Establishment of a Chinese hamster breeding colony

A colony of outbred Chinese hamsters, Cricetulus griseus, was established. Attempts to use previously published methods of physically protecting the males were unsatisfactory. Rather, females were selected for nonaggressive behavior. Breeding was among pairs allowed to cohabit for 5 1/2 days. Production was typically in excess of 180 offspring per month, with an average breeder population of 44 females and 30 males. Litters were weaned at 3 weeks of age. At that time, appropriate numbers of offspring of female parents with a history including nonaggressive behavior, fecundity and freedom from seizures were retained for use as future breeders. Females were first bred at 8-12 weeks of age and males at 8-12 months. The remaining animals were maintained in groups of like-sex littermates until used. With these methods, mortality among breeder males due to overly aggressive female behavior was reduced to 3%. Animal husbandry procedures and record keeping requirements were relatively simple, not labor intensive and would be easily adaptable to most facilities.