EFFECTS OF A COLOSTRUM SUBSTITUTE AND OF DIETARY BREWERS-YEAST ON THEHEALTH AND PERFORMANCE OF DAIRY CALVES

We tested the effects of substituting a whey protein concentrate for d am's colostrum at first feeding and of 1% brewer's yeast in dry feed o n calf health and performance. Eighty-four calves were assigned to fou r preweaning and eight postweaning treatments based on feeding either dam's colostrum or a whey protein concentrate at birth and either yeas t or no yeast in the dry feed both before and after weaning. After the first feeding, all calves were fed colostrum through 4 d of age and a n all milk protein milk replacer from d 5 to 46 of age. Daily feed int akes, health measurements, and weekly BW were recorded. Calves fed whe y protein concentrate at birth had similar health parameters and great er feed efficiency than calves fed colostrum over the preweaning perio d. Addition of 1% brewer's yeast to the dry feed apparently reduced th e incidence of fever and the number of associated antibiotic treatment s during the preweaning period, but had no effects thereafter. Under t he conditions of this study, whey protein concentrate was an effective substitute for dam's colostrum at first feeding, and 1% brewer's yeas t fed in dry feed may reduce susceptibility to infection prior to wean ing.