Effect of lupin grain supplements on lamb birth weight and growth rate and on milk production of Merino ewes

Abstract

Merino ewes lambing in March on dry subterranean-clover-Wimmera ryegrass (Trifolium subterraneum-Lolium rigidum) pastures were fed a lupin grain supplement at different rates for 10 weeks, beginning four weeks before lambing, In two experiments, birth weights of lambs were unaffected by the supplements but both milk production of the ewes and the growth rate and weaning weight of lambs increased linearly with increasing level of supplementation. At the highest rate of supplement (600 g day-1), the ewes produced 46 per cent more milk in a four hour period in the first four weeks of lactation than ewes that were not fed and their lambs were 3 kg heavier at weaning. In a third experiment in which ewes were fed in yards, increasing the protein level in the ration from 8 per cent to 14 per cent using lupin grain gave a 15 per cent increase in milk production and a significantly higher lamb growth rate at the same level of energy intake. At ad libitum levels of intake the high protein ration gave a 33 per cent higher rate of milk secretion over ten weeks and a 40 per cent higher growth rate of lambs than the low protein ration