A note on post maturity in purebred commercial rabbits in Egyptian conditions

Abstract

The present study was carried out on the pure Bauscat (Bau), pure New Zealand (NZW) and pure Californian (Cal) strains of rabbit. Overall reproductive performance for overdue does of the three breeds was determined and compared with that of does delivering at the normal time. Overdue does of the Bau and NZW breeds had a significantly (P < 0·05) higher annual mean number of pups weaned than overdue Cal does. There was a high incidence of pup mortality in post-mature litters, and the causes of this high mortality were crushing of the skull followed by subsequent stillborn-birth difficulties and intra-uterine death in all three breeds. Obliteration of the anterior fontanelle of pups from post-mature litters occurred in 71%, 75% and 69 % of the deaths diagnosed at birth in the Bau, NZW and Cal breeds, respectively. Induction of parturition with either PGF_2α or oxytocin reduced pup mortality in overdue does. The birth-to-remating interval was significantly (P < 0·01) lower in overdue does in which parturition was induced with PGF_2∞ but significantly longer when parturition was induced with oxytocin.