Skip Navigation
Johns Hopkins Bloomberg School of Public HealthCAAT

Animal Welfare Enhancement Awards - 2004 Recipients

Social Enrichment in a Breeding Colony
Vicki Meyers-Wallen, VMD, Ph.D., Dipl. ACT
 Associate Professor, Cornell University


Breeding colonies of dogs present special problems in managing inter-dog interactions. For example, odors produced by adults that are attractive to the opposite sex, mating behavior, and behaviors related to protection of the young, can result in social competition and aggression between dogs. Our study seeks to develop a strategy that will encourage socialization of breeding adults yet prevent inter-dog aggression likely to arise during reproductive cycles. We are testing for behavioral and biochemical differences before and after establishment of a social enrichment program. Thus we expect to benefit the welfare of dogs, broadening and strengthening the scientific knowledge upon which environmental enrichment programs, and related regulations, are based.


Breeding adults are traditionally housed individually while being bred, during pregnancy, and while nursing pups. During other periods they might benefit from more inter-dog interaction. For example, it is hypothesized that stable, socially compatible groups would engage in positive interactions without potentially detrimental interactions, such as competition for food and aggressive behavior.

Study Design:

After one month observation and a one month testing period, we first tested compatibility between dogs and determined optimum pairings or groupings for each adult dog. Then we applied a social enrichment strategy for 3 months, video recording at 1 month after the enrichment had been in place and again at 3 months of social enrichment. The purpose was to determine whether the social enrichment strategy had a significant effect on these dogs based upon behavioral scores made from the video tapes and serum cortisol measurements (below).

Compatibility Testing:

A large room without runs was used as neutral territory for testing. Dogs were kept on a leash and under constant supervision during the first introduction, and as long as needed to be sure of compatibility. First we identified compatible pairs of adult females, socialized them together in pairs, then allowed them to socialize a few hours a day in unsupervised compatible pairs during the anestrous phase of the reproductive cycle. The goal was to find discrete compatible pairs that could be paired without supervision.

Biochemical Testing:

Before the compatibility testing period was begun and after application of the social enrichment strategy for each dog, blood samples for serum cortisol determination are collected as a biochemical indicator of stress. We will determine whether there is a significant change in cortisol levels before and after the social enrichment strategy. All of these dogs have been trained to allow venipuncture, with little or no physical restraint by a human with whom they are familiar, and receive highly palatable food rewards at the conclusion.

Progress To Date:

We have been delayed by a number of video equipment problems that were beyond our control, including delays in receiving equipment orders, as well as delays due to power failures, equipment failures, and equipment replacement. These problems have now been resolved. Due to those delays, we were unable to videotape the compatibility testing as it was being performed. We were successful in videotaping each dog by itself preceding initiation of a social enrichment strategy and at one month after the strategy had been in place. We have applied a social enrichment strategy to all, and have completed all videotaping on 6 dogs. For the remaining dogs, we have only to videotape and obtain serum cortisol measurements at the time when the social enrichment strategy has been in place for 3 months.

Behavioral scoring of videotapes is ongoing. So far we have scored behavior in over 700 hours of videotaped activity, recorded in 56 tapes in time lapse mode. When we have completed behavioral scoring on each dog at all time points (pre-socialization, and 1 and 3 months after the social enrichment strategies have been in place), we can statistically analyze this data. We will determine whether the social enrichment strategy had a significant effect on these dogs based upon statistical analysis of behavioral scores made from the videotapes and serum cortisol measurements. We can currently draw no conclusions, as this would require results of such analysis; this report represents a progress report to date. Allowing for time to perform behavioral scoring of videotapes on all dogs and the statistical analysis, we estimate that we will be able to provide a final report by January 2006.