Effects of lactation on reproductive performances in rabbit does

Abstract

Rabbit does could be fertilized soon after parturition and all over lactation, and be concurrently pregnant and lactating. Nevertheless, receptivity of the females varies during lactation : it is maximal after parturition (near 100 %) and minimal 3-5 days later (40-65 %). Studies of the effects of lactation on ovulation rate and embryonic mortality lead to conflicting results. However, fertility and litter size are lower for lactating rabbits than for non lactating ones. Indeed, lactation decreases the percentage of females wich ovulates (-26 %), gestation rate (-33 %) and foetal viability rate (-10 %). Moreover, lactation leads to an impaired foetal growth (-20 %). Hyperprolactinemia and hypoprogesteronemia in concurrently pregnant and lactating rabbits and nutritional deficicency due to milk production seem to be the main factors involved in these effects.