Abstract
ABSTRACT: Two-stage selection for ovulation rate (OR) and litter size (LS) was performed during 10 generations using a rabbit line previously selected during 6 generations by OR. In both periods, ovulation rate was estimated at d 12 of gestation by laparoscopy. Selection for litter size was based on the average litter size over the first two parities. Total selection pressure in females was about 30% in both periods. Data from 1275 females were analyzed.
After 6 generations of selection for ovulation rate, it increased around 1.6 ova but the correlated response on LS was low (0.5 kits). However, after 10 generations of selection by the index, OR and LS increased around 2 ova and kits, respectively. Correlated response on prenatal survival was observed (+7.7%) mainly due to an increase in embryo survival (+3.5%).
