Social conflict reduction program for male mice.

Aggression within caged groups of unfamiliar male mice can be a serious welfare problem for maintaining mice in the laboratory. At our Center, two observation periods were set aside daily in order to identify, according to previously described behaviors, dominant mice and separate these when indicated. By reducing or eliminating the number of aggressive acts between group members in the same cage, our social conflict reduction program has led to a 57% reduction of mice being reported for clinical signs, death, and euthanasia.