What Stresses Us?
Types of Stressors
Psychological stressors
- Job interview
- Traffic
- Death in family
- Disease diagnosis
Physical stressors
- Broken leg
- Starvation
Psychological stressors most highly activate the HPA system.
Stress Responses
- Sympathetic (adrenaline)
- Hypothalamic-pituitary-adrenal system
- Brain activity
- Behavior
Stressors elevate circulating levels of HPA
Cortisol level is (the best?) measure of stress:
- BUT, it is not a perfect measure
- Not all stressors clearly elevate cortisol
- Cortisol can increase without stress
- System can become dysregulated with prolonged exposure
Cortisol is a good measure of the effect of relatively short-term psychological stressors, when other factors affecting HPA activity are controlled.
Experimental Conditions
Handling control “Base”
- Alone home
- Alone novel
- Dog novel
- Person novel
- Threat
Dogs entering animal shelters are confronted with an array of psychological stressors (e.g., novelty, uncertainty, separation from attachment figures). On entering the shelter, cortisol is higher on Day 1 than in pets at home.
Why should high cortisol levels matter?
- Welfare of dogs
- Long-term effects on behavior
- Adoptability
- Potential health effects
White blood cells are elevated on 1st day in shelter and continue to rise.
Can human interaction reduce the cortisol response?
- Human interaction is a key factor for improving the welfare of dogs in shelters.
- Human-dog interaction can counteract stress.
- Human interaction prevents enhanced cortisol elevation.
Specific human interaction in the shelter reduces cortisol response to:
- additional stressor (venipuncture)
- additional stressor at a later time (novelty)
Presence of a human, regardless whether they ignore, pet or play with the dog, stress response is reduced for the shelter dogs. Suppressed immune systems from high CORT levels of dogs in shelters means there is a potential illness risk throughout entire shelter.
Shelter stresses:
- uncertainty
- loss of control
- social separation
- novelty
- threat
CORT levels differ depending on the kind of life the dog has and medical conditions.
Final Notes
Key ingredient: human interaction away from the main kennel area significantly reduces stress.
Relinquished dogs didn’t find human petting as reassuring (per cortisol tests) as strays.
Circulating levels of the primary stress hormone, cortisol, are about three times higher than observed in pet dogs sampled in their owner’s homes.
As little as 15 minutes of interaction between humans and dogs can reduce the circulating cortisol response.
Multiple sessions continued to produce effects, and dogs entering the shelter as strays appeared more susceptible to stress than dogs released by their owners.
