Let’s discuss why vitamin E is an essential nutrient for horses.
While many horse owners know Vitamin E is important, they may not understand exactly why it’s so essential. This is especially true in the winter months.
Essential antioxidants are less naturally available during the winter months. It’s important to learn how to ensure your horse gets enough. This guide covers how much Vitamin E they need, when supplementation might be necessary, and the best ways to provide it.
The Importance of Vitamin E
There has been new research lately focusing on just how important Vitamin E is throughout the life of the horse.
Vitamin E plays a crucial role in reducing free radicals produced during a horse’s daily activities, especially during exercise.
That means while Vitamin E is very important for all horses, it’s particularly important for those who are exercising and in consistent work. This is because Vitamin E helps with muscle recovery and is also very important for neuromuscular health in general.
Horses can develop specific diseases that have been associated with Vitamin E deficiencies at various stages of their lives. Some of these diseases are reversible. Unfortunately, some of them are catastrophic and irreversible.
Changes in the Winter That Affect Horses Natural Intake of Vitamin E
Horses that are coming off of pasture grass and eating more dry forage means a big change for them nutritionally.
Fresh, green pasture grass naturally contains Vitamin E, but as forage type and quality change in the fall, animals consume less natural Vitamin E.
The amount of Vitamin E in grass is also going to range quite a bit depending on several factors. Studies show horses consume 350 to 3,000 IU of Vitamin E from pasture grass daily. High-quality pasture, especially in spring and summer, usually provides enough Vitamin E to meet their needs.
While there is still grass out in the pastures come fall, albeit likely overgrazed in many situations, that grass is not as nutrient-filled as spring and summer grass, meaning they source less Vitamin E from it. Once the grass goes dormant in the winter, it’s no longer a source of Vitamin E anymore.
As horses are fully switched over to hay forage for the winter, this marks a significant change in the Vitamin E levels they source naturally.
When you cut grass, it dries and turns it into hay. Hay maintains a lot of nutrients even after the drying process and is a great source of necessary fiber for horses. But unfortunately, Vitamin E is one of those nutrients that’s not very stable.
About 50% of Vitamin E is lost in the first month after cutting and drying. After a couple months of storage, hay has almost zero Vitamin E.
This is why we have to rely on other sources for horses to obtain Vitamin E, whether it’s because they’re picking at dormant pasture grass or eating primarily hay as their source of forage during the winter.
Horses That May Need More Vitamin E than the Average Horse and Deficiencies
Some horses, however, need additional Vitamin E even when they have access to good grass.
For example, horses with neuromuscular issues and horses with PSSM type 1 or type 2 may need more because they have some additional stressors on their musculature.
Horses with EPM, or other neurological conditions, may also need more Vitamin E. The reason for this is they’re using up the Vitamin E that they’re consuming more quickly than the normal horse due to the underlying disease.
Unfortunately, it’s hard to tell if your horse might be experiencing Vitamin E deficiency simply based on signs and symptoms. There’s not a specific symptom horses present that points to Vitamin E deficiency specifically.
For example, there’s Vitamin E deficient myopathy, which affects their muscles, and you’ll see significant atrophy and weakness. The good news is that this can be reversed with Vitamin E supplementation.
Equine Motor Neuron disease is a neurological disease, meaning it affects the nerves. This condition develops in horses that have experienced prolonged nutrient deficiencies and is usually identified once neurological symptoms become apparent. These symptoms can vary in severity. They may present as mild ataxia, with the horse showing slight uncoordination, or progress to more severe neurological impairments.
These types of Vitamin E deficiency related diseases are one’s horses don’t tend to fully recover from based on the research, although they can be stabilized.
There are even some disorders seen in very young horses with susceptible genetics. Not every young horse with a Vitamin E deficiency in utero or during early life develops this condition. However, horses with a genetic predisposition who are deficient during that critical time can develop Equine Degenerative Myeloencephalopathy. This is another disease they typically won’t fully recover from.
For this reason, supplementation of Vitamin E in broodmares is very important as well.
The good news is that you can assess and monitor a horse’s Vitamin E levels with a blood test.
This is a great way to ensure horses aren’t becoming deficient before it causes potentially irreversible issues, and to monitor that they aren’t being over supplemented either.
Recommended Daily Vitamin E Levels and When to Supplement Vitamin E in Horses
The NRC, a council that looks at the current research and makes recommendations about the minimum amount of essential nutrients horses should be getting, recommends a minimum of 500 IU’s per day.
This recommendation is based on the maintenance level for a 1,100-pound horse with no exercise. This applies to stallions and broodmares. The level recommended by the NRC is a bit low for most modern-day horses, however.
This is because once a horse’s exercise level increases, so does the recommended minimum for Vitamin E levels. An adult horse in moderate to heavy exercise should be getting at least 1,000 IU’s of Vitamin E a day.
The levels the NRC recommends don’t differentiate between naturally and synthetically sourced Vitamin E, however.
In situations where horses are deficient and you need to increase these levels quickly, natural resources are more bioavailable. Additionally, because they are a more stable source, then they are overall the best way to go.
But when that becomes challenging, such as in winter months, there are options for easily supplementing Vitamin E even in a horses regular feed or with a ration balancer.
For example, Tribute’s Essential K provides 1,000 IU’s per pound. This is a good baseline (with a bit of a buffer) for most modern-day horses Vitamin E level requirements while still being far from levels that could be problematic for horses.
As previously mentioned, horses in higher levels of work are going to require higher levels of Vitamin E. If your horse is in heavier work, you might then feed two pounds a day of Essential K instead of one. This means you’re also doubling the Vitamin E levels. This is also ideal for horses with certain medical issues that need extra supplementation and Vitamin E anyways.
For full-intake feeds like Kalm N’ EZ, which is a feed for both calories and nutrients, it also has 1,000 IUs per day of Vitamin E—even for the minimum recommended feeding rate.
Vitamin E is a very safe nutrient overall, and while it’s possible to over supplement Vitamin E, clinical toxicity related to over supplementation of Vitamin E is rare.
10,000 IUs per day of Vitamin E is considered the maximum safe amount horses can consume. However, you might need to use this high level for short periods in certain cases. This includes severely deficient horses or those with specific diseases, such as newly diagnosed EPM or active neurological conditions.
If your horse needs to be on high levels of Vitamin E for long periods of time in certain circumstances, monitoring bloodwork is important. This is because it can decrease the absorption of some other nutrients, specifically beta-carotene.
Ultimately, as long as horses Vitamin E levels stay in the mid-range, such as around that 4,000 to 5,000 IU’s per day, this is not going to cause any issues.
Article By: Sarah Welk Baynum | Courtesy of Tribute Equine Nutrition