Small Ruminant Parasite Control. DG Pugh DVM MS Dipl ACT, ACVN, & ACVM. College of Veterinary Medicine Auburn University, Al

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1 Small Ruminant Parasite Control DG Pugh DVM MS Dipl ACT, ACVN, & ACVM College of Veterinary Medicine Auburn University, Al Internal parasitism of small ruminants is the most significant health risk affecting production and can result in serious economic losses for producers. Financial losses are a result of decreases in growth, milk and fiber production, as well as increasing treatment and prophylaxis costs. Parasitic infections can also result in death and/or loss of function. Although a major concern in production animals, this can be quiet devastating for pet animal owners. Feeding practices, which increase stocking rates but also increase pasture contamination with nematode parasite eggs, magnify internal parasite infection in grazing small ruminants s. Care should be taken to minimize intake of infective nematode parasite larvae when feeding small ruminants s. Animals with limited nutrient intake or those offered diets deficient in one or more nutrients are more likely to suffer losses from internal parasitism than those fed a balanced diet. Meat small ruminants s infected with internal nematode parasites quickly contaminate pastures through their manure. Others then become infected as they graze on the same pasture. Small ruminant or camelid production systems that use grazing without pasture rotation, particularly in areas of high rainfall and ground moisture, are more likely to have infected animals. Droughts, inclement weather or lack of adequate forage (or pasture) may result in increased animal concentration, which can also equate to an increase in parasitism. Because of the increase in parasite egg production and fecal contamination around late pregnancy/early postbirth, breeding herds usually experience more gastrointestinal parasite problems than mature non-breeding animals. This periparturient rise in nematode egg output in small ruminants s feces can readily lead to pasture contamination and an increased risk of infection in kids living, or weaned, on a heavily contaminated pasture. Routine deworm 30 days prior to kidding and continue deworming through the birthing season for meat small ruminants s will help reduce the pasture contamination associated with this periparturient rise in EPG. Fecal egg count should be monitored during this period. GI parasites appear to have a negative effect on protein and to a lesser extent, on energy metabolism, and increase requirements of these nutrients in small ruminants s. Increasing dietary protein (particularly proteins rich in sulfur containing amino acids) intake will aid in overcoming some of the clinical signs seen with parasitism. Protein quality appears to have a more significant affect than the quantity. Supplemental soybean meal and energy can improve resilience. Dietary supplementation appears is more effective when targeted (ie. specific nutrients are deficient and the small ruminants s requirements for those nutrients are greatest). Given the complicated nature of parasite control and recent documentation of widespread resistance to deworming compounds in North America, meat small ruminants producers take a multi-pronged approach to parasite control: (1) Employ husbandry and feeding practices that minimize parasite infection; (2) Use novel deworming practices that maximize endectocide efficacy and minimize parasite resistance; (3) Consult with your local veterinarian and/or a state agricultural extension specialist.

2 Strategic Deworming Strategic deworming is an effective control regimen if reinfection from pasture grazing is minimal. Using a strategic program, producers should deworm animals: (1) Just before they are placed on dry lot feeding prior to winter management; (2) During winter when freezing conditions kill infective parasite larvae, lowering the incidence of reinfection from pasture grazing; and/or (3) Prior to the peripaturient rise in parasite eggs (one month pre-birthing). After deworming, meat small ruminants s should be moved, if possible, to a pasture with a low level of infective parasite larvae to help minimize the potential of reinfection. Those pastures are typically used for small grain or hay production, and are grazed by horses or cattle, llamas and alpacas. Treating young animals at weaning and moving them to a safe pasture is also a form of strategic deworming. Tactical Deworming Using a tactical program, a de-wormer is administered during the period of greatest pasture contamination. For example, animals are treated 10 to 14 days following a rain, especially if it follows a drought. Tactical deworming can also be used in response to an increase in fecal egg counts. Systems such as the McMasters fecal flotation quantify the number of nematode parasite eggs per gram of feces, allowing producers to identify and address parasitic infections before they become serious. Strategic and tactical regimens may also be combined, but doing so will result in a greater chance of recruiting anthelmintic resistance. Suppressive Deworming While suppressive deworming programs may be appropriate in certain situations and on some farms, many meat small ruminants operations face other challenges as a result of using this regimen. Suppressive programs call for deworming at regular intervals, usually two weeks to three months apart, which is expensive, labor intensive, and fails to use or take into account animals natural resistance to parasites. Using these programs reduces the farm/flocks natural refugia and enhances onset of anthelmintic resistance. If all animals are dewormed routinely, without regard to weather or production status, meat small ruminants s with some natural resistance to internal parasites cannot be identified, and parasite resistance to deworming compounds is magnified. With the exception of strategic and tactical deworming, routine deworming should be used cautiously, as it may result in animals building resistance to anthelmintics more rapidly. Other management Other management tools useful in controlling parasite associated diseases include: (1) Identify and remove animals from pasture that do not appear to be resistant to internal parasites. Culling these animals, while keeping and breeding meat small ruminants s that appear to perform better in the face of parasites, will enhance a herds overall production on a farm where parasites are a major problem. This will rarely be used in pet animal herds; (2) Ensure proper nutrition to help meat small ruminants s naturally ward off internal parasites and recover from parasite-induced damage after deworming; (3) Providing good forages and meeting protein, energy, mineral and vitamin requirements are critical to maximizing flock or individual meat small ruminants s

3 production and reducing dependence on deworming agents; (4) Inclusion of higher quality and higher concentrations of protein in the diet (emphasis on legumes), including browse for foraging animals; (5) Insuring adequate macro and trace minerals (with emphasis on Ca, P, Zn, Cu, and Se); (6) Allowing access to condensed tannin containing forages all will aid in the reduction of internal parasite burdens; (7) Feeding to meet nutritional requirements for optimal growth/production. These animals fed in such a manner as to improve health are usually more prone to have better resistance and resilience. Providing supplemental protein improves resistance & resilience, particularly with protected protein. Feeding forages with condensed tannins may help prevent parasitic disease. Some dietary/herbal modifications of the diet include: Feeding small ruminants s sericea lespedeza hay or pelleting sericea lespedeza. Feeding birdsfoot trefoil and sainfoin for ~ 2 wks appears to reduce the FEC.Feeding 600mg/kg bw of Orange oil emulsion can reduce the FEC by over 90%, Feeding Albizia anthelmintica bark has some effect by reducing the FEC by nearly 80% in some studies. Lippia sioides essential oil may also reduce the FEC by over 50% in some studies. Ethanolic extracts of Iris hookeriana rhizome may reduce the FEC by about 45%, whereas feeding Azadirachta indica (neem) leaves does not affect FEC when studied. Feeding Azadirachta indica seed may reduce FEC by up to 40%. Rotate pastures, allowing meat small ruminants s access to tannin and/or protein rich forages (legumes); use proper pasture fertilization techniques, and administer dewormers to maximize herd production while minimizing the harmful effects of internal parasites. Body condition scoring is the best tool for assessing long term energy adequacy. Body condition should be assessed on all members of the herd or flock on a bi-yearly to monthly basis. Body condition scores should be assessed in a 1-5 scale where 1 is extremely thin, 5 being morbidly obese. Scores of 2.5 to 3.5 are optimal. Animals with these optimal body condition scores will more likely become pregnant, lactate proper, more likely produce adequate, good quality colostrum, and be less likely to succumb to pregnancy toxemia Obesity should be avoided as it is associated with a greater incidence of dystocia, possibly poor milk production, some forms of pregnancy toxemia, and increased production costs. Whenever designing a feeding protocol for meat small ruminants s, Wikse s Four-Step Supplementation system designed for beef cattle operations is very applicable. After fresh, clean water requirements are met, then the nutritionist, veterinarian, and/or care giver should shift their focus on meeting the requirements for: 1) Energy; 2) Protein (maintain ~ 10% CP for entire diet for maintenance, and increasing this nutrient density in the diet based on changing requirements); 3) Vitamins; and 4) Minerals (free choice mineral salt w/ 8-12% Calcium and Phosphorus, and adequate trace minerals). Energy deficiency may occur because of inadequate feed intake, poor quality feedstuffs being offered, the inability to consume provided feedstuffs (eg. hoof or other orthopedic problem resulting in an inability to walk to graze, dental disease, etc). As previously described, body condition scoring systems are the most efficient method of assessing dietary energy adequacy. Energy requirements are affected by the small ruminants s age, body size, growth rate, pregnancy status, number of fetuses, stage or trimester of gestation, lactation, and stage lactation. Environmental effects on dietary requirements include: ambient temperature, humidity, hours of daylight, and wind velocity.

4 The most common sources of feedstuffs used for energy supplementation are carbohydrates, fats and some sources of protein. Forages should supply the largest amount of required energy. Small ruminants s can obtain almost everything they need from well-maintained pastures. Health issues may be associated with poor quality hay and the increased intake of grains. Feeding hay is at least three times as expensive as grazing, thus emphasis should be made on providing a good quality forage and maximizing and maintaining a good productive pasture. From an animal and plant nutritional standpoint, pastures should not be grazed too short:1-2 for bermudagrass and bahiagrass, 2-3 for tall fescue, 2-4 for orchardgrass and Timothy. Good practices for pasture management include: 1) allow time for plants to recover post grazing; 2) have more than one pasture and practice pasture rotation; 3) fertilize based on soil test; 4) maintain multi species of grasses and a good balance of legumes and grasses. Legumes (alfalfa, clover, kudzu, etc) should be part of any forage feeding program. Legumes have a higher concentration of protein, energy, Calcium, Vitamin A, and have a calcium to phosphorus ratio of 6:1. The optimum Calcium to phosphorus ratio should be between 1 and 2 to 1. A mineral with extra phosphorus may be needed to help balance the calcium to phosphorus ratio when legumes are the predominant forage fed. This author prefers to feed legumes at no more than one third of the entire diet, or use them as protein supplements. Grasses, when compared to legumes, tend to be lower in crude protein, energy, higher in fiber, with a more appropriate calcium to phosphorus ratio. Small ruminants s can obtain almost everything they need from wellmaintained pastures, and grass only forages may meet adults nutrient requirements, if offered at a rate of 2-2.5% of BW/day. However, young growing animals, animals lactating or being shown, or animals with debilitating diseases may need grass legume combinations, or concentrate supplementation. Small ruminants s have prehensile lips and small mouths, are active foragers. Small ruminants s can use browse that has woody stems or thorns, and tend to select highly digestible portions of forages. Small ruminants s select grass over legumes and browse over grass, and prefer to graze along fence lines, rough or rocky pastures, and in areas commonly not conducive for cattle grazing. Small ruminants s flourish in areas featuring browse, but perform poorly when compared with sheep or cattle on improved pastures. If given a choice, meat small ruminants s prefer a diet of 80% to 85% browse. Small ruminants s selectively consume forages using their mobile lips and tongue. Small ruminants s are particular about their diet and refuse to consume soiled feeds. Small ruminants s are effectively used for weed and brush control in many production systems, particularly when co-grazing with sheep or cows. Minimizing Resistance to Endectocides Ensure adequate intake of all deworming products by weighing each animal; avoid administering an average body weight dose, and properly use administration equipment.dosing or administering a dewormer based on average body weight will result in underdosing some small ruminants s (ineffective control of parasites), while others are overdosed (increased costs, possible toxicity). Identify small ruminants s that need deworming and only treat them to help diminish resistance to dewormers and slow the onset of dewormer-resistant parasite populations on farms. Management tool that identify individual that need de-worming and those that have greater resistance such as.famacha ), which identifies individual members of the flock that are anemic because of heavy

5 parasite burdens and would benefit from deworming. FAMACHA may also be effective in reducing the long-term use of de-wormers, increasing flock performance and lowering the incidence of parasite resistance to deworming agents. FAMACHA appears to be an effective tool for decision analysis of determining which small ruminants needs to be effectively dewormed, and when it should be dewormed. External Parasites When skin conditions are encountered in NWC, an oral history, physical examination, skin scraping evaluation and/or skin biopsy will help determine a causative diagnosis if mites are involved. Chorioptic mites are the most commonly encountered and the most difficult to control. Sarcoptic mites are less common, particularly in herds where ivermectin is used in the deworming program. Whenever mites are encountered, a complete examination of the herd s management program is warranted. The examination should include general healthcare, internal and external parasite control programs, and dietary analysis, including water, energy, protein, and mineral intake, and adequacies. Herds where large numbers of animals exist, cold, damp environments, lack of biosecurity programs, and large populations of some imported animals are more likely to have infestations. To prevent the infection from spreading halters, brushes, and other equipment should be thoroughly cleaned, or even burned. Your veterinary officer may advise that other animals in the community are treated even if they are not showing signs of the infection. As humans can become infected with the mite, care should be taken to always wash hands thoroughly after handling NWCs. Additional Reading Sheep and Goat Medicine, 2 nd Edition, Elsevier, 2011 Goat Medicine, 2 nd Edition, Wiley-Blackwell, 2009 Sheep and Goat Medicine, Elsevier, 2002 Pugh DG: Camelid Parasites and Nutrition. International Camelid Health Conference for Veterinarians, The Ohio State University, Columbus Ohio, March 21-25, pp SA:55-59.