Vitamin E for horses

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Imagine this scene, a strong castle surrounded by invaders, archers standing 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.

Vitamin E – The warrior vitamin

The castle is the outer membrane of the cells in your horse’s body. The archers are the 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 antioxidant processes in the body.

What is vitamin E for horses?

Vitamin E is the number one antioxidant 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 is unique in being able to cross into the 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 the 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.

Feeding the Young Horse

Vitamin E cannot be synthesized by the horse; therefore, it is considered an essential nutrient. Vitamin E is found in abundant amounts in green and growing horse pasture however between 30 – 80% of vitamin E is lost between cutting and baling of horse forage and this loss is continued while the forage is in storage due to the fragile nature of vitamin E. Winter horse pasture contains little to none of this vitamin so vitamin E supplements are very important.

How to supplement vitamin E for horses

How to supplement can get a little confusing. In nutrition, vitamin E generally refers to alpha-tocopherol but the term vitamin E covers a family of 4 tocopherols and 4 tocotrienols.

Alpha-tocopherol is the form active in the body as an antioxidant. “Natural” on a supplement may mean it contains all forms of vitamin E or may refer to the structure of alpha-tocopherol, the d-alpha or l-alpha form. The d-alpha-tocopherol is the natural, active form, l- being a mirror image which is in many supplements. 

The recommendation of 1 IU/kg/day for adults at maintenance and 2 IU/kg/day for other ages and classes refers to a mixture of d- and l- forms, d,l-alpha-tocopherol. If using pure d-alpha-tocopherol you can cut the amount in half. Supplements labelled “mixed tocopherols” or “full-spectrum vitamin E” contain all eight forms. To know how much to give you would have to know how much of the alpha-tocopherol is in it.

The benefits of vitamin E for horses

  • A good vitamin E supplement supplies your horse with a highly absorbable and readily available source of natural vitamin E that quickly provides necessary nutrients.
  • Vitamin E supplementation offers you an easy and affordable way to meet your horse’s essential vitamin E needs.
  • Vitamin E for your horse does not contain other vitamins or minerals. Horse owners can safely adjust the amount fed to support horses with high vitamin E requirements without worrying about causing imbalances.

Vitamin E deficiency in horses

Inadequate vitamin E intake and vitamin E deficiency are associated with a longer list of medical conditions than any other vitamin. Low vitamin e may cause some problems to the immune system including:

  • Neuraxonal dystrophy (genetic predisposition in several breeds)
  • Equine degenerative myeloencephalopathy (possibly a more severe form of neuraxonal dystrophy , genetic predisposition in several breeds)
  • Pigment retinopathy of the eye
  • Vitamin E deficiency myopathy and masseter muscle atrophy

Many research studies have shown that vitamin E is likely to be deficient in the diets of horses that do not have access to continual grazing on fresh green grass or those grazing on winter pasture. Researchers are continuing to examine the role of vitamin E in horse health, but in agriculture, it has long been known that increased supplementation of vitamin E supports immune function in cattle.

Research now suggests much higher levels of horse vitamin E supplementation than is commonly contained in many horse feedstuffs will be beneficial to maintaining and supporting equine health. Performances horses with demanding workloads, growing horses and seniors or horses suffering from problems can be exposed to increased levels of oxidative stress and therefore may require significantly higher vitamin E levels in their diets. A quality vitamin E supplement would address this issue.

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 Cushing’s will benefit from 5000 IU vitamin E per day. good Vitamin E requirements are important to fight against equine diseases.

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.

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.

Want to know the difference between synthetic and natural vitamin E? Take a look here.

For more articles on Horse Health, take a look here.

Last Updated on December 1, 2021 by Forageplus Team