Characterization of a Colostrum Replacer Containing IgG Concentrate and Growth Factors

The objective of this study was to characterize absorption of colostrum replacer (CR) or supplement (CS) containing fractions of bovine plasma. Immunoglobulin concentrate (IGC) was prepared from abattoir blood to a final purity of approximately 90% IgG. Blood was also processed to produce a fraction containing elevated concentrations of IGF-I and TGF-β (GF). Both IGC and GF were spray-dried and blended with other ingredients to produce CR (30% IgG) or CS (15% IgG) containing 0 or 5% GF. Forty Holstein bull calves were assigned to one of five treatments: 1) Pooled colostrum (MC) - 1.9 L of pooled colostrum at 1 and 8 h of age; 2) Low supplement (LC) - 1.9 L of CS at 1 and 8 h of age to provide 150 g of IgG; 3) Low supplement + GF (LG) - 1.9 L of a CS with GF at 1 and 8 h of age to provide 150 g of IgG; 4) High supplement (HC) - 1.9 L of CR at 1 h of age to provide 150 g of IgG and 1.9 L of a commercial milk replacer (MR) at 8 h of age; and 5) High supplement + GF (HG) - 1.9 L of a CR with GF at 1 h of age to provide 150 g of IgG and 1.9 L of a commercial MR at 8 h of age. Apparent efficiency of IgG absorption was higher for calves fed HC and HG compared to those fed LC and LG and was lower for calves fed LG and HG compared to those fed LC and HC. IgG concentrations at 24 h were highest in calves fed MC compared to other calves and were higher in calves fed HC and HG compared to LC and LG. Calves fed LG and HG had lower IgG concentrations at 24 h of age compared to those fed LC and HC. Xylose absorption was not influenced by treatment in calves fed HG, HC, and MC. These results indicate that 150 g of IgG provided in one dose soon after birth is superior to 150 g of IgG fed in two doses 7 h apart. Also, addition of a fraction of bovine plasma containing elevated concentrations of IGF-I and TGF-β to the CS and CR formulation decreased IgG absorption in the neonatal calf