Released August 20, 2008

UNIVERSITY PARK, Md. – With the heat and humidity comes the potential for horses and humans alike to perspire profusely and to become dehydrated. Excessive sweating may occur when a horse is under stress or exercising intensely. During the summer, horses in intense training, competing at shows, or being transported for long distances can be prone to dehydration.

Dehydration resulting from the excessive loss of fluids can lead to problems including elevated body temperature, muscle malfunction, colic, and even death. Aside from the loss of body fluid or water in sweat, more importantly, there are essential electrolytes that are lost, too. These are key players in normal body function.

What are electrolytes, and what do they do?

Electrolytes are mineral substances that become ionized (charged) in solution, and include sodium, chloride, potassium, calcium, and magnesium. They are required for the proper functioning of the body, notably in muscle contraction, blood fluid balance, and nerve transmission. Since these substances are soluble in water, sweating causes a loss of these valuable players in various body functions. When a horse sweats excessively and then begins cooling down, a whitish haze on their hair coat may be apparent before they are rinsed off. The haze may feel a little gritty to the touch. These areas indicate loss of electrolytes, and much of what you see is salt (sodium chloride).

How do you supplement electrolytes to your horse?

Electrolytes can be supplemented in several ways. One way is feeding a salt (sodium chloride) or a mineral mix to your horses. Horses should have salt available to them at all times to enable them to “self-supplement.” Like many of us, lots of horses like the taste of salt and will self-supplement to meet their requirements. Others, however, are more reluctant. Salt or mineral blocks tend to prompt much lower intakes than do loose or granular mixes. Putting electrolytes into the drinking water is another method of supplementation. The drawback to this method is that some horses will not drink water supplemented with electrolytes. Even if they do drink, some will not consume enough of the water to get adequate amounts of electrolytes into the body in an acceptable time frame.

Electrolytes can also be mixed into the grain ration. If the animal eats their entire meal, this works acceptably. But some wily horses tend to notice any change (texture, smell, taste, etc.) in their grain and will refuse to eat any of the meal when electrolytes are included. To circumvent some of the intake problems, many companies have added flavors, such as apple or orange to their electrolyte products to increase palatability. The flavors can improve consumption rate for some horses, but not others. If time is of the essence, giving your horse a paste preparation allows the electrolytes to be supplemented more quickly. This approach helps you to know the quantity of electrolytes ingested by the horse. Note that giving the oral paste to some horses means that you have to watch them carefully, since they are masterful at spitting out preparations they find questionable. Oral paste is effective for horses that are severely stressed, and which need to more quickly re-establish electrolyte balance in the body.

How do you know if you should supplement electrolytes?

In situations where horses lose a lot of fluid, such as in severe diarrhea cases and during intense exercise for long durations, horses will likely need to be supplemented. Stressful situations, such as transporting in significant heat or over long distances may also indicate the need to supplement. Traveling to and from shows, and performing at shows or exhibitions may increase sweating in horses, and their need for electrolyte supplementation.

Horses that are in consistent, intensive training during hot times of the year may need electrolytes, too. Keep an eye on the hydration level of your horse by taking the thumb and forefinger of one hand and carefully “pinching” a loose area of skin on the horse’s neck. If the skin is elastic, and retracts instantly, the horse typically is adequately hydrated. If the skin remains “tented,” this is an indicator that the horse is becoming or is dehydrated. Note, however, that some horses may develop gastric irritation or even ulcers from electrolyte supplementation for extended periods of time, so ultimately you and your vet must decide what is best for your horse.

Know your horse and carefully evaluate the situation. Individuals respond differently to stress, exercise, and hot weather. There is no “one size fits all” solution to the question of whether to administer electrolytes.

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http://www.agnr.umd.edu/news/article.cfm?id=e06a6c690a5a5a8f0063f7c7b498913d

Contact: Elaine Long Bailey, elbailey@umd.edu