Effects of sheltering on physiology, immune function, behavior, and the welfare of dogs.

Approximately 4 million dogs live in animal shelters each year. However, understanding and measuring the welfare of these kenneled dogs presents a challenge. One way to determine welfare is by assessing how stay at the shelter influences physiology, immune function, and behavior of the dogs. Prior research, from all of these domains, has not resulted in clear conclusions on how the animal shelter influences the well-being of dogs. One robust finding is that, when placed into a kennel environment, dogs experience a spike in cortisol levels followed by a decrease to original at-home levels. Current evidence cannot differentiate between several proposed hypotheses that may be responsible for this pattern. In addition, very few studies have assessed the effects of kenneling on immune function of dogs, and of these, no consistent findings have emerged. However, this line of inquiry can have a large impact as infectious diseases are rampant in animal shelters. The ability of behavioral measures to inform us about the welfare of dogs is discussed by reviewing published and new data on the effects of kenneling on dog behavior. Prior research has suffered from a lack of consistent operational definitions when defining abnormal behavior in dogs, resulting in difficult to interpret results. Research on the well-being of individual dogs, rather than on group averages, may be a fruitful next step in determining and improving the welfare of dogs housed in shelters.