Vitamin E plays an important role in improving fertility. This has been known to humans for some time. But this vitamin also has a positive effect on horses. Vitamin E is often used in conjunction with other antioxidants. It increases the fertility of mares and stallions and ensures better resistance in brood mares and their newborn foals.
The effectiveness of vitamin E in people with fertility problems has been well researched. A number of scientific studies have also been carried out in horses. See the studies we used underneath this article.
Vitamin E deficiency in horses
Vitamin E is an extremely important vitamin. Not only for fertility, but also for the muscles and nervous system of your horse. It is a powerful antioxidant. Since horses do not produce vitamin E themselves, it must come from their diet. Grass contains a lot of easily absorbable vitamin E and horses that are in the pasture all day, therefore get enough vitamin E. The situation is different for horses that mainly eat hay or hay-drying silage. Certainly sport horses and horses that are used for breeding have a higher need for vitamin E. They can become deficient if they are not on grass and do not receive a supplement.
Better fertile and more resistance
In stallions, sperm quality and sperm motility improve when they receive extra vitamin E. This increases the chance of successful fertilization. In mares, supplementing with vitamin E not only improves fertility, it is also good for the transfer of immune substances to the foal in the last month before giving birth. When the mare gets enough vitamin E, this also ensures a higher quality of the colostrum (first milk) that her foal gets to drink. This means that the foal is better protected against diseases and bacteria in the first period of its life.
When to give vitamin E to a pregnant mare?
Most foals are born between February and June. Not all brood mares are already (completely) on the pasture. Researchers therefore recommend giving mares extra vitamin E a month before and a month after foaling. A good vitamin E status ensures a greater transfer of immune substances. This transmission occurs via the placenta before birth and then via the mare’s colostrum. A mare that gets enough vitamin E can give her foal a better and healthier start! Foals and young horses with a severe vitamin E deficiency can develop the muscle disease NMD.
Vitamin E for fertilization
Vitamin E is also of great importance for successful fertilization. Human studies showed that in 30 to 80% of cases of fertility problems in men, oxidative stress and reduced anti-oxidant activity were found in the sperm. This would indicate a shortage of anti-oxidants such as vitamin E, which can be supplemented through the diet. Extra vitamin E resulted in more sperm cells, which were also less often damaged. Also for women, taking vitamin E is recommended to improve fertility. Many women also take vitamin E to reduce menstrual complaints and PMS.
“Natural” Vitamin E
In horses, the supplementary feeding of vitamin E is very accurate. Not all types of vitamin E are properly absorbed. The most absorbable form of vitamin E is the isomer RRR-α-tocopherol. This is for example in wheat germ oil. This is popularly called natural vitamin E, but because RRR-α-tocopherol can also be made in a factory, “natural vitamin E” is a better name. What you shouldn’t have for your horse is “synthetic vitamin E”, meaning dl-α-tocopherol acetate. This is often found in cheaper vitamin E supplements. This isomer is very poorly absorbed by horses and is often “a waste of money”. Choose a combination with grape seed extract instead of selenium.
Read more about why a high dose of vitamin E can never be 100% natural here.
Conclusion: Choose strong antioxidants for better fertility
The anti-oxidant effect of vitamin E is very important for improving fertility. To supplement deficiencies, choose the best naturally-like vitamin E, or RRR-α-tocopherol. Fertility studies in humans and horses often used a combination of antioxidants, including vitamin C. One of the strongest antioxidants on the market for horses is grape extract. A combination thereof with natural vitamin E, possibly supplemented with vitamin C, is therefore recommended. Especially if your breeding animals can eat little or no grass. Vitamin E is also an important supplement for the immune system of the mare and foal.
When and for how long?
In order to increase the fertility of your stallion or mare, it is important that you start supplementing vitamin E in the winter. Horses receive less vitamin E in the winter because they do not eat fresh grass. Continue through the breeding season. For pregnant mares it is important that you start at least one month before giving birth and continue at least one month after.
Deichsel K, Palm F, Koblischke P, Budik S, Aurich C. Effect of a dietary antioxidant supplementation on semen quality in pony stallions. Theriogenology. 2008 May;69(8):940-5. doi: 10.1016/j.theriogenology.2008.01.007. Epub 2008 Mar 20. PMID: 18358523.
Contri A, De Amicis I, Molinari A, Faustini M, Gramenzi A, Robbe D, Carluccio A. Effect of dietary antioxidant supplementation on fresh semen quality in stallion. Theriogenology. 2011 Apr 15;75(7):1319-26. doi: 10.1016/j.theriogenology.2010.12.003. Epub 2011 Feb 4. PMID: 21295825.
Ahmadi S, Bashiri R, Ghadiri-Anari A, Nadjarzadeh A. Antioxidant supplements and semen parameters: An evidence based review. Int J Reprod Biomed. 2016 Dec;14(12):729-736. PMID: 28066832; PMCID: PMC5203687.
Mohd Mutalip SS, Ab-Rahim S, Rajikin MH. Vitamin E as an Antioxidant in Female Reproductive Health. Antioxidants (Basel). 2018;7(2):22. Published 2018 Jan 26. doi:10.3390/antiox7020022
Kentucky Performance Horses. Vitamin E: An Essential Nutrient for Horses. Review. 2018.