Lupins in grain diets for drought-affected lambs weaned at different ages

Abstract

Poll Dorset x (border Leicester x Merino) lambs were removed at 3, 5, 7 or 9 weeks of age from their dams which were being fed drought rations of either wheat or oat grain with 0, 15,30,45 or 60% lupin grain (0.9 kg/ewe.day) and hay (0.3 kg/ewe.day). These weaned lambs were fed the same grain rations ad lib. until they were 17 weeks old and were also offered hay at 10% of the total ration. Survival of the lambs after weaning, had all lambs remained under treatments, would have been 75 and 25%, respectively, for lambs fed wheat or oat grain with no lupins and 75% for those fed lupins and weaned at 3 weeks. Increasing lupin content from 15 to 60% increased wool growth by 80 ¦m/day (P< 0.05) and liveweight at 17 weeks of age by 4.6 kg(P< 0.1) but did not affect feed intake. Efficiency of feed conversion to liveweight (FCR) was better at 15 and 60 than at 30 and 45% lupin content (P<0.05). Lambs fed wheat had higher intakes and liveweights than lambs fed oats, but their FCR was poorer (P< 0.05). Lambs weaned at 5 weeks and fed wheat were 7 kg heavier at 17 weeks than their counterparts fed oats, but this difference decreased with increasing weaning age to 1 kg for lambs weaned at 9 weeks (P< 0.05). Mean daily growth rates of lambs fed wheat and oats were 210 and 169 g/sheep respectively from 12 to 17 weeks (P< 0.05). I conclude that lupin grain is a desirable supplement for high cereal grain rations for early weaned lambs but it would generally be undesirable to wean the lambs at less than 5 weeks of age.