during exploratory chewing. Beattie and O Connell (2002) determined the relationship between rooting and foraging and found that rooting was also performed in the absence of nutritive feedback. This suggests that rooting is performed independently of its appetitive foraging function and is also motivated by curiosity. Environmental enrichment increases the time spent active and the time spent on exploratory behaviour, in comparison with pigs housed in a barren environment (e.g., Beattie et al., 2000a). In addition, it is well known that in the absence of appropriate substrate to explore pigs redirect their exploratory behaviour to pen structures and the bodies of pen mates (e.g., Schouten, 1986; Fraser et al., 1991; Pedersen et al., 1995; Bolhuis et al., 2005; Peeters et al., 2006; Scott et al., 2006a,b; Morrisson et al., 2006). This may lead to behaviour damaging to pen mates like bellynosing, biting and massaging of littermates in weaners and fattening pigs (Schouten, 1986; Beattie et al., 1995, 1996, 2001; De Jong et al., 1998) and an increased incidence of ear- and tail-biting in fattening pigs (Fraser et al., 1991; Beattie et al., 2001; Van de Weerd et al., 2005). These abnormal and damaging behaviours are thus a sign that the needs of the pigs to show certain behaviours are not met. They may lead to pain and injury and thus have negative consequences for pig welfare. It has been suggested that early (pre-weaning) experience with environmental enrichment decreases belly-nosing even when pigs are housed in a barren environment after weaning, whereas rooting pen mates and tail-biting are more affected by the presence of enrichment materials in the actual housing system (Ruiterkamp, 1985 in Schouten, 1986; van de Weerd et al., 2005). In the studies mentioned above either straw, peat or mushroom compost was used as enrichment materials. The ability to explore is not only affected by the presence of enrichment materials per se, but the type of pen enrichment is important for the extent to which exploratory behaviour can be performed. Numerous studies have compared different types of enrichment for pigs. In a systematic approach, Van de Weerd et al. (2003) compared 74 different enrichment objects that were studied during five days in a large number of groups with weaner and grower pigs. From their study it was concluded that enrichment objects that were ingestible, destructible, contained, not particulate and not rootable received sustained attention from the pigs. The characteristics not rootable and not particulate appear to be in contrast to the knowledge that rooting behaviour is important for pigs. This may be explained by the fact that one group of popular objects that 37

53 received sustained interest of the pigs in their study were edible but not rootable. Another group of popular enrichment materials were long straw, lavender straw and compost that all had the characteristics rootable and particulate (Van de Weerd et al., 2003), which is in line with other studies. Expert judgement revealed that sustained animal-material interactions, rootability, manipulability, and chewability were the main material properties for enrichment in pig pens (Bracke, 2006). In a later review Studnitz et al. (2006) concluded that enrichment materials should be complex, changeable and destructible and if the material contains edible parts the foraging behaviour as well as curiosity of the pigs will be stimulated. From a literature review Bracke et al. (2006b) concluded that straw and compound materials were best, metal objects were not suitable enrichment materials for pigs and that rubber, rope, wood, roughage and substrates may be sufficient. In their study welfare indicators such as object-directed behaviour, pen-directed behaviour, tail- and ear-biting, aggression, harmful social behaviour, activity, fear, production and health and hygiene were taken into account (Bracke et al., 2006b). These results were partially confirmed by an expert judgment on enrichment materials which revealed that whole straw with chopped beet roots, maize silage or additional feed, a bale of straw, long straw with fir branches and straw with forest bark and branches were valued highest as enrichment materials for pigs (Bracke et al., 2006a). Studnitz et al. (2006) concluded that peat, mushroom compost, sand, sawdust, wood shavings, branches, beets and silage rank above straw whereas ropes and rags and objects like beams, tyres and chains rank below straw. Indeed, studies comparing either straw or mushroom compost with other enrichment materials like toys concluded that straw or compost were preferred over other enrichment materials (e.g., Pedersen et al., 2005; Van de Weerd et al., 2006; Scott et al., 2006c; Pedersen and Jensen, 2006). In a recent study comparing different rooting materials with straw it was concluded that maize silage with straw, spruce chips and compost were valued higher than chopped straw, but this does not imply that straw is not a good rooting material but that other materials may be better (Jensen and Pedersen, 2006). In a study comparing straw with a hanging toy, pigs spent significantly more time on manipulating the straw, and changing the ratio of pigs to hanging toy did not have an effect on toy manipulation (Scott et al., 2006a). Increasing the quantity of straw provided, from a small quantity to deep straw, reduced the occurrence of potentially damaging behaviours like belly-nosing, ear-chewing and tail-biting (Day et al., 2002). This was confirmed by Van de Weerd et al. (2006) who found that a full bed of straw was most successful in occupying the pigs and preventing tail-biting as compared with a straw dispenser. For proper exploratory behaviour, pigs not only require environmental enrichment but also space. However, proper enrichment material seems to be more relevant (Beattie et al., 1996). In many studies space allowance and environmental enrichment are confounded (e.g., Beattie et al., 2000a,b; De Jong et al., 1998; Morrisson et al., 2006; Scott et al., 2006b). It has been shown that crowding in a barren environment reduced the time spent on exploratory behaviour, but that the time spent on exploration increased even in a crowded environment when it was enriched with toys (Pearce and Paterson, 1993). Beattie et al. (1996) showed that a space allowance of 0.5 m 2 per pig reduced exploratory activity as compared with 1.1 m 2 per pig or more (all pens enriched with peat and straw), but that increasing space allowance above 1.1 m 2 per pig did not have a positive effect on exploratory behaviour (Beattie et al., 1996). Space allowance needed for different activities is discussed more in detail in a previous report (EFSA, 2005). Outdoor rearing not only offers a more complex environment as compared with indoor rearing but also more available space per pig. It has been shown that pigs reared in outdoor systems show more exploratory behaviour and less manipulating of pen mates as compared with pigs reared in indoor systems without enrichment materials (e.g. Cox and Cooper, 2001; Hötzel et al., 2004). The same positive effects on pig behaviour have been described for deep litter group housing including a higher space allowance as compared to standard barren housing conditions 38

54 (Morrisson et al., 2003, 2006). In fully slatted systems it is only possible to provide appropriate enrichment materials like straw or compost in large amounts (straw and compost racks have been used) if solids can be removed from under slats (e.g. by a waste disposal chopping system). As a consequence, only lower quality enrichment materials are provided like hanging toys, indicating a risk for pig welfare as the need for exploration will not be met in these systems. Solid floors facilitate provision of adequate enrichment materials Ability to have proper social interaction Lack of maternal contact See section on Poor Maternal Behaviour in the Sows and Boars Report (EFSA 2007, under adoption procedure) Contact with other pigs Three aspects should be considered here: 1. Group size 2. Mixing of unacquainted pigs 3. Space allowance and access to resources Mixing of unacquainted pigs The mixing of unacquainted pigs has adverse effects on welfare and these have been reviewed in the report of the Scientific Veterinary Committee The Welfare of Intensively Kept Pigs (adopted 30 September 1997) and in the report of EFSA The Welfare of Weaners and Rearing Pigs: Effects of Different Space Allowances and Floor Types (2005). Adverse effects on welfare include physiological consequences as aggressive interactions may increase the release of corticosteroids and adrenocorticotrophic hormone, a reduction in growth rate and an increase in the number and severity of skin lesions. Most aggressive interactions are typically shown during the first few hours after grouping. Work published after the above mentioned reports has shown that number and location of skin lesions provide a means of estimating aggressive behaviour caused by mixing (Turner et al., 2006). The frequency, duration and intensity of aggression interactions after mixing varies depending on several variables, such as enrichment of the environment, whether food is provided as ad libitum or restricted and time of day when pigs are mixed. In order to reduce the amount of aggression at mixing the use of tranquillising drugs has been widely advocated for many years. Although they effectively reduce aggression among grouped pigs, their effect is limited over time and they cannot avoid the rise in the frequency of agonistic interactions that is associated with establishment of the social hierarchy at the end of the drug effect. Work published after the above mentioned reports has shown that socialised piglets, piglets that have been mixed with piglets from another litter before weaning, learn social skills that allow them to more rapidly form stable hierarchies when regrouped after weaning (D Eath, 2005). As mentioned in the previous section, group size may have an effect on how pigs react to being mixed with unacquainted individuals. There may be increased risk of diseases, such as PMWS, when larger groups of pigs are mixed than when smaller groups of pigs are mixed. The available evidence suggests that mixing unacquainted pigs is a hazard and that pigs are likely to be exposed to it once or several times during their lifetime Group size The commonest group size in fattening pigs is animals, but large groups are increasingly common due to their economic advantages (Turner and Edwards, 2004). The effects of large 39

55 group sizes on welfare have been addressed in several papers, although the results are somewhat contradictory. Some studies have found a negative effect of large groups on several variables that are relevant to welfare, including production and health traits. Turner et al. (2003) used regression analyses of data from 20 earlier studies and almost 22,000 animals to study the implications of group size for growth performance. A significant, negative, approximately linear relationship in average daily gain with increases in group size was recorded during the weaner (weaning to 30 Kg.) and grower (31-68 Kg.) stages. Weaners, but not growers, showed a reduction in food intake with increasing group size; consequently the efficiency of growth was compromised during the grower stage. No influence of group size on performance was found during the finisher stage (>68 Kg). None of the other traits measured were consistently affected by changes in group size. The authors concluded that a large group size may compromise the growth performance of young pigs, although the long-term consequences for other traits are likely to be slight. Wolter et al. (2000) used a 2 x 2 factorial arrangement of treatments to determine the effects of group size (20 or 100 pigs per group) and floor-space allowance in weanling piglets. Piglets in large groups were lighter at the end of weeks 1, 4 and 9 of treatment and had lower feed intake from week 1 to 4 than piglets in small groups. Also, pigs in large groups had a greater withinpen coefficient of variation in body weight at the end of the week 9 than pigs in small groups. Finally, McGlone and Newby (1994) found that injury and morbidity rates were greater for pigs held in groups of 40 animals than for pigs kept in groups of 10 or 20. Other studies, however, have failed to find any significant effect of large groups. O Connell et al. (2004) compared groups of 10, 20, 30, 40 and 60 pigs from weaning at 4 weeks of age until 10 weeks of age. Group size did not affect overall levels of aggressive behaviour, growth rate or feed intake. The authors did find that food conversion tended to be poorer in groups of 40 and 60 pigs than in smaller group sizes, although the effect did not reach statistical significance. The only significant adverse effect of large groups were found when groups of 40 and 60 animals were split into groups of 20, as food conversion ratio was poorer in groups split from groups of 60 pigs than in groups split from groups of 40 pigs, or in groups that were kept in a group of 20 pigs throughout the growing and finishing periods. The authors concluded that large groups of up to 60 pigs do not have any adverse effect on welfare when compared with smaller groups, although if pigs are to be housed in groups of 20 during the finishing period, it may be better to house pigs in groups of 40 rather than in groups of 60 during the post-weaning period. Schmolke and Gonyou (2003) compared group sizes of 10, 20, 40 and 80 pigs from 23.2 Kg BW to 95.5 Kg BW and did not find any consistent effect of group size on daily gain, feed intake, feed efficiency or variability in final BW. Similar proportions of pigs were removed from the trial for health reasons in all treatments. Turner et al. (2000) studied the effect of group size (20 vs. 60) and drinker: pig ratios (1:10 vs. 1:20) on skin lesions and found that the number of lesions was not affected by the four treatment combinations. The treatments did not affect performance. In another study, Turner et al. (2001) compared groups of 20 and 80 pigs and found that aggression between pen mates was unaffected by group size Finally, some studies have found positive effects of large group sizes. In the study cited above, O Connell et al. (2004) found that the coefficient of variation for growth was greater in groups of 10 than in groups of 20, 40 or 60 pigs. Wolter et al. (2001) compared groups of 25, 50 and 100 pigs. The effect of group size on production parameters was not consistent, but the proportion of pigs removed due to poor health or injury was higher in groups of 25 pigs compared to the other group sizes. It may be more difficult for stock-people to monitor the health of pigs in the larger groups. Because of the significant risk of diseases such as PMWS or 40

56 post-weaning diarrhoea, large groups have the disadvantage that, as result of mixing during their formation, the probability of appearance of such diseases is increased (Rose et al., 2003; Madec et al., 1998). However, the health status of a group of pigs is generally more likely to be dependent on the origin of the animals than on the group size. More health problems are thus known to occur when animals from different herds are mixed compared with, for example, a group where all animals come from the same farrowing unit with group housed sows (Holmgren and Lundeheim, 1994; Wierup 2001). Group size may have an effect on how pigs react to being mixed with unacquainted individuals. Turner et al. (2001) found that pigs from large groups (80 pigs per group) displayed a marked reduction in aggression towards pigs from other groups compared with pigs from small groups (20 pigs per group). Turner and Edwards (2004) suggest that in large groups less reliance is placed on aggression during the immediate post-mixing phase than in small groups. Data on the effects of group-size at mixing on disease are presented below Space allowance and access to resources The effect of space allowance on social behaviour, particularly aggression, was covered in the report of EFSA The Welfare of Weaners and Rearing Pigs: Effects of Different Space Allowances and Floor Types. Space allowance has an important effect on aggression and, in general, insufficient space allowance results in an increased aggression level. However, as a certain amount of space is needed to perform a threat and an attack, aggression may decrease when space allowance is very low, so that a curvilinear relationship between housing density and aggression has been observed. However the lower space is accompanied by increased adrenal response, suggesting stress in the absence of overt aggression (Barnett et al., 1992). The development of aggressive behaviour is influenced by the space allowance at young ages. When pigs were reared during their first weeks of age with low space allowance, they were more likely to perform abnormal agonistic behaviour later on in life than pigs reared with higher space allowance and this resulted in encounters with unknown individuals being more stressful than expected (Schouten, 1986). Access to some other key resources is discussed elsewhere in this report, such as food and water, but all of the needs of pigs require consideration by pig producers and several other issues are also raised, for example materials to root in and manipulate, that have implications for the provision of space. The available evidence suggests that low space allowances during the fattening periods and before is a hazard as pigs will show more aggressive behaviour, abnormal behaviour or adrenal responses. Although very low space allowances may inhibit aggression due simply to lack of space to perform a threat or an attack, this will result in other welfare problems Ability to avoid fear Fear is an aversive emotional state and has therefore a negative effect on welfare. Fear in fattening pigs can result from other pigs, humans and novel objects or environments. Fear of other pigs may occur when pigs fight or are exposed to unknown individuals; this has been dealt with in a previous section. Fear of humans is related to stockmanship. The effect of stockmanship on welfare was covered in the report of the Scientific Veterinary Committee The Welfare of Intensively Kept Pigs (adopted 30 September 1997). Papers published since then have confirmed what was concluded in the report. In general, research over the last decade has shown a strong variability between farms in animals fear of humans. In addition, high fear levels limit welfare. Poor handling of animals can result in their becoming highly fearful of humans. Day et al. (2002) found that 41

57 pleasant handling makes pigs more difficult to move, probably due to their reduced fear of humans. In the same study there were some indications that pleasant handling appears to improve food intake in the growing period. An important antecedent of stockperson behaviour is his or her attitude towards interacting with animals. Intervention studies have shown the potential of intervention techniques to target those attitudes and behaviours of stockpeople that have a direct effect on animal welfare (Hemsworth and Coleman, 1998; Rushen et al., 1999; Hemsworth, 2003). Enriching the pigs rearing environment with toys has been found to significantly increase the amount of exploratory behaviour as well as reducing the animals responsiveness to novel objects and humans at the end of the rearing period (Pearce and Paterson, 1993). This effect of the quality of the environment on fear in pigs is important because fear has a substantial effect on the welfare of many pigs and on the ease of handling of the animals. Those pigs that are afraid of humans are more likely to be subject to painful and stressful treatment when handled prior to slaughter. This, in turn has consequences for meat quality. There is conclusive evidence that poor stockmanship leads to pigs being fearful of humans and that this results in poor welfare. Therefore, poor stockmanship is a hazard but exposure will vary among farms Ability to groom Grooming is part of body care behaviour. Body care behaviour has a high ranking under maintenance behaviours and in general it can be stated that the provision of appropriate environmental conditions so that animals can maintain themselves is important for good welfare (Fraser and Broom, 1990). In pigs, grooming behaviour consists of wallowing, rubbing and scratching. Although the main function of wallowing behaviour appears to be cooling it has been suggested that wallowing also plays a role in skin and hair care, as wallowing behaviour is not only observed at high environmental temperatures but also lower ambient temperatures (van Putten, 1978 in Olsen et al., 2001; Sambraus, 1981). After wallowing pigs shake themselves and rub their sides and back, they also rub their hindquarters by sitting down and moving forwards and backwards (Sambraus, 1981). In a study of pigs in an outdoor system the pigs used the wallow during the whole temperature range (-4C to 24C) but the duration of the use of the wallow and the bout length of wallowing increased from 14C onwards, indicating that the behaviour changed to temperature regulating behaviour above 14C and that below 14C wallowing is used for skin and hair care (Olsen et al., 2001). Others found an increased use of the wallow from 18-19C onwards (Sambraus, 1981; Stolba and Wood-Gush, 1989). Indoor housing systems lack opportunities to perform wallowing and at high temperatures pigs try to regulate their body temperature by lying in the dunging area (e.g., Hyunh et al., 2005). It is not known if pigs are able to care for their skin and hair sufficiently in the absence of a wallowing opportunity. Rubbing and scratching against scratch posts like trees or the walls of a pen is used for skin care because pigs cannot reach large parts of their body surface themselves (Anonymous, 2001). A high frequency of scratching and rubbing behaviour can be observed in pigs with skin infections like sarcoptic mange (e.g., Loewenstein et al., 2006). There is no literature available about the effect of housing conditions on these behaviours. In general it can be expected that pigs have sufficient opportunities for rubbing and scratching under all housing conditions Thermal inadequacy Temperature is the most important physical environmental variable that can affect the welfare of pigs. The domestic pig only has very sparse thermal protection offered by hair (Craig, 1981). 42

58 Most of its insulation is given by the thick layer of subcutaneous fat. The sparse hair cover allows evaporation from the skin, but as pigs do not sweat when they are exposed to heat, body cooling is based on wallowing or skin wetting. Both young and adult pigs can easily learn to press a button with their snout to obtain heat from an infrared source (Baldwin and Ingram, 1967, 1968; Baldwin and Lipton, 1973; Baldwin, 1974; Heath, 1980). The frequency of this operant response increases as the air temperature decreases (Swiergiel and Ingram, 1986). Similarly, pigs can learn to operate another switch that turns off a draught-creating fan or one that activates a sprinkling device when the temperature increases too much (Bray and Singletary 1948). Baldwin and Ingram (1966, 1967) showed how the hypothalamus, and especially the preoptic area, is responsible for the increase of the heat switch pressing activity when it is cooled. Conversely, when the preoptic area is warmed, there is less tendency to seek heat, even though the air temperature falls near 0C. Similar results are achieved with localised warming of the scrotum skin up to 42C when pigs are exposed to cold air temperature of 15C. Warming up other parts of the skin on the trunk does not cause the same effects (Swiergiel and Ingram, 1987). Pigs are well equipped with behaviour responses to cold temperature. It also seems that pigs do not suffer greatly from being exposed to rain or sunshine. But they often get their skin burned when kept outdoors for a long time in summer. Then they need a shelter. In contrast, pigs greatly dislike to remain exposed to wind. Consequently they look for a convenient shelter and, if in a group, huddle to conserve warmth. A very few minutes after birth pigs already show the tendency to huddle (Mount, 1960). Fattening pigs even prefer to huddle during the night rather than to operate an infrared lamp to obtain warmth (Baldwin 1974). In contrast, the resting group will spread out at high temperature. Mount (1968) defined thermoneutrality as that limited range of ambient temperature over which physiological functions are maintained with the minimum metabolic rate, and therefore with the minimum energy utilisation. This concept is not restricted to the domestic pig but it is typical for all endothermic vertebrate species (Willson, 1984; Pough et al., 1996). In pig production the lower threshold, i.e. the lower critical temperature, is of interest because pigs kept at ambient temperature below thermal neutrality will have lower food conversion efficiency. As the pig increases in size, its critical temperature decreases. Although it is difficult to generalise the thermoneutral temperature for each stage of production, it is likely to be around 34C for newborns (which have little subcutaneous fat), 25-30C for 4-6 kg piglets, 25C for piglets aged 8 to 14 weeks, and 20C for growers (Mount 1960, 1968; Baldwin and Lipton 1973; Baldwin 1979; Morrison et al., 1987). Bockisch, et al. (1999) recommend the following air temperatures (if two values are mentioned, the lower one refers to pens providing the pigs with litter): More than 30C for piglets up to 10 days, 16C (20C) for piglets up to 10 kg, 14C (18C) from kg, 12C (16C) above 20 kg, 17C for non-pregnant sows kept single, 15C for pregnant sows kept in groups and 12C (16C) for fattening pigs. Mayer and Hauser (1999) examined the lying behaviour and the vocalisation of fattening pigs of more than 70 kg. They could establish their lower and upper temperature limit in littered housing systems at 9C and 23C. Investigating the lying behaviour and the adrenocortical response (by taking saliva samples for the analysis of cortisol concentration), the results of Hillmann, et al. (2004) indicate temperature ranges within the thermal tolerance of pigs to be 19-21C for pigs weighing kg, 10-17C for pigs between 50 and 70 kg and 5-17C for pigs of more than 85 kg (all kept in pens with partially slatted floor). Seng (1975) stated that an average air temperature of 20C should be provided in fattening units with fully slatted floor in order to achieve good weight gain and keep loss of animals low. The results of this study also allow the conclusion that by raising temperatures (to about 23C) it is possible to reduce the high numbers of deaths after confinement in pens. 43

59 Bruce and Clark (1979) developed a deterministic model to calculate the lower critical temperature. It shows that for groups of 15 growing pigs with air velocity of 0.15 m/s, this temperature decreases progressively with a concave curve from about 15C for 20 kg pigs kept on concrete floor to 9C for 60 kg pigs and then increases with a convex curve to 13C for 100 kg pigs. In animals housed on straw bedding the above values decreased by 6C at all live weights. Pigs perceive their level of thermoneutrality since, if kept in cool environment, they operate the infrared heat reward at a rate which allows them to maintain the minimal metabolic level (Baldwin and Ingram, 1967). Body condition is important to determine the behavioural response to the thermal environment; cold-reared pigs have a greater thermal demand as they suffer from lesser tissue insulation than warm-reared pigs (Heath, 1980). Young pigs with good nutrition operated infrared heaters less often than others maintained at the same air temperature but with lower nutrition level (Baldwin and Ingram 1968, Swiergiel and Ingram 1986). Nevertheless, the model developed by Bruce and Clark (1979) exhibits no effect of feed level on heat production below the critical temperature. However, the value for the lower critical temperature is very sensitive to feed level. Maintaining pigs at low temperature has both health- and behaviour-related adverse effects. The frequency of coughing, diarrhoea and tail-biting increases with temperature reduction (Sällvik and Walberg, 1984; Geers et al., 1989). Besides, it seems that even sensitive periods exist within the growth period, particularly at the onset of the fattening period, i.e kg, and pigs of that size need special care. Stolpe and Bresk (1979) examined the influence of changing temperatures on fattening pigs. They kept two groups of pigs at daily and, over one fattening period rhythmically, changing temperatures of 5-20C. Additionally, for one group of single-kept pigs they simulated changes in temperature between day and night as they occur in unheated buildings in wintertime, and two groups of single- or group-housed pigs were kept at the optimum environmental temperature of 20C. The results indicate that weight gain and feed consumption do not depend on the single temperature values, but on the average temperature over the whole fattening period, as long as the maximum variation around the average value is +7.0 K and the temperature does not fall below 5C minimum. Diurnal temperature fluctuation may be more critical in weaners, where there is evidence that greater variation can reduce growth and increase risk of disease (Le Dividich, 1981). As each lying individual animal transfers heat to the substratum, the assessment of heat loss to floors is very important. It has been shown that such heat loss affects the metabolic rate and, in turn, the feed conversion rate and growth (Kelly et al., 1964; Stephens and Start, 1970; Stephens, 1971; Versteger and van der Hel, 1974). Straw supplied on the pen floor helps to maintain body temperature close to the thermoneutral zone. The preference of pigs to rest on straw and its beneficial effect on newborn piglets for conservation of body heat is well known (Mount, 1967). Such preference has a strong adaptive value even in older pigs; they prefer to lie down for resting on a straw-bedded floor at 18-21C, while at 25-27C, i.e. above the thermoneutral zone, they select a bare concrete floor (Steiger et al., 1979; Fraser, 1985). This preference gives the pigs that are below the thermoneutral zone the opportunity to move into or closer to thermoneutrality. Unless there is a good supply of straw or other insulating material on the floor, whenever the air temperature falls below the thermal neutrality value, pigs will be less able to adapt to the cold. Air temperatures above thermoneutrality induce an increase of energy utilisation to dissipate the excess heat. As the upper critical temperature is reached, the body is unable to dissipate heat fast enough to prevent the body temperature from increasing. The behavioural response to this situation is to reduce activity, to modify lying behaviour and to seek to reduce body temperature by wallowing. As a result, the lying area within the pens is made much dirtier, 44

60 especially on a solid concrete floor (McKinnon et al., 1989). Moreover, pigs maintained at a high temperature have a decreased feed consumption and delayed return to oestrus (Britt et al., 1985; Biensen et al., 1996). Phillips and co-workers (1992) studied the effect, potentially very important from the welfare point of view, of ground temperature on leg abrasion in piglets. During suckling, piglets often develop lesions on their forelegs from repeated rubbing against the floor. Phillips and coworkers (1992) developed an apparatus to rub stillborn piglet leg specimens against several floor types, i.e. concrete, rubber, metal. They recorded greater damage to leg tissues on warmed floors (34C) than on cool ones (21C), suggesting that the frictional heat build-up combines with the floor abrasiveness. Thus, the common practice to warm piglets pen floors should be considered carefully because it may increase the severity of leg lesions Humidity The pig is more adapted to live in humid conditions than in a dry atmosphere. A dry environment can even be a cause of irritability (Smith and Penny, 1981), and humid or frequently wet skin is essential for thermoregulation. When the relative humidity is very high, the pigs become more dependent on water loss from their skin, even though the respiration rate increases. Therefore it is necessary for them to wallow or lie on a wetted floor (Close, 1981). If no adequate possibility to wet the skin is offered, as temperature rises there is an increasing rate of dirty pigs as they wallow in their own excrement in order to cool down. Massabie and Granier (1996) housed fattening pigs at different levels of air relative humidity, maintaining the temperature at 24C. They found the growth rate significantly reduced by a hygrometry reading of 90% as a consequence of a reduction in spontaneous food consumption. Still the metabolism of the pigs was unaffected since food conversion remained constant whatever hygrometric level. There are no studies indicating the optimal range of relative humidity for pigs kept indoors, Bogner (1982) suggested air humidity to be kept between 50% and 80%, but did not support these values with experimental data. Nevertheless, a moderately high level of humidity is necessary for keeping the respiratory system in good condition. In fact, the incidence of respiratory diseases is greatly reduced by keeping pigs in a very humid environment (Gordon 1963 a, b). A dry atmosphere increases skin evaporation and the consequent lowering of skin temperature. This is harmful for pigs because it removes them from their thermoneutral zone. Bockisch et al. (1999) recommend a relative humidity of 60% to 80% for sows, 50% to 70% for sows with piglets, 50% to 80% for piglet rearing and 50% to 70% for fattening pigs and mention that immoderate dry air leads to coughing. On the other hand, high air humidity values at low temperatures lead to wet skin, loss of body temperature and increasing discomfort. Beskow et al., (1998) mention that outdoor temperature is positively correlated with the indoor temperature, but negatively correlated with the relative humidity. They stated the necessity of a balanced, well functioning heating and ventilation system in order to avoid increased relative humidity at low outdoor temperatures Respiratory disorders This topic has been already discussed in the 2005 Report of floor and space allowance (EFSA, 2005). 45

61 Air quality It is evident from regular inspections of animal carcasses after slaughtering that often between 30 % and 50 % of slaughtered pigs show severe changes in their respiratory tracts, indicating acute or long-term pneumonia, bronchitis or similar diseases (Elbers, 1991). Such problems result from the presence of specific pathogens in the air often in combination with poor air quality. The inspection of a total of 66,033 carcases of slaughter pigs revealed that about 43.7% of the pigs exhibited different degrees of pneumonia. 22.7% showed chronic pleuritis and 6.8% chronic pericarditis (Köfer et al., 2001). It is assumed that air pollutants which are present in the air of piggeries play a major role in the development of these respiratory disorders. This supposition is supported by the fact that usually pigs kept in outdoor units develop distinctly less respiratory disorders (Lebret et al., 2004). However, in experimental set-ups exposing pigs to defined concentrations of dust and ammonia these results are not always conclusive (Done et al., 2005) when compared to field trials which show better performance and lower morbidity and mortality of pig reared outdoor compared to pigs kept in confined houses (Lahrmann et al., 2004). There is a wide range of pollutants such as gases, viable particles, on which there may be microorganisms that usually have an animal source, and non-viable particulate matter (dust) and toxins are present in the airspace of animal houses. Gases include ammonia, carbon dioxide, carbon monoxide, hydrogen sulphide and more than 100 trace gases of different chemical nature. Particulate matter includes undigested and digested nutrients, skin dander, dried dung and urine. A range of microorganisms (bacteria, fungi) and virus is present. Other chemicals include bacterial and fungal toxins and volatile fatty acids. The main source of airborne pollution is the pigs and their excretions. The effects of these pollutants on pig health and production will vary depending on the mixture and concentrations of the pollutants present. The key effects include a range of clinical signs and inflammatory and immune responses. Clinical signs include coughing, sneezing, salivation, loss of appetite and excessive lachrymal secretions, as well as depression of growth rate, which is not limited to pigs with respiratory disease. The inflammatory response is both local and general and involves activation of the immune system. Local inflammatory changes include loss of cilia, thickened epithelia and decreased numbers of goblet cells in the trachea and turbinates, along with activation of epithelial cells, alveolar macrophages, and polymorphonuclear cells releasing of a variety of inflammatory mediators. Non-specific activation of the immune system involves the production of cytokines and is thought to divert nutrients away from growth and accretion of skeletal muscle to support the inflammatory and immune responses. The major detrimental gas found in the airspace of pig sheds is ammonia. The effect on the health of pigs varies depending on the concentration. Concentrations between 5 and 40 ppm are common in pig fattening units. As ammonia gas is lighter than air, it tends to rise towards the ceiling. Hence levels will tend to be highest at slat level, reducing as the gas is dispersed into the airspace. The main sources of ammonia are dung and urine. A number of factors influence the amount of ammonia evaporation from the wastes. Raising the ph of slurry from 7.0 to 7.3 and 7.3 to 7.6 increases ammonia evaporation by approximately 20% and 100%, respectively (Pedersen, 1993). Temperature and wind velocity also have a similar but less dramatic effect on evaporation. The depth of the pit and the distance between the surface of the slurry and the slats both affect air movement over the surface, as well as the temperature of the slurry and evaporation of ammonia. Because buildings are ventilated for temperature control, the concentration of ammonia tends to peak in the early morning, prior to opening sheds (Gerber et al., 1991). As concentrations are highest at slat level, animals in sheds with totally slatted floors are exposed to maximum 46

62 concentrations whenever they are recumbent (Drummond et al., 1978). By comparison, with partially slatted floors, animals lying on a clean solid floor receive minimum exposure. However, if floors are dirty and covered with dung, exposure levels may be higher. Concentrations of ammonia vary in deep litter systems, and are highest when animals or humans disturb the litter. Pigs exposed for short periods to concentrations of ammonia above 35 ppm show inflammatory changes in the wall of the respiratory tract, as well as reduced bacterial clearance from lungs were noted (Johannsen et al., 1987). Pigs exposed to ammonia also harboured more bacteria (non-pathogenic Escherischia coli) in their lungs than pigs in an ammonia-free atmosphere, and the response appeared to be dose-dependent. Interestingly, the clearance of inhaled bacteria was also inhibited when pigs were subjected to low temperatures of 6C with younger pigs harbouring more viable bacteria in their lungs than older pigs (Johannsen et al., 1987). Humans experience respiratory symptoms when ammonia concentrations are around 7 ppm, especially in dusty conditions and suffer severe eye and nose irritation at levels above 35 ppm. The clinical signs attributed to ammonia exposure include coughing, sneezing, salivation, loss of appetite and excessive lachrymal secretions. Ammonia may also interact with other biological agents, such as respirable dust and endotoxins, resulting in further inflammatory change. For example, although nebulisation with endotoxin alone had no direct effect on the nasal mucosa of healthy pigs, animals nebulized with endotoxin after exposure to ammonia (50 ppm) had increased neutrophil counts and elevated albumin concentrations in nasal lavage (ΝΑL). Carbon dioxide gas is heavier than air and therefore tends to accumulate at pig level. Ambient air contains ppm of carbon dioxide gas and carbon dioxide concentration is a good measure of the ventilation rate. It can also be used as an indicator of the general level of ventilation inside livestock buildings. Recommended levels vary between 1500 and 3000 ppm being the maximum (DIN , 2004). Carbon dioxide is produced mainly by the animals. A smaller amount of about 5 % comes from the manure. The indoor concentrations depend especially on stocking density and ventilation rates, as well as pig activity. Carbon dioxide can cause tiredness, lethargy and also death in pigs and humans. However, such levels are rarely found in piggery buildings. Reduced growth rate and increased prevalence of respiratory disease in pigs have been associated with levels of carbon dioxide above 1500 ppm. Hydrogen sulphide is a highly hazardous, colourless, flammable gas with an offensive odour resembling that of rotten eggs. Hydrogen sulphide is usually not present in great quantities in pig sheds, however when slurry is stirred up after longer storage periods dangerous concentrations ( ppm) can be released within seconds and has been responsible for several human deaths in North America and Europe, as well as mortalities in pigs. Recommended levels in pig sheds are less than these concentrations. Pigs continually exposed to hydrogen sulphide concentrations of 20 ppm had reduced feed intake, increased stress and a fear of light (Robertson and Galbraith 1971). Levels of 200 ppm caused pulmonary oedema, breathing problems and death. In humans, hydrogen sulphide levels between 10 and 20 ppm may cause eye and upper respiratory tract irritation while levels between 50 and 100 ppm can cause vomiting, nausea and diarrhoea. Levels greater than 100 ppm cause unconsciousness and death. Carbon monoxide is highly poisonous colourless and odourless gas, with no inherent warning properties. It is only problem where combustible fuel is used for heating. Carbon monoxide concentrations of 150 ppm can induce porcine abortion, increase the incidence of stillborn pigs, and reduce growth rate among young pigs. 47

63 Airborne dust is measured in mg/m3 of air and is classified in several ways, according to particle size. Total dust refers to particles up to a maximum size of 20 μm. The larger particles are trapped in the nasal cavity with only those less than 10 microns proceeding into the trachea. Inhalable dust is similar to total dust. Inspirable dust refers to all particles inhaled into the airways, or more specifically, to particles between 5 and 10 μm, which are deposited in the trachea and large bronchi. Respirable dust refers to all particles less than 5 microns and can be deposited as deep as the alveoli and air sacs of the lungs. The major sources of dust are feed, litter and the animals themselves. The effects of dust are difficult to quantify because of the nature and source of the dust. In most cases the dust will contain other bioaerosols, such as bacteria and endotoxins, as well as volatile fatty acids and gases such as ammonia. Reduced performance has been demonstrated in pigs exposed to an artificial dust, which was manufactured from feed, barley straw and faeces, mixed by weight in the proportions 0.5:0.1:0.4. Pigs exposed to 5.1 or 9.9 mg dust/m3 had depressed growth rates compared to pigs exposed to lower concentrations. The study also demonstrated that the pigs' response was not dependent upon ammonia concentration and, in general, there was no interaction between ammonia and dust exposure (Wathes et al., 2002). The airborne bacteria in a pig shed are mostly Gram-positive organisms with the majority being non-pathogenic. Possibly less than 10% of the organisms present are viable. The rest are dead or decaying. However, the cell wall components of dead (or non-viable) bacteria are just as capable of engaging the immune system of pigs and humans as viable bacteria. Bacterial lipopolysaccharide (LPS) or endotoxins are released in high concentrations in the lungs upon infection with Gram-negative bacteria (Lamp et al., 1996; Kadurugamuwa and Beveridge, 1997) and these endotoxins are present in varying concentrations in dust in swine buildings (Zejda et al., 1994). The release of LPS by Gram-negative bacteria, such as H. parasuis, P. multocida, B. bronchiseptica may explain the more severe disease in the experimental dual infections with PRRS and these bacteria (Brockmeier et al., 2000). Van Reeth et al. (2000) demonstrated that dual inoculations with PRCV followed by bacterial LPS seriously aggravate respiratory signs in gnotobiotic pigs, while the respective single inoculations were subclinical. Same observations have been performed by Labarque et al. (2003) with PRRSv and LPS and more recently with PCV2 (Chang et al., 2006). Endotoxins, 1,3 beta-glucan and peptidoglycan are cell wall components of Gram-negative bacteria, Gram-positive bacteria and fungi, and all bacteria, respectively. Studies in pig sheds have focused on endotoxins and levels from 10 to 60 times greater than the maximum recommended levels for occupational health and safety standards have been recorded. Endotoxin levels were up to 2 times higher in fattening units than in sow units. Straw based systems showed on average higher concentrations of endotoxins than slatted floor systems (Seedorf et al., 1998). The effect of airborne non-pathogenic bacteria on the health of animals and humans is unclear. The percentage of organisms that is inhaled into the lungs will vary from shed to shed and will depend on the percentage of the particles containing microorganisms that are respirable. It is hypothesised that the organisms themselves, and their products and components, are capable of triggering immune responses and physiological changes in animals. In the case of birds, this may be a reduction in feed intake, as well as a diversion of protein and energy away from the development of muscle to the immune system. Several in vivo studies have demonstrated that endotoxins, moulds, and organic dust activate the epithelial cells and alveolar macrophages in humans (Müller-Suur 1997 and 2000). Aerosol exposure to endotoxins and 1,3 beta-glucan also modifies the cell population present in the respiratory tract. In humans, exposure to bioaerosols has also been shown to cause broncho-constriction, hyper-responsiveness and increased inflammatory cells in bronchial alveolar lavage fluids. Experiments using nasal lavage show that pig house dust containing different concentrations of endotoxins increases the 48

64 inflammatory reaction of the nasal mucous membranes in humans significantly. Endotoxins provoked prominent reactions associated with an inflammatory response in humans, whereas dust, which was free of endotoxins, did not (Nowak et al., 1994). The broncho-constrictive effects of bioaerosols have also been demonstrated in guinea pigs as well as stockpersons in Sweden and North America. Management has a significant effect on respiratory health of pigs. In a study by Crowe et al. (1994), it was found that pigs reared in isolated all-in/all-out nurseries were heavier at the end of the trial than littermates weaned in conventional farm nurseries. The isolated environments also had less dust and endotoxin levels than the conventional environments (Carpenter et al., 1986). It was suggested that these low levels of pollutants were achieved by rigorous cleaning and disinfecting of the facilities between batches and that a possible explanation for the improvement in growth involved decreased stimulation of the immune system. The importance of cleaning has also been demonstrated in other studies where pigs reared in cleaned rooms grew from 8 to 10% faster than pigs reared in uncleaned or dirty rooms. Other studies also demonstrated that maintaining a high standard of hygiene resulted in increased growth rates. As expected, when pigs were housed in a clean environment where all air quality parameters were at least 10% below target maximum levels, pigs housed in single pens grew 38 g/day faster than group-penned pigs (10/pen). However, in the dirty environment where concentrations of dust, bacteria and ammonia were 50 to 100% above target levels, there was no difference in growth rate between single-penned and group-penned pigs (Murphy and Cargill, 2004). Single-penned pigs in the clean environment grew significantly faster (77 g/day) than the pigs in the dirty environment, as did group penned pigs in the clean environment. Hence, a dirty environment not only reduced growth rates, but also eliminated the positive effect of housing pigs in single pens. Significant differences were also recorded in ammonia, dust and carbon dioxide between the sections and neutrophil function, lymphocyte proliferation and plasma concentrations of acute phase proteins were significantly higher in pigs reared in the dirty environment. Managing air quality and shed hygiene in existing sheds can be a real challenge. Adopting more innovative management systems is essential for improving air and surface hygiene in both new and existing sheds. Systems that incorporate all-in/all-out (ΑΙΑΟ) management, and cleaning facilities between batches, must be regarded as "best practice" in terms of maximising hygiene and air quality (Murphy and Cargill, 2004). Stocking density has a major influence on air quality and pen hygiene and both have been identified as risk factors for enteric disease and respiratory disease. Overcrowding is also associated with poor dunging patterns, which in turn reduce hygiene and air quality standards. Reducing stocking density (kg pig/m3 of airspace) will improve air quality by reducing dust levels and bacterial load within sheds. The finding that stocking density may reduce air quality in terms of increased bacterial load, and hence reduce growth rate in the absence of respiratory disease, is significant and emphasises the importance of providing adequate airspace for animals. Reducing ventilation to maintain an optimal thermal environment may also increase concentrations of pollutants and reduce air quality. Purging or flushing the airspace, by increasing ventilation rates or opening shutters for short periods will clear both carbon dioxide and ammonia, without a long-term drop in temperature. Robertson et al. (1990) flushed sheds for periods of up to five minutes at regular intervals with fresh air to reduce concentrations of ammonia and bacteria. However, the time and frequency of flushing would need to be validated under different external environments. Modifying ventilation systems, so that air inlets are at human head height and outlets are below the slats has successfully reduced the exposure level of humans to both respirable and total dust. Air filtration systems have been used, but these are difficult to assemble and operate in 49

65 naturally ventilated sheds. Ionisation of the airspace has been found to increase the rate of dust deposition in sheds, but the method has not been widely examined under commercial production conditions. Because effluent is a major source of key airborne pollutants, factors such as the type of effluent system, the use of recycled water, and the distance between the surface of the slurry and the base of the slats all influence air and surface hygiene. Regular fogging of sheds with water or oils can also help reduce bacterial levels (Rule et al., 2005) However, the results tend to vary from shed to shed and are influenced by the ventilation system (Hölscher, 2005). Recent experiences with fogging disinfectants appear to be superior to fogging with oil or water only (Hartung, personal communication). Concerning air quality, a pig breathes about 40kg of air per day. Therefore, dust can be a major environmental trigger of responses in the pig. However, hen considering effects on the animals, the size of dust particles is relevant. Indeed, only respirable dust particles (<5 microns) are able to reach the alveoli of the lung. In humans, threshold values of respiratory dust eliciting effects are less than 5 mg/m 3, 40hrs/week (Thrusfield, 1995). Concerning gases, ammonia has an effect on pulmonary clearance (Drummond et al., 1978; Jones et al., 1996). For H2S, concentration is normally not detectable with Draeger tubes. However, manure handling operations within the building can generate very high H2S concentrations with acute mortality syndrome (Hoff et al., 2006). Therefore, effective ventilation of animal houses is crucial for good air quality Gut disorders Postweaning diarrhoea Postweaning diarrhea (PWD) is also named, with good reasons, postweaning colibacillosis as enterotoxigenic E. coli is involved. The condition is that E. coli fimbriae F4 or F18 attached to glycoprotein receptors expressed in the brush border cells lining the intestinal villi. However, without other factors, E. coli is not able to cause disease. Indeed, probably 99% of the swine herds are infected by such enterotoxinogen E. coli with the fimbriae F4. PWD is a typical disease of the transition, weaning. Figure 10 reports the interactions between different factors. Slower intestinal transit time and relative stasis (reduced functional capacity), as well as physiological villous atrophy (morphological changes), with undigested food particles in the lumen of the small intestine which allow substrate for bacteria. The large intestine has also an influence on the pathophysiology of PWD. Indeed, the pig s absorptive capacity is not well developed at weaning (maximum 2 weeks after weaning). This reduced large intestine absorption may exacerbate the effects of enterotoxins in the small intestine (Nabuurs, 1998). An inability to thermoregulate adequately often results in cold stress, which alters intestinal motility and is thought to be another important predisposing factor (Wathes et al., 1989). Social stresses from mixing and fighting trigger blood cortisol, depressing the immune response to bacterial infection at a time where there is no longer any protective passive immunity provided by sow s milk. The passage from one meal per hour in lactation (milking sow behaviour in lactation) to feed available 24h/24h disturbs appetite and feed behaviour. Some piglets do not eat for some time and overeat thereafter. This behaviour has been linked to an increase occurrence of PWD in these animals (Hampson and Smith, 1986). The composition of the weaning diet has a central role in the pathogenesis of PWD as it influences intestinal morphology, digestive and absorptive ability, intestinal motility and transit time, and selective growth of the microflora and their resultant fermentations patterns. It has 50

66 been known for a long time that it is possible to influence the development of PWD by changing the composition of the weaner diet (Pluske et al., 2002; see review by Hampson, 1987). Figure 9. Interactions between different factors that allow substrate for bacteria Diarrhoea during finishing period Jacobson (2003) has summarized the diarrhoeal diseases during the finishing period. During that period the importance of diarrhoeal diseases usually decreases. Within the first weeks after arrival, the animals might be affected by diarrhoea that is presumably induced by the stress during transport and mixing of animals, or by environmental factors such as contaminated water remaining in the water system. Sometimes, mild diarrhoea that is considered to be osmotic and seemingly does not affect the pig s health or growth is seen (Jensen 1995). None of this is considered as any problem of major importance. However, disease or sub-clinical infection caused by certain main pathogenic agents can result in considerable production losses: Swine dysentery caused by Brachyspira hyodysenteriae is an important disease in swine of all ages (Alexander et al., 1969; Meyer 1978). Salmonellosis is a very important zoonotic disease globally (Nielsen 2002) and is in some countries subjected to extensive control programmes (Wahlström et al., 1998; Wahlström et al., 2000). Lawsonia intracellularis caused diarrhoea and decreases weight gain especially in fattening pigs (Haelterman and Hutchings, 1956; Pritchard, 1982; Rowland et al., 1972) Gastric ulcers The pig industry needs to be concerned about the welfare implications of a high level of stomach lesions (Friendship, 2006). Gastric ulceration is common and widespread, with a high herd-to-herd variation as well as within-herd variation in prevalence and severity. Ulceration occurs rapidly and the progression from normal pars oesophagea to complete ulceration may take less than 24 hours. Ulcers occur very rapidly but healing may also be very quick: it is why it is difficult to relate lesions at slaughter with performance during growerfinisher stage. The exact cause of gastric ulceration is not completely understood, but many of the risk factors are today well known (Table 8). Moreover, there are interactions at the pig level as well as the herd level. At the pig level, we may indicate the fluidity of the stomach content, the speed of 51

67 passage of the ingesta through the stomach, and whether or not the stomach contains feed. Interactions at the herd level are illustrated in the column Housing/management of Table 8. Table 8. Risk factors associated with ulceration of the pars oesophagea in pigs (Friendship, 2006). Nutrition Housing/Management Other Feed particle size Type of grain Milling Pelleting Grinding vs. rolling Heat processing Lack of fiber Vitamine E/Se deficiency Rancid fat Withdrawal of feed Confinement rearing Herd size Mixing pigs Overcrowding Holding and transport Feeding regimen Season Concurrent disease Parturition Heredity Somatotrophin Histamine Helicobacter infection PCV2 Besides feed particle size, the method by which the grain is processed affects also the prevalence of ulcers. Grain ground with a hammer-mill tends to be more ulcerogenic than if a roller-mill is used. Feed particle size is affected by grain component, milling procedure, and processing. For example, grains such as wheat are more likely to shatter during and result in finer particle size particle compared with oats or barley. The overall effect of a feed with very fluid and the emptying time is relatively rapid, and as a result, the ph gradient between the neutral proximal part of the stomach and the acidic distal region is lost. The method of feeding may as important as feed processing and composition. A major risk factor of ulcer development is an interruption of feed intake (Henry, 1996). Fasting of pigs has been a consistent method of experimentally producing gastric lesions, always with interactions. As in HBS/PIDS, interruption of normal feed intake commonly occurs on almost all herds because of mechanical or human error. Even if there has been a great interest in finding an infectious cause of porcine gastric ulcers similar to the human situation, the link is far from evident. Recent studies suggest that a high carbohydrate diet and gastric colonisation by swine-origin gastric Helicobacter pylori facilitate development of clinically significant gastroesophageal ulcers (Krakowka and Ellis, 2006). This infection seems very common in pigs (Ellis et al., 2006). The pars oesophagea has a cornified stratified squamous epithelium and does not secrete protective mucous. Chronic insult results in hyperplasia of epithelial cells and thickening from layers of cells to layers of cells and keratinisation. Rapid cell development results in the production of immature cells, and the thickened layers of cells tend to overgrow their nutrient supply. As a consequence, the tight junctions between epithelial cells break down, allowing digestive juices access to underlying tissues. Initially, superficial layers of epithelium are lost, but if the insult continues, deeper erosions develop and affect the lamina propria and, eventually, the muscularis mucosa and submucosa. Erosion and damage can spread rapidly, destroying the entire pars oesophageal region. Gastric ulcer presence is not all or nothing pathology: there are gradations. One possibility for categorising ulcers that has been suggested, but not universally accepted, is that proposed by Muggenburg et al. (1964). Stomachs can be scored for severity of oesophagogastric ulcers as follows: 1 = normal stomach; 2 = erosion; 3 = oesophagogastric ulcer; 4 = severe oesophagogastric ulcer. The scoring system for keratinisation is: 1 = normal; 2 = mild keratosis; 3 = moderate keratosis and 4 = severe keratosis. A similar score system to assess the 52

68 signs of parakeratosis and ulceration in the pars-oesophageal region was described by Potkins et al. (1989), where 0 indicates no abnormality and 5 indicates a large and bleeding ulcer. A detailed method to score (0 to 6) the different stages of lesion of the pars oesophagea has been more recently used by Hessing et al. (1992), cited by Amory et al. (2006). In this latter system 0 indicates an intact epithelium; 1 = small degree of hyperkeratosis (<50 per cent of total surface); 2 = distinct hyperkeratosis stage 1 (>50 per cent of total surface but < 1mm thickness); 3 = distinct hyperkeratosis stage 2 (>50 per cent of total surface but > 1mm thickness); 4 = hyperkeratosis plus fewer than five erosions < 2.5 cm in diameter; 5 = hyperkeratosis plus more than five erosions and/or erosions >2.5 cm in diameter; 6 = hyperkeratosis plus more than 10 erosions and/or erosions > 5 cm in diameter, and/or ulcers (with or without bleeding) or stenosis of the oesophagus towards the stomach. The observation of the integrity of the stomach mucosa cannot be presently regarded as a routine survey at slaughtering. Concerning prevention, we are facing zootechnical and economical constraints. A costbenefit analysis of the prevention programme is important in determining what action should be taken to reduce losses from gastric ulcers on a particular farm. As the risk factors and the losses from disease vary from herd to herd, each case needs to be considered separately. Many of the factors associated with an increased risk of ulcer development are closely tied to economic competitiveness such as the finely ground feed and fast-growing, lean genetic. Therefore, steps to reduce the prevalence of gastric ulcers need to be carefully balanced between economic considerations and welfare concerns. As there are many causal factors and complex interactions of nutrition, environment, and management, only an integrated and coordinated approach with feed providers, owners, production personnel, and herd veterinarians will lead to amelioration. For example, in the same farm and on similar diets, ulcers are less severe in pigs in straw bedded housing, probably because they can ingest fibre from bedding (Scott et al., 2006d). The issue of non specific colitis has been considered and it is clear that good quality information on this subject is lacking Production - related and other diseases PMWS has been a major health issue in weaned pigs within the EU in recent years. Whilst the exact cause of the disease is still the subject of debate, there is clear evidence that the severity of symptoms can be greatly influenced by aspects of the housing and management system (e.g. batch management, solid pen divisions, mixing of litters) (Madec et al., 2000). A feature of modern swine production is that different production systems tend to have different disease problems, even when located in the same geographic region. This fact suggests that the production system, in particular the pig flow, has a considerable influence on which and when infections will occur. The most important factors are continuous flow as compared with all in-all out, on or offsite weaning, single or multiple source of growing pigs, home grown or outside replacements, gilt acclimatisation units, and parity segregation. The effect of the environment on productivity and disease has been recently reviewed (Gonyou et al., 2006a). There are three general levels of response for animals submitted to environmental stressors (Moberg, 1985). The least costly response is behavioural. If this response is not enough to alleviating the stress, a change in biological function occurs. Such changes may involve a redirection of energy or substrates at the detriment of growth, reproduction and defence strategies. 53

69 Animal predisposition (behavioural, physiological, immunological) Environmental Factors Temperature Dust Gases Noise Light Equipment Space Social Stockpersons Hygiene Animal/Environment Interaction Animal Reponse (Behavioural, Functional, Pathological) Figure 10. Animal/environmental interaction (Gonyou, 1993 and cited by Gonyou et al., 2006a) The relationship between environment and productivity and/or disease is multifactorial. There is at least an additive effect of the stressors (Hyun et al., 1989). Several diseases are affected by more than one environmental factor (review by Whittemore, 1993). For example, Done (1991) suggests 20 environmental factors only for pneumonia. Thermal environment influences not only production but also health status but the results are controversial: - in weaned piglets, experiences with negative effects by Hessing and Tielen, 1994 or Le Dividich and Herpin, 1994 (but not confirmed by Nienaber and Hahn, 1989), and Shelton and Brumm (1986); - in grower-finishers, experiences with negative effects by Christison (1988) but not confirmed by Lemay et al. (2001) who concluded that healthy pigs are not negatively affected by large daily temperature fluctuation (around 15C) as long as this fluctuation is progressively achieved. It is why pig s health status is not altered by cold temperature alone but more by rapid air temperature fluctuation. The effect of high temperature on sow mortality is also well known (D Allaire et al., 1996). Therefore, a thermal comfort zone depends on many environmental factors and changes with pig weight Injuries Injuries may result from aggressive interactions with other pigs, tail-biting, badly designed or maintained pen structures and poor flooring. Tail biting is covered in the EFSA Scientific Opinion on The risks associated with tail biting in pigs and possible means to reduce the need for tail docking considering the different housing and husbandry systems (EFSA, 2007 under adoption procedure). Skin lesions measured on farm and at the slaughterhouse are an important welfare measure. Lesions can be assessed according to number, nature (scratch or crust, opened wound, abrasion, blotch or haematoma), size and whether they are fresh or healed (Velarde, 2007). The effects of poor flooring on welfare were dealt with in the report of EFSA The Welfare of Weaners and Rearing Pigs: Effects of Different Space Allowances and Floor Types. 54

70 Floors can cause physical injury, either as a result of slipping and consequent muscle and joint injury, or as a result of abrasion / incision and consequent infection. Inadequate flooring is a main factor for physical damage to the legs and claws of the growing pig. In addition, flooring may give rise to abrasions or pressure swellings on other body areas, notably to the shoulders, teats or hocks. Several difficulties arise when the effect of flooring on injuries in growing and finishing pigs is to be determined, as many studies have confounding factors and few reports describe the characteristics of the floors which were involved in the studies in a detailed and objective manner. In addition, the types of flooring, and the technologies and materials used in their production, have changed significantly over time. Apparently, no new data has become available since the last EFSA report on pig welfare was adopted. 8. RISK ASSESSMENT APPROACH 8.1. Introduction Animal welfare problems are generally the consequence of negative animal-environment interactions, resulting from animal management factors or housing factors, so called design criteria (Anonymous, 2001). Presently there are not any standards for animal welfare risk assessment, but previous studies exist where risk assessment for animal welfare and tail biting has been explored (Anonymous, 2001; Bracke et al., 2004a, b; EFSA 2006 report on calves; Bracke et al., submitted; Cagienard et al., 2005). Risk assessment is a systematic, scientific-based process to estimate the likelihood and severity of a hazard impact and include 4 steps: hazard identification; hazard characterisation; exposure assessment and risk characterisation. In food risk assessment terminology (Codex Alimentarius), a hazard is a biological, chemical or physical agent in, or condition of, food with the potential to cause an adverse health effect. The risk is a function of the probability of an adverse health effect and the severity of that effect, consequential to a hazard(s) in food. Making a parallel to the Codex Alimentarius risk assessment methodology, a hazard in animal welfare risk assessment is a design criterion (usually an environment-based factor) with a potential to cause negative animal welfare effect (adverse effect as measured by one or more welfare performance criteria). A risk in animal welfare is a function of the probability of a negative animal welfare effect and the severity of that effect, consequential to the exposure to a hazard(s). Risk has two components: the probability or likelihood of the adverse effect at population level and the magnitude of that effect at an individual level on the same population. While hazards and risks usually relate to negative welfare impacts, the risk assessment approach can also be extended to include positive welfare consequences (resulting in riskbenefit analysis). Hazard characterisation includes identification of factors whose absence increases animal s chances of well-being. The degree of confidence in the final estimation of risk depends on the variability, uncertainty, and assumptions identified and integrated in the different risk assessment steps. Uncertainty arises in the evaluation and extrapolation of information obtained from epidemiological, experimental, and laboratory animal studies and whenever attempts are made to extrapolate (i.e. to use data concerning the occurrence of certain phenomena obtained under one set of conditions to make estimations or predictions about phenomena likely to occur under other sets of conditions for which data are not available). 55

71 Uncertainty analysis describes the fact that we have incomplete knowledge. Uncertainty could be treated formally in conducting more studies or quasi-formally in using expert opinions or informally by making judgment. Variability is a biological phenomenon (inherent dispersion) and is not reducible. Reduction in variability is not an improvement in knowledge, but instead would reflect a loss of information. For the two steps of the process; Hazard Characterisation and Exposure Assessment, the experts were asked to individually fill the tables for each population (i.e. docked and undocked weaned, growing and fattening pigs in Europe), based on their scientific knowledge and data described in hazard identification section. These values were compared and discussed to reach a consensus Table (see Appendix 3) Steps of Risk Assessment 1) Definition of the target populations The first step on the development of the RA was to identify the target populations to be considered, depending on the animal categories (and life stages) and the different husbandry systems. The target populations considered for the RA were the following: a) Sows and Boars: Dry Sows - from weaning to 4 weeks of service Pregnant Sows (from 4 weeks after service) Farrowing Sows Boars Piglets (up to weaning) b) Fattening: Weaning (up to 10 weeks) indoor Weaning (up to 10 weeks) outdoor Growing (from 10 weeks onwards) indoor Growing (from 10 weeks onwards) outdoor Fattening pigs (over 110 kg) c) Tail biting Docked pigs Undocked pigs 2) Hazard identification The aim of this step is to identify hazards, i.e. causes or factors that affect the animal s welfare needs (negatively as well as positively). In this step, the scientific evidence of association between the exposure to a given production factor (hazard) and the consequent impact on animal welfare are reviewed. Once the target populations were defined, a list of hazards with their adverse effects affecting each of the populations was agreed. The identified hazards are related with the needs of the animals described in Appendix 2 of this Report (not in Tail Biting). Some general examples are shown in Table 9 (Candiani et al., 2007). Table 9. Examples of hazards related to animal needs with related adverse effects. Need Hazards Adverse effect Difficult access to water Thirst Nutrition: Insufficient feed Hunger to drink, to thermoregulate Too low milk T Stress, anxiety Housing: to rest, to exercise Sliding floors Inappropriate ventilation Lameness Pain, malaise Management: To avoid fear, to have proper social interactions Staff without experience Mixing of unfamiliar animals Stereotypes Fear Stress 56

72 For each population, a Microsoft Excel Table was made listing all identified hazards with their adverse effects. If for the same hazard different adverse effects occur, a line for each considered adverse effect was listed (see example Table 12). For the two following steps, Hazard Characterisation and Exposure Assessment the WG experts were asked to individually fill the tables for each population (i.e. docked and undocked weaned, growing and fattening pigs), based on their scientific knowledge and data described in the hazard identification section of the scientific report. 3) Hazard Characterization (HC) The objectives of this step are: to review and describe the consequences of an exposure to one or several hazards in terms of magnitude of adverse effect; to assess the relationship between the level of the hazard in terms of intensity, and duration and the likelihood and magnitude of the adverse effect. The Severity of the adverse effects was scored subjectively by the members of the Working Group based on scientific information about the level of physiological and behavioural responses. Severity scores ranged on a 5 points scale from Negligible (score 0) to Critical (score 4). See Table 10 for the hazard characterisation scores. Table 10. Severity scores of the adverse effects. Severity of the adverse effect Descriptive definition Scores Critical Fatal, death occurs either immediately or after some time 4 Severe Involving explicit pain, malaise, frustration, fear or anxiety Strong stress reaction, dramatic change in motor 3 behaviour, vocalization may occur Moderate Some pain, malaise, frustration, fear or anxiety Stress reaction, some change in motor behaviour, 2 occasional vocalization may occur Limited Minor pain, malaise, frustration, fear or anxiety Physiological effects may be recorded as well as 1 moderate behavioural changes Negligible No pain, malaise, frustration, fear or anxiety 0 The Duration of the effect was expressed as the number of days where a pig was believed/expected to be experiencing the adverse effect, once it would be exposed to the hazard. The life time in days for each target population was agreed by the WG, therefore the numbers of days was converted to a % of the life time. Both values were showed in the Tables except in the case of the tail biting hazard characterisation. The experts were asked to score the Quantitative Assessment of Likelihood that an adverse effect can occur for a given exposure to a hazard (defined in term of intensity and duration). The experts opinion were modelled using a Beta-Pert distribution that requires three parameters, namely minimum, most likely and maximum. The three parameters range from 0-100% (see example in Table 12). 57

73 The Qualitative Assessment of Uncertainty for each assessment according with the availability of any scientific evidence was also scored (see Table 11). The scored values were compared and discussed to reach a consensus Table (see Appendix RA Outcomes). Table 11. Qualitative uncertainty scores for the likelihood and exposure. Low Medium High Solid and complete data available; strong evidence provided in multiple refs; authors report similar conclusions. Some but no complete data available; evidence provided in small number of refs; authors conclusions vary from one to other. Solid and complete data available from other species which can be extrapolated to the species considered. Scarce or no data available; rather evidence provided in unpublished reports, based on observations or personal communications; authors conclusions vary considerably between them. Once all the scores were agreed and the consensus tables completed, from the severity and duration of an adverse effect, the Magnitude of an adverse effect was calculated as follows (values not shown in the Appendix, but used for Risk estimation): Magnitude = (Severity score/4) * Duration of the effect (number of days) 4) Exposure assessment (EA) EA is the quantitative assessment of the probability of the specific scenario of exposure. The different exposure scenarios were defined by the experts. The scenario takes into the account the Intensity and Duration of an exposure to one or several hazards during the considered period of the animal s life within the considered population (i.e. 140 days and European populations of docked and undocked pigs, respectively). The considered life time for each target population was also agreed by the WG in order to get consensus on the scored %. The Intensity of exposure to a hazard is measured either as full exposure/no exposure or exposure to a given range of intensity of the hazard (ammonia concentration example). If there are different levels of exposure, one line was created for each level (see Table 12). This is relevant when data on the frequencies of the different level of exposures and data on the relationship between the level of exposure and the severity and likelihood of the consequences (adverse effect) are available. The probability of each exposure scenario (Quantitative Assessment of Probability of Exposure) for a defined target population was assessed by the experts and modelled using a Beta-Pert distribution (as before three parameters minimum, most likely and maximum, ranging from 0 to 100% are required). The Uncertainty score (see Table 11) for each assessment, was estimated as in the HC. 58

74 Table 12. Example of a consensus. Table for scoring the hazards. Animal Health and Welfare in Fattening Pigs Target population: Dry Sows a Hazard description Hazard characterisation Exposure assessment Quantitative Quantitative assessment of Magnitude assessment of P. of likelihood e (%) Exposure i (%) Adverse effect b Severity c Duration d ( %) min ml max Qualitative assessment of the uncertainty f Duration g (%) Intensity h min ml max Qualitative assessment of the uncertainty j High Conc. Ammonia (above pm) Respiratory Disease Limited Medium ppm High Respiratory Disease Moderate-2 80 X ppm Table 12 Legend: a = Name of the Target population. b = Adverse effect in relation to the needs and consequence of not fulfilling the needs. c = Severity of the adverse effect. Classification based on the criteria in Table 12. d = Duration of the adverse effect given the indicated exposure, during the life time: value from 0% to 100%. Also, when the adverse effect is fatal the duration is 100%. e = Quantitative Assessment of Likelihood: minimum (min), most likely (ml) and maximum (max). This range of values describes the uncertainty and not the variability. f = Qualitative Assessment of the Uncertainty, based on data available for the quantitative assessment (Table 11) g = Duration of the exposure relative to the life time: value from 0% to 100%. h = Intensity of exposure to a hazard, measured either as full exposure/no exposure or exposure to a given range of intensity of the hazard. If there are different levels of exposure, one line was created for each level. I = Quantitative assessment of Probability of Exposure: minimum (min), most likely (ml) and maximum (max).. j = Qualitative Assessment of the Uncertainty, based on data available for the quantitative assessment (Table 11). 5) Risk characterization (RC) Risk characterisation uses HC and EA scores to calculate a RC score expressing the magnitude of risk of animals in the population exposed to a given hazard. 4 The example shows a sow which is through her life as a sow, exposed to a levels of ammonia of ppm during 70% of her lifetime, and which, as a consequence of this exposure, suffers from a respiratory disease of a limited severity during 80% of the sow s lifetime. 59

75 This step aims to estimate the likelihood of the occurrence of the adverse effect in a specific husbandry system in a specific period of the animal s life. It aims to give information to the risk manager to evaluate a specific situation regarding the fulfilling of animal needs and maximising good welfare. This risk estimate was calculated for each hazard, and expresses its animal welfare burden in the considered population: Risk = (Magnitude of the effect) * (Likelihood of the effect given a scenario of exposure * (Probability of the considered scenario of exposure) This formula assumes the following: - that there is linearity on the severity scores (e.g. 2 days suffering from an intensity score 2 is equivalent to 1 day suffering from an intensity score 4). - that there is no interaction between hazards. - that the hazards are mutually exclusive. Because the previous assumptions are extremely tentative and could not be verified within the scope the WG s mandate, the risk calculation has to be interpreted with extreme caution. A simple interpretation is to consider the risk calculation as the number of days the animals are suffering from poor welfare induced by the exposure to the considered hazard. To asses the effect of an exposure to several hazards, summation is avoided by precaution, as the different exposures are not mutually exclusive and it is needed to weight the different outcomes before summation. The risk calculation mainly serves the purpose of ranking the importance of the different considered hazards within the examined populations. Because the risk formula input, likelihood of the effect given a scenario of exposure and likelihood of the considered scenario of exposure, are both random variables the risk assessment output is a random variable. The risk formula was run for iterations using Monte-Carlo sampling method (Palisade, Ithaca, USA) add-in for Microsoft Excel. The risk output distribution was described using its median, 5 th and 95 th percentiles. The qualitative assessment of the uncertainty on the risk output was derived accordingly the classification matrix (Table 13). Table 13. Classification matrix of the qualitative assessment of the uncertainty Exposure uncertainty High Medium Low Likelihood uncertainty High High High High Medium High Medium Medium Low High Medium Low 8.3. Graphical presentation of the Risk Characterisation The consensus Tables in the Appendix are divided in three sections: Hazard Characterisation (HC), Exposure Assessment (EA) and Risk Characterisation. HC and EA sections include all values agreed by the experts and used to calculate the Risk Characterisation for each hazard 60

76 listed in the consensus Tables. The Risk estimate (CI 95%) values are reported by the median and the 5 th and 95 th percentiles. The qualitative uncertainty of the risk estimate is calculated from Table X6 (by multiplying EA and HC uncertainties). In the Appendix 3, for each hazard within each population, values of the risk estimate (median, 5 th and 95 th percentiles) and magnitude of the hazard are presented as a histogram. Hazards have been ordered in each population by decreasing risk estimate value. Conclusions from the risk assessment process have been explicitly detailed in the tail biting scientific opinion. In the case of the Fattening and the Sows and Boars scientific opinions the results of the risk assessment process also allowed the confirmation of some conclusions obtained from the data presented in the scientific reports. 9. FOOD SAFETY CONSIDERATIONS Food safety aspects are considered in the Scientific Opinion of the Panel on Biological Hazards on a request from the European Commission on food safety aspects of different pig housing and husbandry systems. The EFSA Journal (2007) 613, 1-20, available at: < 61

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102 APPENDIX 1. WELFARE AND ITS ASSESSMENT The wording of the Treaty of Amsterdam (EU, 1997) reflects the concerns of the public about the welfare of the animals and hence there is a requirement that there be an evaluation of animal welfare with a scientific basis. Farmed animals are subject to human imposed constraints and for a very long time the choice of techniques was based primarily on the efficiency of production systems for the provision of food. However, it is important to protect these animals against mistreatment and poor welfare, therefore it is essential to know how their welfare is affected by the various methods for keeping and managing animals. Broom (1986) defines animal welfare as follows: the welfare of an animal is its state as regards its attempts to cope with its environment. In this definition, welfare includes pleasurable mental states and unpleasant states such as pain, fear and frustration (Duncan, 1996; Fraser and Duncan, 1998) because feelings are a part of many mechanisms for attempting to cope with good and bad aspects of life and most feelings must have evolved because of their beneficial effects (Broom, 1998). Although feelings cannot be measured directly, their existence may be deduced from measures of physiology, behaviour, pathological conditions, etc. The word "health", like "welfare", can be qualified by "good" or "poor" and varies over a range. According to Broom and Kirkden (2004) and Broom, (2006) health refers to the state of body systems, including those in the brain, that combat pathogens, tissue damage or physiological disorder and hence welfare is a broader term than health, covering all aspects of coping with the environment and taking account of a wider range of feelings and other coping mechanisms than those associated with physical or mental disorders. Pathology is the detrimental derangement of molecules, cells and functions that occurs in living organisms in response to injurious agents or deprivations (Broom and Kirkden 2004, modified after Jones et al., 1997 who omit the word detrimental ) and the study of such conditions. Disease, implying that there is some pathology rather than just pathogen presence, may have has some adverse effect on welfare, the extent depending on the severity and type of the pathology (Broom and Corke, 2002). Sub-clinical disease processes, by definition, have no effect on the welfare of the individual. The pain system and responses to pain are part of the repertoire used by animals to help them to cope with adversity during life. Pain is clearly an important part of poor welfare (Broom, 2001b). However, prey species may show no behavioural response to a significant degree of injury (Broom and Johnson, 1993). In some situations responses to a wound may not occur because endogenous opioids that act as analgesics are released. However, there are many occasions in humans and other species when suppression of pain by endogenous opioids does not occur (Melzack et al., 1982). Physiological measurements can be useful indicators of poor welfare. For instance, increased heart-rate, adrenal activity, or adrenal activity following ACTH challenge, or reduced heartrate variability, or immunological response following a challenge, may all indicate that welfare is poorer than in individuals which do not show such changes. The impaired immune system function and some of the physiological changes can indicate the pre-pathological state (Moberg, 1985). In interpreting physiological measurements such as heart rate and adrenal activity it is important to take account of the environmental and metabolic context, including activity level. Glucocorticoids have various important functions in the body including facilitation of learning in pigs (Poletto et al., 2003) and are not produced in all potentially damaging situations. Some hormones, such as oxytocin, can be pleasure indicators (Panksepp, 1998; Carter, 2001). In this report, the term stress is defined as an environmental effect on an individual which over-taxes its control systems and reduces its fitness or appears likely to do so. 87

103 Behavioural measures are also of particular value in welfare assessment (Wiepkema, 1983). The fact that an animal avoids strongly an object or event, gives information about its feelings and hence about its welfare (Rushen, 1986). The stronger the avoidance the worse the welfare whilst the object is present or the event is occurring. An individual which is completely unable to adopt a preferred lying posture despite repeated attempts will be assessed as having poorer welfare than one which can adopt the preferred posture. Other abnormal behaviour, which includes excessively aggressive behaviour and stereotypies, such as bar-biting or shamchewing in sows, indicates that the perpetrator's welfare is poor. Very often abnormal activities derive from activities that cannot be expressed but for which the animal is motivated. For example, pigs deprived of manipulable materials may be more likely to develop tail-biting. A single physiological, behavioural or other measure indicating that coping is difficult, or that the individual is not coping, can be sufficient evidence that welfare is poor. Studies of the brain inform us about the cognitive ability of animals and they can also tell us how an individual is likely to be perceiving, attending to, evaluating, coping with, enjoying, or disturbed by its environment so can give direct information about welfare (Broom and Zanella, 2004). Pigs have complex brains so must have a great range of possibilities for good or poor welfare. In studies of welfare, we are especially interested in how an individual feels. As this depends upon high-level brain processing, we have to investigate brain function. Abnormal behaviour and preferred social, sexual and parental situations may have brain correlates. Brain measures can sometimes explain the nature and magnitude of effects on welfare. Although the biological abilities of animals to adapt to the environments that they encounter are of major importance in determining the individual s welfare, it is only in this way that welfare is related to what is, or is not, natural. Good welfare is certainly not limited to natural environments and there are many ways in which what happens to animals in the wild leads to poor welfare. Whilst the wild conditions may give some indications as to what are important resources for animals, welfare will depend on the coping ability of animals of the genetic strain kept in captivity. The majority of indicators of good welfare, which we can use, are obtained by studies demonstrating positive preferences by animals (Dawkins, 1990). Methods of assessing the strengths of positive and negative preferences have become much more sophisticated in recent years. The price, which an animal will pay for resources, or pay to avoid a situation, may be, for example, a distance travelled, a weight lifted or the amount of energy required to press a plate on numerous occasions. The demand for the resource, i.e. the amount of an action which enables the resource to be obtained, at each of several prices can be measured experimentally. This is best done in studies where the income available, in the form of time or energy, is controlled in relation to the price paid for the resource. When demand is plotted against price, a demand curve is produced. In some studies, the slope of this demand curve has been measured to indicate price elasticity of demand but in recent studies (Kirkden et al., 2003) it has become clear that the area under the demand curve up to a particular point, the consumer surplus, is the best measure of strength of preference. Good welfare in general, and a positive status in each of the various coping systems, should have effects that are a part of a positive reinforcement system, just as poor welfare is associated with various negative reinforces. Once we know what animals strongly prefer, or strongly avoid, we can use this information to identify situations that are unlikely to fulfil the needs of animals and to design better housing conditions and management methods (Fraser and Matthews, 1997). However, as pointed out by Duncan (1978, 1992) and Dawkins (2004), all data from preference studies must be interpreted taking account of the possibilities that, firstly, an individual may show a positive preference for something in the short-term which results in its poor welfare in the long-term, and secondly, that a preference in a simplified experimental environment needs to be related to the individual s priorities in the more complicated real world. 88

104 In order to promote good welfare and avoid suffering, a wide range of needs must be fulfilled. These needs may require the animal to obtain resources, receive stimuli or express particular behaviours (Hughes and Duncan, 1988; Jensen and Toates, 1993; Vestergaard; 1996). Evidence for needs is either indications of poor welfare when an individual does not have the resource or opportunity for action, or the results of studies that show that the individual has strong positive or negative preferences. The list of the needs of pigs in the following section includes those which, if not fulfilled, result in death in a few minutes or days or weeks and those that do not result in death (for a review see e.g. Bracke et al., 1999 and Anonymous, 2001). However, the impact of an unfulfilled need on welfare depends on motivational mechanisms as much as on imminence of death. For example, avoidance of severe but non-lethal pain has high priority. When the welfare of pigs or other animals is assessed, sets of measures often have to be integrated, for example, physiological measures, behavioural and pathological measures. Whilst a single measure can indicate poor welfare, because of the variety of coping mechanisms used (Koolhaas et al., 1999) and effects on individuals, a range of measures will usually provide better information about welfare. Each assessment of welfare will pertain to a single individual and to a particular time range. In the overall assessment of the impact of a condition or treatment on an individual, a very brief period of a certain degree of good or poor welfare is not the same as a prolonged period. However, a simple multiplicative function of maximum degree and duration is often not sufficient. If there is a net effect of poor welfare and this is plotted against time, the best overall assessment of welfare, the magnitude of poor welfare, is the area under the curve thus produced (Broom, 2001b). For further modelling of animal welfare see e.g. Bracke et al. (2002a, b). Figure 11. The net severity of poor welfare is plotted against the duration of that poor welfare in two examples here. The relative amount of poor welfare is greater in (a) than in (b). (modified after Broom, 2001b). 89

105 APPENDIX 2. THE NEEDS OF PIGS Pigs, like other animals, need to maintain bodily and mental integrity while growing and during adult life. In order to do this, pigs have a series of needs that are satisfied or frustrated depending on the housing and management conditions imposed upon them by humans. The needs of pigs are described in several places (e.g. Stolba and Wood-Gush 1989; SVC, 1997; Bracke et al., 1999). In listing needs and in later consideration of how to provide for them, it is assumed that extreme human actions, such as deliberately in different ways hurting the pigs will not occur. The list of needs below is not in order of importance. Some of the needs mentioned here are discussed briefly here but at greater length in a previous report (SVC, 1997). Many of the references upon which this list of needs is based are in the text of other chapters in the EFSA reports on the welfare of pigs. Some needs require satisfying only at intervals of some hours or only when young or when adult. The causes of some problems of pigs (i.e. welfare hazards) are multifactorial and related to more than one need. Some needs of pigs involve not only the avoidance of poor welfare (e.g. that resulting from fear and injury) but also the increasing of the likelihood of good welfare (e.g. when preferred activities can be carried out). 1. To breathe Pigs need air that has sufficient oxygen and a low level of noxious gases in it. Pigs may be adversely affected by some of the gaseous products associated with the breakdown of animal faeces or by dust and they show preferences that help them to avoid any harm that these may cause (Smith et al., 1996; Jones et al., 1999). On commercial pig farms the main factors compromising good air quality are ammonia and dust. 2. To have appropriate sensory input Pigs use their eyes to achieve many objectives in life and need to be able to see well enough to carry out the actions that help them to achieve these objectives. Ambient light that is not bright enough, or an inappropriate wavelength or that is flashing at certain frequencies can cause poor welfare in pigs. Very bright lights, very loud noises and certain others, including fear pheromones, can also cause poor welfare. A temporal pattern of lighting can be inadequate because there is too short a light period or too short a dark period. Too much sensory input in total and too little sensory input can cause poor welfare in pigs directly or through the frustration of other needs. 3. To rest and sleep Pigs need to rest and sleep in order to recuperate and avoid danger. They need to use several postures which include one in which they rest on the belly with at least two legs folded under the body and another in which they lie on the side with all four legs stretched out (Ekkel et al., 2003). Sleep disruption may occur if pigs cannot adopt comfortable lying positions, or if there is disturbance to lying animals because they are trodden on or otherwise disturbed by other pigs. Moreover, sleep may be disrupted if pigs are huddling in cold conditions (Hillmann et al., 2004b). 4. To exercise Exercise is important for normal bone and muscle development (Marchant and Broom, 1996). Furthermore, leg weakness is affected by floor quality and stocking density (Jorgensen, 2003). Exercise can be difficult with some types of floors, space allowance or social conditions, e.g. where aggression is likely. The genetic selection of pigs has had effects on the ability of pigs to exercise without having cardiovascular problems. 90

106 5. To feed and drink Sucking Piglets need to obtain nutrients from the earliest stages of life and at a very early stage after birth they show behavioural responses that maximise the opportunity to obtain necessary nutrients. As a consequence, pigs have a very strong need to show sucking behaviour in the pre-weaning period and show belly-nosing directed at pen mates if they are weaned early (Fraser, 1978). The need to suck a teat continues for longer than the time when most piglets are weaned in commercial practice at 3-4 weeks of age. The age of termination of this need will vary amongst individuals and is not known but could be as late as the weeks at which piglets are weaned under natural conditions (Jensen, 1986). The first milk produced after farrowing is rich in immunoglobulin and is needed to help in disease control. If milk substitutes are fed to piglets, there is a possibility that they may include allergenic proteins. Drinking In the early days after birth, pigs are motivated to suck and obtain milk. However, for osmoregulation piglets also have a need to obtain sufficient water and will drink water even when fed milk. If the temperature is high, pigs need to drink higher amounts of water, and sick pigs may also need more water. If water is not available, over-heated pig and sick pigs may become dehydrated. The quantity of water required varies with metabolic state. Nutrients A variety of macro- and micro-nutrients are needed by pigs. If any are lacking in the feed, there will be adverse consequences if essential nutrients cannot be provided by other means. With dry pregnant sows and gilts, provision of a sufficient quantity of bulky or as well as highenergy food is essential to satisfy their hunger and the need to chew. High-fibre diet reduces stereotyped behaviour in sows significantly (Robert et al., 1993; Brouns et al., 1994). Foraging behaviour Even when pigs are fully supplied with the daily nutrient requirement for good health and performance, they may have other needs relating to the quantity or form of the diet. For example, with dry pregnant sows and gilts, provision of a sufficient quantity of bulky, as well as high-energy, food is essential to satisfy their hunger and the need to chew. High-fibre diet reduces stereotyped behaviour in sows (Robert et al., 1993; Brouns et al., 1994), since one situation promoting occurrence of stereotypies is when pigs are chronically hungry in environments where appropriate expression of foraging behaviour is precluded by lack of substrate. Foraging behaviour accounts for a large proportion (up to 75%) of the daily activity of pigs kept in a semi-natural enclosure and they show a wide range of behaviours to investigate and manipulate the environment (Stolba and Wood-Gush, 1989). In addition to the need to feed, pigs therefore need permanent access to a sufficient quantity of material to enable proper investigation and manipulation activities. There is a close relationship between foraging and exploration needs. Pigs are highly motivated to work for access to foraging material like straw or wood shavings (Ladewig and Matthews, 1996). Insufficient provision of foraging material increases the incidence of tail-biting in fattening pigs (Day et al., 2002; Moinard et al., 2003; van de Weerd et al., 2005) and stereotyped behaviour in sows (Fraser, 1975; Spoolder et al., 1995; Whittaker et al., 1998). In the absence of an appropriate foraging environment, welfare is often poor. 6. To explore Pigs have a natural tendency to explore, as pigs are very curious (Wood-Gush and Vestergaard, 1991). Exploration is shown by all pigs, allowing the individual to be prepared for effective food acquisition, response to danger from predators, attack by conspecifics and response to 91

107 other adverse conditions or needs. Exploration is therefore not solely linked to nutritional needs or foraging motivation. In barren environments, pigs redirect exploratory behaviour at the body of pen mates (Fraser et al., 1991). Exploration will be difficult if there is insufficient space available. All pigs are motivated to explore by digging and manipulating with their nose and mouth. 7. To have appropriate social interactions Piglets respond to maternal calls and are attracted to their mothers heat, skin and udder texture. Mother sows show responses to piglets. The needs of young pigs are met most effectively by the presence and actions of their mothers. After weaning, the lack of various stimuli from the mother can lead to abnormal behaviour and poor welfare. In order to develop normal social and other behaviour, piglets need to show play behaviour. Apart from adult boars and sows around parturition, pigs are social animals associating and interacting in a friendly way much more than in an aggressive way (Stolba and Wood-Gush, 1984; Newberry and Wood-Gush, 1986; Petersen et al., 1989). Sleeping in pigs is often a social activity in that pigs prefer to rest near or alongside other pigs. Pigs naturally live in stable groups. Lack of social contact causes poor welfare in pigs. However, mixing of unfamiliar pigs results in aggressive interactions to establish dominance relationships (Arey and Edwards, 1998; Turner et al., 2001). In order to avoid further aggression, sub-dominant animals avoid dominant animals (Fraser, 1974; McGlone and Curtis, 1985; Rushen and Pajor, 1987; Waran and Broom, 1993). Moreover, a restriction in access to important resources, such as the number of feeding places results in increased levels of aggression (Hodgkiss et al., 1998; Spoolder et al., 1999). 8. To avoid fear The need to avoid fear, which may also be called the need for safety, is a consequence of several sources of risk, for example: predators, aggressive conspecifics and sudden impacts of the physical environment. Pigs living in natural conditions would be very vulnerable to predation. As a consequence, the biological functioning of pigs is strongly adapted to maximise the chance of recognition of danger and escape from it. Pigs respond to sudden events and approaches by humans or other animals perceived to be potentially dangerous with substantial sympathetic nervous system and hypothalamic-pituitary-adrenocortical (HPA) changes. These physiological changes are followed by rapid and often vigorous behavioural responses. Fear is a major factor in the life of pigs and has a great effect on their welfare. There can also be fear due to aggressive acts of conspecifics. This aggression may relate to the mixing of unfamiliar pigs or competition over resources, especially feed. 9. To show body care and eliminatory behaviour Pigs need to keep the body surface free of harmful substances or organisms. Hence they may scratch themselves and may dislodge unwanted particles by wallowing in water or mud. Given the space, pigs move several metres away from the nest to defecate and urinate (Stolba and Wood-Gush, 1984, 1989). In indoor housing, pigs of all age classes show a clear tendency to leave the lying area (nest site) for excretory behaviour, provided that the pens are spacious enough (Whatson, 1985; Simonsen, 1990; Amon et al., 2001). If there is insufficient space for there to be a separate dunging area, the welfare of pigs is poor and the risk of health problems is increased. 10. To thermoregulate Pigs need to maintain their body temperature within a tolerable range. If the ambient temperature is too high or too low, or there is too high humidity, welfare will be poor. As they cannot lose heat by sweating (Ingram, 1965), they rely on behavioural measures such as a reduction in physical contact with pen mates, panting and reducing general activity, as well as 92

108 evaporation by making the skin wet through wallowing (Scientific Veterinary Committee, 1997). Over-heated, or potentially over-heated, pigs adopt positions that maximise the surface area from which heat can be lost, often involving in postural changes from sternal to lateral recumbent lying. Some pigs are provided with an inappropriate space design for thermoregulation. If too cold, pigs fold the legs and lie in a posture that minimises surface area. They also seek body contact to pen mates and, especially in younger pigs and when conditions are cold, huddling behaviour takes place (Hillmann et al., 2004a). When temperatures rise, pigs lie on cold, preferably wet surfaces, and seek shade (Blackshaw and Blackshaw, 1994). Finishing pigs increase lying on the slatted floor at about 19C and reduce activity heat production above 24C (Huynh et al., 2005). In housing systems for fatteners, fouling of the lying area is often observed when ambient temperature rises above 25C with pigs of 25 kg and above 20C with pigs of 100 kg (Schmid, 1994; Aarnink et al., 2000). The pigs then use the dunging area, which is usually wet and made of perforated floor, for resting, as it has a greater cooling effect than the dry lying area. Moreover, pigs also increase average inter-individual distances at high ambient temperatures (Hillmann et al., 2004a). Conversely, when pigs become too cold, they seek a bedded area to rest in (Fraser, 1985). When temperatures rise above 18C, adult pigs reduce body temperature by wallowing in boggy places, if available (Stolba and Wood-Gush, 1989). In indoor housing, they may also show this behaviour on wet surfaces and in the dunging area. Over-heated pigs will attempt to drink in order to increase the efficiency of methods of cooling themselves. 11. Reproduction and maternal functions Pigs which are sexually mature make substantial attempts to find and mate with appropriate partners. At this time they could be said to need sexual activity. Females in a late stage of pregnancy also show clear signs of having specific needs at this time. The day before farrowing in a semi-natural enclosure, the sow will separate herself from the social group and seek for a suitable nest site (Stolba and Wood-Gush 1984; Jensen 1986). In the last few hours before farrowing, she is highly motivated to gather straw (Arey, 1992) and shows intensive nest-building behaviour (e.g. Castrén et al., 1993). Maternal behaviour of pigs have been studied in wild boar, feral and domestic pigs (Hanson and Karstad, 1959; Grundlach, 1968; Jensen and Recén, 1989; Horrell, 1997). There are large similarities in the maternal behaviour of wild-type and domestic pigs (Jensen, 1986). Comparing domestic sows with sows with a wild boar father both genotypes showed the same type of nest building pattern and authors concluded that motivation for nest building, early maternal behaviour and nursing behaviour was largely unaffected by degree of domestication as was the actual pattern of nest building behaviour (Gustafsson et al., 1999). Sows with piglets are well-known to show maternal behaviours like defending the young against potential predators, including humans. 12. To avoid and minimise disease Pigs may suffer from injuries and disease and have adaptations designed to combat such challenges, including sickness behaviour (Hart, 1988). All pigs need to minimise contact with pathogens that might cause disease, which they do by various behaviours, anatomical adaptations and physiological responses. They also need to minimise the adverse impacts of pathogens, again using a range of responses. During the first few hours of life, the vigorous attempts of the piglets to find a teat and suckle should result in obtaining colostrum from the mother. This colostrum includes immunoglobulins that provide passive protection against infectious agents. Hence the needs of the piglets have an evident function that is not just nutritional. Any circumstances which result in immunosuppression in pigs will decrease their resistance to exposure of e.g pathogens and toxins. Since chronic physiological stress responses may give 93

109 rise to immunosuppression, pigs have to minimise stressful experiences in order to have an effective immune system. 13. To avoid harmful chemical agents Pigs need to avoid ingesting toxic substances and may react appropriately if harmful chemical agents are detected within their bodies or their environment. These substances can be in food, water, bedding or the air and other materials. 14. To avoid pain Pigs need to avoid any environmental impact or pathological condition that causes pain. In pig husbandry, castration, tail-docking, tooth-clipping, nose-ringing, excessive aggression, tail-biting, vulva-biting, are some examples of sources of pain that is acute and perhaps also chronic. Lameness resulting from claw or joint disorders can be associated with serious chronic pain, as can lesions resulting from bad floor quality. 94

110 GLOSSARY Agonistic behaviour Behaviour which has a role in social interaction but which is not sexual or other reproductive behaviour, for example threatening, aggressive or collaborative behaviour. Cope Have control of mental and bodily stability. This control may be short-lived or prolonged. Failure to be in control of mental and bodily stability leads to reduced fitness. Drained Floor A solid floor that is sloping so that fluids drain off it. Fattening pigs This term includes weaners, growers and finishers, as defined below. Exploration Any activity which has the potential for the individual to acquire new information about its environment or itself. Foraging The behaviour of animals when they are moving around in such a way that they are likely to encounter and acquire food for themselves or their offspring. Grooming The cleaning of the body surface or rearrangement of pelage by licking, nibbling, picking, rubbing, scratching or application of aqueous liquids. Growers and Finishers Pigs from 10 weeks to the age at which pigs kept for meat production are typically slaughtered ( but locally up to 170kg). Animals which will be kept for reproduction are included in this category and in the weaner category, when they are of these ages. Hierarchy A sequence of individuals or groups of individuals in a social system which is based upon some ability or characteristic. Need A requirement, which is part of the basic biology of an animal, to obtain a particular resource or respond to a particular environmental or bodily stimulus. Slat The solid part of a slatted floor, which would support the claw of the pig. i.e. the parts between the gaps. Slatted Floor A combination of solid parts, which would support the lower surface of the claw of the pig, and gaps which would allow manure and other liquids to pass through. (Also called perforated, slotted floor). Solid Floor A continuous flat surface which allows full contact with and support to the lower surface of the claw of the pig. Space Allowance The measure of floor area and height in animal accommodation per individual animal or per unit of body weight of animals present. Stereotypy A repeated, relatively invariate sequence of movements which has no obvious function. 95

111 Stocking Density The number or body weight of animals per unit area in their accommodation. Stress An environmental effect on an individual which over-taxes its control systems and reduces its fitness or appears likely to do so. Thermoneutral zone The temperature range within which metabolic heat production and energy expenditure are minimal, most productive processes are at their most efficient level and an animal is thermally comfortable without the need to change heat production. The zone is limited by the lower critical temperature (LCT) and the upper critical temperature (UCT), above and below there are energy costs of thermoregulation. Weaner A young pig from the time of weaning from its mother to 10 weeks at which time (plus or minus 2 weeks) many pigs are moved to different accommodation. In the commonest breeds of pigs the weight range of weaners is 5 35 kg. Welfare The state of an individual as regards its attempts to cope with its environment. 96

112 ABBREVIATIONS EC: European Commission. EFSA: European Food Safety Authority. EU: European Union. LCT: Lower Critical Temperature. MS: Member State. SVC: Scientific Veterinary Committee of the European Commission. UCT: Upper critical temperature. 97

113 INDEX OF TABLES AND FIGURES Table 1. Factors or hazards with their related needs. Table 2. The number of pigs, whose meat is certified for human consumption, from 2004 to 2006 in the European Countries. Table 3. Consumption of pork and self-sufficiency for the pig meat in the European Union in the last four years. Table 4. Distribution of housing systems for weaned pigs (weaning to kg) in European countries. Table 5. Distribution of housing systems for fattening pigs in European countries. Table 6. Minimum space requirements for organic pigs (EC Regulation 1804/99). Table 7. Risk factors influencing Salmonella infection in swine from herds in Denmark, Germany, Greece, Sweden and The Netherlands. Table 8. Risk factors associated with ulceration of the pars oesophagea in pigs. Table 9. Examples of hazards related to animal needs with related adverse effects. Table 10. Severity scores of the adverse effects. Table 11. Qualitative uncertainty scores for the likelihood and exposure. Table 12. Example of a consensus. Table for scoring the hazards. Table 13. Classification matrix of the qualitative assessment of the uncertainty. Figure 1. The number of pigs, whose meat is certified for human consumption, from 1995 to 2005 (in red, the provisional value) in the European Union. Figure 2. Partly-slatted and convex floor with iron or plastic slats. Figure 3. Example of flat decks with fully-slatted plastic flooring and sloped concrete floor underneath to separate faeces and urine. Figure 4. Rearing unit with partly-slatted floor and two-climate zones. Figure 5. Example of growing-finishing unit with a fully-slatted floor. Figure 6. Example of a) Partly-slatted floor with deep slurry pit b) Partly-slatted floor with fast removal of slurry and littered external alley. Figure 7. Growing-finishing unit with a partly-slatted floor. Figure 8. Outdoor growing hut for fattening pigs. Figure 9. Interactions between different factors which allow substrate for bacteria. Figure 10. Animal/environmental interaction. Figure 11. The net severity of poor welfare is plotted against the duration of that poor welfare in two examples here. The total amount of poor welfare is greater in (a) than in (b). 98

114 Animal Health and Welfare in Fattening: Appendix 3 Risk assessment outcomes 1 1 Running numbers in the first column of the tables cross reference the hazards in the chart. 99

115 Animal Health and Welfare in Fattening: Appendix 3 100

116 Animal Health and Welfare in Fattening: Appendix 3 101

117 Animal Health and Welfare in Fattening: Appendix 3 Weaning Indoors I Magnitude Risk Magnitude Lack of space - Rest and sleep disruption. Stress and lesions; behavioural restriction. Disturbed bone growth. (7) Lack of space - Rest and sleep disruption. Stress and lesions; behavioural restriction. Disturbed bone growth. (8) No comfortable lying place - Rest and sleep disruption (20) Too low quality of enrichment material - Damaging behaviour from pen mates (6) Lack of space for proper exploration - Damaging behaviour from pen mates (10) Too little amount of enrichment material of sufficient quality - Damaging behaviour from pen mates (5) Early weaning before 28 days - Increased susceptability to disease and increased prevalence of abnormal behaviour. (47) Lack of space - Rest and sleep disruption. Stress and lesions; behavioural restriction. Disturbed bone growth. (9) Absence of wallow - Skin irritation (1) Food: Inadequate hygienic conditions - Enteric diseases (40) Absence of wallow - Skin infections (2) Inadequate air quality: ammonia, dust - Respiratory disorders (49) Inadequate quantity of water - Reduced growth, Irritability (38) Poor stockmanship: inadequate or inaproppriate contact - Fear of humans, mistreatment (28) Poor stockmanship: inspection - Fear of humans, mistreatment (27) Poor Hygiene: infection via humans-biosecurity - infectious diseases (25) Poor Hygiene: cleanliness of pen, buildings, - infectious diseases (24) Mixing of unacquainted animals - Stress and lesions (32) Inaproppriate materials in feed - Reduced growth, Organs damage, Enteric diseases (46) Microbiological contamination of feed - Reduced growth, Organs damage, Enteric diseases (45) Unbalanced diets - Stereotypies, other abnormal behaviour (44) Poor flooring (slippery) - Slipping (31) Unbalanced diets - Pathological consequences (43) Early weaning before 21 days - Increased susceptability to disease and increased prevalence of abnormal behaviour. (48) No comfortable lying place - Rest and sleep disruption (19) Risk 102

118 Animal Health and Welfare in Fattening: Appendix 3 Weaning Indoors II Risk Magnitude Magnitude Poor flooring (slat slot dimension) - Lesions and lameness; pain and behavioural restriction (29) Absence of wallow in high T environments - Thermo-regulatory difficulty (3) Poor quality of water - Reduced growth, GI troubles (39) Noise - Rest and sleep disruption (26) Poor flooring (too abrasive) - Lesions (30) Unbalanced diets - Hunger, Irritability (42) Environmental temperature outside the thermo neutral zone - Discomfort, behaviour disruption and disease consequences (14) Environmental temperature outside the thermo neutral zone - Severe health consequences or death (18) Parasitism by nematodes - Reduced growth, organ damage, disease (50) Absence of enrichment material - Damaging behaviour from pen mates (4) Environmental temperature outside the thermo neutral zone - Discomfort, behaviour disruption and disease consequences (17) Inadequate quantity of food - Hunger, Irritability (41) Inappropriate pen design: inadequate separation of dunging and lyng area - Rest and sleep disruption (22) Environmental temperature outside the thermo neutral zone - Discomfort, behaviour disruption and disease consequences (16) Too short period of light - Inability to carry out some normal perception behaviour (11) Inappropriate pen design:other inadequacy - Rest and sleep disruption (23) Inappropriate pen lay out: open sides to pens - Rest and sleep disruption (21) Large group size >40 an./group - Stress and lesions, diseases (33) Environmental temperature outside the thermo neutral zone - Discomfort, behaviour disruption and disease consequences (15) Environmental temperature outside the thermo neutral zone - Death (13) Genotype problems: infectious disease susceptibility - Infectious diseases (34) Too short period (< 6 h) of low light intensity (< 4 lux) per day - Rest and sleep disruption (12) Genotype problems: body form and growth - Locomotor disorders (35) No water - Dehydration, Nervous diseases, Death (37) Genotype problems: body form and growth - Cardiovascular disorders (36) Risk 103

119 Animal Health and Welfare in Fattening: Appendix 3 104

120 Animal Health and Welfare in Fattening: Appendix 3 105

121 Animal Health and Welfare in Fattening: Appendix 3 106

122 Animal Health and Welfare in Fattening: Appendix 3 107

123 Animal Health and Welfare in Fattening: Appendix 3 Weaning Outdoors I Magnitude Risk Magnitude Parasitism by nematodes - Reduced growth, organ damage, disease (50) Poor stockmanship: inadequate or inaproppriate contact - Fear of humans, mistreatment (28) Poor stockmanship: inspection - Fear of humans, mistreatment (27) Environmental temperature - Discomfort, behaviour disruption and disease consequences (17) Environmental temperature - Discomfort, behaviour disruption and disease consequences (14) Food: Inadequate hygienic conditions - Enteric diseases (40) Sunburn - Pain, stress (52) Inadequate quantity of water - Reduced growth, Irritability (38) Microbiological contamination of feed - Reduced growth, Organs damage, Enteric diseases (45) Poor flooring (slippery) - Slipping (31) Unbalanced diets - Pathological consequences (43) Inaproppriate materials in feed - Reduced growth, Organs damage, Enteric diseases (46) Poor quality of water - Reduced growth, GI troubles (39) Large group size >40 an./group (management difficulties) - Stress and lesions, diseases (33) Environmental temperature - Discomfort, behaviour disruption and disease consequences (16) Absence of wallow in high T environments - Thermo-regulatory difficulty (3) Environmental temperature - Discomfort, behaviour disruption and disease consequences (15) Mixing of unacquainted animals - Stress and lesions (32) Noise - Rest and sleep disruption (26) Unbalanced diets - Hunger, Irritability (42) Predation - Stress, pain, death (51) Absence of wallow - Skin irritation (1) Unbalanced diets - Stereotypies, other abnormal behaviour (44) Environmental temperature outside the thermo neutral zone - Death (13) Absence of wallow - Skin infections (2) Poor flooring (too abrasive) - Lesions (30) Risk 108

124 Animal Health and Welfare in Fattening: Appendix 3 Weaning Outdoors II Magnitude Risk Magnitude Poor Hygiene: infection via humans-biosecurity - infectious diseases (25) Inadequate quantity of food - Hunger, Irritability (41) Early weaning before 28 days - Increased susceptability to disease and increased abnormal behaviour (47) Poor Hygiene: cleanliness of pen, buildings - infectious diseases (24) Environmental temperature outside the thermo neutral zone - Severe health consequences or death (18) Inappropriate pen design: inadequate separation of dunging and lying area - Rest and sleep disruption (22) No water - Dehydration, Nervous diseases, Death (37) Inappropriate pen design: other inadequacy - Rest and sleep disruption (23) Lack of space - Rest and sleep disruption. Stress. Disturbed bone growth. (9) Too low quality of enrichment material - Damaging behaviour from pen mates (6) Poor flooring - Lesions and lameness; pain and behavioural restriction (29) Too little amount of enrichment material of sufficient quality - Damaging behaviour from pen mates (5) Genotype problems: infectious disease susceptibility - Infectious diseases (34) Absence of enrichment material - Damaging behaviour from pen mates (4) Inappropriate pen lay out: open sides to pens - Rest and sleep disruption (21) Lack of space - Rest and sleep disruption. Stress. Disturbed bone growth. (8) No comfortable lying place - Rest and sleep disruption (20) Genotype problems: body form and growth - Locomotor disorders (35) Too short period (< 6 h) of low light intensity (< 4 lux) per day - Rest and sleep disruption (12) Too short period of light - Inability to carry out some normal perception behaviour (11) Lack of space for proper exploration - Damaging behaviour from pen mates (10) Lack of space - Rest and sleep disruption. Stress. Disturbed bone growth (7) Genotype problems - Cardiovascular disorders (36) Early weaning - Increased susceptability to disease and prevalence of abnormal behaviour (48) Inadequate air quality - Respiratory disorders (49) No comfortable lying place - Rest and sleep disruption (19) Risk 109

125 Animal Health and Welfare in Fattening: Appendix 3 110

126 Animal Health and Welfare in Fattening: Appendix 3 111

127 Animal Health and Welfare in Fattening: Appendix 3 112

128 Animal Health and Welfare in Fattening: Appendix 3 113

129 Animal Health and Welfare in Fattening: Appendix 3 Risk Growing Indoor I Magnitude Magnitude Environmental temperature - Severe health consequences or death (18) Environmental temperature - Discomfort, behaviour disruption and disease consequences (17) No water - Dehydration, Nervous diseases, Death (37) Genotype problems: infectious disease susceptibility - infectious disease (34) Inadequate quantity of food (accidental) - Hunger, Irritability (42) Too short period of light - Inability to carry out some normal perception behaviour (11) Large group size >40 an./group - Stress and lesions (33) Early weaning before 21 days - Increased susceptability to disease and abnormal behaviour (49) Too short period (< 6 h) of low light intensity (< 4 lux) per day - Rest and sleep disruption (12) Noise - Rest and sleep disruption (26) Mixing of unacquainted animals - Stress and lesions (32) Parasitism by nematodes - Reduced growth, organ damage, disease (51) Inappropriate pen lay out: open sides to pens - Rest and sleep disruption (21) Inadequate quantity of water - Reduced growth, Irritability (38) Early weaning before 28 days - Increased susceptability to disease and abnormal behaviour (48) Absence of enrichment material - Frustration or damaging behaviour (4) Poor quality of water - Reduced growth, GI troubles (39) Inappropriate pen design: other inadequacy - Rest and sleep disruption (23) Poor flooring (too abrasive) - Lesions and lameness (30) Inappropriate pen design - Rest and sleep disruption (22) Environmental temperature outside the thermo neutral zone - Death (13) No comfortable lying place, i.e. no bedding material like straw - Rest and sleep disruption (20) Absence of wallow - Skin infections (2) Absence of wallow in high T environments - Thermo-regulatory difficulty (3) Food: Inadequate hygienic conditions - Enteric diseases (40) Unbalanced diets - Hunger, Irritability (43) Risk

130 Animal Health and Welfare in Fattening: Appendix 3 Absence of wallow - Skin irritation (1) Poor Hygiene: infection via humans-biosecurity - Disease (25) Genotype problems: body form and growth - Cardiovascular disorders (36) Unbalanced diets - Stereotypies, other abnormal behaviour (45) Unbalanced diets - Pathological consequences (44) Inaproppriate materials in feed - Reduced growth, Organs damage, Enteric diseases (47) Microbiological contamination of feed - Reduced growth, Organs damage, Enteric diseases (46) Poor flooring (slat slot dimension) - Lesions and lameness; pain and behavioural restriction (29) Inadequate quantity of food - Hunger, Irritability (41) Poor flooring (slippery) - Slipping (31) Poor Hygiene: cleanliness of pen, buildings - Disease (24) Lack of space - Rest and sleep disruption. Stress. Disturbed bone growth. (9) Poor stockmanship: inspection - Fear of humans, mistreatment (27) Environmental temperature - Discomfort, behaviour disruption and disease consequences (16) Lack of space for proper exploration - Damaging behaviour from pen mates (10) Too little amount of enrichment material of sufficient quality - Frustration or damaging behaviour (5) Too low quality of enrichment material - Damaging behaviour from pen mates (6) Environmental temperature - Discomfort, behaviour disruption and disease consequences (14) No comfortable lying place - Rest and sleep disruption (19) Genotype problems: body form and growth - Locomotor disorders (35) Poor stockmanship: inadequate or inaproppriate contact - Fear of humans, mistreatment (28) Environmental temperature - Discomfort, behaviour disruption and disease consequences (15) Inadequate air quality: ammonia, dust - Respiratory disorders (50) Lack of space - Rest and sleep disruption. Stress. Disturbed bone growth. (8) Lack of space - Rest and sleep disruption. Stress. Disturbed bone growth. (7) Growing Indoor II Risk Magnitude Magnitude Risk 115

131 Animal Health and Welfare in Fattening: Appendix 3 116

132 Animal Health and Welfare in Fattening: Appendix 3 117

133 Animal Health and Welfare in Fattening: Appendix 3 118

134 Animal Health and Welfare in Fattening: Appendix 3 119

135 Animal Health and Welfare in Fattening: Appendix 3 Environmental temperature - Discomfort, behaviour disruption and disease consequences (15) Poor stockmanship: inadequate or inaproppriate contact - Fear of humans, mistreatment (28) No comfortable lying place - Rest and sleep disruption (19) Genotype problems: body form and growth - Locomotor disorders (35) Parasitism by nematodes - Reduced growth, organ damage, disease (50) Unbalanced diets - Pathological consequences (43) Unbalanced diets - Stereotypies, other abnormal behaviour (44) Environmental temperature - Discomfort, behaviour disruption and disease consequences (16) Poor stockmanship: inspection - Fear of humans, mistreatment (27) Sunburn - Pain, stress (52) Poor Hygiene: cleanliness of pen, buildings - Disease (24) Unbalanced diets - Hunger, Irritability (42) Inadequate air quality: ammonia, dust - Respiratory disorders (49) Inaproppriate materials in feed - Reduced growth, Organs damage, Enteric diseases (46) Inadequate quantity of food - Hunger, Irritability (41) Inadequate quantity of water - Reduced growth, Irritability (38) Genotype problems: body form and growth - Cardiovascular disorders (36) Food: Inadequate hygienic conditions - Enteric diseases (40) Poor Hygiene: infection via humans-biosecurity - Disease (25) Poor flooring (slippery) - Slipping (31) Absence of wallow in high T environments - Thermo-regulatory difficulty (3) No comfortable lying place - Rest and sleep disruption (20) Large group size >40 an./group - Stress and lesions (33) Inappropriate pen design - Rest and sleep disruption (22) Poor quality of water - Reduced growth, GI troubles (39) Inappropriate pen design: other inadequacy - Rest and sleep disruption (23) Magnitude Growing Outdoor I Magnitude Risk Risk 120

136 Animal Health and Welfare in Fattening: Appendix 3 Risk Magnitude Growing Outdoor II Magnitude Absence of wallow - Skin irritation (1) Absence of wallow - Skin infections (2) Inappropriate pen lay out: open sides to pens - Rest and sleep disruption (21) Microbiological contamination of feed - Reduced growth, Organs damage, Enteric diseases (45) Poor flooring (too abrasive) - Lesions (30) Mixing of unacquainted animals - Stress and lesions (32) Noise - Rest and sleep disruption (26) Poor flooring (slat slot dimension) - Lesions and lameness; pain and behavioural restriction (29) Absence of enrichment material - Damaging behaviour from pen mates (4) Too low quality of enrichment material - Damaging behaviour from pen mates (6) Too little amount of enrichment material of sufficient quality - Damaging behaviour from pen mates (5) Predation - Stress, pain, death (51) Genotype problems: infectious disease susceptibility - (34) Early weaning before 28 days - Increased susceptability to disease and abnormal behaviour (47) Too short period (< 6 h) of low light intensity (< 4 lux) per day - Rest and sleep disruption (12) No water - Dehydration, Nervous diseases, Death (37) Too short period of light - Inability to carry out some normal perception behaviour (11) Lack of space for proper exploration - Damaging behaviour from pen mates (10) Lack of space - Rest and sleep disruption. Stress. Disturbed bone growth. (9) Environmental temperature - Discomfort, behaviour disruption and disease consequences (14) Early weaning before 21 days - Increased susceptability to disease and abnormal behaviour (48) Environmental temperature - Death (13) Environmental temperature - Severe health consequences or death (18) Environmental temperature - Discomfort, behaviour disruption and disease consequences (17) Lack of space - Rest and sleep disruption. Stress. Disturbed bone growth. (8) Lack of space - Rest and sleep disruption. Stress. Disturbed bone growth. (7) Risk

137 Animal Health and Welfare in Fattening: Appendix 3 122

138 Animal Health and Welfare in Fattening: Appendix 3 123

139 Animal Health and Welfare in Fattening: Appendix 3 124