Electrolyte Supplementation for Horses

Horses & Electrolyte Supplementation

What are Electrolytes?

Electrolytes are 5 of the 7 required micro-minerals for horses which include sodium, chloride, potassium, magnesium and calcium. Sodium, chloride and potassium are the most important electrolytes. Calcium and magnesium are adequate in forages.

Electrolyes serve many important functions. They are essential for fluid balance (hydration), digestion, blood acid-base balance, muscle contraction, and nerve conduction.

Sodium is more prevalent outside the cell, and potassium is more prevalent inside the cell. Exercise and sweating influence the loss and balance of these minerals. The more salt consumed, the more salt that is excreted. Primary loss is via urine and sweat, and some is via feces. Electrolytes are associated with water, so water loss is electrolyte loss.

Which Horses Need Electrolyte Supplementation?

Primarily horses that exercise at heavy to very heavy workloads need supplementation. This includes endurance, racing, event, polo, and some ranch working horses. Athletic conditioning is also a factor.

Some moderate working horses may require supplementation, particularly if temperature and humidity are factors. Inactive, pleasure to light working horses do not generally require electrolyte supplementation; forage based diets are adequate with access to brick/block or granulated salt.

When Should Electrolyte Supplements be Given?

This depends on duration and intensity of work and the influence of temperature and humidity.

Provide electrolytes to your horses before, during and after hard work.

Supplementation options include:

  • 1 hour prior to exercise, every 1 hour during exercise, 1 hours after exercise OR
  • 2 hours prior to exercise, every 2 hours during exercise, 2 hours after exercise

For horses that work hard or perform in heavy competition, feed electrolytes for up to 3 days after work as a safeguard during recovery.

Relative to temperature and humidity, a guideline for when electrolyte supplementation may be needed is

  • F + %RH > 150 (F = Fahrenheit; RH = Relative Humidity)
  • < 130 = heat loss is not a problem
  • 150 = heat loss is compromised especially if humidity contributes more than 50% of the total score
  • 150 – 170 = Competition … with caution
  • 180 = little heat dissipation can occur

How Much Electrolytes?

Most commercial mix feeds contain approximately 0.5% salt: some as high as 1.0%. For supplementation during exercise, use 1 – 3 oz. of NaCl and “lite” salt mixture. 1 tablespoon of salt approximates 17 grams (0.6 oz).

Electrolyte Recipes

  • 3 parts table salt (NaCl) & 1 part “lite” salt (NaCl & KCl); mix & top-dress 1 – 2 ½ oz.
  • 2 parts table salt, 2 parts lite salt, and 1-part crushed Tums tablets (Ca) or dolomite powder (for calcium & magnesium). Approximately 2 oz for days of hard work and heavy sweating.

Electrolytes can be delivered via feed top-dress or mixed in paste. It is critical that there is free access to water. During intense competition, the total of electrolyte loss cannot be replaced during the exercise; with heavy – very heavy competition electrolyte supplementation may need to continue for 1 -3 days.

For endurance horses during competition, recent recommendations from studies suggest targeting approximately 25 – 40% of the expected losses during competition. If there is a concern with fluid loss for inactive to light work, top-dress (add) 1 oz./day of table salt or table/lite salt mixture to the daily feed.

What Not to Do

Over-supplementation is not a preventative. Do not feed in excess. Feeding excess salt results in drinking more water, thus more urination, and may adversely influence the body’s fluid balance. Excess salt in feed may also lead to feed refusal.

Some horses may acclimate to water with added salt, however adding electrolytes to drinking water has potential challenges. This may adversely influence water consumption and the inability to manage the amounts of electrolytes consumed.

Feeding excess protein will increase fluid loss via urine; horses drink more water to rid the body of the excess nitrogen from the protein.

Electrolyte Sources

Pasture and hay have adequate levels of potassium relative to requirements. This emphasizes the importance of feeding adequate forage. Long-stem forage is encouraged since long-stem forage promotes water consumption. Forages are not adequate for sodium and chloride with heavy to very heavy workloads, thus the importance of feeding commercial balance formulas that contain salt and when needed supplementing horses working at heavy to very heavy levels.

White or trace salt brick/block are adequate sources of sodium and chloride; however, not all horses will voluntarily “lick” the brick/blocks. Granulated trace mineral salt is inexpensive and easy to top-dress to ensure consumption. For a homemade electrolyte paste to deliver the salt mixture, use yogurt or low sugar apple sauce as a paste delivery via a large syringe or oral plunger.

The first two ingredients for a commercial electrolyte product should be sodium chloride and potassium chloride. If a sugar (dextrose or glucose) is prevalent in the ingredient label then continue shopping.

Digestible fiber sources, such as beet pulp and soy hulls, are ideal for athletic horses. Digestible fiber feeds have an affinity for water, thus a reservoir for water during exercise, therefore a reservoir for electrolytes. The first two ingredients for Integrity Adult/Senior and Integrity Lite are beet pulp and soyhulls. Integrity formulas are balanced for Sodium, Chloride, Potassium, Magnesium and Calcium.

If unclear of the source, rate of supplementation or conflict in information, seek guidance from an expert in equine nutrition or professional who is experienced with your type of competitive equine athlete.