Computer-controlled milk replacer feeding strategies for group-reared dairy calves

The objective of this study was to compare the effects of ad libitum and restricted computer-controlled milk replacer (MR) feeding strategies on performance of group-reared dairy calves during preweaning (from 0.5 to 2.0 months of age), weaning (2.0 to 2.5) and postweaning (2.5 to 6.0) periods. Two feeding trials comprised a total of 34 Finnish Ayrshire and 6 Holstein–Friesian bull calves. The calves were randomly (balanced for breed) allotted to pens (5 calves/pen) which were thereafter randomly allotted to two experimental treatments: 1) ad libitum MR feeding (F) with ad libitum access to MR and 2) restricted MR feeding (R) where the calves were given 6.0 L of MR daily. All the calves had free access to water, commercial starter and grass silage before weaning. The weaned calves had free access to water and silage and were given 3 kg/day (air-dry basis) of a concentrate mixture. Due to increased metabolizable energy intake (16.4 vs. 12.7 MJ/day; P < 0.05), the daily gain of the F calves was higher (690 vs. 543 g/day; P < 0.05) than that of the R calves during the preweaning period. Due to the more rapid increase in concentrate intake of the R calves during the weaning period the R calves grew better than the F calves (482 vs. 1038 g/day; P < 0.01) and the differences in live weight evened out during the weaning period. During the postweaning period there were no treatment differences in feed intake or gain. The average gain during the whole study was not affected by either of the treatments. Ad libitum feeding increased the variation in the MR intake and gain compared to restricted feeding.