When a horse’s kidneys are working efficiently, they manage the correct absorption and excretion of fluids and can balance salt and mineral levels if there is a small fluctuation in the amount of electrolytes in the body. A greater fluctuation in the amount of electrolytes in the body - through hard work, racing and exercise, hot weather or illness - usually requires supplementation with electrolytes for horses.
All year round your horse's diet is the main source of electrolytes and minerals. Sodium and Chloride (known to us as common salt) are the main electrolytes missing from a horse's normal diet. In average conditions, a horse needs about one ounce (28.45 grams) of salt a day to stay properly hydrated - because sodium is the mineral that exerts control over how much water stays in the horse's body. With hard work, sport, training or in warm or hot weather the basic salt needs for an average sized horse may increase to 75 - 100 grams a day.
Sodium and potassium are normally filtered and excreted in the horse’s urine and faeces according to the level the horse’s body needs to retain. But the natural level of electrolytes can be impacted by illness, some medications or a dietary imbalance.
All horses rely on sweating to control their body temperature during exercise. Some 90% of a horse's weight loss after exercise is due to sweating. It is important that owners and trainers keep a close eye on this situation and that fluid and electrolyte losses are replaced as necessary, otherwise the horse’s performances will deteriorate.
If electrolytes are not replaced the result for a horse can be serious tiredness and damage to muscle, bone and cartilage tissue.
Be wary of cheaper, poorly-formulated products that may well be missing the whole point of Oral Rehydration Therapy, or ORT. Our Pegasus Health Electro-Lytes contain dextrose which helps the horse's body efficiently absorb the salts. Other products may contain an alternative carbohydrate - but if the horse's body does not absorb the electrolytes properly it will not be able to absorb water and rehydrate.
In the fourth edition of Equine Nutrition and Feeding, published in 2010 by Wiley-Blackwell, author David Frape says: "The first requirement of exhausted dehydrated horses is water, followed closely by electrolytes. Bodily energy resources must then be rejuvenated, and, if the weather is cold, the horse must be kept warm but not hot."
He adds: "Isotonic dehydration depresses thirst so that rehydration is also stimulated by the provision of these electrolytes" - referring to potassium chloride (KCl) and sodium chloride (NACI). By encouraging water consumption, electrolytes can have the effect of improving performance, he says.
During long endurance events, horses that do not drink enough are likely to tire more quickly and may not finish.
Salt licks are provided for many horses, but these normally contain sodium chloride only and in hot weather horses in race training generally do not consume enough salt from licks.
When sodium is in short supply to a horse, it will automatically compensate by secreting less sodium in its urine and replacing it with potassium. This results in more concentrated urine. This also robs the tissues around water cells of salt in order to keep up the quantity in the circulating blood. This is why if you pinch the skin of a dehydrated horse, the skin stays peaked up for a while.
As well as unexplained poor performance, other symptoms which may indicate a need for supplementing electrolytes for horses include: listlessness, depression, sunken eyes, a dull coat and dark urine.
Electrolyte losses can be heavier if a horse exercises hard in hot weather. Even under normal exercise conditions, an average horse weighing 500 kilos could lose 10 litres of sweat in a two-hour period. This sweat would contain approximately 80% as much potassium as sodium and twice as much chloride as sodium. In hot weather, or if exercise is more strenuous, the losses can be much higher.
After a spell of prolonged sweating it will take several days of supplementation with electrolytes for horses to completely make up the losses of these vital salts.
Horses fed minimal amounts of forage may also need electrolytes. Most commercial horse feeds will not contain sufficient electrolytes to counter-balance losses through exercise, so supplementation may be needed.
