Leading Vet Advice on Magnesium for Horses

There has been a lot of discussion about supplementing magnesium for horses. It is known as the ‘super mineral’ and has been reported to have a calming effect as well as being beneficial for obese horses, those prone to grass induced laminitis, insulin resistance and equine metabolic syndrome. However, before using a magnesium supplement for your equine friend it is important to understand exactly how magnesium works in the horses’ body.

What is Magnesium for horses all about?

Approximately 60% of Mg is found in bone and 30% in skeletal muscle tissue. It plays an especially important role in muscle contraction, by increasing oxygen delivery to the muscle tissue promoting muscle strength, endurance, and relaxation. Magnesium also activates the many enzymes throughout the body including those involved in the production of cellular energy.

Magnesium Deficiencies

Magnesium is often the most neglected mineral in horse feeds. We have already established that it plays an important role in nerve and muscle function so what happens when a horse has a magnesium deficiency?

Deficiency has varying effects, some horses do not suffer or show any signs, while others can have a poor tolerance to work showing signs of nervousness, wariness, excitability, and muscle tremors. Spring grass is typically deficient in magnesium due to the fast growth rate at this time of year, and owners can often overlook that horses showing the symptoms mentioned earlier, may be deficient in magnesium.

Magnesium has a reputation for having a calming influence on our equine friends because when a horse gets excited, its body uses magnesium to calm down and relax. To understand why magnesium affects the horse in a calming manner, it is important to know what is happening in your horse’s body when there is a magnesium deficiency.

Calcium is responsible for muscle contraction and magnesium looks after the relaxation or release of the muscles. When magnesium levels are low, muscles could contract too much and cause symptoms such as cramps or muscle spasms because the muscle cannot completely relax. This puts the horses’ body into a continually stressed state. A shortage of magnesium makes nerve endings hypersensitive exacerbating pain and noise creating a negative reaction in the body triggering the release of adrenaline and adding to the behaviour we see in some deficient horses.

Magnesium for horses may play an important part in reducing equine obesity lessening the risk of laminitis in horses prone to it during periods of strong spring grass growth. In those with insulin resistance and equine metabolic syndrome, blood magnesium levels rise following a meal high in starch or sugar, indicating that magnesium is involved with the action of insulin to clear the glucose from the blood. If magnesium levels are low, there will be impaired carbohydrate metabolism and reduced insulin response (insulin resistance).

No wonder Magnesium for horses is known as the ‘super mineral’!

Recommended Daily Intake

Magnesium is natural to your horse’s diet and efficiently regulated by the body. Plentiful supply of magnesium is critical to supporting a healthy response to stress and especially useful when performance is paramount. For an adult horse of 600kg, in light to moderate work an intake of 7.8g of magnesium would be needed to maintain blood levels at the minimum value.