Note: Prescription only after diagnosis; never as sole treatment.

The old paradigm dismissed fear, anxiety, and stress as unavoidable side effects of medical care. "The cat is just mean" or "The dog is being dominant" were common refrains. This led to a cascade of negative outcomes: misdiagnosis (aggression mistaken for dominance rather than pain), compromised welfare, and burned-out veterinary professionals facing defensive, dangerous patients.

The concept of allostatic load (the wear and tear on the body from chronic stress) is now a cornerstone of veterinary science. When an animal is in a prolonged state of fear or anxiety, the hypothalamic-pituitary-adrenal (HPA) axis remains activated, flooding the body with cortisol. The physiological consequences are measurable:

Evolutionary biology dictates that prey species (horses, rabbits, cattle, and many birds) mask signs of illness to avoid predation. By the time a clinical symptom (such as recumbency or tachycardia) is obvious, the disease process is often advanced. Veterinary science relies on the early detection of behavioral deviations—such as a horse standing isolated from the herd or a rabbit exhibiting reduced fecal output—to intervene successfully.