Feeding and Supplementing the Endurance Horse, Part II: Electrolytes and Digestive Aids

Providing optimal nutrition to high-end performance horses like endurance athletes depends on multiple factors. Aside from good-quality forage and appropriate concentrates, endurance horses often require targeted supplementation. In the first part of this series, antioxidants were reviewed, underscoring the importance of vitamin E, coenzyme Q10, and other nutrients. In this second installment, electrolytes and digestive aids are the focus.

Electrolytes

Electrolytes are ions (charged particles) found inside and outside of cells in the body. They play an important role in maintaining osmotic pressure, fluid balance, and nerve and muscle activity. A horse sweats to get rid of excessive heat that has built up in muscles. Sweat consists of water and a high concentration of electrolytes. When an endurance horse sweats, it loses essential electrolytes (particularly sodium, chloride, potassium, calcium, and magnesium) that are necessary for top performance.

Excessive sweating with subsequent loss of electrolytes can cause fatigue and muscular weakness. The amount of sweat produced by an endurance horse during a ride far exceeds that of any other sport horse. It may be difficult to realise the volume lost as the sweat may evaporate before it is even seen. Because electrolyte balance is critical for maximal performance, replacement of lost electrolytes is imperative. Sodium losses may reduce thirst so replacement of sodium stimulates a horse to drink and chloride helps prevent alkalosis. During long rides, calcium and magnesium may also be lost in amounts high enough to contribute to metabolic disorders such as thumps or gut-sound issues.

Specific electrolyte supplementation can be provided to the horse before, during, and after the ride, but it may also be necessary to provide a daily dose for horses that are in training. Free-choice water should always be available to the horse when electrolytes are used. Restore is a great electrolyte for training, whilst new Race Recovery with high levels of bioavailable calcium and magnesium and buffered Restore Paste are research-proven products ideal for use at the ride.

Digestive Aids

The rigours and routines of training often interrupt the natural grazing behaviour of performance horses and consequently their stomach acid buffering mechanism. During exercise, acid splash in the stomach can aggravate existing ulcers and, as endurance horses are trained for hours, they have an increased risk of gastric ulcers. This has been shown in scoping studies.

Many endurance horses enjoy the luxury of having 24-hour turnout on pasture, which is ideal for the prevention of ulcers. However, when this lifestyle is interrupted and the horse is loaded on a float, put in a stressful situation at the ride, fed differently than normal, and then asked to compete for hours with limited meals, he may end up with ulcers that will affect performance or attitude. Medications are designed to treat ulcers, or stomach buffers and coating agents can help horses with these problems. It has recently been recognised that glandular ulcers need prolonged treatment with both omeprazole and sucralphate. Sucralox is a palatable source of sucralphate available from your vet.

For horses that are not being treated, choose Neigh-Lox or Triacton to prevent a negative impact on stomach health. With its combination of fast-acting antacids and coating agents, Neigh-Lox quickly neutralises excess gastric acid, protecting the stomach lining and restoring the normal gastric environment. Targeted to buffer acid in the stomach and the hindgut of the horse, Triacton contains research-proven KER BMC, which works in both areas as well as strengthening bones.

Given the importance of hindgut stability to gut sounds and recovery, EquiShure, a time-released hindgut buffer, may be useful. It is designed to act in the caecum and colon by maintaining optimal pH, thereby reducing the risk of hindgut acidosis and disturbances to the microbiome. It is also a slow-release source of sodium, which encourages a horse to drink.

Keeping an endurance horse fit and healthy involves more than just putting in miles on trails. The work required of these horses is quite different to any other equine athlete. The challenge is to provide the correct combination of nutrients that will support the special needs of these athletes during both training and competition.