Abstract
Maximization of intensive breeding in the animal colony can be approached using a simple mathematical treatment of the production-time curve. It has been found that in a colony of specified-pathogen-free albino rats whose breeding dams were averaging litters of 11 at 6-week intervals, the stock should be entirely replaced at intervals of 27-28 weeks to maximize the output of weanlings. Some data on litter size and sex ratio are also presented.