Studies on rapeseed meal from different varieties of rape in the diets of gilts. II. Effects on farrowing performance of gilts, performance of their piglets to weaning and subsequent conception of the gilts

Gilts were fed from about 25 kg live-weight on diets containing either rapeseed meal (Rsm) or soyabean meal (Sbm) as the sole protein supplement. Two rapeseed meals from seed of B. napus varieties were compared, those currently grown in Britain (Brsm) and Tower (Trsm) grown in Canada. The effect of these dietary treatments on the reproductive performance during the first parity of the gilts and the performance of their litters to weaning was assessed.The mean weight of live piglets at birth was significantly (P < 0·05) lower for those born to gilts given Brsm (1·24 kg) than those born to gilts given either Sbm (1·35 kg) or Trsm (1·37 kg). The number of piglets born alive per litter did not differ significantly among groups and the differences in birth-weight diminished during the suckling period so that by three weeks of age there were no significant differences among dietary treatment groups in either number of piglets alive or in their weights.The interval between weaning and first observed oestrus was significantly shorter for gilts given the Brsm diet than those given the Sbm diet but there were no significant differences among treatment groups in the interval between weaning and conception.