This study aimed to investigate the effect of applying various silage additives to whole corn crops at ensiling on growth performance, rumen fermentation, and blood physiology in growing-finishing bulls. Sixty Simmental × Yellow Cattle crossbred bulls were blocked by initial body weight (BW; 324.0 ± 5.4 kg) into 15 blocks. Animals in each block were randomly assigned to one of four diets formulated based on the following corn silage: control (CON), inoculated with complex lactic acid bacteria (CLB), ensilaged with mixed organic acid salts (MS), and ensilaged with CLB and MS (CLBMS). The feeding experiment lasted over 155 days, with an additional 7 days for adaptation. The results showed that bulls fed CLB-inoculated silage had greater (p < 0.05) daily dry matter intake than the other groups. The experimental treatment had no significant effect on average daily gain (p = 0.33) and feed-to-gain ratio (p = 0.13), although bulls fed CLB-inoculated silage had a larger numeric average daily gain. All additive-treated silage increased ruminal NH3-N content (p < 0.05) and reduced the acetate-to-propionate ratio (p < 0.05) of bulls compared with the control group. Bulls fed CLB-inoculated silage had a lower ruminal pH value (p < 0.05) than that of the other groups. Compared with the control group, bulls fed CLB-inoculated silage had greater blood cholesterol, albumin, and urea nitrogen (p < 0.05). Blood physiological responses were similar in bulls fed MS-treated and control silage, whereas those in cattle fed CLBMS-treated silage were between bulls fed CLB- and MS-treated silages and more similar to the former. Taking animal performance and cost effectiveness into consideration, the application of CLB alone to whole corn crops at ensiling appears to be a better choice compared with the application of either MS alone or both of them together.
Keywords: beef cattle; complex lactic acid bacteria; corn silage; growth performance; mixed organic acid salt.