Comparison of immunoglobulin G absorption in calves fed maternal colostrum, a commercial whey-based colostrum replacer, or supplemented maternal colostrum.

Successful passive transfer of antibodies in neonatal calves can be achieved by feeding an adequate quantity and quality of maternal colostrum (MC) or colostrum replacer (CR). An alternative could be feeding low-quality maternal colostrum (LMC) with added IgG from a CR. The objective of this study was to determine if a commercial whey-based CR product containing low levels of casein (Premolac PLUS Bovine IgG; Zinpro Corporation, Eden Prairie, MN) fed to replace MC or supplement LMC could lead to adequate serum IgG levels and apparent efficiency of absorption (AEA) in neonatal dairy calves. Holstein calves (n = 20 per treatment) were separated from their dam after birth and randomly assigned to be fed 3.79 L of MC (106 g/L of IgG; 401 g of IgG fed), LMC (30 g/L IgG) supplemented with CR (41 g/L IgG; 154 g of IgG total fed; LMC-CR), or 1.3 L of 1 of 2 levels of CR (110 or 150 g of IgG fed; CR-110 or CR-150) within 1.5 h of birth. Colostrum was obtained from the first (MC) or second and third milkings (LMC) of cows from Pennsylvania State University dairy and pooled by source into large batches. Blood samples were taken from calves before colostrum feeding and 24 h after birth and were analyzed for serum total protein, total IgG, hematocrit, and Brix percentage. Calves fed MC had higher 24-h IgG values (means ± SEM) than calves fed LMC-CR (27.04 ± 1.07 vs. 22.33 ± 1.08 mg/mL, respectively). Feeding 150 g of IgG from CR led to higher 24-h serum IgG values than feeding 110 g of IgG (16.90 ± 1.09 vs. 12.79 ± 1.08 mg/mL). Serum IgG levels were different between the CR-fed calves and the calves fed LMC-CR and MC, but all had average values >10 mg/mL IgG. Calves fed LMC-CR had greater AEA than calves fed MC (54.58 ± 2.39 vs. 24.38 ± 2.36%, respectively). Among calves fed CR-110 or CR-150, AEA did not differ. Serum total protein and Brix percentage had strong correlations with actual IgG values across the entire study. We found no differences in average daily gain or health variables measured, and no differences in final hip width, withers height, or body weight for calves fed MC, LMC-CR, CR-150, or CR-110. These results indicate that CR can be fed successfully as an alternative to MC or as a supplement to colostrum with low IgG.