Effect of milk feeding strategy and lactic acid probiotics on growth and behavior of dairy calves fed using an automated feeding system

Automated milk feeders offer flexibility to feed calves high milk allowances, to change the daily quantity of milk offered, and also to dispense additives like probiotics on an individual basis. Our objectives were to test the effects of 2 milk feeding protocols and a lactic acid bacterium probiotic on performance and behavior in calves. Heifer dairy calves (n = 96) were enrolled at birth in a 2 x 2 factorial study design comparing feeding (1) 2 milk feeding protocols and (2) a lactic acid bacterium-based probiotic program, or a placebo, using automated milk feeders. The early milk feeding strategy (EM) offered a maximum of 11 L/d on day 1 and a peak maximum allowance of 15 L/d on day 21. The late milk feeding strategy (LM) offered a maximum of 7 L/d on day 1 and increased slowly to its peak at 13 L/d on day 28. Both feeding strategies gradually weaned the calves after peak milk allowance until complete weaning at day 53, offering a total of 543 liters of milk. Probiotics or placebo were fed orally in a gel once after colostrum, and twice daily in the milk until weaning. Water and calf starter were provided ad libitum. The experimental period was divided into 3 periods: from day 1 on the automated feeder to day 28 (Period 1), from day 29 to day 53 (Period 2), and the week post-weaning (Period 3). For Period 1, the average daily gain (ADG) of the probiotic group was greater than that of the placebo group (0.84 +/- 0.10 kg/d vs. 0.74 +/- 0.10 kg/d, respectively), but was not different between milk feeding strategies. For Period 2, ADG was not affected by probiotic or milk feeding strategies. For Period 3, ADG was greater for EM compared to LM (1.27 +/- 0.10 kg/d vs. 1.02 +/- 0.10 kg/d, respectively), but not between probiotic and placebo groups. During the whole experimental period, LM calves consumed significantly more milk than the EM calves (431.84 +/- 33.0 liters vs. 378.64 +/- 34.2 liters, respectively). During Period 3, probiotics affected the frequency of visits to the calf starter feed bunk (37.72 +/- 2.8 vs. 23.27 +/- 2.8 visits per day for probiotic and placebo groups, respectively), but did not affect total time spent at the feed bunk. The supplementation of a lactic acid-based probiotic improved ADG during early life and altered some aspects of the feeding behavior of dairy calves. Calves receiving an early accelerated milk allowance had improved growth during post-weaning and consumed less milk in total, which may indicate better use of solid feed.