Basics of Swine Behavior: Behavioral Adaptation a Selection Tool?

Transcription

1 Basics of Swine Behavior: Behavioral Adaptation a Selection Tool? Janeen L. Salak-Johnson, PhD Associate Professor of Stress Physiology and Animal Wellbeing University of Illinois December 5, 2013

2 Domestication involved behavioral selection Early agricultural societies, pig production very common Highly resilient Mature quickly, Large litters Sustain on low-quality feedstuffs == Wild Pig traits Selection for domestication resulted in Reduced anti-predatory response Reduce aggression toward humans Successful reproduction in captivity

3 Genetically changed in relation to ancestors, which affected Various aspects of their behavioral adaptation traits, thus domestic pig uses slightly different strategies than wild counterparts Domestication changed reproduction/sexual behavior lead to increase in social tolerance between animals modified behaviors

4 Evolution of behavioral strategies Selected for FITNESS in natural environments Reproductive success not necessarily related to welfare MUST be equipped w/ FLEXIBLE behavioral strategies, which involves: Behavioral outputs and a decision mechanism enables animal to select best behavior under different conditions = Best strategy that renders largest fitness outcome One specific social situation requires animal to avoid conflict and assume subdominant rank; different situation [same animal] better off seeking conflict and attempt to be dominant == Trait selected is net benefit animals expected to assess costs//benefits of each behavior; select one that provides largest benefit

5 No new behaviors have developed No behaviors have completely disappeared Some fundamental behavioral patterns unaffected Essentially, altered release thresholds which results in modified strategies Example: strategies in wild vs. captivity are in different outcomes to achieve highest fitness [food searching different; maternal behaviors no differences

6 ONF ONF Lie Drink Lie Drink Sit Stand Sit Stand ASTRESSIN CRF ONF Lie Drink Sit Stand SALINE

7 Previous Experiences? Age? Adaptability? Lick Sit Walk Root Root Lick Walk Stand Sit

8 Behavioral disorders? Re-directive behaviors provide a behavioral outlet; appropriate in context, but toward an inappropriate stimulus [e.g., feather pecking==food pecking; but rooting?] Displacement behaviors appear irrelevant to the situation, some performed incompletely [e.g., sham-chewing incomplete satisfaction of innate drive; foraging and consuming; ranting and biting inability to nest build] Stereotypies are behaviors show repetitive pattern of activity w/ no obvious purpose or context [e.g., bar biting, pacing, tongue rolling] Evidence not always the case

9 Pig Behavior, Welfare and Health Issues Coping or adapting to challenges stress is part of life [feral and domestic swine], most often occurs in the content of social dynamics [feeding, mating, aggressive interactions] In principle, issues arise in pig production when there is a mismatch between a pig s instincts and its environment behavioral impulses expressed inappropriately when instinctual behavior is thwarted Feral pigs spend 75% of their active time in foraging-related activities [includes rooting, grazing and exploring w/ snout] Domestic pigs, uncertainty of these behaviors in confinement do they imply feeding motivation or exploratory behavior

10 * G X E * Age, Sex * Previous experience * Physiological status * Social status * Fundamental process * Sensory and CNS control * No behavior independent of genetics or environmental

11 Behavioral response to stressor Broad range that are adaptive in nature Highly dependent on characteristics Organism coping ability, dominance order Stressor duration, severity Most often indicative of fear & anxiety Exploratory, social interactions Locomotor, vocalization, inappropriate behaviors Changes in normal, not always causing new behaviors [magnitude and intensity, or frequency or combo]

12 Behavioral response to cope Doesn t always alleviate the stressor, but some component will still be part of every biological response to a stressor Provide clues to distress Limited knowledge about most behaviors == difficult to use it to predict [bad idea to use as only measure] interpretation Correlated w/ other measures? Behavior change w/out altering other functions Theoretical Framework (thermal stress)

13 Health or Behavioral Level Stress Response Behavior, health, and welfare Theoretical Framework Behavior Response Health Response Endocrine Response A B Graded Stress Level Behavior adjust to normal No physiological responses Mild stress, only behavioral Env t changes require behavioral/ physiological w/in normal range Not until prolonged period, behavioral changes not adequate Other physiological processes affected prepathological state or development of pathology Behavioral adjustments no longer adequate to return to homeostasis

14 Maternal behaviors Maternal ability behaviors [affects piglet wellbeing] Behavior during farrowing and lying down Nursing behavior Reaction to piglet s vocalizations Crushed piglets Factors affect maternal care behavior of sow Breed Crossbreds inferior instinctively than purebreds Yorkshire > Landrace [better care] Durocs > Landrace [aggression] Hormonal status Environment and management

15 Maternal behaviors Economic trait influenced by behaviors: # live piglets and # of piglets per farrowing, but increase in # farrowed does not affect # weaned Sow dependent and maternal care [Rothschild and Ruvinsky, 2011] Sow toward piglet--calmness [low cortisol to minor stressors], care when lying down to avoid piglets, few changes in behavior, and remaining in the nursing posture following milk ejection, protectiveness toward piglets Summary: differences in length of time spent caring for piglets and frequency of postural behaviors [postural changes standing up and laying night; different patterns of behavior toward the piglets

16 Maternal behaviors Farrowing disposition a new trait? High correlations [-0.66 to 0.67] and all favorable but 1 [exception WW] Schneider et al., 2011 Reaction toward litter Nervousness [piglets laid on] Agitation or aggressive toward piglets Genetic correlations 0.67 for WEI and disposition vs for activity score 0.53 for birth BW of piglet and activity score vs for farrowing disposition Lack of variation in farrowing disposition in data set may have masked significant genetic correlations?

17 Aggression Welfare and economic problems but serves variety of functions in an animal s life Obtain food Facilitate access to sexual partner Establish place in group [social aggression is extremely important form blind-folded] Teat order by 6 th day same teat 90% of time [heaviest and fist born most dominant] Hierarchy formation {weanling to older pigs] strong will assume rank if when separated Genetics, environment and hormonal control No clear evidence that selection for growth has had negative influence on aggression of pigs toward group members, progeny or humans UNLIKE poultry

18 Social Aggression Hierarchy Social animals [includes sexual and parental] Adv. reduce predation, improves foraging and rearing of offspring, thermoregulation and mating Disadv. more conspicuous to predator, competition within group reduces access to resources, and increase risk of disease Contributes to with-in group interactions Support: Social rank impacts pig well-being stress consequences based on rank Dominant sows birth more male pigs [best predictor of sow rank is her dam] Sows receive most aggressive acts less estrus behavior Subdominant sows smaller litters, lower pig birth BW [not due to genetic potential as much as poor nutrition]

19 Stress Reactivity and Aggressive Behavior HPA-related genes related to aggressive behavior and stress response potential useful markers? Murani et al., 2010 Stress elicited by aggressive encounters negative consequences on various biological functions Two gene candidates associated w/ stress responsiveness and aggressive behavior NR3C1 [both] and AVPR1B [aggressive only] Cortisol and Lesion scores Other potential candidates are lysine vasopressin and serotonin receptor 1A for high trait aggression in prepubertal gilts [D Eath et al., 2005]

20 Feeding behavior Feeding behavior changes, varies with age and stage of production dependent Greatly affected by social facilitation groups consume more than individuals One goes they all go May increase food intake offset by opposing tendency of sub to eat less in presence of dominant Appetite can have a genetic basis select genes that promote appetite?

21 Learning Behavior Can learn to perform many tasks make more correct response when trials are spaced in time rather than grouped [four trials four ten days rather than 40 in one day] Breed, Sex, and age differences exist Artificially raised pigs less errors on visual discrimination than do sow-raised pigs Yorkshires > Poland Chinas and crossbred intermediate Females > males Younger pigs > older pigs

22 Selection for production traits easier, why behavior? Serves as an interface between animal-environment and affected by internal and external factors Behavior of an animal [e.g., feeding, maternal] contributes to its fitness Modification in behavior may be indicative of potential welfare problem [stressors or difficulty adapting] Behavior Welfare [vice-versa] Biological response thwart negative consequences

23 Selection for production traits easier, why behavior? Behavioral adaptation enables animal to adjusts to favor its fitness in a particular environment Too much energy allocated to production reduces chances of success More robust animals maintain performance despite environmental changes

24 Adapted Animal = Good Welfare? Live in environments with certain features, types of food, opportunities to find and create shelter, types of social groupings, etc., == expectations for them to thrive when possess adaptations and fail to thrive when they lack adaptations Adaptations are reflective of Animal s evolutionary ancestry Genetic modifications [via domestication] Involve learning and development If animals are kept in environment similar to which adaptation evolved and individual developed expect close correspondence between an animal s adaptations and challenges it faces unlikely to be case

25 Circle A Adaptations possessed by animal Circle B Challenges faced by animal in its current circumstances Adaptations no longer serve important function Challenges for which Ex. Nest-building animal HAS corresponding Challenges for which animal LACKS corresponding adaptation adaptation Fraser et al., 1997; 2008

26 coping/adaptability strategies differ Short and Long-term: Physiology, Behavior, Health, Performance and Productivity Related to functional traits [low heritability] reproduction and health preserve or enhance fitness [survival] COMPLEXITY: Genotype x Environment dependent Other factors rank, management, feeding, etc.,

27 Behavioral adaptations of pigs to environmental changes is essential, but the genetic variation [esp. individual variation] in behavior is considerable, still should we consider animals and genotypes with a larger behavioral capacity for adaptation [ability to cope to changing environments] in our breeding programs? Which behavioral responses [ traits ] would be likely candidates? Remember strategies differ not only between species but within species based on age, environment, etc. But also based on challenges.

28 Behavioral traits and Selection? Evidence: G X E form behavioral characteristics and patterns Problems: Behavioral traits involve multiple gene actions [ complex array of neural and endocrine mechanisms], but may be single genes Many desirable traits are lowly heritable, Negative correlation with other traits Individual animal variation Possible solutions: Changes in environmental elements [e.g., social interactions, diets, temperature] and management strategies Genetic and phenotypic correlations with other measures

29 Leave you with one final thought.. A better understanding of the separate and interactive effects of the physical environment, pig traits and physiological and behavioral adaptations may provide novel, useful insights to further improve current management strategies and production systems, as well as overall well being of the pig