Are You Over-Supplementing Your Horse?

Types of supplements available to horse owners

In years past, it was not uncommon for owners to simply provide extra vitamins and minerals with their horse’s daily feed ration. Nowadays, owners are giving their horses a wide range of supplements for a variety of reasons. However, it is becoming more common for owners to either overfeed supplements or feed supplements that are not truly needed, which results in owners spending too much money trying to meet their horses’ nutritional needs. More importantly, over feeding certain supplements can be a danger to a horse’s health!

Horse Diet Ingredients

  • Forage. The base of every horse’s diet. Most horses’ nutritional needs can be met by feeding good quality forage. With this, the horse is receiving most of its daily protein (amino acids), fiber, fat, carbohydrate, vitamin, and mineral requirements.
  • Concentrate (horse feed). The purpose of a concentrate is to fill in the gaps of the nutrients that are lacking in a forage. Read more in our Why Hay Is Not Enough article. Generally, a horse will receive extra amino acids, vitamins, minerals, fat, and other nutrients. When combined with quality forage, this meets the horse’s daily nutrient requirements.
  • Supplements. In certain cases, nutritional supplements may be needed to provide extra nutrients above and beyond those of the quality forage and horse feed.
  • Nutraceuticals. This term is associated with supplements. These are food-derived supplements that are associated with providing a health benefit to the horse. These can include anything from a joint supplement, to feeding herbs that are associated with calming behavior.

When Does Your Horse Need A Supplement?

To determine if your horse needs a supplement, it would be wise to first evaluate the nutrients currently being provided in their total diet. A forage analysis is a great start to see which nutrients are being provided. This will help owners see where the nutritional gaps are that need to be filled. Learn how to understand a forage analysis here. Then, the purpose of a concentrate is to fill those gaps. This means that most horses’ nutritional needs should be met by these two components of their diets.

With advancements in equine nutrition and formulation technologies, it is important to note that many horse feeds are more “advanced” than in past decades. For example, many high-quality feeds have beneficial nutrients already added in the bag, which in years past, were supplemented. For example, Kalm ‘N EZ® provides horses with the following:

  • Essential fatty acids, Omega 3 and 6, to support healthy skin and hair coats.
  • Optimal balance of amino acids to support muscle maintenance and recovery.
  • Optimal levels of antioxidants, organic minerals, and vitamins to support a healthy immune system and overall health.
  • Equi-Ferm XL®, a pre-and probiotic, to support a healthy gut.

When feeding a quality horse feed, additional supplementation of fatty acids, amino acids, immune system support and pre- and probiotics would not be needed for most horses.

Specific products in the Tribute® line provide even more benefits. For example, Kalm ‘N EZ® GC Plus has the benefits listed above, with the addition of:

  • Glucosamine, chondroitin sulfate, and MSM to support healthy joints and range of motion.

By choosing the GC Plus option, horse owners may not need to feed additional joint supplements. In another example, Essential K® with Fly Control has the addition of Clarifly®, which helps prevent flies from emerging from a horse’s manure. Again, this added benefit is included in the bagged feed and no longer needs to be fed separately in the form of a supplement.

How Overfeeding Supplement Can Be Hazardous To Your Horse?

Overfeeding certain supplements can be dangerous to your horse. Some supplements, when overfed, just result in a loss in money to the owner. Horses do not utilize excessive nutrients and excrete them out in their urine and feces. Yet, others can be dangerous or result in nutrient deficiencies:

  • Vitamin toxicity. Most vitamins have a large safety margin and, if overfed, do not result in toxicity. However, fat-soluble vitamins (A, D, E and K) can be a problem if fed in massive amounts (quite rare).
  • Mineral toxicity. Similarly, most minerals have a large safety margin. However, selenium and iodine are two that have slim safety margins. Meeting selenium requirements can safely be done by feeding a quality horse feed. Iodine can be a concern with certain products made from certain sources of kelp.
  • Dietary Imbalances. This is the most common problem when supplements are overfed. Certain nutrients, when fed in high amounts, can result in the nutrients competing with each other for absorption or utilization. In some instances, two nutrients fed in excess may bind to each other, resulting in neither being used by the horse. In both circumstances, the owner was intending to provide more of a nutrient, which actually resulted in the horse being deprived of them.


The take home message here is that many supplements that were once fed to horse separately are generally no longer needed in a horse’s daily diet. However, there are situations where additional supplements may be warranted, such as certain health issues. A good read is our Do You Feed a Joint Supplement? Article, which discusses when a supplement (or feed additive) would be appropriate. If you have any questions or need any advice on whether your horse truly requires supplements or if you are feeding the correct supplements, please contact us

Article By: Chris Mortensen, Ph.D.
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