Voluntary food intake in a limited time of lambs and calves given diets containing rapeseed meal from different types and varieties of rape, and rapeseed meal treated to reduce the glucosinolate concentration

Abstract

ABSTRACTThe voluntary food intake in a limited period, 30 or 60 min after morning and afternoon feeds, and during 24 h, by lambs and calves given diets containing rapeseed meal (RSM) or soya bean meal (SBM) as the only protein supplement was determined. Four rapeseed meals were compared, one from seed of British-grown winter Brassica napus varieties (BRSM), and the others from seeds of the varieties Tower (TRSM) and Loras (LRSM), or from seeds of Canadian spring sown varieties (Canola; CRSM). The effects on food intake of treating BRSM with heat and ammonia, steam, steam and ammonia, or calcium hydroxide and ammonia were also determined.In lambs, intakes in a limited period of BRSM and CRSM were significantly lower than that of SBM, and there were no differences between intakes of BRSM and CRSM. In calves, intake in a limited period of BRSM was significantly lower than intake of SBM, TRSM and LRSM: those of TRSM and LRSM were lower, but not significantly so, than that of SBM. Treatment of BRSM with steam, steam and ammonia or calcium hydroxide and ammonia, increased food intake significantly but by small amounts: intakes of the treated meal diets were markedly lower than that of the control SBM diet. The glucosinolate concentration of untreated RSM influenced intake in calves but not in lambs. The effects of treatment of RSM on intake were not closely related to changes in glucosinolate concentration.