Horses will sweat when exerted through stress or work, or when the temperature in their environment rises. This sweating releases body fluids via the sweat glands, and through the sweating process a horse will lose chloride, sodium and potassium and smaller amounts of calcium and magnesium commonly known as electrolytes. It is very important that a horse keeps their body fluids at the correct concentration, otherwise they may suffer with general and muscle fatigue as well as inability to concentrate and also reduced co-ordination. For any horse this could spell trouble, possibly reflected in poor performance, even in an otherwise healthy horse.
Horses in relatively light work might feel the result of electrolyte imbalances if the weather is excessively hot and they have no access to shade. But in general, most horses on a fully balanced diet, and in light to moderate work, will receive sufficient electrolytes to meet their daily requirements. That said, many people add a small amount of salt to their horse’s diet each day or provide a free access salt lick.
However, horses that compete, travel long distance or participate in cross country, endurance riding or show jumping in very hot weather may need the support of an additional electrolyte supplement. Similarity, a horse that is hunting, even in cold winter weather, may need a boost if they are working hard and sweating profusely.
An electrolyte supplement replaces salts that are lost during exercise or work and help maintain the concentration of a horse’s body fluids at the right level. Electrolytes come in a range of formulas, some in a syringe paste, a powder or a liquid. They are easy to administer, via a feed, in water or orally with a syringe much like a worming paste. In some cases, a horse will reject the water and some owners find adding apple juice or the water from soaked sugar beet can make the drink more appetising. If an electrolyte supplement is fed in a feed, it is important that the feed is wet and sloppy. A small amount of wet soaked sugar beet pulp, perhaps with a handful of alfalfa or chaff added, can be used as a basis for adding electrolytes and is safe to offer after exertion such as cross country. Another point that is important to remember is that electrolytes are “hydroscopic” (attract water). If insufficient water is provided, the electrolytes will draw fluid into the gut from the surrounding tissues, worsening the horse’s dehydration. If you are feeding electrolytes, it is very likely they will make your horse thirsty so provide a constant supply of fresh water.
Unfortunately, a horse’s system cannot store electrolytes so it is impossible to ‘pre feed’ and stock up levels before travel or a competition. However, it is known that electrolytes can stay in a system for up to four hours, so careful feeding can help support any imbalances later on in the day. In addition, if a horse receive electrolytes within an hour of work being completed, recovery is improved greatly, so this is another consideration when going out competing in (hopefully!) warmer weather this summer.