Most farmers supplement their animals with various major and trace elements through many mechanisms. These supplements are designed to take the place of elements that are lacking in pasture to aid in getting the best animal health and growth rates when the animals are in a state of mineral deficit. Identifying the deficits is achieved by blood testing, liver biopsy and herbage analysis. All these tests have value, but the herbage test probably has the most in the sense that the animal is the result of whatever it is eating. Mineral deficits in the feed results in mineral deficits in the animal.