Growth performance, carcass traits, blood parameters, rumen enzymes, and fattening earnings of cattle fed corn silage/corn stalk silage based finishing diets

This study was conducted to investigate the growth performance, carcass traits, blood parameters, rumen enzymes, and fattening earnings of beef cattle when substituting corn stalk silage with corn silage or corn grain in finishing rations. Forty-five Bohai Black steers were selected and fattened in a three-phase (4 weeks-4 weeks-16 weeks) way with one of three diets based on corn silage (CS), corn stalk silage (SS) without/with equivalent corn grain supplement (SSC), respectively. During the 24-week trial, individual feed intake and body weight were recorded every four weeks. By the end, blood and rumen fluid were sampled, and all the cattle were slaughtered to evaluate carcass performance. There were no significant differences found in the body weight gain, daily feed intake or feed efficiency among different dietary treatments over the whole finishing period except that the cattle fed CS achieved higher weight gain and feed efficiency in Phase 2 than those fed SS or SSC along with a lower feed intake than that of cattle fed SSC. No significant effect was found on the hot carcass weight, chilled carcass weight, dressing percentage, aging loss, loin eye area, and the weights of chuckeye, ribeye, striploin, and tenderloin. The cattle fed CS showed lower blood concentrations of ALT and glucose along with a higher ratio of AST and ALT than those fed SS. The cattle fed SSC also presented a higher activity of avicelase in the rumen fluid and their fattening earnings were approximately $27.50 less than those of the cattle fed CS or SS. These results suggest that substituting corn stalk silage with corn silage or corn grain could not improve animal performance and it is more economical to substitute corn stalk silage with corn silage rather than supplement equivalent corn grain in a high-concentrate finishing ration.