Effects of a combination of live yeast and yeast cell wall products supplemented before and after weaning on beef heifer growth performance, immune function, and body temperature

ABSTRACT Objective This study aimed to evaluate the effects of a combination of live yeast and yeast cell wall fed before weaning and through backgrounding on heifer growth performance, health, and body temperature. Materials and Methods Angus crossbred cow-calf pairs with heifer calves (n = 95; BW = 165 ± 27 kg) were stratified based on BW, birth date, sire, and dam parity and assigned randomly to pasture (10 pastures, 9 or 10 cow-calf pairs/pasture). Pastures were assigned randomly to treatments: (1) no yeast (CON) or (2) addition of 3 g of live yeast and 1 g of yeast cell wall (Y+CW; Phileo by Lesaffre) in a randomized design with 5 replicates. Calves were offered creep-feed at 0.5% of BW (as fed) for 35 d before weaning. Heifers remained in preweaning treatment groups and were fed 1.8 kg/d of a concentrate supplement while grazing bermudagrass (Cynodon dactylon) pastures for 42 d with Y+CW continuing to provide 4 g of Y+CW per day. Results and Discussion Average daily gain and creep-feed consumption before weaning did not differ (P ≥ 0.29) between treatments. However, CON heifers had greater (P = 0.01) ADG from weaning to the end of the backgrounding period compared with Y+CW heifers. Body temperatures were not affected (P ≥ 0.31) by treatment before or after weaning. White blood cell concentrations, serum haptoglobin concentrations, and the percentage of cells positive for phagocytic activity did not differ (P ≥ 0.15) between CON and Y+CW heifers. Implications and Applications Based on the results of this study, Y+CW supplementation before or following weaning was not efficacious.