The addition of this supplement to mares and stallions feed should be commenced six weeks before covering. For stallions it will improve covering performance and sperm quality. For mares it will help prevent premature abortion and protect colostrum. High levels of beta carotene and vitamin A in the colostrum and milk will help protect the foal from the risk of infection. In addition, vitamins A and E have a combined effect on the production of the hormone progesterone.