Reproduction and Breeding

Abstract Reproductive performance can be measured according to several different parameters including age at first mating, number of litters sired, number of pups per litter, and the frequency with which a strain has productive matings. Table 4.1 shows the values obtained for these different parameters with the most commonly used inbred strains of mice. As the table shows, inbred strains vary widely in their reproductive fitness. The first important measure of reproductive fitness is the frequency with which a mating pair will produce any offspring at all. With some strains, such as C3H/HeOuJ, CBA/CaJ and FVB/N, over 90% of all matings that are set up will produce offspring. The C3H/HeOuJ strain is at the extreme end of this group with a 99% frequency of productive matings.