Minerals and Endurance Horses

What is Equine Endurance Racing?

What special considerations are needed for making sure an endurance horse is fit and has the stamina to participate in an endurance race?

According to Equine Canada “Endurance is a race against the clock that tests a horse-and-rider team over varying and sometimes challenging terrain. The race may be 80, 120, or 160km in distance, and can be completed in one or over several days.”[1] The horse’s welfare is of upmost importance so frequent veterinary check-ins are done throughout a race to evaluate if a horse is fit to continue. In addition to the veterinary check-ins depending on the length of the race there may be rest and feed periods for the horses as well. Given what is necessary to complete an endurance horses diet is very important to its welfare and success.

What an endurance horse needs to be fit and successful for training and races are a source of energy, electrolytes (MINERALS) and water. These needs vary depending on if a horse is in training or if they are actively participating in an endurance race. Energy is provided when the horse metabolizes starch, fat, fiber, and protein in its digestive tract. Water and electrolytes are also very important for endurance horses. During an endurance race, horses may need to cool themselves and this is accomplished by sweating. This helps to disperse heat if the sweat can evaporate but, in the process, fluids and electrolytes are lost which need to be replaced for a horse to be able to safely continue. Simply put sweat loss = fluid and electrolyte loss. While sweating, sodium, potassium, and chloride are all lost, which can cause fatigue, muscle weakness, and dehydration. Other electrolytes such as magnesium and calcium are also lost in smaller amounts. The minerals that are lost are responsible for a remarkable variety of crucial functions in the body. According to Kentucky equine research electrolytes are important for endurance horses because they “play an important role in maintaining osmotic pressure, fluid balance, and nerve and muscle activity.”[2] The amount a horse will sweat is dependant on factors such as the heat, humidity, intensity of exercise and duration of exercise. Kentucky Equine Research says, “In general, horses exercising at low intensity (12-18 km/hr) will lose between 5 and 10 liters (1.3 and 2.6 gallons) of sweat per hour. During higher intensity exercise (30-35 km/hr), sweat loss levels reach as high as 15 liters per hour.”[3] Replacing lost electrolytes in endurance horses is crucial.

Electrolyte requirements for training:

During training daily electrolyte requirements can be calculated based on the distance the horse has logged during training over the period of a week. Environmental conditions are also considered. For example, a horse will sweat much less and therefore lose less electrolytes while training in cooler weather then it would during hot, humid conditions. According to Kentucky equine research the rule of thumb is 2 ounces of good quality electrolyte supplementation for each hour of exercise in moderate climates.[4] This rate of supplementation would double in a hot climate. This can either be given with feed or given as a paste. Please note that electrolytes can only be given as a paste if the horse access to and will drink water as these pastes are hypertonic (a greater concentration of electrolytes) compared to blood and they will draw fluid into the gut if they are not diluted by drinking water. Which can result in colic, dehydration or even death.

Electrolyte requirements on race days:

On race days competitors give electrolytes in a variety of ways. Pre-ride the horse should be starting out with adequate levels of both water and electrolytes. Electrolyte supplementation during a race is slightly different then supplementation during training. During a race extra calcium and magnesium should be supplemented in addition to sodium, potassium, and chloride. These should be administered at vet check-ins when water is offered. It is common for electrolyte pastes to be used during races. Again, it is crucial that electrolyte pastes be given with water for the same reason as above. Post race electrolytes are usually given top dressed on feed for a 24-hour period to eliminate any electrolyte deficits.