Fear and Distress Adroaldo J. Zanella ANS 305

Objectives 4 1) to understand the concept of homeostatic control 4 2) to explore the inter- relationships between behavioral and physiological changes during difficult situations

Introduction 4 Freedom from fear and distress is listed in the Brambell Report and in the World Veterinary Association Policy Statement –Animal welfare codes/laws in many parts of the world.

Definitions 4 State of alarm or dread 4 An unpleasant or painful emotion elicited by danger 4 An expectation of pain 4 A behavior system which has evolved to ensure survival

Fear x anxiety 4 Anxiety is less specific and longer lasting “emotion” than fear. –General anticipation –Experienced before Behavioral signs oftentimes are identical

The flight response 4 When a fear-inducing stimulus is encountered, the animal adopts a vigilant or “orienting” posture. –Flee –Hide –Urinate and defecate more frequently –Decrease exploratory behavior and feeding –Reduced interactions with conspecifics

Stages of fear 4 Exposure to the frightening situation 4 Activation of the brain and neuroendocrine system 4 The animal will show one or more of a number of fear responses –Fight; flight or immobility 4 Individual responsiveness to the same challenge may vary

Assessment of fear 1) Approach latency 2) Behavioral responses defecation, urination 3) Physiological responses Open field test

Immobility 4 Some animals become immobile in fear- inducing situations 4 Prey animals –Tonic immobility in birds –Freezing behavior and bradycardia in rodents –Related to the intensity of the stimulus and duration

Other tests 4 Emergence tests 4 Responses to novelty 4 Exploratory behavior 4 Responses to positive and negative handling

Genetic & Environment 4 Individual differences –geneticaly determined –environmentaly induced 4 Control of the stressor 4 Predictability of the stressor 4 Emotional stress and physical stress

Our stress models 4 Maternal separation early in postnatal life: –(Yuan et al., 1999) –Hyperactivation of the hypothalamic-pituitary adrenocortical (HPA) axis (up to 3 days PW) –Development of behavioral abnormalities

Stress 4 An environmental effect on an individual that overtaxes its control systems and reduce its fitness of appears to do so.

HPA-AXIS ACTH Glucocorticoids Hypothalamus Pituitary Adrenal Glands CRF Adrenocorticotropic hormone Corticotropin Releasing Factor (Vasopressin)

HHPA-AXIS ACTH Glucocorticoids (GC) Mineralcorticoids (MC) Hippocampus Hypothalamus Pituitary Adrenal Glands CRF Antagonist Adrenocorticotropic hormone Corticotropin Releasing Factor GC/MC 11ß-HDS 1&2

Time to come near stockmanShorter the time to come near, larger the number of piglets reared per sow Time spent near stockmanLonger the time spent near the stockman, larger the number of piglets reared per sow Number of interactionsLarger number of interactions, the larger the number of piglets reared per sow Seabrook, 1984 Behavior of the stockmanPerformance

Behavioral Observation Results (Milk Yelding) HigherLower Mean entry time of cows to parlor9.9 sec/cow16.1 sec/cow Field flight distance0.5 m2.5 m Approaches to observer (herd)10.2 x min3.0 x min Dunging in the parlor3.0/hour18.2/hour Stockman touching the animals2.1 x min0.5 x min Stockman talking to the animals4.1 x min0.6 x min Behavior of the stockman & performance

ParametersPleasantAversive Time to interact119 sec157sec Growth rate709 g/day669g/day Glucocorticoids2.1ng/ml3.1ng/ml Hemsworth and Barnett (1987) (pigs & humans)

Hemsworth and Barnett (1987) (pigs & humans) ParametersPleasantMinimalAversive Time to interact48 sec96 sec129 sec Pregnancy rate 88%57%33% Age of mating161 days176 days193 days Glucocorticoids1.7 ng/ml1.8ng/ml2.4 ng/ml

Rushen et al, Cows handled in a negative way showed a larger amount of residual milk* than cows handled in a positive way (in the presence of the experimenter). 4 Cues used for recognition were mainly visual (color of clothes) – *milk obtained after injecting the cows with oxytocin,post-milking