Trace Mineral Salt Block Provides essential salt plus an optimal balance if trace minerals for healthy diets of cattle, horses, swine and other large animals. - Trace minerals include manganese, iron, magnesium, sulfur, copper, cobalt, zinc and iodine. - Durable, weather resistant 4 lb. bricks for easy free choice feeding. - Allow livestock free access to this feed salt, and place near an adequate water supply. 15 bricks per case.