Effects of dietary supplementation of a yeast product on performance and morbidity of newly received beef heifers

Two truckloads of beef heifers (n = 237; average initial BW = 191 kg) were used to evaluate the effects of a yeast culture/ enzymatically hydrolyzed yeast extract product (Celmanax; Varied Industries Corporation, Mason City, IA) included in a 65% concentrate receiving diet on growth performance and bovine respiratory disease morbidity during a 35-d receiving period. Treatments (replicated in 12 pens of 9 to 11 heifers per pen over the 2 truckloads) included 1) the 65% concentrate receiving diet with the addition of Celmanax (1.8 g/d per heifer of enzymatically hydrolyzed yeast cell wall and yeast cell metabolites, diluted with a carrier to a total of 14 g/d per heifer) or 2) the receiving diet without Celmanax (control; 14 g/d per heifer of carrier only). No load × treatment interactions (P > 0.15) were detected for any measures of performance or bovine respiratory disease morbidity. Initial BW did not differ (P > 0.53) between treatments nor did BW on d 35 (P = 0.33). Average daily gain for d 0 to 14 (P = 0.05) and for the overall 35-d (P = 0.08) period tended to be greater for Celmanax heifers than for control heifers. Receiving-diet DMI was greater (P = 0.03) by the Celmanax heifers than by the control heifers at all the measurement periods during the experiment, but G:F did not differ (P = 0.17) between treatments. The proportion of heifers treated one time for bovine respiratory disease tended (P = 0.09) to be less with the Celmanax treatment (4.1 ± 2.09% for Celmanax vs. 10.5 ± 3.92% for control). Results suggest that feeding Celmanax at 14 g/d per heifer can have positive effects on short-term performance and health of newly received beef cattle fed a 65% concentrate (steam-flaked corn-based diet) during the summer.