By Heather Loveridge
Sweat. It’s a natural part of a horse’s existence. But its mere existence also means your horse is losing essential minerals. Eventually, the loss of those substances can lead to decreased performance, dehydration and other severe issues—all of which can be combated by simple prevention, usually in the form of access to fresh water and electrolytes.
“Electrolytes are substances that have a positive or negative charge, which allows them to transfer energy,” said Kelsey A. Hart, DVM, PhD, DACVIM, clinical instructor in the large animal medicine department at the University of Georgia’s College of Veterinary Medicine. “In people and animals, electrolytes are found inside every cell in the body, in the fluid surrounding cells and in the blood. In the body, electrolytes are used to transfer energy within and between cells, just like positive and negative charges in a battery are used to transfer energy to start your car. The function of every organ in the body—especially the heart, nervous system and muscles—requires such transfers of energy, and thus depends on the balance of electrolytes inside and outside of cells.”
According to Dr. Hart, sodium, potassium, chloride, calcium, magnesium and bicarbonate are the most important electrolytes in both people and animals and are typically dissolved in water within the body. Horses’ bodies consist of 50-75 percent water and dehydration greater than 10 percent can be life threatening.
“Hydration depends on the concentration of dissolved electrolytes in the blood and the fluid in and around cells,” Hart said, “so the maintenance of appropriate concentrations of electrolytes in the body is absolutely critical for preventing dehydration.”
Every time you exercise your horse, its heart, lungs and muscles require great amounts of energy. If electrolytes, like potassium and calcium, are lacking, muscles can’t contract efficiently. That alone can lead to poor performance. But when you also consider that something like running a pattern means your horse’s body temperature increases, which leads to sweating as a cooling mechanism, and then in turn causes water and electrolyte loss and potential dehydration, the case for electrolytes becomes even more important.
“Too many people have to experience a negative situation before they actually do something,” champion barrel racer Lance Graves said. “It’s best to practice prevention instead. If you’ve ever seen a horse that gets dehydrated and then ties up, it’s not a good situation. You sure wouldn’t want to put your horse through that on purpose.”
At Graves’ ranch, every competition horse or horse in training gets a powdered electrolyte daily during the hot, humid Oklahoma summers. Graves also takes paste electrolytes on the road with him and supplements as needed during shows.
“I tell people to find a good powered electrolyte and keep your horse on it daily during the summer,” he said. “If you’re going somewhere over the weekend, make sure you take a couple of paste electrolytes, too. If you think your horse is going to get hot, and it’s going to be tough on him, I would use those paste electrolytes.
“Instead of saying ‘If I get into trouble, what should I do?’ just avoid the problem from the beginning. It’s a very simple way to alleviate undue stress and aggravation and possible serious health problems with your animal.”
If you’re horse isn’t getting enough water and electrolytes during a heavy workout or at a show, the consequences can be dire.
“In mild dehydration, organs can partially compensate for decreased nutrients, but they don’t work as efficiently,” Hart said. “For example, muscle strength may decrease, and muscles may tire more easily, so the horse may not perform as well as expected.
“In severe dehydration, organs can no longer compensate for the decreased nutrients and oxygen and can be severely damaged, or even fail, if dehydration isn’t treated quickly. A severely dehydrated horse might stop urinating from damage to the kidneys, seem very lethargic or weak from damage to the brain or spinal cord, colic from intestinal damage or collapse from injury to the muscles or heart.”
A good rule of thumb for how much water a competition horse needs is about a gallon of water per 100 pounds of body weight, according to John Sylvester, PhD, director of research and quality for MARS Horsecare US, Inc. The easiest way to determine if a horse’s water intake is adequate is the capillary refill time—the time it takes for blood to return to a horse’s gum after pressing on it. Two seconds is normal. Any longer than that, and something’s wrong. You can also do the pinch test. Pinch the skin on the side of their neck and count how long it takes to go flat. Again, within two seconds is good.
“When it comes to electrolytes, too many people still think they can give their horses Gatorade,” Sylvester said. “It’s not a good alternative. A horse’s sweat has a different composition than human sweat. You need an equine-specific electrolyte. The form (powdered vs. paste) isn’t as much of an issue as long as its composition is right.
“It needs to have some salt (sodium chloride) and small levels of calcium and magnesium. It should not contain much sugar (dextrose), dicalcuim phosphate and bicarbonate. Bottom line, it should say it’s formulated to match equine sweat.”
With electrolytes, like almost anything else, too much of a good thing can be bad. It’s possible to overdose a horse with electrolytes, which can cause potentially fatal sodium imbalances.
“Never give electrolytes in any form to a horse without ensuring they have free access to fresh, plain water,” Hart said. “Never give more than the labeled amount. Do not give electrolytes to horses with heart problems or kidney problems, as they may not be able to handle them safely. And finally, do not use electrolyte supplements containing potassium in horses with hyperkalemic periodic paralysis, a genetic muscle disease in Quarter Horses and related breeds, as that could cause a HYPO episode.”
Access to water is a re-occurring theme when discussing electrolytes. Proper water intake can prevent a host of problems. But what do you do when you have a horse that won’t drink at shows or on the road?
“Typically, we recommend getting a water-soluble electrolyte and start giving it at home,” Sylvester said. “If they’re used to drinking it at home, when they travel they’ll be less likely to refuse water because the electrolyte helps give it the same taste.”
You can also bring water from home or add a small amount of sweet feed or juice to their water. Just make sure you also provide a bucket of plain water, so they have a choice.
And, while it’s easy to remember the importance of water during the hot summers, don’t forget that your horse needs it just as much during the winter.
“We get lots of calls in the winter from people with horses that are colicing and it’s because they don’t have access to an adequate water supply,” Sylvester said. “People are breaking the ice once a day and thinking that’s enough. It isn’t.”
So whether it’s a blazing hot summer day or a frigid winter morning, do whatever it takes to ensure your horse has access to water. And, if needed, supplement with electrolytes. After all, the key to a healthy horse is prevention, prevention, prevention.
Cool him out efficiently (e.g. hose or sponge with tepid water and walk/rest him in the shade) to minimize more water loss in sweat. Allow him to take sips of plain water as he cools out and provide free access to plain water once back at the trailer or stall. You can also provide access to a bucket of water with an equine electrolyte powder added or administer one dose of a commercial equine electrolyte paste (there are many on the market that are safe if used according to the label directions) to replace electrolytes lost in sweat.
In general, horses will drink as much water and consume as much salt or electrolyte water as they need to restore losses in sweat. Do not force the horse to consume large volumes of plain water or electrolyte products, as this could result in dangerously high or low levels of the sodium in the blood.
If your horse is showing signs of dehydration—he seems lethargic, weak, stiff or colicky, his legs and ears are cold, his gums are dry and the skin on his neck stays “tented up” when you pinch it for a few seconds and then let go—he should be evaluated promptly by a veterinarian. Mild dehydration can be treated effectively with administration of oral electrolytes and water, but severe dehydration usually requires treatment with IV fluids.
“My Take” by Stacy Westfall
Though she’s known as a sought-after clinician and reining horse trainer, Stacy Westfall was also a barrel racer back in the day. She first began using electrolytes after seeing the top barrel racers use them for their horses. Here’s her take on electrolytes:
“My philosophy is always prevent, prevent, prevent, and it’s saved me so much in the long run. I think people have this misconception that they don’t need to give electrolytes, but electrolytes are cost effective and can really improve the recovery time for a competition horse. They’re one of those things I encourage people to just try and see what they think.
“When I was younger, I just gave them at shows, but now, I work my horses a lot more consistently, so I give electrolytes more consistently. If the weather’s hot enough that everyone’s just standing around sweating, then I’ll give electrolytes to everyone, including broodmares. Or sometimes I’ll have a horse that’s not working that hard, but is stressed—maybe one in a clinic that’s being asked to do different things, and it’s stressing and sweating because of that—I’ll give that horse electrolytes as well. Stress and work are the two biggies for me. I usually don’t use electrolytes in the winter though, unless I’m really working one into a full-body sweat.
“If you have a horse that’s picky when traveling, then I would recommend using electrolytes more at home because the last thing you want to do is change everything when you go on the road. If I have a horse that’s stresses on the road, I like to be able to take something consistent with me.
“As always, prevention is key. I don’t have horses tying up, colicking, etc., and I believe it’s because of prevention.”