Copper and Selenium Metabolism and Supplemental Strategies for Grazing Beef Cattle

Trace minerals have long been identified as essential components in the diets of domestic livestock species. Chromium, cobalt, copper, iodine, iron, manganese, molybdenum, nickel, selenium, and zinc are included in the category of essential trace minerals (or microminerals). Trace minerals exist in cells and tissues of the animal body in a variety of chemical combinations, and in characteristic concentrations, depending on the trace mineral consumed and the tissue in which the trace mineral is metabolized (McDowell, 1992; Underwood and Suttle, 1999). Concentrations of trace minerals must be maintained within narrow limits in a cell (McDowell, 1989, 1992; Underwood and Suttle, 1999). Trace mineral deficiencies, toxicities, and imbalances require the animal to metabolically compensate for the nutrient deviation (McDowell, 1989, 1992; Underwood and Suttle, 1999). In doing so, certain metabolic diseases can manifest and overall animal production can be depressed, thus decreasing overall animal performance and health.