Signs of Anxiety and Salivary Copeptin Levels in Dogs Diagnosed with Separation-Related Problems in a Short Separation Test

SIMPLE SUMMARY: Up to 56% of the general dog population show signs of separation-related problems, a group of problems characterized by highly variable phenotypes on which research, to date, has mostly provided contradictory findings. In the present study, we analyzed the behavior and salivary concentrations of copeptin, a biologically stable biomarker of stress, in dogs with separation distress and in dogs with no problems. The animals were tested before, during and after three-minute separation from the owner, in a new environment. Dogs in the two groups differed significantly in their activity levels and stress-relief activities during the three observation phases. In addition, a different tendency in the two groups was found in salivary copeptin concentration behavior. ABSTRACT: The need for faster diagnosis and more accurate treatment decisions in separation-related problems (SRPs) in dogs is urgent, and a more precise behavioral phenotyping and the development of biomarkers may be of great value. Vasopressin could be a potential non-invasive biomarker of anxiety in dogs with SRPs, but reliable measurement of its concentration is challenging. Here, we compared the behavior and salivary concentrations of copeptin, an arginine vasopressin surrogate, in dogs with SRPs (Case group, n = 13) and with no problems (Control group, n = 15) as they were introduced to a novel environment and subjected to a short episode of separation and reunion with the owner. Dogs in the Case group had greater odds of showing locomotory or oral behaviors during the pre- and post-separation than Controls, while the odds were significantly lower during separation. They also had greater odds of being persistent in seeking attention and proximity from the stranger during reunion. Overall, dogs with SRPs were more likely to express an anxiety-like state during the entire test than Controls, with separation from the owner, and even its anticipation, possibly accounting for this group difference. Although salivary copeptin concentrations did not differ between the two groups, a different trend was detected in Cases and Controls that is worth exploring in further validation studies involving a larger sample.