Horsepower Mineral SupplementUnder ideal conditions, a horse sources all of its mineral requirements from its daily diet, selectively grazing on a wide variety of plants over an extensive area. In reality, however, this is rarely the case. The levels of macro minerals (calcium, phosphorus and magnesium) and trace elements (copper, manganese, zinc, iron, selenium, cobalt etc) in pastures and manufactured feeds can vary greatly depending on soil type, agricultural practice and