PS1-1. Effects of Brewer’s Yeast Supplement on Calf Starter and Grower Diets

Abstract The objective of this study was to determine the effect on calf growth and health when supplementing MicroGold MC (Kent Nutrition Group, Muscatine, IA), a concentrated brewer’s yeast from a high-quality strain of Saccharomyces cerevisiae, in the calf starter and grower. Twenty-four purebred Holstein heifer calves 0-3 d of age were randomly assigned to either a control calf starter and grower (CON) or the addition of MicroGold MC at 7 g/hd daily, figuring 0.91 kg/hd daily feed intake of starter and 3.40 kg/hd daily feed intake of grower (MG). All calves were fed the same milk replacer at 2.60 L twice daily from d 1-14, 3.31 L twice daily from d 15-35, and 3.31 L once daily from d 36-42. Calves were offered starter d 1-56, a transition diet comprised of a 50:50 blend of starter and grower d 57-70, and grower d 71-98. Intakes were recorded daily for milk replacer, starter, and grower. Starter, grower, and water were all offered ad libitum. Bodyweights and measurements (wither height, body length, hip height, hip width, and heart girth) were collected weekly. Health scores (fecal, nasal, eye, and ear) were collected daily. Calves were housed in individual pens from 0-42 d. On d 42, calves were weaned and moved to a group pen with 2 calves per pen, both on the same treatment, until the conclusion of the study on d 98. Data were analyzed using the MIXED procedure of SAS 9.4. Calf was considered the experimental unit preweaning and pen was considered the experimental unit postweaning. Serum total proteins and bodyweights did not differ (P ≥ 0.48) at study initiation. During the preweaning and postweaning phases, calves receiving MG were significantly heavier (P 0.01). Average daily gains and bodyweight gains were similar preweaning (P ≥ 0.51) but had a tendency (P 0.06) to be greater for MG calves compared to CON calves postweaning. Wither height, body length, and heart girth were similar (P ≥ 0.25) at the start of the study but hip height and hip width were greater (P 0.05) for MG calves compared to CON calves. Wither height, heart girth, hip height, and hip width were similar (P ≥ 0.14) on d 98 but body length tended to be greater (P 0.10) for MG calves compared to CON calves. Dry matter intakes were similar (P ≥ 0.36) for starter and grower throughout the study. All health scores were similar (P ≥ 0.12) preweaning. Fecal scores were lower (P 0.01) postweaning for MG calves compared to CON calves. Nasal, eye, and ear scores were similar (P ≥ 0.21) postweaning. In conclusion, MicroGold MC supplementation increased bodyweight and improved fecal scores in young dairy calves.