There are several vitamins that are important for horses to maintain good health. Here are a few:

  1. Vitamin A: This vitamin is important for healthy vision, immune function, and skin health. It can be found in leafy green vegetables and carrots.
  2. Vitamin E and selenium are important nutrients for horses. Vitamin E is an antioxidant that helps protect cells from damage and is important for muscle function and a healthy immune system. It can be found in vegetable oils, nuts, and grains. Selenium is a trace mineral that is important for proper immune function and muscle health. It is found in small amounts in the diet and is often supplemented in areas where the soil is low in selenium.
  3. Vitamin B: B vitamins are important for metabolism, nerve function, and muscle health. They can be found in grains, legumes, and leafy green vegetables.
  4. Vitamin C: This vitamin is an antioxidant that helps protect cells from damage. It is important for collagen production, which is important for healthy skin, bones, and connective tissue. It can be found in fruits and vegetables.

It is important to consult with a veterinarian before giving your horse any supplements, as too much of certain vitamins and minerals can be harmful. An excess of selenium, for example, can lead to selenosis, which can cause symptoms such as loss of hair, lameness, and respiratory problems. The proper dosage of vitamin E and selenium will depend on the individual horse’s age, weight, and overall health.