EFFECTS OF QUALITY, QUANTITY, AND TIMING OF COLOSTRUM FEEDING AND ADDITION OF A DRIED COLOSTRUM SUPPLEMENT ON IMMUNOGLOBULIN G(1) ABSORPTION IN HOLSTEIN BULL CALVES

Three experiments were conducted to examine the effects of quality, qu antity, and timing of colostrum feeding and the administration of a dr ied colostrum supplement on serum Ig in Holstein bull calves. In Exper iment 1, calves were fed colostrum that had low concentrations of immu noglobulin (Ig; 23.9 mg of IgG(1)/ml) as follows: group 1-1 (n = 6), 2 L at birth and 2 L at 12 h; group 1-2 (n = 6), 4 L at birth and 2 L a t 12 h; and group 1-3 (n = 6), 2 L at birth, 2 L at 6 h, and 2 L at 12 h. Doubling the volume of colostrum administered at birth did not res ult in higher serum Ig at 48 h, but additional colostrum at 6 h did in crease serum Ig. In Experiment 2, calves received 2 L of colostrum tha t had low concentrations of Ig (25.7 mg of IgG(1)/ml) at birth and 2 L at 12 h. Calves in group 2-1 (n = 6) received colostrum only. Calves in groups 2-2 (n = 5) and 2-3 (n = 5) were fed additional dried colost rum supplement (136 and 272 g, respectively) at each meal. Addition of the supplement reduced efficiency of IgG(1) absorption and did not re sult in higher serum Ig at 48 h. In Experiment 3, calves were fed as f ollows: group 3-1 (n = 6), 2 L of colostrum containing 32.9 mg of IgG( 1)/ml (low Ig) at birth and 2 L at 12 h; group 3-2 (n = 6), 2 L of col ostrum containing 60.1 mg of IgG(1)/ml (high Ig) at birth and 2 L at 1 2 h, and group 3-3 (n = 5), 4 L of colostrum containing 60.1 mg of IgG (1)/ml at birth and 2 L at 12 h. Colostrum high in Ig resulted in high er serum Ig concentrations at 48 h; the concentrations were highest wh en 4 L of colostrum high in Ig were fed to calves at birth.