principle by xiuliliaofz

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									  Behavior in Domestic Animals




Andrew U Luescher Dr med vet, PhD, DACVB, ECVBM-CA
        Definition of Behavior
• Behavior could be defined
  as that part of regulatory
  mechanisms that is
  observable at the level of
  the entire animal
• The relationship between
  behavior and physiology is
  similar to the one between
  physiology and
  biochemistry
    Control of Drinking Behavior
• Lateral Hypothalamus: Osmoreceptors
  – Mild dehydration results in increased release of
    ADH from posterior pituitary
  – Stronger dehydration stimulates thirst centers
• Baroreceptors in cardiac blood vessels
  – Increase vasopressin (=ADH) release
  – Via vagus nerve initiate drinking
    Questions about Behavior

• Why do pigs     • Stimulus control of
  wallow in mud     behavior
• Why do pigs     • Motivation
  wallow in mud
• Why do pigs     • Behavior genetics
  wallow in mud
• Why do pigs     • Evolutionary
  wallow in mud     causes of behavior
Causes of
Behavior

• Stimulus control
• Motivation
• Genetics
  (Domestication)
• Evolutionary causes
  (Adaptation)
• Effects of experience
  (Learning)
 Proximate Causes of Behavior:
       Stimulus Control
Behavior could be classified as to how rigid
  the association between the behavior pattern
  and the triggering stimulus is
• Reflex
• Fixed action pattern
• Modal action pattern
• Learned behavior
Reflex
• Consistent, predictable
  response to specific
  stimulus
• Rigid stimulus-response
  association
• Simple neural pathways
• Highly genetically
  programmed
• Involuntary, not
  influenced by motivation
    Proximate Causes of Behavior:
          Stimulus Control

•   Reflex
•   Fixed action pattern
•   Modal action pattern
•   Learned behavior
    Fixed Action Pattern (FAP)
• Fairly consistent
  response to a
  specific stimulus
  (key stimulus)
• Can occur alone
  or as an element
  of a behavioral
  sequence
• Influenced by
  motivation
 Proximate Causes of Behavior:
       Stimulus Control

• Reflex
• Fixed action
  pattern
• Modal action
  pattern
• Learned
  behavior
  Modal Action Patterns (MAP)
Most species-specific
  behavior of domestic
  animals is made up of
  MAPS
Similar to FAP but more
  variable SR association,
  and more influence of
  learning
Defined by:
• Motor pattern
• Releasing stimuli
• Motivational factors
        Modal Action Pattern




• Genetically pre-programmed
          Modal Action Pattern
• Variable within limits.
  Influenced by
   – Spatial restriction
   – Availability of
     releasing stimuli
   – Learning
   – Early experience
          Modal Action Pattern
• In absence of
  natural releasing
  stimuli:
   – redirected activity
   – vacuum activity
   – Stereotypy/
     Compulsive
     behavior
Redirected and Vacuum Behavior
    Proximate Causes of Behavior:
          Stimulus Control

•   Reflex
•   Fixed action pattern
•   Modal action pattern
•   Learned behavior
    – see lecture on learning
       Causes of Behavior

•   Stimulus control
•   Motivation
•   Genetics (Domestication)
•   Evolutionary causes (Adaptation)
•   Effects of experience (Learning)
 Proximate Causes of Behavior:
          Motivation
• Animals do not always respond to releasing
  stimuli
• In absence of releasing stimuli, animals may
  – show appetitive behavior
  – redirect behavior
  – perform vacuum activity
• Variability of input/output necessitates
  concept of motivation
       Models of Motivation
• Homeostatic model of motivation:

 Behavior Program         Actual Value

 Comparison               Perception

 Target (set) Value
Variables Influencing
     Motivation
                 Homeostasis
• Control of drinking behavior
• Control of food intake: effect of physiological
  signals on hypothalamus
• Temperature control
Hormones and
Behavior

• Priming of the
  male brain
      Hormones and Behavior
• Melatonin and yearly breeding cycle
• Hormones and estrus cycle (estrogen and
  progesterone)
• Hormones and maternal behavior
  (progesterone , estrogen and prolactin ,
  oxitocin
     Pheromones and Behavior
• Chemical signal, often
  non-volatile
• In urine, skin glands,
  anal glands, etc
• Often need
  transformation by
  bacteria
          Vomeronasal Organ
• Perceived through
  vomeronasal organ,
  flehmen response
• Opens into mouth
  and nose except
  dog (mouth only)
  and horses (nose
  only)
     Pheromones and Behavior

• Primer pheromones
  – Physiological effect,
    e.g., earlier puberty
• Signaling pheromones
  – Immediate behavioral
    effect on receiver, e.g.,
    individual recognition
     Time Since Behavior was
         Performed Last
• Increased
  frequency and
  intensity with
  increased
  deprivation
  time
• Only valid
  within certain
  time limits
Circadian
Rhythms

• Internal biological
  “clock” with a phase
  length of
  approximately (circa)
  24 hours
• “Clock” needs to be
  reset every day by
  external stimuli like
  light/dark cycle
           Releasing Stimulus
• The releasing stimulus
  (target) enables the
  animal to perform a
  behavior
• Presence of the
  releasing stimulus also
  motivates animal to
  perform the
  corresponding
  behavior
           Social Facilitation




• One animal performing a behavior motivates other
  animals to perform the same (type of) behavior
• Results in synchronization and successful
  competition within group
      Learning and Motivation

• Conditioned,
  discriminatory and
  reinforcing stimuli
• See lectures on
  learning
Effects of Motivation
         • Animal will be motivated
           for appetitive and
           consummatory behavior,
           i.e. all behaviors related to
           that motivational system
         • In animal husbandry,
           frequently only
           consummatory behavior is
           accommodated
         • Examples: feed search,
           nest building
       Causes of Behavior

•   Stimulus control
•   Motivation
•   Genetics and Domestication
•   Evolutionary causes (Adaptation)
•   Effects of experience (Learning)
Domestication
• Involves genetic
  changes in response to
  association with
  humans, captive
  environment and
  husbandry, and
  developmental events
  reoccurring during
  each generation.
Domestication: Genetic Changes
• Adaptation (natural
  selection) to co-habitation
  with humans
• Genetic adaptation to
  captive situation
• Relaxation of natural
  selection pressure
• Inbreeding
• Genetic drift
• Artificial selection
        Times of Domestication
•   Wolf               12,000
•   Bezoar Goat        10,000
•   Sheep?              9,000
•   Eurasian Boar       9,000-11,000
•   Auerochs            9,000
•   Przewalsky Horse    4,000- 6,000
•   Libyan Cat          4,000- 5,000
•   Red Jungle Fowl     4,000
•   Turkey              1,000
      Effects of Domestication
• Behavior change due
  to physical change
• Hypertrophy or
  Hypotrophy of
  behavior
• Decreased selectivity
  for releasing stimuli
• Disruption of behavior
  sequences
        Effects of Domestication
• Neoteny
  – retention of juvenile
    characteristics that is
    produced by
    retardation of somatic
    development
  – prolonging juvenile
    developmental stages
    (e.g. allometric
    growth of skull) or
    arresting development
    at a juvenile stage
    (e.g. predatory
    behavior)
Neoteny in Various Breeds of Dogs
    Effect of Domestication on
    Behavioral Repertoire of a
              species
• Generally surprising little change: Most
  behavior patterns are still intact, no new
  patterns have developed
• Example: periparturient behavior in sows
       Causes of Behavior

•   Stimulus control
•   Motivation
•   Genetics (Domestication)
•   Evolutionary causes (Adaptation)
•   Effects of experience (Learning)
Arguments for Evolution Theory
• There is
  considerable
  variation among
  individuals
  belonging to
  any population
  of animals of
  the same species
• Much of this
  variation is
  genetically
  inherited
Arguments for Evolution Theory
• There are many more
  individuals born in
  each generation than
  can survive to
  maturity
           It Follows That...
• Individuals are not equally likely to survive
• Individuals with traits that make them best
  fitted (most successful) to that environment
  survive
• They are more likely to reproduce
• Their genes will spread through the
  population
  Example of Natural Selection
    Resulting in Adaptations
• Peppered Moth
  – Naturally, very small
    percentage are black.
    Select appropriate
    background
  Example of Natural Selection
    Resulting in Adaptations
• Peppered Moth
  – England 1895: 98%
    black in industrial
    areas
         Cultural Transmission

• Traits can be
  passed on from
  one generation to
  next through
  learning =
  cultural
  transmission
Cultural
Transmission

• Many traits have a
  component of both
  (e.g., bird song)
              Sexual Selection
• Sexual selection occurs in species with differential
  input into parenting.
• The partner of the gender that puts more effort
  into parental care becomes a limited resource. It is
  choosy, other sex develops features to attract
  partners and out-compete competitors.

								
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