Premature parturition in commercial strains of rabbits in Egypt

This study teas carried out on Bauscat (B), New, Zealand (N), Californian (C), N X C (NC) and B X NC (BNC) rabbits. Overall reproductive performance for does with premature parturition (pre-term) of the five breeds was determined and compared with that of does delivering at the normal time (full-term). Full-term does showed a reproductive performance superior to that of pre-term does in all five breeds with larger litter size at weaning, more pups weaned per doe and a lower proportion of stillbirths. Pre-term B, N and BNC does had a larger number of pups weaned than pre-term C and NC does (P < 0.01). There was a high incidence of pup mortality in premature litters, and the main causes of this high mortality were respiratory distress syndrome, crushing of the skull and starvation and chilling. The mean serum oestradiol 17-beta concentrations and degrees of cervical mucous ferning in pre-term B does were higher than in fill-term does (P < 0.01) but the mean serum progesterone concentrations in pre-term B does were lower than in full-term does during the gestation period (P < 0.01). Treatment with either dexamethasone or progestin reduced pup mortality in pre-term does and the birth-to-remating interval was shorter in pre-term does treated with dexamethasone (P < 0.01) but longer when treated with progestin (P < 0.01).