A magnesium supplement designed to address magnesium deficiency in horses. New Zealand pastures are generally low in magnesium, particularly in the spring and autumn. Pastures where potassium fertilisers have been used, such as dairy pastures, tend to have lower magnesium levels. Potassium also reduces the uptake of magnesium in the horse’s gut. One of the early symptoms of magnesium deficiency in horses is that they become more excitable and harder to handle. Supplementing with magnesium works quickly in bringing blood magnesium levels up, resulting in more settled and calmer behaviour.