PSXI-13 Effect of Lactobacillus spp. and Saccharomyces cerevisiae alone or in combination, on ruminal fermentation, total tract nutrient digestibility and performance of growing beef cattle

Abstract The study evaluated the effect of Saccharomyces cerevisiae alone or in combination with Lactobacillus spp. delivered through silages as a direct fed microbial (DFM) on the nutrient digestibility and performance of growing beef cattle. Chopped and kernel processed corn silage was treated with either distilled water (CON), or with (cfu g1 fresh forage) 1.1 × 105 of a Lactobacillius plantarum and Lactobacillus buchneri (LAB) mixture (INOC1), 1.0 × 104 S. cerevisiae strain 3 (INOC2), or 1.1 × 105 LAB + 1.0 × 104 S. cerevisiae strain 3 (INOC3) and ensiled in AgBags®. Eight ruminally cannulated beef heifers in a replicated 4 × 4 Latin square and 60 crossbred individually fed beef steers in a randomized complete block design were used for the metabolism and feedlot growth performance experiments, respectively. The treatments were four total mixed rations composed of 65.0% of one of the four corn silages, 17.0% barley grain, 13.0% canola meal and 5.0% vitamin-mineral supplement (dry matter (DM) basis) for both experiments. Data were analyzed using the MIXED procedure of SAS. The molar percentage of ruminal acetate in heifers fed INOC2 and INOC3 were lower (P < 0.01) than those fed CON. The DM (P = 0.03), organic matter (P = 0.02), acid (P = 0.03) and neutral detergent fiber (P = 0.03) digestibility of heifers fed INOC2 were higher than those fed CON. The DM intake as a % of body weight tended (P = 0.08) to be lower for steers fed INOC2, while the average daily gain was similar to those fed CON. There is potential for delivering S. cerevisiae through silage as DFM for improving ruminal fermentation, total tract nutrient digestibility and the growth performance of beef cattle.