Effect of Supplemental Trace Mineral (Zinc, Copper, and Manganese) Source on Growth Performance, Morbidity, and Trace Mineral Status in Beef Cattle

A series of studies were conducted to determine the effect of supplemental trace mineral source on growth performance, morbidity, and trace mineral status in growing beef cattle. The first experiment evaluated supplemental trace minerals from sulfate, organic, or hydroxy sources on growth performance and morbidity. Crossbreed beef calves were assigned to 1 of 3 treatments consisting of supplemental zinc (360 mg/d), copper (125 mg/d), and manganese (200 mg/d) from inorganic, organic, or hydroxy sources fed daily over a 42 to 45-d backgrounding phase. After removal of chronic and dead calves from the data set, trace mineral source had no effect on final or intermediate weights (P > 0.55) or average daily gain (P = 0.51). For all calves, dietary treatments had no effect on any morbidity measurements (P ≥ 0.53). Overall, trace mineral source had no effect on total weight gain, average daily gain, or morbidity during the receiving phase in shipping stressed cattle. A second experiment was conducted to study the effect of trace mineral source on trace mineral status, superoxide dismutase activity, and performance in beef heifers fed diets high in sulfur. Crossbreed heifers were stratified into 3 treatments consisting of 1) no supplemental trace minerals; 2) supplemental copper (55 mg/d), zinc (165 mg/d), and manganese (110 mg/d) from sulfate sources; or 3) supplemental zinc, copper, and manganese at isolevels to treatment 2 from hydroxy sources fed daily over a 55-d trial. Final and intermediate weights (P = 0.73), average daily gain (P = 0.70), and plasma copper and zinc concentrations (P ≥ 0.37) were not affected by treatment. Liver copper concentrations on d 55 were greater for the sulfate treatment (P > 0.004) compared to control and hydroxy treatments, however, liver zinc concentrations were not affected (P > 0.29). Treatment had no effect on (P ≥ 0.36) on totalor manganese-superoxide dismutase activity, however, a day effect (P ≥ 0.002) was observed. Overall, trace mineral source had no effect on growth performance, plasma mineral concentration, liver zinc concentrations, or superoxide dismutase activity. However, liver copper concentrations on d 55 were affected by trace mineral source.