LUPINS, BARLEY, OR BARLEY PLUS VIRGINIAMYCIN AS SUPPLEMENTS FOR SHEEP AT DIFFERENT FEEDING INTERVALS

This experiment compared the efficiency with which lupins, barley, and barley plus virginiamycin were used as supplements for sheep when fed at daily, twice weekly, weekly, and fortnightly rates. Merino wethers, about 1 year of age and 35 kg liveweight, were penned individually in 12 groups of 17 animals. There was a 3-week introduction to grain, followed by 10 weeks of supplement feeding. There was an interaction (P<0.05) between type of grain and feeding interval, for liveweight gain, wool growth, and wool strength. The linear response between liveweight gain, wool growth, or wool strength and the interval of feeding was significantly (P<0.05) different for sheep supplemented with barley and those supplemented with lupin grain. Increasing the interval of feeding reduced the efficiency of grain utilisation; the effect was more pronounced when untreated barley was fed. Over the period of supplement feeding, there was no significant (P>0.05) difference in liveweight gain between sheep supplemented with lupins and those suppplemented with barley plus virginiamycin. The addition of virginiamycin (34 g/t) resulted in a significant (P<0.01) reduction in the incidence of diarrhoea in sheep supplemented with barley plus virginiamycin compared with sheep fed barley alone. This effect may be of importance in reducing the incidence of breech strike in sheep fed cereal grains.