Vitamin A is most commonly associated with disorders of the eye such as night blindness and zerophthalmia. However, vitamin A is also important for the hoof as it plays a role in the formation and protection of epithelial tissue, which comprises the bulk of the hoof wall. Vitamin A promotes tissue growth, strong bones and hoofs, healthy skin, hair, teeth and gums, building resistance to disease.
Vitamin D is metabolized in the horse through the exposure of sunlight.
If horses are not receiving adequate sunlight, supplementation is important for the proper metabolism of both calcium and phosphorus, which are needed for proper hoof development. Vitamin E and Selenium work synergistically as antioxidants to protect molecules that are vulnerable to oxidation. Both work to retain cellular integrity, as they are important for cell membranes. Selenium works as part of the intracellular enzyme, glutathione peroxidase. This helps prevent free radicals from causing damage to tissues.