Abstract

Some farmers believe shearing lambs improves weight gain. On four separate farms, lambs were randomly drafted into two groups in summer, one was shorn while the other was crutched but left unshorn. They were subsequently run as one mob until all were shorn as yearlings in spring. Corriedale lambs (n = 100 x 2 years and 50 per treatment in a third year) were used on one farm, Halfbred lambs (n = 100 per treatment x 1 year) on another farm and two farms used Merino lambs (n = 50 per treatment on each farm x 1 year). Averaged across three consecutive years, the Corriedales shorn as lambs were 2.8 kg heavier as yearlings (P <0.001) and grew 629g more wool (P <0.001), which could be profitable. Halfbred yearlings shorn as lambs were 0.85 kg heavier (P = 0.041) and although not significant, grew more wool (120 g). Shorn Merino lambs produced 140 g more wool on one farm (P = 0.019) only, with no significant live weight differences between shearing treatments on either farm. International literature suggests the decision to shear lambs should be based on availability of feed, cost of shearing, time of year, temperature and the riskof flystrike, grass seed damage or adverse weather.

DR, Scobie, AJ Marshall, and C van Koten

Proceedings of the New Zealand Society of Animal Production, Volume 73, Hamilton, 120-125, 2013