Question

I own a 16-year-old Missouri Fox Trotter gelding that weighs 950 lb (430 kg). I ride him four days a week, twice in dressage lessons and twice on trails. He is turned out all day with access to grass six hours each day and then free-choice hay in a slow feeder for the remainder of the day. I also feed him an all-purpose vitamin and mineral supplement, and one-third cup flax year-round. He’s in good shape. Should I also supplement with vitamins C and E?

Answer

It looks like you have a balanced and reasonable feeding program for your horse.  Additional supplementation with vitamin C should not be necessary, as horses usually make adequate amounts of vitamin C (from glucose in the liver) to meet their requirement. Supplemental vitamin C would be useful when horses are in a prolonged stressful situation or when suffering from an illness.

There is vitamin E in the supplement you mentioned as well as the forage, but it is lowest in the hay. Additional vitamin E could be a useful complement to the diet when the horse is consuming hay  and no fresh green forage. The amount of supplementation of vitamin E would be around 500 to 1,000 IU per day and preferably as natural vitamin E rather than synthetic because of its enhanced availability to the horse.

One excellent source of vitamin E is Nano-E from Kentucky Equine Research (KER). The natural-source vitamin E in Nano-E is distributed throughout the body by a unique delivery system called nanodispersion, which allows the vitamin E to be absorbed more quickly than other vitamin E supplements.