The importance of mineral nutrition may be one of the most unrecognized factors contributing to grazing cattle performance. Forages and grains, the common feedstuffs fed to cattle, are nutritionally incomplete. The extent to which nutrients are lacking depend on feedstuff quality and cattle nutrient needs. Forages, the foundation of grazing cattle diets, rarely, if ever, provide all the minerals required by grazing cattle. The nutritional content of feedstuffs can vary tremendously depending upon