Welfare Assessment in Shelter Dogs by Using Physiological and Immunological Parameters

SIMPLE SUMMARY: In “no-kill policy” countries, many dogs live in shelters. Several social, environmental, and management challenges can put the welfare of shelter dogs at risk. More knowledge is still needed on how to assess shelter dog welfare. This study aimed to evaluate the state of welfare of a group of dogs entering a shelter using physiological and immunological parameters by exploring the value of some biological indicators obtained by non-invasive methods. Considering that early welfare assessment could improve the management of subjects more prone to developing distress, measurements were taken at the time of admission and four weeks after the dogs entered the shelter. A multivariate statistical approach was used to comprehensively evaluate the relationship between the variables investigated. A reduction in the values of the measured physiological and immune parameters over time suggested an improvement in the dogs’ welfare after four weeks of being in the shelter compared to the initial capture and admission time. Findings also highlighted that some of the parameters investigated, such as neutrophils, lymphocytes, and fecal cortisol and lysozyme could be used for the welfare assessment of dogs entering a shelter. ABSTRACT: This study aimed to evaluate the state of welfare of a group of dogs during the first month after entering the shelter by using different stress parameters. Blood and fecal samples were collected from a group of 71 dogs at the time of admission to the shelter. In 46 of these dogs, sampling was repeated after four weeks. Well-recognized welfare biomarkers, such as fecal cortisol and leukocytes, as well as some innovative parameters (β-endorphin and lysozyme) were determined. Uni- and multivariate statistical analyses were used to evaluate their interactions and changes over time. Neutrophils (p < 0.01), lysozyme (p < 0.05), and fecal cortisol (p < 0.05) decreased, while lymphocytes (p < 0.05) increased after four weeks compared to the first days of being in the shelter, suggesting an improvement in the dogs’ welfare over time. A principal component analysis extracted three bipolar components (PCs), explaining 75% of the variance and indicating negative associations between neutrophil and lymphocyte (PC1), lysozyme and β-endorphin (PC2), cortisol and lysozyme (PC3). The associations between these variables within each PC also confirmed the intricate relationships between the hypothalamic-pituitary-adrenal (HPA) axis and the immune system as well as the importance of a multiparametric approach in evaluating welfare.