Neuro-endocrine basis of Behavioural Disorders in Farm Animals
1. Neuro-endocrine basis of Behavioural Disorders in Farm
Animals
Hari Om Pandey
ICAR-IVRI, Izatnagar
Bareilly-243122 (UP), INDIA
2. Behaviour
Observable activity in a
human or animal
The aggregate of responses
to internal and external
stimuli
A stereotyped, species-
specific activity
Behaviour?
4. Behaviour
qInstinct in the inherent inclination of a living organism toward
a particular complex behavior
qPerformed without exposure of prior experience
qAn instinct should be distinguished from a reflex, which is a
simple response of an organism to a specific stimulus
5. Fixed Action Pattern
q Sequence of unlearned innate behavior that is unchangeable
q Once initiated, usually carried to completion
q Triggered by sign stimulus
7. Acquired Behaviour
qConditional reflexes
qLearned responses
qGeneral habits
q A conditioned reflex is one acquired as the
result of experience
q When an action is done repeatedly the
nervous system becomes familiar with the
situation and learns to react automatically,
and a new reflex is built into the system
q Habits: a settled tendency or usual manner of
behavior
8. Acquired Behaviour
General habits
qA settled tendency or usual manner of
behaviour
qNew behaviours can become
automatic through the process of
habit formation
qOld habits are hard to break and new
habits are hard to form because the
behavioural patterns which become
imprinted in neural pathways,
qBut it is possible to form new habits
through repetition
11. Basis of Behavioural Disorders
Emotional and
feelings:
qHunger
qPain
qFear
qRage
qStress
qExcitement
(Fraser, 1980)
12. Behavioural Disorders
Emotional and Behavioral
Disorders
Anxiety disorders:
q Excessive fear
q Excessive worrying about
incidents
q Unnecessary repeated
behavior and thought
patterns
q Sudden rapid heartbeats
and dizziness
q Repeated flashbacks of
traumatizing events that
have occurred in the life
13. Emotional and Behavioral
Disorders
1. Biological factors:
q Genetics
q Abnormalities in the
neurological and
biochemical development
q Injuries to the central
nervous system
2. Psychoanalytical factors
Traumatic experience
3. Behavioural factors
q Lack of adaptive behaviours
q Exposure to maladaptive
behaviours
q Exposure to poor
environment
Emotional and Behavioral
Disorders
4. Phenomonological
q Improper use of defense
mechanisms
q Failure to learn about
oneself
5. Sociological/Ecological
q Destructive family
q Poor living condition
q Rejection by peers
q Expectation
q Culture
Factors Responsible for Behavioural Disorders
14. Factors Responsible for Behavioural Disorders
Emotional and Behavioral
Disorders
1. Biological factors:
q Genetics
q Abnormalities in the
neurological and
biochemical development
q Injuries to the central
nervous system
2. Psychoanalytical factors
Traumatic experience
3. Behavioural factors
q Lack of adaptive behaviours
q Exposure to maladaptive
behaviours
q Exposure to poor
environment
Emotional and Behavioral
Disorders
4. Phenomonological
q Improper use of defense
mechanisms
q Failure to learn about
oneself
5. Sociological/Ecological
q Destructive family
q Poor living condition
q Rejection by peers
q Expectation
q Culture
15. Denial of Behavioural Needs
Feelings and emotions
Kinetic behavior—intensive
animal husbandry
16. Animal Sociology
q Communication
q Aggression
q Territorialism
q Dominance and
q Symbiotic relationship
q Space
q Ventilation
q Illumination
q Bedding
q Diet
q Companionship
17. Behavioural Disorder?
q Discomfort relates to any adverse interference with animals normal
state of health and well being
q Stress is physical condition with extensive manifestations revealing
undue ‘tension’ or ‘anxiety’ relating to environmental factors
q Pain is recognizable by more positive behavioural signs such as
struggling, screaming, squealing, and convulsions
Stress and pain
(Fraser, 1980)
19. Neuro Endocrine Basis of Behaviour
qNeurons in neural system collect information
from both external and internal environment of
animal and produce responses to the
environment
qEndocrine system relies on hormones that
carry signals from glands via the body fluids or
blood to target organs
qSensory systems, a subset of the neural system,
act as the interface between an animal and its
external environment
(Breed and Moore, 2015)
21. Neural circuits and social decision
qNeural circuits are organized at three stages of social
processing i.e. input, integrative and output
qThe input stage contains specialized sensory channels that
eventually transduce socially important information like
pheromone-sensing systems —vomeronasal organ in rodents
(Keverne, 1999)
22. Neural circuits and decision
qThe input stage contains specialized
sensory channels that eventually
transduce socially important
information like pheromone-sensing
systems —vomeronasal organ in
rodents
qThe output stage of social processing
comprises socially-specific motor
patterns, including highly stereotyped
behaviours like allogrooming,
ritualized play, and threat and
submission gestures
(Keverne, 1999; Schino et al., 1988; Grant and Mackintosh; 1963, Deag, 1977; Moll et al., 2005)
23. Social Interactions
qAcute sensory inputs are
recognized by another individual
and are transformed into a
behavioural decision; the decision
of second individual may in turn
generate new sensory cues for the
first individual, who will
consequently exhibit a behavioural
decision based on these cues
Figure adapted from; Chen and Hong, 2018
24. qThe behavioural decision of an individual is influenced by a high level of
uncertainty due to the inability to reliably predict the behavioural response
from the other individual
qFor instance, if a male is exposed to a male intruder, it may initially engage
in sniffing or close investigation and subsequently decide to attack the
intruder, or, alternatively, simply ignore it
qDifferences in behavioural progression and action selection can be shown
by the same animal, despite the fact that the exact same sensory cues are
present
q Factors that are internal to the individual, which we loosely and broadly
refer to as internal states, may directly modulate the sensorimotor
transformation into behavioural decisions
Social Interactions
(Anderson, 2016; Dayan, 2012)
25. • The diversity and social specificity of
sensory cues make social behaviours
uniquely complex
• The coordinated combinations of cues
are used in shaping the behavioural
output
• A classic example is that a male mouse
exposed to female cues may initiate
behavioural programs related to
mating, while exposure to male cues
may lead to displays of aggression
Social Interactions
(Figure reproduced from; Chen and Hong, 2018)
26. Influence of Hormones on Animal Behaviour
qHormones are strongly involved in brain
development and expression of
fundamental behaviours like feeding,
fleeing, fighting, and mating
qNeuropeptides, set the tone for state-
specific neuronal signaling by altering
chemical transmission within individual
neurons as well as across networks of
neurons
(McEwen, 2007, Keverne, 2004, Adkins-Regan, 2005; Belin and Moos, 1986)
27. qOxytocin and vasopressin are primarily involved in basic reproductive
functions in mammals for example parturition and lactation in females and
erection and ejaculation in males
qExogenous application of oxytocin can promote emotions like trust and
encourage generosity, in a context-dependent and sometimes
idiosyncratic fashion
qThe anxiolytic effects of oxytocin may have served as a preadaptation for
the prolonged interaction necessary for high-intensity parental care in
mammals by promoting approach behaviour and enhancing tolerance
Influence of Hormones on Animal Behaviour
(Donaldson and Young, 2008; Kosfeld et al., 2005; Zak et al., 2007; Bartz et al., 2011)
28. Neuro Endocrine basis of behaviour
q Physiologically both endocrine and nervous system are highly integrated affecting animal
behaviour to a great extent.
q Nerve cells can synthesize and secrete hormones; the behavioural effects of hormones are mediated
by their actions on neurons, and the brain regulates the endocrine axes.
30. Influence of stress on animal behaviour
qSAM axis parameters such as assessment of
heart rate variability and endocrinological
parameters like cortisol levels are typically
taken into account to measure acute stress
qHypothalamic corticotropin releasing factor
(CRF), arginine vasopressin (AVP), pituitary
adrenocorticotropic hormone, and adrenal
glucocorticoids comprise the HP Aaxis
qBehavioural measures and HPA axis
functioning are most often used to infer
potential chronic stress
(Bunt, 1986 ; Smith and Vale, 2006) SAM: Sympathetic-adrenal medulla
HPA: Hypothalamic-pituitary-adrenal cortex
31. Influence of stress on animal behaviour
qGlucocorticoids are produced in
response to disruptions of the
homeostasis and are necessary to
mobilize the energy required to cope
up from prevailing stress
qChronic stress has always been of
major interest in animal welfare
research, since concerning behaviour
stereotypies were associated with
compromised welfare and chronic
stress
(Smith and Vale, 2006; Goel and Bali, 2006; Mastorakos and Pavlatou, 2005; Baker et al., 2015)
32. Influence of stress on animal behaviour
qAlternation in long-term HPA axis is assessed by measuring fecal or hair
cortisol
qHPA axis stimulation tests such as adrenocorticotropic hormone (ACTH) or
corticotropin releasing factor (CRF) challenge tests are considered as potential
tools for the assessment of long-lasting effects of stress
(Bunt, 1986; Mastorakos and Pavlatou, 2005; Baker et al., 2015)
33. qSeveral management factors as well as personality traits have been
investigated in relation to stress responsivity in horses. For instance, a
lack of social contact was linked to changes in stress-related
physiology and behaviour
q Feeding patterns, a restriction of forage intake or pasture time —
stereotypies as indicators of chronic
qIn captive and domesticated animals, chronic stress can be seen as a
result of unnatural husbandry practices, such as early weaning, social
isolation, or dietary restriction, which can negatively affect the HPA-
axis
Influence of stress on animal behaviour
(Denver, 2009; Turnbull et al., 1995; Gross et al., 2015; Redei, 2008; Myers et al., 2014)
34. Different behavioural disorders
In conflictive or frustrating situations,
a particular fixed-action pattern is
observed with no apparent goal or
function
Stereotypic disorders
Stereotypies can be defined as repetitive,
relatively invariant or constant patterns of
behaviour and appear to serve no obvious
purpose
(Dantzer, 1986; Mason, 1991; Mason, 2006; Cooper and Dourish, 1990, Stein, 1992)
35. Different behavioural disorders
• Represent a partial sequence of
the fixed-action pattern
• In horses and other ungulates,
different forms of stereotypies
exist, including crib-biting,
windsucking and weaving
• The neurobiological substrate for
these phenomena is complex,
there is evidence for involvement
of the dopaminergic and
serotonergic systems
(Mason, 2006; Cooper and Dourish, 1990, Stein, 1992)
36. • Crib-biting: the horse anchors its upper incisor teeth on
a surface, leans back, tenses its neck muscles, retracts
its larynx, and engulfs a bolus of air
• Sequelae include teeth erosion, neck hypertrophy, and
flatulence
• Horses may occasionally present with self-mutilation
stereotypies. There is anecdotal evidence of response
to narcotic antagonists
• Horses with self-directed aggression may have other
abnormalities such as circling, kicking and head
movements, and squealing
(Kiley-Worthington, 1983; Ralston, 1982; Dodman et al., 1988; Rushen, 1984, Appleby and Lawrence, 1987 )
Different behavioural disorders
37. • These symptoms may respond to neuroleptics,
clomipramine, and opioid antagonists
• These behaviours are initially locomotive and
investigatory, but may progress to become self-
directed
• Endogenous opioids may play a role in the
persistence of swine stereotypies, and naloxone
has been shown to inhibit these behaviours
(Kiley-Worthington, 1983; Ralston, 1982; Dodman et al., 1988; Rushen, 1984, Appleby and Lawrence, 1987 )
Different behavioural disorders
38. Aggression
• Moyer (1968) classified these into seven classes,
predatory, intermale, fear-induced, irritable,
territorial, maternal, and instrumental.
• They are normal forms of aggression and should not
necessarily be labelled as pathological aggression.
• Reis (1971) reclassified these classes into two
categories, affective aggression and predatory
aggression.
• Affective aggression is generally between members
of the same species, is accompanied by significant
arousal, and may be offensive or defensive
(Borchelt, 1983, Hart, 1985).
39. Aggression
• Predatory aggression is generally between
members of different species and is not
accompanied by marked arousal
• In the cat, for example, stimulation of the
lateral hypothalamus leads to predatory
aggression, whereas stimulation of the medial
hypothalamus evokes affective aggression.
• Tricyclic antidepressants decrease predatory
aggression but increase affective aggression in
rats
• Intermale aggression and maternal aggression
are mediated by hormonal factors, but other
forms of aggression may be less hormonally
dependent
(Moyer, 1968; Eichelman, 1992; Houpt and Wolski, 1982)
40. • Environmental factors
• Crowding or prior social isolation
• Threat to the young has a specific role in
initiating maternal aggression
• Pathological aggression
• Psychomotor epilepsy with aggressive
episodes has been documented in dogs
• Simple environmental measures may be
useful in reducing
Aggression
(Carithers, 1973; Borchlet and Voith, 1985; Chapman and Voith, 1990
41. • Providing pigs with objects to chew on or soil to root in reduces
tail-biting
• Socialization during development is important in reducing
territorial social aggression toward humans
• Castration is commonly used to prevent intermale aggression,
and long-acting progestins may also be helpful
• Hormonal treatments and ovariohysterectomy may be useful in
controlling maternal aggression
• Antiaggression psychotropics for domestic animals
(Van Putten, 1969; Hart, 1973, Hopkins et al., 1976, Blackshaw, 1991; (Hart, 1980, Symoens and van
den Brande, 1969)
Aggression
42. Anxiety disorders
• Fearful responses to harmful stimuli are normal behaviours
seen in all domestic animals
• Genetic factors may comprise an important determinant of
animal anxiety; genetically nervous breed of pointer dogs
• In cats, “anxious personality” is associated with preferential
transmission of stimuli from basal amygdala to ventromedial
hypothalamus” but the effects of psychotropics are not well
studied
(Reese, 1979, Weiss and Uhde, 1990; Murphree et al., 1974; Trancer et al., 1990; Adamec, 1991).
43. Anxiety disorders
• Environmental determinants of chronic anxiety in domestic
animals have also been noted
• Scott and Fuller (1974) have described how nervous mothers
unwittingly teach their pups nervous behaviours
• In addition, disruption of normal attachment processes may
lead to separation anxiety
• Treatment of fearful companion animals traditionally consists
of behavioural therapy
44. Eating disorders
• Anorexic behaviour is uncommon in most domestic animals and may
indicate an organic disorder.
• However, psychogenic anorexia may be seen in cats, typically in
kenneled animals. Diazepam may be useful for anorexia in some
domestic species.
• Psychogenic polyphagia and polydipsia have occasionally been
reported in dogs (Fox, 1968)
• Pica in domestic animals is rarely the result of nutrient deficiency, and
more usually represents a habit (Houpt and Wolski, 1982)
• Given the paucity of studies on animal eating disorders, the
relationship between animal and human eating disorders remains
unclear
45. Sexual disorders
• Problems with sexual behaviours of breeding males are common in domestic
species. These include disinterest in females, impairment in erection, and
impairment in ejaculation. Also, male animals raised away from females or with
another species may not develop normal responses (Beach, 1968; Zenchak and
Anderson, 1980)
• Too much sexual experience too early can also lead to decreased libido later on
(Houpt and Wolski, 1982)
• New or different surroundings or a slippery floor may lead to sexual reluctance. In
some species, problems can arise if the breeding male is submissive to males in
nearby pens or if a young male is used with an older, more dominant female
• Decreased libido can develop in stallions used as “teasers” for detecting estrus
but not breeding, and in stallions submitted to excessive discipline and rough
handling. Treatment methods include olfactory stimulation and stimulation by
watching mating animals (Pickett et al., 1977)
46. • In 1979, Cort Pedersen and Arthur Prange injected oxytocin directly
into the nervous system
• A quick onset of maternal behaviour in estrogen-primed, naive
females; they were also able to block maternal responses with an
oxytocin antagonist
• In studies of maternal behaviour in sheep conducted in the early
1980s, Barry Keverne and his colleagues also proved that oxytocin
was involved in the formation of the mother–infant bond.
• Oxytocin has since been implicated in the downregulation of anxiety
and fear, while vasopressin and the functionally related peptide,
corticotropin releasing hormone, typically have opposing effects on
these processes
Role of Hormone in Parenting and Pairing Behaviour
47. Disorders associated with parenting and pairing
behaviour
• One of the clearest activational effects attributed to
hormones is female parental behaviour. To ensure
the survival of young offspring and occurs in both a
juvenile-directed (juvenile grooming) and non-
juvenile-directed (defense against intruders)
manner
• Investment in parental care is often higher by
females compared to males, although this is highly
species and context dependent
(Clutton-Brock and Parker, 1992)
48. 1. Freedom from hunger and thirst – ready access to
water and a diet to maintain health and vigour
2. Freedom from discomfort – by providing an
appropriate environment including shelter and a
comfortable resting area
3. Freedom from pain, injury and disease – by
prevention or rapid diagnosis and treatment
4. Freedom to express normal behaviour – by providing
sufficient space, proper facilities and company of the animals
own kind
5. Freedom from fear and distress – by ensuring conditions
and treatment which avoid mental suffering
In 1965, the United Kingdom (UK) government commissioned an
investigation, led by Professor Roger Brambell, into the welfare of
intensively farmed animals, partly in response to concerns raised in Ruth
Harrison’s 1964 book, Animal Machines
Five Freedoms
