Colostral immunoglobulin absorption linearly related to concentration for calves.

This experiment shows colostral immunoglobulin concentration is a major factor in the rate of immunoglobulin absorption and the amount of absorption when it is fed to newborn calves. First-milking colostrum was collected from two cows and blended with fresh whole milk in immunoglobulin concentrations ranging from 7.5 to 123.8 mg/ml for immunoglobulin G, .38 to 5.53 mg/ml for immunoglobulin A, and .46 to 11.19 mg/ml for immunoglobulin M. Six batches of colostrum were prepared separately with each having a different range of immunoglobulin concentration. Calves were separated from their dams at birth and fed either 1 or 2 liters of the prepared colostrum at the appropriate concentration. Feeding was repeated after 12 h. One-hundred and twenty Holstein-Friesian calves were fed in six blocks, a block for each freshly prepared colostrum, of 20 animals each. Blood samples were taken at prefeeding and at 12 and 24 h postpartum. The three isotypes in serum and colostrum were quantitated by single radial immunodiffusion procedure. Immunoglobulin G and A concentrations in serum of the calf at 24 h after feeding colostrum had a positive linear relationship with immunoglobulin G and A concentrations in the colostrum fed, whereas immunoglobulin M concentrations in the serum had a quadratic response. When compared on equal mass, the amount of colostrum fed, 1 or 2 liters, had less influence on immunoglobulin absorbed than did concentration.