Effect of colostral immunoglobulin G1 and immunoglobulin M concentrations on immunoglobulin absorption in calves.

Twenty-three calves were fed colostrum at 110 ml/kg body weight divided into two feedings at 1 and 13 h of age. The concentrations of immunoglobulins were measured in the colostrum fed and in the calves' sera following colostrum feeding. Apparent efficiency of immunoglobulin absorption was calculated for each calf. Significant negative correlations between efficiency of absorption and mass of immunoglobulin fed were observed for both immunoglobulins. A separate group of 225 calves born on a commercial dairy were fed 2.84 L of colostrum by 4 h of age. Concentrations of immunoglobulin G1 in the colostrum fed and in the calves' sera at 48 h were measured. Negative correlation was observed between the efficiency of absorption and the mass of immunoglobulin G1 fed. These results suggest a physiologic limitation to the mass of immunoglobulin that can be absorbed to serum from a given volume of colostrum. No indication of a selective immunoglobulin absorption mechanism was observed.