A host of nutrients are needed by cattle to support functions associated with life, and to grow, reproduce, and nourish their offspring (i.e., produce milk). A vast amount of resources have been expended to quantify the amounts of specific nutrients needed to perform these function so that economically efficient diets can be formulated. Feeding diets that provide adequate, but not excessive, amounts of nutrients helps improve profitability of dairy operations while reducing the environmental impact of dairy farms. The trace minerals zinc, copper, manganese, and selenium are components of a wide variety of enzymes and proteins that support metabolism, growth, production, and reproduction. Trace mineral supplements are added to dairy cattle rations to prevent mineral deficiencies, and supplementation has traditionally been provided in the form of inorganic salts.