Milk Replacer Acidification for Free-Access Feeding: Effects on the Performance and Health of Veal Calves

Abstract

Objectives of this study were to investigate the effects of milk replacer (MR) acidification for freeaccess feeding on pre-and post-weaning performance, morbidity and mortality of calves. Calves were randomly assigned to free-access feeding of acidified (ACID, n = 31) or non-acidified (NON, n = 31) MR, and weaned at 42 days. ACIDMR was prepared to pH 4.0 -4.5 using formic acid. Intakes were measured daily and weights weekly. Samples of ACID and NON MR were analyzed for coliform and aerobic bacterial growth. After weaning, calves transitioned to a grain-fed veal diet, weighed every 2 weeks. At slaughter (approximately 6 months of age), lungs were evaluated for gross pathological changes and dressed carcass weights were obtained. Generalized linear mixed models were constructed to examine the effects of MR acidification. Differences by treatment group for pre-and post-weaning morbidity and mortality were tested using Pearson's χ 2 and Fisher's exact tests. ACID calves consumed less MR than NON (10.6 vs. 11.7 L/d, P = 0.02). Acidification tended to promote earlier onset of starter ration consumption (32.0 vs. 39.5 d, hazard ratio = 1.5, P = 0.07), but did not affect average daily starter ration or water intakes across the preweaning period. ACID and NON calves did not differ for BW at weaning, pre-or post-weaning ADG or dressed carcass weight. ACID MR had less coliform (P < 0.001) and aerobic bacterial growth (P < 0.001) than NON MR, but odds of disease treatment and mortality did not differ. ACID calves tended to have lower odds of pulmonary lesions during post-mortem inspection than NON calves (OR = 0.3, P = 0.07). These results indicate that under free-access feeding conditions, acidification * Corresponding author. C. G. Todd et al. 235limited bacterial growth and MR intake, but there were no long-term impacts of acidification on calf performance or health. In conclusion, acidification to pH 4.0 -4.5 will significantly reduce bacterial growth in milk fed to calves.

Effect of acidified milk feeding on the intake, average daily gain and fecal microbiological diversity of Holsten dairy calves

“…In the present study, the total counts of bacteria and E. coli in AM were lower than in PM, which indicated that the acidification of milk strongly inhibited the growth of bacteria. This result was consistent with the study of Todd et al [11] on acidified MRs.…”

“…Erickson et al [2] reported that 6-week-old calves fed acidified MR had higher nitrogen retention than the calves fed general MR, but acidified MR was not beneficial to 1-week-old calves. Moreover, the higher frequency of feeding AM or acidified MR increased the feed intake [2,11]. As calves consumed more milk or feed, the body weight of calves fed AM was higher than those fed PM in the current study.…”

“…The abundance of Bacteroidetes in the feces of calves fed AM before weaning positively correlated with the colonization resistance of gut harmful microorganisms, which would prevent the entry of pathogens in the early stage of infection [25,29]. The results of Todd et al [5,11] showed that an AM replacer diet decreased harmful bacteria and had a decreasing trend of morbidity and mortality, which were beneficial to calf growth. Heyman and Ménard [30] pointed out that feeding acidified formula powdered milk to infants changed intestinal pathological conditions and decreased the incidence of diarrhea.…”

“…AM with low pH provides more suitable pH in the gastrointestinal tract, and the lower pH reduces the rate of infectious scours [10,24]. Todd et al [11] found that the odds of disease and mortality were not different between the calves fed MR and acidified MR, but acidified MR had less coliform and aerobic bacteria. Our results showed that AM had lower counts of total bacteria and E. coli compared with PM.…”

“…Feeding acidified MRs prevented the rapid growth of pathogenic organisms in the alimentary tract [2,11]. Therefore, some results showed that feeding acid milk or MR improved the fecal consistency score [8], decreased the proportion of diarrhea days [12] and reduced the diarrhea rate [13].…”