Imagine this scene ……. a strong castle surrounded by invaders, archers stand behind the walls, their arrows firing at the enemy. As the invaders advanced one by one they are picked off by the huge numbers of archers protecting the inner castle, at the castle walls.
The castle is the outer membrane of the cells in your horse’s body. The archers are vitamin E protecting the cell membrane from damage by free radicals. Free radicals are a normal product of body metabolism but they are damaging if not kept in check by anti-oxidant processes in the body.
Vitamin E is the number one anti-oxidant vitamin in the body. Without adequate amounts of this vitamin your horse’s cells are vulnerable to damage by the free radicals generated by normal body metabolism. If your horse is sick or in heavy exercise more free radicals are produced so more vitamin E archers are needed. Nerve tissue especially requires Vitamin E to function properly. Horses quickly get deficient if they engage in moderate to high amounts of physical activity.
Vitamin E is in every cell of your horse’s body and unique in being able to cross into spinal cord, brain, liver, eyes, heart, skin, and joints. According to a University of Florida study, in addition to being an antioxidant, Vitamin E is also a “potent anti-inflammatory when given in high levels.” However, unlike other vitamins which are non-essential, this essential vitamin cannot be manufactured in the body, it has to be obtained from the diet and obtained in sufficient quantities to allow those archers to protect the walls.
In summer horses out grazing on fresh pasture have access to large amounts of vitamin E, however they need to be grazing on good pasture for 6 hours or more. If your horse is on bald pasture, a track system where hay or haylage is the predominant forage fed or has poor teeth, which mean it cannot graze efficiently, it will be short of vitamin E so supplementing is wise.
Fresh grass changes throughout the year in its amount of Vitamin E. In October, the amount of Vitamin E in grass is very little. Levels in the winter (November-March) are at zero. On 12 hours of grazing April-September, horses will get an estimated 2000-3000 units a day which is adequate for a 500 kg horse up to moderate exercise. A horse on less grazing, and or exercising at high levels is going to need more supplementing to maintain the all important numbers of archers around those battlements.
How much Vitamin E does your horse need?
If your horse is sick then it makes sense that you need more archers because increased body metabolism, coping with illness, creates more free radicals. Neurological conditions like EPM require large doses of Vitamin E due to high oxidative stress quickly depleting Vitamin E. Some vets recommend 10,000 IU a day for several months, some will have horses go on 20,000 IU a day for 7-10 days and drop back to 10,000 a day in severe neurological/PSSM cases. In older horses, Vitamin E supplementation has been proven to increase antibody levels which can protect them from sickness and help ward off infections from Cushing’s disease. An average sized horse with Cushings will benefit from 5000 iu vitamin E per day.
Research has also indicated that in broodmares supplemented Vitamin E passed through to milk increasing Vitamin E levels in foals, increasing immunity cell levels from the mare to the foal. Enhanced levels of vitamin E are then believed to avoid many early-stage infections in foals.
Levels for an average 500 kg horse should be as follows:
– Maintenance up to moderate work, 2000 units (IU) a day
– Moderate to heavy work, 5000 units a day
– Sick horses (or horses diagnosed with cushings), a minimum of 5000 units, higher levels of 10,000 units may be beneficial whilst acute symptoms persist.
For horses in heavy exercise such as racing, hunting or eventing and endurance then more free radicals will be generated. Even on pasture then it is unlikely that there will be adequate levels of vitamin E to protect the cell membranes from damage. Higher levels are useful not just for this effect but also for the anti-inflammatory effect. For these horses then 5000 iu per day is a must.