Management Strategies to Reduce Stress-induced Behavioural Changes in Dogs and Cats

Description of the stress response

The term "stress" has been widely used in biology to describe a set of physiological and behavioural changes triggered by an unpleasant stimulus. In 1929, Cannon described the stress as an attempt of the sympathetic system to regulate homeostasis when the animal is facing an unpleasant stimulus. Later, Selye made one of his classic studies on the response of the hypothalamic-pituitary-adrenal (HPA) axis against noxious stimuli and suggested that the body reacts against a wide variety of unpleasant stimuli in a non specific way, mainly with an increase in HPA axis activity.

Both the HPA axis and the sympathetic system are generally considered the two key elements of the stress response, and the plasma concentration of glucocorticoids is often used as a measure of stress. However, the problem with this approach is that the HPA axis and the AMS system have a crucial role in energy mobilization and redistribution of nutrients to active tissues. Both unpleasant situations (e.g. fights) and the rewarding ones (e.g. reproduction and mating) can cause a similar physiological response. Therefore, if stress is to be considered potentially negative, considering it as a synonym of the activation of the HPA axis can be misleading.

On the other hand, sufficient currently available evidences show that the negative consequences of an unpleasant stimulus to the animal do not depend on the physical nature of the stimulus, but rather to the capability of foreseeing and control of that animal. Therefore, it has been suggested that the term "stress" should be only used in scenarios where the situation faced by the animal exceeds the capacity of regulation of the body, particularly when the situation involves a certain degree of unpredictability and lack of control. […]