Very few people are aware of the enormous role magnesium plays in a horse’s body. After oxygen, water, and basic food, magnesium may be the most important element needed to maintain health. It is vitally important, yet hardly known. Magnesium is by far the most important mineral, activating over 300 different biochemical reactions all necessary for the body to function properly. Magnesium supplementation has been shown to improve performance and allow human athletes to reach exhaustion later in their exercise routine. It increases oxygen delivery to muscle tissue; it promotes muscle strength, endurance and relaxation. Magnesium also activates enzymes necessary for the metabolism of carbohydrates and amino acids which lead to protein synthesis.
Magnesium is often the most neglected mineral in horse feeds. Spring grass is typically deficient in magnesium due to the fast growth rate and at this time of year many horses seem hotter and more difficult to ride. Owners often attribute this to too many carbohydrates in the grass. While this may be part of the story, what is often overlooked is that these horses may be deficient in magnesium. Magnesium deficiency has varying effects on the horse population. Some horses do not suffer any signs while others are almost unrideable due to their apparent silliness and hyperactivity. Adding magnesium to their diet may have a dramatic calming effect. To understand why magnesium affects the horse in a calming manner, it is important to know what is happening in your horse’s body on a cellular level when there is a magnesium shortfall.
Calcium and magnesium work closely with each other, each requiring the other for balance. Calcium is in charge of contracting the muscle and magnesium looks after the relaxation or release of the muscle much like a gas pedal and a clutch work together. When a muscle cell is triggered, the cell membrane opens, letting calcium in and raising the calcium level in the cell setting off a reaction and the muscle contracts. When the contraction is done, the magnesium inside the cell helps to push the calcium back out of the cell releasing the contraction. This happens very rapidly. When there is not enough magnesium in the cell, calcium can leak back in causing a stimulatory effect and the muscle cannot completely relax. This can put the body into a continually stressed state. Low magnesium makes nerve endings hypersensitive thus exacerbating pain and noise. Magnesium is required for proper nerve and muscle function.