Question
Can you tell me why horses wouldn’t be absorbing a vitamin E supplement? Every horse owner in my barn has been feeding a vitamin E and selenium crumble, and every horse tested so far has been deficient in these two nutrients. As a point of reference, here is the information on my mare, and her diet is typical of many of the horses in the barn: Belgian/Thoroughbred, mare, 11 years old, 1,500 lb (680 kg), 16.3 hands (170 cm), body condition score of 5, 5 to 6 days of light to moderate exercise per week, and a diet that contains haylage and grain two times daily, timothy/alfalfa (lucerne) hay cubes with flax oil, apple cider vinegar, and a B-complex supplement.
Answer
There are different forms of vitamin E that can be used as ingredients in feeds and supplements. It is sometimes difficult to tell which forms are used, as many times they are listed on labels as a generic phrase such as “vitamin E supplement.”
Natural-source vitamin E is extracted from soybean oil and is composed of a single isomer (chemical conformation) of the vitamin E molecule, d-alpha tocopherol. Typically, manufacturers of products that include this form, since it is preferable and more costly, tout its inclusion.
Synthetic vitamin E is also produced. This is derived from petroleum products and is composed of eight different isomers, of which the horse is only able to use one. This form is called d,l-alpha tocopherol.
Kentucky Equine Research (KER) has carried out extensive studies on different forms of vitamin E and found that synthetic vitamin E was ineffective at raising blood levels of vitamin E. Conversely, the natural acetate form (d-alpha tocopheryl acetate, a powder) and the natural alcohol form (d-alpha tocopherol, a liquid) were effective with the liquid form being more so.
KER has developed two different antioxidant supplements based on this research. Preserve PS (Preserve in Australasia) is a dry supplement that provides natural-source vitamin E and organic selenium as well as magnesium and vitamin C to provide broad-spectrum antioxidant support. Nano-E is a nanodispersed, water-soluble, natural-source vitamin E liquid that provides a rapidly available source of the nutrient.
More reading:
What Is the Best Way to Supplement Vitamin E?
What Type of Vitamin E Is Most Efficiently Absorbed by Horses?
