Addition of sodium bicarbonate to either 1 or 2 feedings of colostrum replacer: Effect on uptake and rate of absorption of immunoglobulin G in neonatal calves1

Forty Holstein dairy calves were blocked by birth date and sex, and randomly assigned to 1 of 4 treatments within each block to elucidate the effect of feeding regimen and sodium bicarbonate (NaHCO3) supplementation on absorption of IgG from colostrum replacer (CR). Calves received CR containing 191.4 g of IgG fed either in 1 feeding at 0 h (within 45 min of birth), with or without 30 g of NaHCO3, or in 2 feedings (127.6 g of IgG at 0 h, with or without 20 g of NaHCO3, and 63.8 g of IgG at 6 h, with or without 10 g of NaHCO3). The treatments were (1) 1 feeding of CR + 0 g of NaHCO3; (2) 1 feeding of CR + 30 g of NaHCO3; (3) 2 feedings of CR + 0 g of NaHCO3; and (4) 2 feedings of CR + 30 g total of NaHCO3. Only calves born with no dystocia were used on this study. Blood samples were taken at 0, 6, 12, 18, and 24 h postpartum and were analyzed for IgG using a radial immunoassay. Results indicated that, individually, feeding regimen and NaHCO3 treatments had no effect. However, the interaction was significant for 24-h IgG and area under the curve, and showed a trend for apparent efficiency of absorption. Absorption rate data indicated that, for calves fed within 45 min of birth, most IgG absorption occurred in the first 6 h after birth. From 6 to 12 h postpartum, IgG absorption started to decrease; however, IgG absorption remained higher for calves fed in a single feeding than in 2 feedings. These data indicated that NaHCO3 may increase IgG absorption when calves are fed colostrum in a single feeding but is not beneficial when colostrum is fed in 2 feedings.