War Exposure and Canine Cortisol Responses: Country Differences in Cortisol Profiles of Therapy Dogs

Dog-assisted interventions (DAIs) are an established procedure to support military staff, but their implementation during active warfare has not yet been systematically studied. In addition, the welfare of therapy dogs participating in DAIs during war remains unexplored. Therapy dogs may develop clinically relevant emotional disorders, including trauma-related stress responses, analogous to human psychopathologies. The present study sought to monitor physiological arousal in therapy dogs performing DAI sessions with their handlers in two Ukrainian military hospitals (Vinnyzja and Kyiv). Biomarkers of hypothalamic-pituitary-adrenal (HPA) axis activity, including salivary, urinary, and hair cortisol concentrations, were assessed in Ukrainian (UA) therapy dogs to capture their acute and long-term stress responses. Additionally, cortisol levels in German (GE) therapy dogs performing similar DAIs under peaceful conditions were measured to compare cortisol levels between dogs from both regions. Results suggest that GE therapy dogs exhibited significantly higher urinary concentrations, reflecting alterations in longer-term glucocorticoid secretion that is possibly caused by war-related stimulation in the UA cohort. In contrast, no significant differences in salivary cortisol emerged as a consequence of performing DAIs. The present findings suggest that the environment rather than involvement in DAIs has an impact on therapy dogs' cortisol secretion.