Barley grass seed and shearing effects on summer lamb growth and pelt quality

Abstract

The effects of mature barley grass (Hordeum spp.) pasture on lamb growth rates, carcass180 crossbred lambs finished on summer pastures. The effect of shearing at weaning, using 2 types of combs (traditional or cover) was compared with a 'no shearing' treatment.Exposure to barley grass pasture over November and December produced growth rates of 82 ¦ 5 g/day for lambs slaughtered in January compared with growth rates of 141 ¦ 5 g/day on lucerne pasture over the same period. On the barley grass pasture, shearing gave an immediate and sustained advantage (P<0.05) in growth rate but no difference between cover or traditional comb. Carcass weights were 21.4 ¦ 0.3 and 19.0 ¦ 0.4 kg for lambs grazing lucerne pasture and barley grass pasture, respectively. Shearing reduced pelt damage from barley grass seed to the extent that 85% of unshorn pelts had >5 scars per pelt compared with 13% in pelts from shorn lambs. Type of shearing comb did not influence the result. The results suggest that maturing barley grass pastures must be avoided if adequate growth rates are to be achieved in weaner lambs.