WELFARE - Welfare Assessment

Question 1

Define a ‘stressor’

Answer 1

A stressor is an external challenge that has been imposed upon as animal

Question 2

Define ‘stress’

Answer 2

The biological response elicited when an animal perceives a threat to its homeostasis or when an animals is challenged beyond its behavioural and physiological capacity to adapt to its environment

Question 3

What are the three different types of stressors?

Answer 3

Psychological
Physical
Physiological

Question 4

What are the different types of stress?

Answer 4

Physical stress (distress)
Psychological stress (non-threatening stress)

Question 5

Describe the differences between acute, repeated and chronic stress

Answer 5

Acute stress: stress in response to a short term stressor
Repeated stress: stress in repose to the repeated application of a short term stressor
Chronic stress: stress in response to the long term exposure to stressors

Question 6

What does it mean when an animal has ‘habituated’?

Answer 6

An animal has habituated when the animal begins to respond in a less intense way/not respond at all to a repeated stressor

Question 7

What does it mean when an animal has ‘sensitised’?

Answer 7

An animal has become sensitised when the animal becomes more and more reactive in response to a stressor

Question 8

What are the biological defence responses seen in animals responding to stress?

Answer 8

Behavioural response
Autonomic nervous system response
Neuroendocrine response
Immune response

Question 9

Give an example of a neuroendocrine biological defence response

Answer 9

Hypothalamo-pituitary-adrenal (HPA) axis

Question 10

Give two examples of autonomic nervous system biological defence responses

Answer 10

Sympatho-adrenal system
Stress induced hyperthermia

Question 11

Describe briefly how the Hypothalamo-pituitary-adrenal (HPA) axis acts as a biological defence mechanism

Answer 11

1. In response to stimulation, the hypothalamus secretes a corticotrophin-releasing factor (CRF) which acts on the anterior pituitary gland
2. The anterior pituitary gland secretes the adrenocorticotrophic hormone (ACTH) which stimulates the secretion of glucocorticoids (cortisol or corticosterone) from the adrenal cortex into the bloodstream

Question 12

Describe briefly how the sympatho-adrenal system acts as a biological defence mechanism

Answer 12

1. Stimulation of the sympathetic nervous system directly innervates the adrenal medulla, triggering the secretion of catecholamines (adrenaline and noradrenaline)

Question 13

How does the HPA axis response differ from that of the sympatho-adrenal response?

Answer 13

The glucocorticoids secreted from the HPA axis show a graduated secretion depending on the severity of the stressor whereas catecholamine secretion from the sympatho-adrenal system is almost immediate and decays very quickly

Question 14

Why is measuring the catecholamine levels in the blood not very useful for welfare assessment?

Answer 14

Because catecholamines are released almost immediately and decay very quickly

Question 15

(T/F) Adrenaline release is associated with physical stress

Answer 15

FALSE. Adrenaline is associated with psychological stress and noradrenaline is associated with physical stress

Question 16

What are the advantages of measuring stress through hormone release?

Answer 16

Proportional results (i.e. increased stress, increased hormone present in the bloodstream)

Question 17

What are the disadvantages of measuring stress through hormone release?

Answer 17

• Lack of valance (hormones can increase and decrease in response to other positive and negative stimuli)
• Invasive (blood sampling and handing)

Question 18

Describe stress induced hyperthermia

Answer 18

An acute vascular response to stress leading to vasoconstriction causing a rapid increase in blood flow leading to an increase in core body temperature

Question 19

List the different methods that can be used to measure stress induced hyperthermia

Answer 19

Rectal probe
Implants
Thermography

Question 20

What are the advantages of using thermography to measure stress induced hyperthermia?

Answer 20

Non-invasive
Non-contact
Continuous assessment
Can capture the surface temperature changes also associated with stress