title: Hair cortisol varies with season and lifestyle and relates to human interactions in German shepherd dogs.
abstract: It is challenging to measure long-term endocrine stress responses in animals. We investigated whether cortisol extracted from dog hair reflected the levels of activity and stress long-term, during weeks and months. Hair samples from in total 59 German shepherds were analysed. Samples for measuring cortisol concentrations were collected at three occasions and we complemented the data with individual scores from the Canine Behavioural Assessment and Research Questionnaire (C-BARQ). Generalised linear mixed model (GLMM) results showed that hair cortisol varied with season and lifestyle: competition dogs had higher levels than companion, and professional working dogs, and levels were higher in January than in May and September. In addition, a positive correlation was found between the cortisol levels and the C-BARQ score for stranger-directed aggression (r = 0.31, P = 0.036). Interestingly, the factor "playing often with the dog" (r = -0.34, P = 0.019) and "reward with a treat/toy when the dog behaves correctly" (r = -0.37, P = 0.010) correlated negatively with cortisol levels, suggesting that positive human interactions reduce stress. In conclusion, hair cortisol is a promising method for revealing the activity of the HPA-axis over a longer period of time, and human interactions influence the cortisol level in dogs.
authors.affiliation: Linköping University, IFM Biology, 581 85 Linköping, Sweden.
authors.forename: Lina S V
authors.initials: LS
authors.lastname: Roth
authors.affiliation: Linköping University, Department of Medical and Health Sciences, 581 85 Linköping, Sweden.
authors.forename: Åshild
authors.initials: Å
authors.lastname: Faresjö
authors.affiliation: Linköping University, Department of Clinical and Experimental Medicine, 581 85 Linköping, Sweden.
authors.forename: Elvar
authors.initials: E
authors.lastname: Theodorsson
authors.affiliation: Linköping University, IFM Biology, 581 85 Linköping, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Jensen
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D004285:Dogs; D005260:Female; D006197:Hair / Q000737:chemistry*; D006801:Humans; D006854:Hydrocortisone / Q000737:chemistry*; D008019:Life Style; D008297:Male; D012621:Seasons
chemical_list: D006854:Hydrocortisone