Lecture 18

Question 1

What is aggression?

1pt

Answer 1

A physical act by one individual with the actual or potential result of harming, limiting or depriving the “fitness” of another.

Question 2

What is agonistic behaviours?

1pt

Answer 2

Broader term, includes all forms of behaviours associated with a conflict between animals, including both aggression and submission (e.g. threats, displays, retreats, immobilization)

Question 3

What is aggressiveness?

2pt

Answer 3

• is a personality trait shaped by genotype and early experience, and modulated according to psychological (win-loss ratio), physical (presence of horns, antlers) and physiological (hormonal status, health status) characteristics.
• Costly behaviour, important for animals to learn or give up soon.

save energy

Question 4

what are the types of aggressive behaviour?

5pt

Answer 4

• Offensive behaviour: Individual trying to gain access to a specific resource
• Defensive behaviour: Avoidance of an external intrusion
• Predatory: initiated by a hungry individual in the presence of a prey item.
• Organic origin: Irritable state elicited by a broad range of health issues (stress/frustration, pain, brain tumors, rabies).
• Mock fighting: A feature of social reactivity, is a variant of play behaviour. No harm is caused, but it’s a good experience to refine their motor skills.

aggression is the main cause for euthanasia

Question 5

What is offensive behaviour like?

4pt

Answer 5

Offensive: Individual trying to gain access to a specific resource
* Territorial: occurs in an area in which the animal has established itself. 40-60% of the cases.
* Sex related: stimulated by the proximity of 2 males not familiar with each other. Elicited by the same stimuli that elicit sexual responses.
* Instrumental Aggression: Learned response (reinforced)

Question 6

What is defensive behaviour like?

3pt

Answer 6

Defensive: Avoidance of an external intrusion
* Fear-induced: characteristic of confined or cornered animals that feel threatened, is preceded by escape movements.
* Maternal: elicited by the proximity of some agent that is threatening to a female’s young.

Question 7

How do you differentiate aggressions?

3pt

Answer 7

• Posture: Is not voluntary, is triggered by the neurons activated with each type of aggressive behaviour.
• Circumstances: When approached, when food is around, when you want to touch it
• Who is the aggression directed to: Owners, one individual in particular, other dogs

Question 8

What Causes aggression in farm species

4pt

Answer 8

• Mixing of unfamiliar animals
• Competition over food
• Spatial factors and overcrowding
• Frustration, Fear, Pain

Question 9

What are the differences in aggression between species?

6pt

Pig, cattle, sheep, goats, horses, chickens

Answer 9

• Pigs slash with tusks at opponents neck and shoulder, bites directed towards shoulder, neck, front legs and ears, some head knocks against opponent (no kicking).
• Cattle use horns and head to butt neck, shoulder, flank and buttocks. Kick with hind legs to the side (no biting).
• Sheep butt with head, often back up and charge - clashing head on (sheep do not kick or bite).
• Goats similar to sheep, butt heads, rear on hind legs and clash heads on downward thrust (goats do not kick or bite during fighting).
• Horses bites directed towards neck, shoulders, flank and legs, kick with hind legs. May defend front legs from bites by kneeling
• Chickens face each other with raised hackles and direct pecks at head and body: scratch with feet and spurs as they fly towards opponent.

Question 10

What are the consequences of fighting?

5pt

Answer 10

• Lacerations: Provide avenue for infections; skin damage & bruising results in reduced revenue. Leads to increased cut outs and downgrading of meat products.
• Injuries: The most common reason for culling bulls used in community pasture systems is lameness, often due to injuries suffered during male-male fighting.
• Natural activation of HPA axis, which may lead to immunosuppression.
• For pigs carrying a genetic defect can be lethal (Sudden death, Porcine Stress Syndrome) or cause a reduction in carcass value (PSE = Pale, Soft and Exsudative).
• Fighting depletes glycogen stores in muscles, which results in high pH and dark cutters

Question 11

How do you control aggression?

9pt

Answer 11

• Make accurate diagnostic on the reason of aggressive behaviours: offensive, defensive, organic source
• Castration: For offensive aggressions. Doesn’t work in females. May need additional treatment.
• Drugs: Useful while the drug is active, so you can implement other measures.
• Behavioural training: Change of dominance rank, socialization, flooding/habituation
• Increase serotonin: Through diet, exercise, drugs
• Castration, dehorning, tail docking, teeth clipping -Does not remove the cause of the aggression, but provide long term benefits. Most of them under close examination.
• Environmental design: Adequate space provision Allow animals to remove themselves from the situation.
• Provide sufficient food for group, and feeding space.
• Avoid mixing: Not always feasible