The effect of feeding a whey-based colostrum replacer product to calves during the first two weeks of life on calf heath and performance.

Feeding transition milk to dairy calves to improve calf health is an approach that is gaining adoption on farm. However, management of transition milk can be laborious and may limit implementation. The objective of this study was to determine the effect of prolonged feeding with a whey-based colostrum replacer product (CR, Premolac, Zinpro Corporation, Eden Prairie, MN) added into the milk replacer for the first 14 d after arrival to a calf ranch on health and growth of dairy calves. A total of 1,037 newborn calves sourced daily into a calf raising facility were enrolled in the study. Calves were randomly assigned to one of three treatment groups upon arrival and fed through day 14: 1) 3.78 L/d of milk replacer not supplemented with CR (CON), 2) 3.78 L/d of milk replacer supplemented with 23 g of the CR providing 10 g.calf-1.d-1 of IgG (CR10), or 3) 3.78 L/d of milk replacer supplemented with 46 g of the CR providing 20 g.calf-1.d-1 of IgG (CR20). Treatments did not have an effect on overall grain intake (P = 0.295). However, calves fed CR20 gained more weight than calves fed CR10, and calves fed CR10 gained more than CON calves during the first 14 d of the study (P < 0.01). Average daily gain through 14 d was 0.15, 0.20, and 0.24 kg.d-1 for calves fed CON, CR10, and CR20. Supplementing milk replacer with CR20 tended to reduce (P = 0.06) the incidence of calves treated with antibiotics for diarrhea. There was no treatment effect (P = 0.11) on incidence of calves with an overall respiratory score ≥ 5 or for any of the respiratory score components (eye, nasal, ear, cough, and breathing scores). Overall, CR supplementation significantly reduced (P = 0.03) the incidence of calves treated with antibiotics for any reason. The incidence of calves treated with antibiotics was 92.4%, 88.7%, and 86.2% for CON, CR10, and CR20. Finally, mortality was significantly reduced (P < 0.01) by more than two-thirds for CR20. Mortality was 6.6, 5.4, and 2.0% for CON, CR10, and CR20. In conclusion, supplementing milk replacer with 46 g of CR (20 g IgG) for 14 d after arrival at a calf ranch was a successful strategy to significantly reduce disease incidence, antimicrobial use, and calf mortality. The addition of 46 g of CR (20 g IgG; CR20) had a greater magnitude of effect on reducing disease, antibiotic use, and mortality than 23 g of CR (10 g IgG; CR10).