Effects of lysocellin on performance, ruminal and plasma characteristics of growing cattle

Twenty-four Hereford steers averaging 228 kg initially were used to evaluate four levels of lysocellin (0, 11, 22 and 33 mg/kg diet) when individually fed a corn silage-based diet. Gains were similar for all lysocellin levels over the 112-d study. As lysocellin level increased, there was a linear decrease in dry matter intake and an improvement in feed conversion (P less than .05). Feed to gain ratios were 6.27, 6.14, 5.67 and 5.59 for the 0, 11, 22 and 33 mg/kg of lysocellin treatments, respectively. Molar proportion of acetate was lower (P less than .05) and propionate was higher (P less than .05) for steers fed lysocellin than for controls at d 84. Ruminal fluid concentrations of soluble Cu and Zn were higher (P less than .05) in steers fed lysocellin at 28 and 84 d and increased as lysocellin level increased. Plasma Zn was lower (P less than .05) at both 28 and 84 d in steers fed lysocellin, whereas plasma Cu concentrations were similar for controls and for those fed lysocellin. Both ruminal fluid soluble P and plasma P concentrations were higher (P less than .05) in steers fed lysocellin than in controls at d 84. These results are interpreted to indicate that feed conversion of growing cattle is improved by lysocellin and that metabolism of certain minerals is affected by this ionophore.