As grasses will soon grow, so does your cattle’s need for magnesium. With the fresh green grasses of spring, cattle can develop what is known as Grass Tetany. Grass Tetany is a metabolic disorder when cattle do not have enough magnesium in their system and can be fatal. It is easily spotted as cattle will act nervous or have trouble walking. It is preventable. An easy prevention is to provide Purina Wind and Rain Hi Mag Cattle Minerals for consumption.