Abstract

Dorset ewes rearing twin lambs were offered herbage allowances of 2, 5 and 8 kg DM/ewe/d during a 6-week lactation period. Ewes and lambs were shifted at 3-day intervals. At 6 weeks lambs were weaned, combined into 1 mob and offered a fresh area of pasture ad lib every 3 days. Lambs were slaughtered at 6, 12 and 18 weeks of age. Carcass weight and fat measurements recorded. There were significant live-weight differences (2.5 kg) between low and high allowances during the trial, but differences in carcass weight were only significant at 6 and 18 weeks. Average growth rate between 6 and 18 weeks was 176 g/d in all groups. Fat measurements suggested no differences in carcass fatness between groups. It was concluded that herbage allowance preweaning had little effect on subsequent lamb growth and carcass fatness when ewes were shifted to new pasture at 3-day intervals.

WH, McMillan

Proceedings of the New Zealand Society of Animal Production, Volume 43, , 33-36, 1983