Abstract
Holstein- Zebu calves 222·8 ± 19·8 days old, were managed in one of three ways for 118 days: (a) kept indoors and given cut grass; (b) grazed from 15.30 to 08.30 hours daily; or (c) grazed from 08.30 to 15.30 hours daily. A daily supplement of 1.4 kg meal was given to each of the seven calves per treatment. There were no significant differences in live weight gains, or gains in chest girth, body length or height between treatment groups. In a second experiment crossbred Holstein male and female calves, 178-4 ± 8·5 days old, were rotationally grazed full-time for 180 days on good Pangola grass pastures. A daily supplcment of either 1.36 to 2.04 kg meal was given to each of the 12 calves per treatment. The extra meal resulted in 44 per cent greater weight gains, 21 per cent greater gains in chest girth, 52 percent greater gains in body length and 20 percent greater gains in height at the withers. Sex had no significant effect. Regression equations allowed the prediction of weight gain from initial age and weight in both experiments. A multiple regression analysis of the relationship between livewcight and linear body measurements in the second trial showed that chest girth was most closely correlated with weight gain, more so at the higher Ievel of the supplmentation. Under these conditions, turning calves out to full-time grazing before six months of age resulted in poor rates of growth. Possible reasons for these results are discussed.
