The performance of lactating ewes offered diets containing different proportions of fresh perennial ryegrass and white clover

Abstract

ABSTRACTSix ewes with twin lambs were allocated to each of six restricted feeding treatments with 10, 0·8, 0·6, 0·4, 0·2 or 0 of the diet as perennial ryegrass and the remainder as white clover, and to two treatments with either perennial ryegrass or white clover offered alone ad libitum. Fresh herbage was offered and measurements were made over 8 weeks, with the exception of the ad libitum clover treatment which was terminated after 5 weeks. All lambs were allowed access to clover from 14 days of age. Digestibilities of the herbages were measured during four periods in the experiment.Increasing the proportion of clover in the diet significantly increased the intake of nitrogen by the ewes and the growth rate of their lambs, but had no effect on the live-weight changes of ewes on the restricted treatments. When there was no restriction of intake, ewes ate slightly more clover than ryegrass and lost less weight, but mean daily live-weight gains of their lambs over the first 5 weeks did not differ significantly (0·30 and 0·34 kg for ryegrass and clover, respectively).When ryegrass and clover were eaten alone or together their organic matter digestibilities (OMD) did not change, although OMD declined with increasing level of intake.Initial body condition of the ewes had a significant effect on the decline of ewe live weight and body condition during lactation, and on lamb live-weight gain