A correlated response to selection of mice based on progeny or performance tests

A comparison was made of a correlated response to selection between populations of mice selected for body weight at weaning on the basis of their own performance or their progeny. Selection was conducted throughout 15 generations and during the last two generations, three replicas were crossed within each group. A correlated response to selection of the body weight on day 42, weight gains between day 21 and 42 and litter size at birth was significantly higher in the group of mice evaluated on the basis of their progeny. A negative correlated response occurred in the litter size at birth in the group evaluated on the basis of animals' own performance. The realized genetic correlations in the group evaluated on the basis of animals' own performance was 0.9, 0.1 and 0.8, respectively, between the body weight on day 21 and 42, body weight on day 21 and weight gains between day 21 and 42, body weight on day 21 and litter size at birth.