As if aging isn’t hard enough! Creaky joints, sagging backs, loose teeth, increased infections, poor digestion, and embarrassing gassiness -- just a few of the problems associated with getting older (for your horse, not you!). But what was once a given in youth, now turns into a deficiency – vitamin C must now be added to the diet. You see, young horses are able to produce all the vitamin C they need for every-day health. This is why you typically do not see it added to commercially fortified horse feeds. But as horses get up in years, they are less able to manufacture vitamin C. Decreased liver function is the main reason, but it can also be due to a decline in hindgut microflora and an increased propensity for pituitary dysfunction.
It prevents oxidative damage to your horse’s tissues and organs. In other words, it is an antioxidant. Antioxidants donate electrons to highly volatile, damaging molecules known as free radicals. Free radical production is accelerated during any type of physical or mental stress, muscle and joint inflammation, allergies, illness/injury, or exposure to toxins and pollutants. But once free radicals receive their missing electron from vitamin C, they are neutralized – calmed down – and are no longer harmful.
While its antioxidant capability is paramount to your horse’s overall health, vitamin C protects your horse in two other significant ways:
Vitamin C is known as ascorbic acid. It can be derived from food or flowers (e.g., rose hips) or can be made in a laboratory. Regardless of the source, they are chemically identical, so there is no need to spend more on natural vitamin C. Ascorbic acid comes in several different forms, all similar in absorption and efficacy:
Since vitamin C is water soluble, excess amounts are easily excreted in urine. Therefore, it is best to divide dosages between meals to avoid urinary losses. It also tends to be bitter-tasting, so less at one time will be better received.
I routinely recommend vitamin C supplementation for all horses in their late teens (unless they are grazing on healthy pasture for at least 8 hours each day). Start by adding 3 to 5 mg per pound of body weight per day. Once your horse is over 20, give him 10 mg for every pound of body weight. For more intense needs, the National Research Council (NRC) suggests an upper safe limit of 44 mg of vitamin C per kg of body weight. For an 1100 lb (500 kg) horse, this can be as high as 22,000 mg per day.
If you have a container of vitamin C sitting in your hot barn, protect it from a cruel fate — keep it in a cool, dry place where the container is sealed shut. Refrigeration is fine. Purchase small sizes unless you are feeding it to several horses. Your supply should be finished within six months.
Remember, your older horse needs vitamin C to replace what he no longer produces on his own. Therefore, he should be supplemented indefinitely, for the remainder of his life.
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