Effect of divergent selection for uterine capacity on embryonic survival and development at 30 h post-mating in unilaterally ovariectomized rabbit females

Abstract

[EN] Uterine capacity has been proposed as an indirect way to increase litter size. The aim of this work is to study the effect of a divergent selection for uterine capacity (UC) on reproductive traits at 30 h post mating in unilaterally ovariectomized (ULO) females. A total of 62 ULO females from the high line (selected to increase UC) and 39 ULO females from the low line (selected to decrease UC) were used. Ovulation rate was estimated as the number of corpora haemorrhagica and early embryonic survival was estimated as the ratio between number of embryos and ovulation rate. No differences in ovulation rate and early embryonic survival at 30 h post mating were found between high and low lines. Selection for UC did not change the embryonic stage of development either, the majority of embryos being at 4-cell stage. Additionally, the embryos were evaluated according to morphological criteria and more than 95% of the embryos were evaluated as good or fair quality. No differences in embryonic morphological criteria between high and low lines were found either. Thus, selection for UC did not modify the early embryonic survival and development in ULO females at 30 h post mating.