Salt an important source of electrolytes for horses
Sodium chloride (NaCl), often provided to horses in the form of white salt, is an important source of electrolytes. These minerals are a critical part of the regulation of body fluids, nerve transmission, acid-base balance, muscle contractions, and even the health of cell membranes. Therefore, maintaining a healthy intake of white salt is important to many aspects of horse health.
Voluntary intake is salt that a horse consumes free choice (it was not included in the feedstuffs). The voluntary intake of salt by horses plays a critical role in electrolyte balance. In past studies, horses have opted for diets containing a lower content of salt, addressing their body’s needs throughout the day by consuming salt from a block. Voluntary intake is highly variable and dependent on a myriad of factors including the salt (sodium) concentration in feeds and water, salt lost through sweat, and even the preference of salty taste in one horse vs another. Salt is generally provided in diets at a rate of 0.1% and up depending on the horse’s physiological status and workload. Diets containing up to 3 or 5% salt may augment the absorption and retention of other important minerals, such as calcium and phosphorus, and generally do not inhibit metabolism of other minerals. However, this level of dietary salt could approach toxicity if water is limited.
Ultimately, there needs to be a balance. A horse that sweats abundantly during a workout is not only losing water, but also valuable electrolytes such as sodium, chloride, and potassium. If this horse rehydrates by drinking water, but is not allowed access to salt, the end result can be an animal that is deficient in electrolytes that are necessary to performing the important roles described above. Both water and the electrolytes need to be replenished.
Most horses are able to acquire enough salt through voluntary intake. Therefore, it is important to provide access to salt blocks or loose salt in addition to fresh, clean water throughout the day. Endurance horses, on the other hand, are working at moderate to high intensities for extended periods of time. In these cases, horse will require additional access to carefully balanced sources of water, sodium, chloride, and other electrolytes that will be lost in large volumes during this type of workout.