Studies on rapeseed meal from different varieties of rape in the diets of gilts. I. Effects on attainment of puberty, ovulation rate, conception and embryo survival of the first litter

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. Three rapeseed meals from seed of different B. napus varieties were compared: (i) those currently grown in Britain (Brsm), (ii) Tower (Trsm), grown in Canada and (iii) Erglu (Ersm), grown in Germany. The influence of these dietary treatments on the early phases of reproduction was assessed from records of age and weight at puberty and conception, ovulation rate and embryo survival.There were no significant effects of any of the Rsm diets on any aspect of the early stages of reproduction except ovulation rate, measured as number of corpora lutea. This number for Brsm (15·3) was significantly greater (P < 0·01) than those for Sbm (13·0) and Trsm (12·6); it was 14·5 for gilts given Ersm. However, there were no significant differences in the number of live embryos at about 34 days for Sbm, Brsm, Trsm and Ersm, means were 11·1, 10·5, 9·3 and 9·9 respectively.