Absorption of colostral proteins by newborn calves fed unfermented, fermented, or buffered colostrum

Unfermented, frozen colostrum from the first three postpartum milkings of 10 cows was thawed, pooled, and treated to produce three diets: 1) unfermented, 2) fermented (7 days at 25 to 27 C), and 3) fermented (as in 2) with pH adjusted to match that of unfermented colostrum. Eighteen newborn, unsuckled Holstein calves were assigned randomly to one of the three diets. Colostrum diets were thawed and fed at 0, 8, 16, 24, and 36 h. Blood was sampled at 0, 4, 8, 16, 24, and 48 h. Minimal breakdown of colostral gamma-globulin and immunoglobulin G (IgG) occurred during fermentation. Protein breakdown during fermentation was associated primarily with the casein fraction. Concentrations of gamma-globulin in serum of calves receiving unfermented colostrum were higher than those of calves fed fermented colostrum at all sampling times beyond 0 h. Concentrations of gamma-globulin in serum of calves fed buffered colostrum were intermediate. Concentrations of IgG followed a similar trend. Health problems were not encountered, indicating potential for passive immunization of newborn calves via fermented, buffered colostrum in emergency situations.