Electrolytes are minerals that play an important role in the horse’s fluid balance, normal muscle function and recovery after sweating. The most important electrolytes include sodium, chloride, potassium, magnesium and calcium.
Horses lose electrolytes especially when they sweat. Sweat is not just water – it also contains a significant amount of salts. This is why simply offering water may not always be enough if the horse has sweated heavily, for example during training, competition, transport, hot weather or excitement.
When electrolytes are lost through sweat, it is important to replenish them through the diet. Electrolytes are part of the basic feeding routine for a sweating horse, together with clean water and an adequate salt intake.
When Does a Horse Need Electrolytes?
The need for electrolytes increases especially when a horse sweats more than usual. An electrolyte supplement can be used as part of the feeding routine, for example:
in warm weather
after training or competition
during transport
during clinics, training camps and competition trips
during several consecutive training or competition days
if the horse sweats heavily or for a long time
when you want to replenish minerals lost through sweat
Electrolytes should not be seen only as a summer product, even though they are often needed more during the warmer months. A horse can also sweat in winter, for example under a rug, during transport or in an active indoor training session.
Sweating Increases the Need for Electrolytes
Horse sweat contains plenty of minerals. Through sweating, the horse loses especially sodium, chloride and potassium. Sodium and chloride together form common salt, which is a central part of the diet when considering the horse’s fluid balance.
Horses often receive a good amount of potassium from forage, but during heavy sweating, potassium is also lost through sweat. The more a horse sweats, the more important it is to ensure an adequate intake of both water and electrolytes.
Electrolytes do not replace water – they work alongside it. Horses should always have free access to clean drinking water.
Sugar and Electrolytes – Is Sugar Needed?
Many electrolyte products contain sugar or glucose to improve palatability. However, the main purpose of an electrolyte product is not to provide energy, but to replenish the minerals lost through sweat.
Horses do not need sugar in order to utilise electrolytes. On the contrary, a large amount of sugar can make an electrolyte drink less favourable from a nutritional point of view and may negatively affect the absorption of fluids and minerals. This is why a well-designed electrolyte product can work without added sugar.
A sugar-free electrolyte product is a particularly good option when the aim is to keep the sugar and starch level of the diet low. This can be important, for example, for easy keepers, ponies, horses with a sensitive metabolism, or horses whose diet is otherwise planned to avoid unnecessary sugar.
If a large part of the product consists of sugar, it takes up space from the actual electrolytes: sodium, chloride, potassium, magnesium and calcium. Therefore, the quality of an electrolyte product should be assessed above all by how much it contains of the salts lost through sweat – not by how sweet or energy-rich it is.
The function of electrolytes is based on the mineral composition. The most important thing is that the product provides enough sodium, chloride and other electrolytes that are relevant when the horse sweats.
Replenishing Electrolytes in Practice
Electrolytes can be given mixed into the feed or dissolved in water according to the product’s feeding instructions. If electrolytes are mixed into water, the horse should always also have access to plain clean water. This allows the horse to drink according to its own needs.
The amount of electrolytes should be adjusted according to how much the horse sweats. After light sweating, the need is usually smaller, whereas heavy sweating, hot weather, long transport or several consecutive days of exertion can clearly increase the need.
During the competition and training season, electrolytes can be part of the normal feeding routine whenever the horse sweats. It is usually wiser not to wait until the horse already appears clearly tired or dehydrated, but to replenish electrolytes proactively when the situation calls for it.
Don’t Forget Basic Salt
In addition to electrolyte supplements, ordinary salt should also be considered in the horse’s daily diet. Many horses do not lick a salt block enough in relation to their actual needs, so adding salt to the feed may be necessary.
An electrolyte product does not always replace the daily basic need for salt. Instead, it is used especially to cover the additional need caused by sweating. A good overall approach is built on clean water, enough basic salt and electrolytes according to the situation.
Summary
Electrolytes are an important part of feeding a sweating horse. Through sweat, the horse loses not only water but also minerals, especially sodium, chloride and potassium. This is why, after sweating, it is important to make sure the horse receives enough water, salt and electrolytes.
A sugar-free electrolyte is a good choice when you want to replenish minerals lost through sweat without adding unnecessary sugar. The purpose of electrolytes is not to sweeten the diet, but to help replace salts lost through sweating as part of the horse’s overall feeding routine.
Clean water, enough salt and an electrolyte supplement when needed form a good foundation for feeding a sweating horse – in summer, during the competition season, during transport and whenever the sweat has been flowing.
Sources
Lindinger, M. I. 2022. Oral Electrolyte and Water Supplementation in Horses
A useful scientific review of electrolyte and water balance in horses. Supports the sections explaining that electrolytes are lost through sweating and that the intestine rapidly absorbs water and ions.
MSD Veterinary Manual – Nutritional Requirements of Horses and Other Equids
Supports the statement that horses lose especially sodium, chloride and potassium when sweating.
National Research Council / National Academies – Nutrient Requirements of Horses
A key reference on the nutrient and mineral requirements of horses. Includes background on the horse’s need for minerals, salt and electrolytes at different levels of work.
Rutgers Equine Science Center – The Basics of Equine Nutrition
Clearly states that sweating reduces sodium, potassium and chloride in the horse’s body, and that electrolyte supplementation may be useful for horses that sweat heavily.
Kentucky Equine Research – Electrolytes
Supports the sugar section: sugar is not required for optimal electrolyte absorption, and a large proportion of sugar can dilute the essential electrolyte content of the product.
Kentucky Equine Research – Electrolyte Supplementation in Horses: No Benefit to Include Sugar
Supports the wording that adding sugar or starch to electrolyte mixtures did not increase the rate of electrolyte absorption or retention. This is a useful source for the sugar-free electrolyte angle.
Saracen Horse Feeds / Kentucky Equine Research – Electrolyte Loss and Rehydration Strategies
