Endurance horses lose huge amounts of electrolytes in sweat during a race. It's not surprising that supplementation of horses with concentrated electrolyte paste at frequent intervals is a common practice among endurance riders.
Researchers at Oklahoma State undertook a study to determine the effects of this on the horse's stomach, particularly on gastric-ulcer score. There were 14 horses divided into two groups. One group received a placebo of 2 oz. of water every hour for 8 hours. The other got 2 oz. of concentrated electrolyte paste every hour for 8 hours.
The concentration of individual electrolytes per ounce was: 5,528 mg (5.528 grams) sodium, 11,886 mg (11.886 grams) chloride, 3,657 mg (3.657 grams) potassium, 754 mg calcium and 153 mg magnesium. Horses had their stomachs scoped before and after the eight-hour period.
There was a significant increase in both the number and severity of gastric ulcers in the horses receiving the concentrated electrolytes, so the authors concluded that frequent dosing of electrolytes could be harmful to the stomach. It should be mentioned, though, that exercise itself is a risk factor for gastric ulcers, so this schedule of dosing in a horse that is also exercising could pose an even greater risk.
You may minimize any potential harm from electrolyte supplementation by using one or more of the following modifications of dosing:
• Administer electrolytes in drinking water.
• Administer concentrated electrolytes immediately after the horse has a chance to drink, preferably a few gallons.
• Wait until after the horse has eaten to give electrolytes. When you must syringe-in the electrolytes, using a liquid antacid or corn oil as the carrier for electrolyte powders may help.
Finally, don't count on signs of colic to alert you that your horse may have gastric ulcers. Nervousness, poor performance, poor eating and drinking during the ride-even poor recovery rates-may be nonspecific signs caused by ulcers. Note: A 2004 University of California study scoped endurance horses at the end of either a 50 or 80 km race and found that 67% had gastric ulcers.
Put It To Use
• Horses need a minimum of 1 oz. salt daily; more in hot weather or when in hard work.
• Even if you supplement electrolytes, be sure the horse consumes salt.
• Make up for electrolyte losses during and after exercise.
A low blood-potassium level is a frequent electrolyte problem found in hard-working horses. The usual response, understandably, is to supplement with potassium, but that often doesn't work. Why? The reason is that many horses with chronically low-end potassium values are actually sodium/salt depleted. When making urine, the kidney secretes variable amounts of either sodium or potassium. Since the horse's body is set up to conserve sodium in preference to potassium, if the body's sodium levels are low, large amounts of potassium will be excreted in the urine.
Five pounds of hay supplies all the potassium a horse needs for maintenance. Potassium lost in sweat can be replaced with extra hay or a good electrolyte replacer. If low potassium continues to be a problem, your horse probably isn't taking in enough plain salt. Try adding a minimum of 1 oz. of salt to his meals for a few days. If you use table salt, 2 tablespoons = 1 oz. salt by weight.
Remember, when checking your horse's electrolyte status, wait at least an hour after doing any work. Electrolyte shifts occur during exercise but reverse themselves once the horse stops working.
