Electrolyte Supplementation & Horses

What are they?

  • Electrolytes are 5 of the 7 required micro-minerals: Sodium, Chloride, Potassium, Magnesium and Calcium.
    • More important electrolytes are Sodium, Chloride & Potassium.
    • Calcium and Magnesium are adequate in forages.
  • Important Functions: fluid balance (hydration), digestion, blood acid-base balance, muscle contraction, nerve conduction.
  • Sodium more prevalent outside the cell, Potassium 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, some via feces; electrolytes are associated with water, so water loss is electrolyte loss.


  • Primarily horses that exercise at heavy to very heavy workloads; includes endurance, racing, event, polo, and some ranch working horses. Athletic conditioning 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 base diets are adequate with access to brick/block or granulated salt.


  • Depends on duration and intensity of work and the influence of temperature and humidity.
  • Provide electrolytes before, during and after hard work; options include…
    • 1 hr. prior to exercise, every 1 hr. during exercise, 1 hr. after exercise.
    • 2 hrs. prior to exercise, every 2 hrs. during exercise, 2 hrs. after exercise.
  • 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 when electrolyte supplementation may be needed; F + %RH > 150.
    • F = Fahrenheit; RH = Relative Humidity.
    • < 130 = heat loss 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?

  • Most commercial mix feeds contain approximately 0.5% salt: some as high as 1.0%.
  • Supplementation during exercise, 1 – 3 oz of NaCl & “lite” salt mixture.
  • 1 tablespoon of salt approximates 17 g (0.6 oz).
  • 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; 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 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 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.
    • May adversely influence water consumption.
    • 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.


  • Pasture and hay have adequate levels of potassium relative to requirements; emphasizes the importance with feeding adequate forage. Long-stem forage 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. Not all horses will voluntarily “lick” the brick/blocks.
  • Granulated trace mineral salt is inexpensive and easy to top-dress to ensure consumption.
  • 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 continue shopping.
  • Digestible fiber sources, beet pulp and soy hulls, are ideal for athletes.
    • Digestible fiber feeds have an affinity for water, thus a reservoir for water during exercise, therefore a reservoir for electrolytes.
    • First two ingredients for Integrity Adult/Senior & Integrity Lite are beet pulp and soyhulls.
    • Integrity balance formulas are balanced for Sodium, Chloride, Potassium, Magnesium and Calcium.
  • Homemade electrolyte paste: to deliver a homemade salt mixture use yogurt or low sugar apple sauce as paste delivery via large syringe or oral plunger.
  • If unclear of source, rate of supplementation or conflict in information, seek guidance from an expert in equine nutrition or professional that is experience with your type of competitive equine athlete.