Although normally horses will provide themselves with all the vitamins they need if they have a good basic diet (even if its pasture only) and access to daylight etc, Vitamin E
(Alpha Tocopherol) is an essential vitamin – meaning that the horse has to ingest it daily and its source is green feed – i.e. good quality pasture. It is possible therefore, levels can become low at times and unlike other vitamins, at these times horses will need supplementation of this vitamin. This occurs firstly when the green feed intake is reduced - typically when on winter pasture, or wet trampled pastures, it is likely that Vitamin E intake will be below the required daily intake. Also this applies when horses are deliberately restricted from pasture in the spring in order to keep the hype of spring grass affecting the behaviour. A shortfall can also occur when low pasture intake or poor quality pasture kept animals or stabled horses are not being given fresh lucerne chaff a good source of this vitamin . Note storage of fodder will also reduce the availability of Vitamin E.
Vitamin E is needed for the correct functioning of the nervous system so low levels of Vitamin E in the diet can result in horses being nervy. It also can affect muscular efficiency and performance and has been attributed to creating susceptibility to tye up syndrome. It is often recommended in conjunction with selenium for horses prone to tying up.
The other very specific need is for breeding stock - both mares in foal, weanlings and stallions. The demand for Vitamin E is higher in breeding stock, necessary for proper function of the reproductive systems, and therefore these animals require supplementation.
The greater the performance demands on a horse – the greater the need for Vitamin E. This is because of its contribution as an efficient anti-oxidant and therefore supplementation is appropriate to offset the development of free radicals (the result of cellular energy transfer) which is of course increased in horses working harder. It is vital to offset these negative effects with good anti-oxidant supplementation in order to maintain the integrity of the muscle structure, and prevent muscle damage.
Two types of Vitamin E are available - synthetic and natural. It has been put forward that natural vitamin E is better as it has a higher biological activity. The negative is the very high cost. In animals other than horses the size of the dose can be substantially reduced with natural Vitamin E therefore offsetting the cost, however, in horses this does not apply and the slight dose reduction still leaves the cost very high. It is more economic to give a higher synthetic Vitamin E dose. Synthetic Vitamin E will still provide the daily requirement and optimum levels in the plasma achieved at a lower overall cost. At the end of the day it has been scientifically shown to lift the levels in the physiology of the horse to prevent the effects of low consumption from green feed, high work demand and breeding levels.
With regard to breeding animals, scientific study (Hoffman et Al 1999) showed that Vitamin E is easily transferable and mares that were supplemented with vitamin E showed increased passive transfer of antibodies to foals, which greatly enhances the immune system. It also showed an advantage of feeding Vitamin E during late gestation and early lactation; and that serum and colostrum IgG levels were greater in mares supplemented with vitamin E. The foals from all mares had similar levels of IgG, IgA, and IgM at birth prior to nursing. After nursing, foals from mares fed the high level of vitamin E were found to have higher serum levels of IgG and IgA, which were reflected in the dam’s colostrum.
It has also been suggested (Harper, 2002) that mares known to have poor-quality colostrum, or that had foals with failure of passive immunity transfer in previous years, should be supplemented with twice the Vitamin E normally fed for at least a month before and after foaling. It was also recommended that pregnant mares fed lower quality hay should be given Vitamin E supplementation a month before and after foaling.
Vitamin E has been linked with increased libido and semen quality in stallions. In addition to these characteristics, one of the most important functions of vitamin E in stallions is cell membrane protection. The lipids in cell membranes are vulnerable to attack from harmful compounds known as free radicals or reactive oxygen species (ROS) that are produced in the mitochondria of cells. The body's defence mechanisms against free radicals and ROS are enzymes and nutrients referred to as antioxidants. Vitamin E, a natural antioxidant, reacts with free radicals and ROS to protect cell membranes.
Research has suggested that fatty acids in sperm cell membranes are crucial to fertilizing capacity, so the nutrients that protect the fatty acids are just as important. Sperm motility is commonly used as an indicator of oxidative stress. Practices such as chilling, freezing, and shipping semen increase oxidative stress.
A 500Kg horse on pasture and resting needs 375 iu per day, a lactating mare or a working horse needs 1200 iu daily. However when green feed is restricted foals and yearlings need 500-1000 iu, working horses 2000 – 4000 iu, pregnant and lactating mares 2000 – 4000 iu and stallions 1000 – 2000 iu.
Vetpro Vitamin E supplement contains 67,000 iu per Kg. Therefore a 15gm scoop will provide 1005 iu and a 30gm 2010 iu.
Products containing iron should not be added to the same feed as Vitamin E as the vitamin will be destroyed by the iron. A separate feed at a different time will solve that issue.