EFFECTS OF SOYFLOUR IN MILK REPLACER ON THE PERFORMANCE OF ARTIFICIALLY REARED LAMBS

Abstract

Two artificial rearing experiments were conducted to evaluate both preweaning and postweaning performance of artificially reared lambs, ad libitum fed a milk replacer having one-third of the milk protein replaced by soyflour protein (S) compared with those fed MR with all the protein provided by milk products (M). From weaning at 21 d of age to 91 d of age all the lambs were fed the same high-concentrate diet. In the first experiment there were no significant differences in lamb weights, daily gains, postweaning feed conversion or lamb survival. In the second experiment there were lower (P < 0.05) postweaning daily gains, lower (P < 0.05) 91-d weights and higher (P < 0.05) postweaning feed conversion (2.69 vs. 2.52 kg feed kg−1 gain) for S lambs compared with M lambs, although there were no significant differences due to MR treatment for weaning weights, preweaning daily gains or lamb survival. In both experiments the S lambs consumed slightly more MR than M lambs. Using prices prevailing at the time of the study the lower ingredient cost of the soyflour resulted in a saving in MR cost of $1.45 per lamb weaned. In the second experiment, the lower MR cost would have been partially offset by the approximately 1 kg extra liveweight per lamb at 91 d of age. It was concluded that soyflour could contribute one-third of the total protein in MR for ad libitum fed, artificially reared lambs with little, if any, reduction in lamb performance. However, savings in feed costs resulting from the cheaper ingredient cost might be partially offset by lower postweaning lamb gains. Key words: Lambs, artificial rearing, milk replacer, soy protein