ANBI 411.3 Lecture 10: Lecture 10 and 11 ANBI411
20 Jun 2018
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Lecture 10: Fear and Distress
Fear: is an emotional response to the perception of immediate danger
Fearfulness: characteristic of an individual, susceptibility to fear
Stress: not all stress is bad
- Eustress (good) vs. distress (bad)
- Some stress is unavoidable
Anxiety: reaction to a potential threat
Fear and anxiety are stressors
- Primary emotions affecting animal welfare
- Responses characterized by physiological and behavioral reactions, preparing the animal
to respond
oSAM (sympathetic, adrenal, medullary)- epinephrine and norepinephrine
oHPA (hypothalamus, pituitary, adrenal) ACTH and cortisol
- Individuals vary in their fear response- affected by genes and experience
John Watson:
- Did experiments with baby albert
- Experiment was designed to show that fear could be learned and controlled by
experience
- He demonstrated classical conditioning
Fear is ideally an adaptive state, with fear responses protecting the animal from injury
- Fear is not innate, it can be learned
oRecognized that both genes and environment can contribute to fear response
- Function: animals in the wild benefit from fear responses. Increased
awareness/vigilance, protection from/avoidance of predation
ogroup of animals, one or more checking the environment while others are
grazing- protective feature to avoid predation
- in domestic environment: fear can be harmful
oacute fear: poultry piling, claw injuries, suffocation
oChronic fear, anxiety: reduced growth, poor feed conversion
Fear factors:
-Novelty: changes or new environments (handling, grouping, transport, multiple
stressors= synergistic)
-Human interaction: humans are responsible for handling and painful procedures; less
positive association with automated feed systems
-Domestication: selection has occurred for calmer temperaments, but fear response
persists
-Intensive systems: controlled, predictable environment, with low levels of stimulation.
Leads to overreaction to novel events
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Consequences of fear (acute or chronic) and anxiety:
- Energy wastage, reduced growth
- Delayed maturation
- Poor reproduction
- Handling stress
- Injury and pain
- Death losses/ disease susceptibility
- Financial losses
Measuring Fear:
- Fear is an emotional state
- Fearfulness is an individual trait
- Neither can be measured directly in animals
- Behavioral tests:
oOne test: fear “state”
oMultiple tests: “fearfulness trait”
- Physiological measures related to stress
oMetabolic and psychological markers
ometabolic changes could be due to stress response like muscular changes
opsychological markers as well
Measuring fear: Novel object test (NOT)
- behavioral test
- assesses fear and exploratory behavior directed towards a novel object
- animals tested singly or in groups
- a novel object is introduced into the centre of the pen
- less fearful animals are faster to approach and make contact
- measurements?
odistance between them and the object
ohave a stop watch and record the latency till the first animal makes contact
ocould measure how many pigs come in a certain distance over time
othe amount of time spent in contact with the object
- in a group you will have social interactions as well so the dominant animals way explore
first and the subordinate will hang back
- singly can influence responses as well because the animal is social and would be isolated
to do this test
Measuring fear: Human approach test (HAT)
- measures level of fear associated with humans
- handler enters the pen and remains stationary
- less fearful animals are faster to approach and make contact
- measure contact latency, frequency, duration
oamount of time it takes animal to make contact and the frequency of contact
Measuring fear: Novel arena test (NAT)
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find more resources at oneclass.com
- “open field test”
- measure of fear and exploratory behavior in a novel arena
- animal enters the pen and is observed over set time period
- rodents’ entry into the center squares indicated lack of fear
- rodent has a box and they see how long it takes the rat to come into the open arena and
then over a period of time they determine the penetration into the middle squares is
there lack of fear, also will measure defecate rates- increases defecate would indicate
fear
other behavioral tests for measuring fear
- tonic immobility in poultry
odeath feigning or playing possum
- startle/freeze response
otime to resume activity following startle
- eye white in cattle
ounder stress you see more of the eye white
- elevated plus maze
oexploration of open maze arms
ofearful would be in the closed arms and if less fear will spend more time on the
open arms
oused in testing of anxiolytic drugs
physiological measures of fear and stress:
- respiration rate
- heart rate; heart rate variability
- epinephrine, norepinephrine
- ACTH, cortisol
- CPK: creatine kinase- released from muscle with stain or bruising
- Blood lactate: physical exertion, product of anaerobic glycolysis
- Glucose in blood, glycogen in muscle or liver
Cortisol: the stress hormone
Most commonly used “welfare” measure- but use is limited as results are hard to interpret
- Levels not constant- follows “diurnal rhythm” (increases in the morning)
- Increase in response to excitement or stress
- Used to measure acute or chronic stress
- High individual variation; associated with temperament
- Sampling process causes stress- affecting results
Complex biochemistry
- Blood samples= total cortisol (free and bound)
- Saliva sample= free cortisol only (effective level)
- Feces= multiple cortisol metabolites
- Blood sampling is invasive and causes stress
- Saliva and feces are non-invasive methods
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Fear: is an emotional response to the perception of immediate danger. Fearfulness: characteristic of an individual, susceptibility to fear. Responses characterized by physiological and behavioral reactions, preparing the animal to respond: sam (sympathetic, adrenal, medullary)- epinephrine and norepinephrine, hpa (hypothalamus, pituitary, adrenal) acth and cortisol. Individuals vary in their fear response- affected by genes and experience. Experiment was designed to show that fear could be learned and controlled by experience. Fear is ideally an adaptive state, with fear responses protecting the animal from injury. Fear is not innate, it can be learned: recognized that both genes and environment can contribute to fear response. Function: animals in the wild benefit from fear responses. Novelty: changes or new environments (handling, grouping, transport, multiple stressors= synergistic) Human interaction: humans are responsible for handling and painful procedures; less positive association with automated feed systems. Domestication: selection has occurred for calmer temperaments, but fear response persists.
