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.

Analysis of cortisol in dog hair - a potential biomarker of chronic stress: a review

“…Competition dogs had higher hair cortisol concentrations than both companion and working dogs and this was especially obvious in January (Roth et al 2016). Cortisol increases could possibly be related to variations in the number of training days, as competing dogs usually train less during the winter and more during the spring, in accordance with the competition season.…”

“…It had been assumed that the amount of cortisol in a dog's coat increases with increasing age, but the research has not confirmed this hypothesis (Bennet and Hayssen 2010; Svendsen and Sondergaard 2014;Roth et al 2016). No correlation between HCC and age was found in grizzly bears (Macbeth et al 2010), polar bears (Bechshoft et al 2011) or humans (Kirschbaum et al 2009).…”

“…Cortisol increases could possibly be related to variations in the number of training days, as competing dogs usually train less during the winter and more during the spring, in accordance with the competition season. Alternatively, the dogs might simply be less exercised after the competition season, which might induce restlessness (Roth et al 2016). Due to the gradual growth of dog hair after trimming or shaving, hair regains its initial length at varying rates (for example, in Labradors kept indoors, the hair grows back in approximately 14.5 weeks according to Diaz et al 2004).…”

“…The body areas used for hair sampling prior to HCC analysis have varied slightly in different studies. Hair was taken from the cephalic vein area (Ouschan et al 2013) at two sites -the chest and neck (Veronesi et al 2015;Rosen 2016;Roth et al 2016;Willen et al 2017), the ischiadic region (Accorsi et al 2008;Bennet and Hayssen 2010;Siniscalchi et al 2013;Svendsen and Sondergaard 2014;Park et al 2016), right and left shoulders (Bryan et al 2013) or from the xiphoid region (Corradini et al 2013). Hair was collected either by an electric shaving razor or surgical scissors, and is gathered by cutting as close to the skin as possible without injuring the dog.…”

Cortisol Concentrations in Hair, Blood and Milk of Holstein and Busha Cattle

“…As can be seen from the results of this study, the cortisol concentration in Busha cows and heifers was significantly lower in the distal part of the hair, in comparison to proximal part. Since it was reported that solar (UV) radiation destroys cortisol (23,24), we believe that this also happened with the cortisol in hair of Busha cattle. These were kept outside and exposed to varied weather conditions which might have resulted in gradual cortisol degradation in the hair.…”