| A series of 3 studies were conducted at the University of New Hampshire and at a local New Hampshire farm to investigate possible methods of improving IgG uptake and accuracy of measuring apparent efficiency of IgG absorption. The first study utilized 40 Holstein calves, which were allocated to 1 of 4 treatments: 1) 1 feeding of colostrum replacer + 0 g of NaHCO 3; 2) 1 feeding of colostrum replacer + 30 g of NaHCO3; 3) 2 feedings of colostrum replacer + 0 g of NaHCO3; and 4) 2 feedings of colostrum replacer + 30 g total of NaHCO3. A total of 191.4 g of IgG were fed to calves, with split fed calves being provided 2/3 of total dose at birth (0 h) and 1/3 of total dose at 6 h. Individually, NaHCO 3 and feeding regimen did not affect IgG absorption but there was an interaction (P = 0.02) indicating that addition of NaHCO 3 in a single feeding increased 24 h serum IgG concentrations compared to single feeding calves not supplemented with NaHCO3, while addition of NaHCO3 in a split feeding regimen was not beneficial compared to split feeding calves not supplemented with NaHCO3. The second study utilized 80 calves, which were assigned to 1 of 8 treatments: 1) 1 feeding of colostrum replacer; 2) 2 feedings of colostrum replacer; 3) 1 feeding of colostrum replacer + 30 g of NaHCO3; 4) 2 feedings of colostrum replacer + 30 g of NaHCO3; 5) 1 feeding of colostrum replacer + milk replacer feeding; 6) 2 feedings of colostrum replacer + milk replacer feeding; 7) 1 feeding of colostrum replacer + 30 g NaHCO3 + milk replacer feeding; and 8) 2 feedings of colostrum replacer + 30 g NaHCO 3 + milk replacer feeding. A total of 184.5 g of IgG were fed to calves, with split fed calves being provided 2/3 of total dose at birth (0 h) and 1/3 of total dose at 6 h. Calves assigned to treatments with milk replacer were fed 2 L of milk replacer 6 h after the final feeding of colostrum replacer (either 6 or 12 h). There was no effect of colostrum replacer feeding regimen or milk replacer feeding. Addition of NaHCO3 decreased 24 h serum IgG, apparent efficiency of absorption of IgG, and area under the curve for IgG compared to calves not supplemented with NaHCO3. The final study utilized 28 calves assigned to 1 of 2 treatments: 1) 1 feeding of colostrum replacer (184.5 g of IgG) or 2) 2 feedings of colostrum replacer (2/3 of total dose at birth and 1/3 of total dose at 6 h) to investigate the effect of feeding regimen on plasma volume at 6, 12, 18, and 24 h. Using Evans blue dye to estimate plasma volume, no treatment effects were noted at any time points. Mean PV for all calves regardless of treatment at 6, 12, 18, and 24 h were 8.1, 9.3, 9.1, and 9.5% of BW, respectively.;(Key Words: Calf, colostrum replacer, NaHCO3, IgG, plasma volume). |
