Horses cool themselves by sweating as we do, but they can sweat three times more than humans from the same surface area of skin. Altogether, horses can sweat up to four gallons an hour, particularly in hot, humid weather. Equine sweat is hypertonic, meaning that it contains more salt than body fluids. Because of this, horses lose more dissolved salt and other minerals — known as electrolytes — through sweat than humans do.
Why are electrolytes important?
Electrolytes are needed for a wide range of functions including regulation of body fluid levels in and out of the cells, nerve impulse transmission, muscle contraction, pumping of the heart, movement of food and water through the gut and filtering waste products through the kidneys and liver. There are five major electrolytes:
• Sodium helps balance the body’s water levels and maintain blood pressure.
• Chloride is required by the body to maintain the balance of acids and bases.
• Potassium helps balance fluid inside the cells and is vital for muscle, heart, and kidney function.
• Calcium is essential for maintaining normal skeletal and heart muscle contractions, and contributes to nerve function and proper blood clotting.
• Magnesium is important for normal muscle function.
Although the loss of any of these minerals will disrupt functioning of nerve and muscle, the loss of both sodium and potassium will cause a rapid decrease in thirst and appetite, and will delay rehydration.
Electrolytes in the equine diet:
The electrolyte minerals are in grasses, hays, and commercial feeds. However, for working horses, additional electrolytes must be supplemented. Salt should always be provided for horses even if they are not in work. Mineral salt blocks can supply adequate salt most of the time, but in high heat and humidity additional salt supplementation is recommended.
Best sources of electrolytes:
- Celtic sea salt is one of the best sources of electrolytes, and is harvested in Brittany, France by the centuries-old tradition of sun-drying seawater and hand-raking the moist crystals that form. No other processing is done. Celtic sea salt contains 70 trace minerals and sulfur plus all five of the major electrolytes listed above.
- Himalayan salt is also an excellent source of all major electrolytes, in addition to providing 84 trace elements and sulfur. Himalayan salts were formed 200 million years ago in ancient seabeds that were then covered in lava. When Himalayan salt is harvested from these ancient beds, it is sun-dried and unprocessed. Some claim that it may be the purest salt on the planet.
How about table salt?
Table salt is highly processed under heat and stripped of its mineral complex, leaving only sodium chloride. It is bleached, treated with anti-caking agents and aluminum derivatives, and no longer provides the other essential electrolytes. Strange as it may seem, some table salt is the flaky residue from crude oil extraction.
Equine electrolyte supplements – Reading the labels:
Because supplement companies are not required to include the sources of their ingredients, reading the guaranteed analysis of an electrolyte supplement can be a bit mystifying. Where does the sodium and chloride in the formulas come from? Table salt, perhaps?
By reading the ingredient statements, however, we can get clear clues as to what is in these formulas. In reviewing several popular electrolyte supplements, I found the following ingredients:
• maltodextrin (genetically modified corn used as a sweetener)
• natural and artificial flavors (which could be 25 -200 different chemical combinations)
• vegetable oil (blend of GMO soy and corn oils, heat extracted with the solvent hexane)
• artificial apple flavor (100% synthesized in a lab with solvents, emulsifiers, flavor modifiers and preservatives which make up to 80-90% of the mixture)
• artificial orange flavor (similar to artificial apple flavor)
• artificial colors (many of these are now banned in the EU)
• FD&C yellow no. 6 – aluminum lake (these are color additives used in food and cosmetics, formed by reacting straight dyes such as FD&C yellow no. 6 with precipitants, salts and aluminum; aluminum “lakes” are commonly used to make eye shadows)
Only two brands that I looked at contained no sweeteners, highly processed oils, artificial colorings, flavorings, or aluminum lakes: Platinum Performance and Peak Performance Nutrients.
BioStar, of course, does not use additives of any kind.
Heat stress and electrolytes:
According to Dr. Michael Lindinger from the University of Guelph, Ontario, Canada, providing water alone after periods of heat stress results in a dilution of already-depleted electrolyte solutions in the body. Kidneys read this ingested water as an overload, resulting in excretion of more water, taking with it even more electrolytes. A horse will become even more dehydrated when drinking water only.
Dr. Lindinger points out that electrolytes in too great a concentration—as slurries or pastes—are equally troublesome. This causes the horse’s body to direct water into the upper intestinal tract to dilute the electrolytes, thus dehydrating the horse further. This highlights the fact that if your horse refuses to drink, you should not administer an electrolyte paste, as it will further dehydrate. Trailering in hot weather can also bring on heat stress.
If your horse is under heat stress, get the horse cool. You may even add ice or isopropyl alcohol to the wash water for better cooling. Scrape the water off immediately, reapply cold water, and scrape off again to prevent it from becoming an insulator. Use fans or a shady area. Horses in severe heat stress may need many liters of intravenous fluids administered by a veterinarian.
Feeding a wet feed, soaking hay before exercise, and providing adequate electrolyte supplementation on a daily basis can help reduce the potential for dehydration. Horses that have a high level of forage or hay intake before they are worked can store extra water and electrolytes in the large intestine.
Feeding for recovery after training or competition:
After your horse has cooled down and is drinking water, you can feed some soaked alfalfa cubes or pellets, or soaked timothy cubes or pellets with 1-2 teaspoons of sea salt or Himalayan salt plus a banana. The banana provides additional sodium, potassium, chloride, magnesium, and calcium, plus the important fat-soluble antioxidants vitamin E and vitamin A. The glucose in the banana helps replenish vital muscle glycogen stores, and the protein in the alfalfa is crucial as well, because protein after exercise aids in muscle fiber repair. This recovery meal should be given 1-3 hours after training or showing.
Horses diagnosed with equine hyperkalemic periodic paralysis (HYPP) should avoid high-potassium feeds such as alfalfa, brome hay, soybean meal, molasses, and bananas.
If you feed electrolyte supplements, please follow the manufacturer’s directions for use. If you are feeding sea salt or Himalayan loose salt without additional electrolyte supplementation, give 1 tablespoon once or twice per day in hot weather. Give 1-2 teaspoons once or twice per day in cool weather.
If you feed an electrolyte supplement along with sea salt or Himalayan salt, follow directions on the supplement and add 1 teaspoon sea salt or Himalayan salt once or twice per day.
BioStar products providing cooling and electrolytes:
Star Lyte EQ: a unique electrolyte formula that provides a range of mineral-dense salts from land and sea, plus sea vegetables and mangoes for additional nutritional support. With electrolytes from Himalayan Sea Salt, Hawaiian Black Lava Sea Salt, and Celtic Sea Salt.
Cool Star EQ: provides specific ingredients for cooling, which is particularly important during the heat and humidity of summertime. This unique combination may be helpful in increasing hydration. The food variety in Cool Star provides diversity of foods, plants, and probiotics that can be beneficial to the microbiota in the GI tract.