Cortisol is a widely used biomarker for assessing stress in dogs, but traditional invasive sampling can compromise welfare and influence physiological parameters. To address this, Kaszycka et al. (2025) reviewed over 18,000 studies, identifying 78 that directly examined methods of cortisol assessment in canines.
The review reveals a clear trend toward non-invasive approaches, including saliva, urine, feces, hair, and even integumentary samples. These methods avoid stress-induced hormonal changes triggered by invasive sampling, thereby improving the reliability of results. The authors stress that research ethics committees now recommend minimizing discomfort to animals whenever possible.
Despite this progress, challenges remain. Many studies suffer from small sample sizes, inconsistent protocols, and difficulties in controlling for environmental, genetic, and social factors that influence cortisol levels. These limitations restrict the comparability of findings across different research groups.
The authors call for greater use of interdisciplinary approaches, integrating behavioral observations with physiological measurements to refine cortisol testing techniques. Such strategies not only strengthen the validity of welfare research but also ensure that canine stress studies adhere to the highest ethical standards.
Ultimately, the review underscores that advancing non-invasive cortisol testing is key to improving dog welfare while maintaining robust scientific integrity in stress-related research.
Source: Kaszycka, K., Goleman, M., & Krupa, W. (2025). Testing the Level of Cortisol in Dogs. Animals, 15.
