The effects of choice feeding on growth performance of dairy calves after weaning

The aim of the study was to investigate the effects of choice feeding in preweaning period on growing performance of calf performance pre and postweaning period. 28 male and 28 female calve were used to test 2 feeding systems (TMR:total mixed ration- containing 10% alfalfa hay and choice feeding) and 2 sex (male and female) in a factorial arrangement. Before weaning calves were fed with TMR containing 90% calf starter and 10% alfalfa hay and after weaning all calves were fed with the same TMR containing 50%calf grwer and 50 % alfalfa hay. Choice fed calve before weaning prefered the diet containing lower alfalfa (10% vs 5.78%, P<0.05) and barley (52.29% vs 15.87%, P<0.05), and higher wheat bran (17.28% vs 30.07%, P<0.05) and SBM (17.73 vs. 45.39%, P<0.05). Sex had no significant effects on diet preferences (P>0.05). Choice feeding increased feed and nutrient intake (protein and fiber) and daily gain significantly (P<0.05). After weaning, sex and feeding system during preweaning period had no effects on any parameters investigated (P>0.05). But sex and feeding system interaction had significant efffects on daily gain, feed and nutrient intakes (P<0.05). The male calves fed TMR before weaning consumed more feed and nutrients and had higher daily gain than females but, choice fed calves in both sex had similar daily gain, feed and nutrient intake after weaning. When overall performance were evaluated, male calves had higher daily gain than females (P<0.05). Sex x feeding system interaction had significant effects on feed and nutrient intake (P<0.05). The male calves fed with TMR consumed more feed and nutrients than the females ones but this differences disappered in choice feeding group. In counclusion, the results revealed that choice feeding may improve growth performance of calves by increasing protein intake before weaning and this effect may disappear after weaning. The female calve gave better response to choice feeding in respect to feed intake. Key words: Choice feeding, Calf, Feeding System, sex ,pos weaning performances, feeding behaviour.