Abstract:

Several results of a divergent selection experiment for environmental variability of birth weight in mice are presented. Genetic control of environmental variability of birth weight is shown to be possible through selection. It is also shown that selection for homogeneity improved litter size, embryo and fetal survival, but also at birth, at weaning and at reproductive stage. It also improved fertility, reproductive longevity, and the response to feed restriction. Homogeneous animals were individually smaller, but females weaned 42% more total weight than heterogeneous ones. Signs of robustness and welfare were identified related to uniformity, suggesting this kind of selection would be very useful in livestock species.