10. Stress and stereotypies Flashcards
What is stress?
an inferred internal state
Events that precipitate stress (called stressors) elicit any of a number of coping mechanisms or adaptive changes, including behavioural reactions, activation of the sympathetic nervous system and adrenal medulla, secretion of stress hormones (e.g., glucocorticoids and prolactin), and mobilization of the immune system
Why does stress occur?
Stress occurs when animals have to make extreme and/or prolonged physiological and behavioural adjustments in order to cope with their environment (HSA, 2020)- not necessarily correct despite having a reference, if it were ‘chronic’ this statement would be more accurate
define stress
S Situations T That R Release E Emergency S Signals for S Survival
What are glucocorticoids?
glucocorticoid hormones- cortisol (mammals/fish) and corticosterone (amphibians/birds/reptiles
What are the roles of glucocorticoids?
- Drive gluconeogenesis
- Suppress reproductive processes
- Alter movement and feeding rates
- Impact immune functions
- Generally help an individual enter a “state of emergency” when an environmental stressor induces their release
What is the Hypothalamic-Pituitary-Adrenal (HPA) axis?
In response to stress, the hypothalamus releases Corticotropic Releasing Hormone, which activates the pituitary and secrete of Adrenocorticotrophic Hormone. ACTH stimulates adrenal to secrete glucocorticoid. Glucocorticoid performs a negative feedback on the secretion of CRH and ACTH.
What are the key attributes to stress responses?
- To promote physiological and psychological adaptation and are, therefore, beneficial and desirable
- Apparent stress reactions can occur in situations unrelated to stress, and therefore their presence alone is not sufficient to indicate stress
- Stressors may not necessarily be unpleasant (defined by the animal’s willingness to terminate the stressor), they can be pleasurable (eustress)
- Physiological and behavioral responses are stressor-specific and so the processes engaged to restore homeostasis or well-being also differ
- Responses to stressors are variable due both to individual (some individuals are better able to cope than others) and intraspecies difference
What types of stress is there?
- Physical – due to fatigue or injury
- Physiological – due to hunger, thirst or temperature control
- Behavioural – due to the environment, unfamiliar people or surroundings
What are stressors?
factors which cause stress such as noise or unfamiliar environment
What does the animals ability to cope with stress depend on?
The genetic background of the species, and the animal’s past experiences
How does stress become distress?
distress develops over a relatively long period of time; however, short, intense stressor(s) can also compromise animal well-being and induce acute distress.
Thus, an animal may be in distressed even if it appears to recover rapidly after the removal of the stressor or the conclusion of the procedure
define distress
Most definitions characterise distress as an aversive, negative state in which coping and adaptation processes fail to return an organism to physiological and/or psychological homeostasis (Carstens and Moberg 2000)
Distress can follow both acute and chronic stress, provided that the body’s biological functions are sufficiently altered and its coping mechanisms overwhelmed (Moberg 2000)
What is a maladaptive state?
learned helplessness, when an animal fails to respond to coping mechanisms
What factors influence stress and distress?
- Stressor duration and intensity, either of which is likely to produce behavioural or physical signs of distress
- Predictability and controllability i.e., the ability of the animal to control its environment
- Stress may induce insufficient or inappropriate changes in the behavioural and physiologic control systems, or inadequate or undesirable responses to their output signals
How does stress influence animal welfare?
by identifying how the stress affect the animal’s quality of life
