The effect of nutritional restriction during early and mid pregnancy on the reproductive performance of crossbred ewes

Abstract

Border Leicester x Merino ewes were confined to dry annual pasture residues and fed limited quantities of hay for 90 or 108 days after joining in January at Werribee, Victoria. They were then transferred to irrigated pasture and their performance was compared with that of a control group grazing the irrigated pasture throughout pregnancy. Liveweight fell while the sheep were on dry pasture and rose rapidly when transferred to the irrigated pasture. At transfer the 90-day group weighed 57.7 kg and the 108-day group 56.8 kg. At 140 days their liveweights were 74.1 and 71.3 kg respectively. The weight of the control ewes at 90, 108, and 140 days was 69.5, 73.1, and 80.9 kg. There were no differences in the number of lambs born or the liveweight gain to weaning, but the 90 and 108-day ewes produced less wool (4.63 and 4.31 kg against 5.03 kg for control), and had more tender fleeces (32.6 and 58.3 per cent against 14.6 per cent).