Effects of Direct-Fed Microbials on Growth, Health, and Blood Parameters of Young Holstein Calves

Direct-fed microbial supplementation and the performance of Holstein calves were evaluated. Calves were assigned to treatments that included: 1) colostrum only at birth; 2) colostrum at birth plus Biomate FG Concentrate for 35 d; 3) colostrum and medicated milk replacer at birth plus Biomate FG Concentrate for 35 d; or 4) colostrum at birth plus Biomate LA-20 for 35 d. Blood samples taken at birth, at 12 h or 24 h after birth, and at about 3, 10, and 35 d of age revealed no treatment differences in total serum protein, serum immunoglobulin G (IgG), packed cell volume (PCV), or hemoglobin. Calf BW and feed refusal were measured twice weekly. Significantly different calf BW were accounted for by differences in birth weight. No differences were detected in calf performance, health, or blood parameters, regardless of the microbial fed. Calves receiving a reduced level of colostrum ate more grain, but there were no differences in calf performance or health as compared with other treatments. No advantage was shown for microbial supplementation of young Holstein calves, except possibly when there was lowered colostrum intake.