Vitamin E levels in horses tend to be low when they do not have good access to green grass. When there is a drought, pastures that are normally green are poor quality and the hay is poorer quality than usual. Vitamin E deficiency has been liked to several serious equine diseases and may be linked to other less obvious immune system problems. Vitamin E is critical for a healthy immune system. A simple blood test for vitamin E levels can be done by your veterinarian. Supplementation with a natural source of Vitamin E is the most effective way to improve vitamin E status. If your horse is deficient in Vitamin E it is best add about 1,000 IU or more per day. This will need to be done without added selenium, since most vitamin E and selenium products contain much lower levels of vitamin E than you need for deficient horses. Selenium, which is a mineral deficient in many parts of the country, can also be checked by a blood sample.
Natural vitamin E is absorbed at a higher and more complete rate than synthetic E. When you examine your supplement to see which type you have look for “d-tocopherol” as this is natural source vitamin E. if you see “dl-tocopherol”, look for different brand next time.