Effect of live yeast (Saccharomyces cerevisiae boulardii CNCM I-1079) feed additive on health and growth parameters of high-risk heifers in a commercial feedlot

Saccharomyces cerevisiae boulardii CNCM I-1079 (live yeast; ProTernative®, Lallemand Animal Nutrition) was evaluated for effects on health and performance in high-risk feeder heifers. A total of 1,274 beef heifers (average body weight = 547 ± 28.7 lb; 248 ± 13.0 kg) were procured from auction markets in the southern United States. Heifers were randomly assigned to 1 of 2 treatments: 1) Control (CON; no yeast products) or 2) ProTernative® (PRO) fed at 1 gram/hd/day to provide 20 x 109 CFU/hd/day for the first 45 days-on-feed (8 pens/treatment). After 45 days-on-feed, PRO was removed from the diet and both the PRO and CON treatment groups were fed the same basal diets throughout the rest of finishing. Feeding PRO during the first 45 days decreased bovine respiratory disease first treatment 28.4% compared to CON (P=0.01), and improved average daily gain (P=0.05; +4.5%), feed:gain (P=0.02; -5.0%), cost of gain (P=0.04; -4.7%), percentage USDA quality grade Choice (P<0.01; +6.8%), and reduced A+ liver abscesses (P<0.01; -45.9%). Carcass weight and percentage USDA Choice carcasses decreased (P<0.01) concomitant with increased (P<0.01) percentage USDA Select carcasses as the number of times treated for bovine respiratory disease increased. Addition of PRO to the ration during the first 45 days improved health, performance, and carcass outcomes through closeout in high-risk feeder heifers.