Effect of Yeast Culture on Steer Performance, Apparent Diet Digestibility, and Carcass Measurements When Used in a Barley and Potato Finishing Diet

Yeast culture has been used in corn and milo diets to improve animal performance and stabilize shifts in ruminal microbial populations due to diet changes. The purpose of this study was to determine the effects of yeast culture in a barley and potato processing residue diet on steer growth performance, apparent diet digestibility, carcass characteristics, ruminal VFA, and liver mineral concentrations. Seventy-two crossbred beef steers were assigned to one of two treatments in a completely randomized design. The control treatment received a finishing diet consisting of 84% (DM basis) barley and potato residue. The yeast culture treatment received the same diet plus 85g of yeast culture per steer daily for the first 28 d, then 28g per steer daily for the remaining 85 d. Total trial steer ADG (1.46 and 1.56 kg/d) and gain:feed (151.8 and 158.6 g:kg DM) control and yeast, respectively, were increased ( P <0.01) by the addition of yeast culture to the diet. No differences ( P >0.24) were noted for total DMI. Carcass characteristics also did not differ ( P >0.38). Liver mineral concentrations were within normal ranges and were similar ( P >0.14) for control and yeast culture treatments. Apparent DM, CP, ADF, NDF and GE diet digestibilities were similar ( P >0.21) between treatments. No difference ( P >0.86) was noted in total ruminal VFA concentration, however the acetate:propionate ratio decreased ( P <0.05) for the yeast culture treatment due to increased propionate concentration in steers fed yeast culture. Feeding yeast culture in a barley and potato processing residue finishing diet improved ADG 6.9% and feed efficiency 4.5%.