In dry heat, trail riders might not be aware of how much body fluid their horses are losing as sweat evaporates quickly. While providing water is essential, electrolytes can help keep the horse’s body chemistry in balance.

Electing Electrolytes
Consider electrolyte supplements for times when your horse may lose important salts through sweating. Not all horses need electrolytes, so ask your vet, or closely monitor your own horse’s needs. Steer clear of mixtures with too much sugar, which can interfere with electrolyte assimilation. Choose powder, gel or paste products depending on your horse’s eating and drinking habits.

How Electrolytes Work
Electrolytes are body salts that break down into positive or negative ions when they dissolve. Those ions let cells “fire up” to do their job. Different salts are necessary for different cells, but they all work together in a precise balance that controls nearly every function of the body—especially nerves and muscles. They also help signal to the horse that he is thirsty.

Electrolytes are primarily lost through sweat when horses (or people) overheat, overwork or overstress. Although we tend to think of sweat as hot and annoying, it is actually a form of natural air conditioning that lowers body temperature by evaporating on the skin. When horses overheat, blood transfers heat from the body core up closer to the skin, which is being cooled by that evaporating sweat. This is why photographs of fit, sweaty horses during or after major exercise show bulging, hard-working blood vessels. 

In a frustrating cycle, the hotter the horse gets, the more blood is needed to lower the body temperature. But some of the liquid needed for that cooling sweat is pulled from guess where? This lowers blood volume. So, as the demand for blood volume increases, the amount of fluid available for that blood decreases as more and more water is sweated away.

High humidity can produce buckets of visible sweat, but dry heat can be just as dangerous because evaporation may occur so rapidly that you might not realize how much moisture your horse is actually losing. Astoundingly, a horse that is working hard in hot weather or is highly stressed can lose more than three gallons of water in an hour.

If it’s tank top weather and your horse is going to be traveling, a dose of electrolytes might be advisable before you hit the road.

That sort of loss maintained over many hours without electrolyte support and a great deal of water produces dehydration and electrolyte imbalance. Depending on how severe this gets, the result can be extreme fatigue, muscle cramps, colic, heart problems, interference with communications between brain, nerves and muscles, and eventual collapse.

The all-too-true “you can lead a horse to water, but you can’t make him drink” makes things worse. Exercise can suppress a desire to drink, even though the body might be dehydrating. You can make yourself drink while exercising, even if you don’t feel thirsty, because you have been taught to do so. Some endurance riders actually teach their horses to drink on command.

Could you just slip your horse some of your bright blue power drink? Well, he may or may not enjoy a swig, but horses and people use different levels of different electrolytes so it is probably a better idea to give him what he really needs.

Dehydration is your horse’s enemy. When skin loses its elasticity, he could be in trouble. The salts in electrolytes are an important aid in preventing dehydration.

Electrolyte Recipes

You can make your own electrolytes by mixing up equal quantities of table salt and Morton’s Lite Salt. Add an ounce or two as needed to your horse’s grain. Endurance riders have a number of wonderful recipes for electrolyte-laced horse cookies that are easy to carry with you and that horses enjoy. There are a number of variations on these, and we appreciate the cooperation of Endurance Net in passing them along. Most horse cookie recipes are pretty forgiving, so feel free to experiment with your own (actually, your horse’s) favorite yummies. Ranges of ingredients are given. Start out with the smaller amounts and adjust if dough seems too gooey or too dry. It should be about the same consistency as those tubes of cookie dough available in the refrigerated section of your grocery store. 2-3 cups of a combination of grain and oats (rolled, crimped or instant oatmeal) 3 cups of bran ¾ to 1 cup of molasses ¾ cup maple or pancake syrup (hold on this if you want to limit sugars) 1 to 1¾ cup hot water or corn oil or a mixture of the two 24 oz. of powdered electrolytes You can also add shredded carrots, chopped dehydrated apples, or other horse goodies. Mix all ingredients together. If you have added extra goodies, you will probably have to add extra water. Much depends on your altitude. Place spoonfuls of dough on cookie sheet (greased if using a conventional sheet) or in muffin cups, pans, etc. Bake at 350 degrees for about 30 minutes, but watch closely. Depending on your proportions, there may be a tendency to burn. Cook until firm. Remove from cookie sheet to cooling rack immediately. Storing them in plastic zippered bags and shoving them into a pocket or saddle bag seems to be perfectly okay by the horses, who evidently like the crumbles as much as the perfectly formed cookies. One endurance rider even recommends not baking the mixture at all, but putting it in a plastic tub, storing it in the fridge, and offering it as a handful treat.

Supplementing Electrolytes
Unless you are seriously competing in endurance or combined training, most horses do fine on good quality feed, forage (pasture and/or hay), a salt block and occasional supplementation as needed. It’s the “as needed” part that can be the puzzle.

Tack shops, catalogues and websites overflow with commercial electrolyte products for horses. The best ones contain sodium, chloride, potassium, calcium, phosphorus and magnesium. Some add other trace minerals and nutritional supplements. Others add sugar, flavors and various “fillers,” which add to cost but may tempt the horse to eat something that otherwise might not taste very good. Too much sugar, however (anything that ends in “ose” on the label), actually interferes with electrolyte assimilation.

Do not give electrolytes containing bicarbonate as a supplement for stress and exercise. This is formulated for horses with diarrhea.

Like everything in horsekeeping, administering electrolytes is (pardon the pun) a matter of balance. First, ask your vet. Your horse is an individual, not an industry norm. Not all horses need electrolytes before a trailer ride.

Most experts do not recommend daily electrolyte supplements, although a horse who does not like licking salt in summer may benefit. On the other hand, while horses mostly eliminate excess electrolytes in a matter of hours through urination, giving one great whacking mega-dose when a horse is already stressed can actually cause dehydration by drawing fluid to the intestinal tract from the rest of the body.

What is the best strategy for giving electrolytes? That depends on the horse and the activity.

If you do decide to supplement, relatively low levels of electrolytes should be administered the night before (essentially to get him to tank up on water) and then an hour or so before you start to load or ride. If the stress will last all day, plan on giving electrolytes every three to four hours, with more at the end and a bit more for a day or two after.

Electrolyte powders can be added to feed and/or water. Drinking just electrolyte-laced water can actually lead to more dehydration, so always provide ample fresh water as well.

There are differences of opinion on how to time electrolyte-laced water so the horse will drink more. Some experts say to give the salty stuff first (possibly disguised with apple juice) so the horse will drink more plain water later. Others note that if the horse takes one sip and rejects the flavored water, he is going to be suspicious and unlikely to down the fresh bucket. Find out what works best for your own horse well before he is going to be stressed enough to need electrolyte supplements.

Pastes are squeezed directly onto the back of the tongue, like dewormers. For horses with nimble upper lips that can separate powders from their dinner more efficiently than a chef’s sieve, you can buy gels that will stick to grain. Both types are handy because you can be (relatively) sure that the correct dose actually goes down the horse’s gullet. You can also make electrolyte-laced horse cookies that can be carried in a plastic bag while on the trail. (See sidebar on page 54.)

So the next time you saddle up for some hard work on a hot day, “lyten up” your horse and take a couple bottles along for yourself as well. But remember that conditioning and a healthy dose of common sense are the best supplements you can give. If the heat is extreme and/or your horse is not rock-hard fit, hang out in a shady, breezy spot with something nice and cool to drink while you quietly and happily enjoy each other’s company. Horses are very good at that.