Observational behaviors and emotions to assess welfare of dogs: A systematic review

Observing dogs’ behavior to assess their welfare is relevant in various applied settings, such as veterinary clinics and animal-assisted interventions. Yet, no field-wide consensus or complete overview of observable behaviors to assess dogs’ welfare seems to exist. In this review, we carefully analyze and categorize observational measures of a) dog welfare and b) their emotional state as described in the literature. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we searched two major electronic databases (PubMed, ScienceDirect) between October and December 2021 and included peer-reviewed articles—published in the last 10 years—about observable indicators of the welfare and/or emotional state of dogs. We included 39 studies in total. Based on these studies, nine overarching themes of behavioral indicators could be formulated, of which vocalizations, stress-related behaviors, and interaction with the nonsocial environment were mostly mentioned in the literature. Most articles described observable indicators that were both positively and negatively framed. Only five articles mentioned some form of validity assessment, while 23 studies mentioned inter-rater reliability measures. We conclude that having more validated observation instruments would be valuable for both research and practice. Although a clear and simple way of observing dog welfare without complicated tools is of great importance, the field would also benefit from instruments using combinations of physiological parameters and observable behaviors to assess dogs’ welfare.