Performance Horse Nutrition
By May 9, 2006
Welcome to Kent University study of Performance Horse Nutrition. The equine athlete requires more nutrients and calories to support speed, stamina, and the power to move faster and jump higher. The challenge is to understand the horse’s delicate digestive system and how the stress of a performance horse lifestyle can interrupt the digestion process. In this section, we will demonstrate how physical demands placed on performance horses affect their nutrient requirements and feeding management
Specifically, we will address the energy, protein, mineral, and vitamin requirements for a performance horse. In addition, feeding management is important.
The most significant challenge of feeding a performance horse is maintaining the horse in ideal body condition. Because of the physical demands placed on the horse, performance horses don’t always eat sufficient feed to meet energy requirements. Energy intake is the primary nutrient of concern for performance horses. To help provide a “rough” estimate of a performance horse’s energy needs, its digestible energy requirements are determined by classifying them into one of the following groups: light work, moderate work, and heavy or intense work. Light work is defined as that of a Western or English pleasure horse. Moderate work is that done in ranch work, roping, cutting, barrel racing, jumping, etc. Heavy or intense work is that done in race training, polo, etc. It is recommended that a horse be evaluated according to their work on an individual basis and this should be determined by the person exercising the horse.
Energy intake for a performance horse is important. It is the dietary nutrient that directly influences whether a horse can go the distance. It is the measure of the feed’s potential to fuel body functions and muscle contractions during exercise. Because a horse can not eat while working, it must depend on stored energy. Animals including horses store energy as glycogen or sugar in muscle and the liver, and as intramuscular fat.
The energy stores that a horse utilizes during exercise depends on the intensity of the exercise. During mild exercise when the circulatory system provides sufficient oxygen to cells, the horse’s body can use glycogen and fat stored in cells. Essentially, the stored fat is converted to glucose that the cell uses. With sufficient oxygen available, this is known as aerobic metabolism.
During intense exercise, when there is insufficient oxygen at the cellular level, glycogen is the primary energy source. In simple terms, do to a lack of oxygen, a horse can not utilize stored fat as an energy source. During intense exercise, lactic acid accumulates in the cells and blood stream resulting in fatigue.
To replenish the loss of stored energy after exercise, dietary starch is the energy source of choice for the horse’s body to regenerate muscle and liver glycogen. However, there is a limit to the amount of starch that can be included in the diet. Dietary fat from vegetable oils can be used as a source of energy to partially replace starch. In addition, the fiber of the roughages that the horses consume provides energy. The fiber is digested by microbes in the cecum and large intestine. The fermentation products from bacteria are absorbed and utilized as energy by the horse.
Added fat in the diet can be utilized by the horse. Fat fed in moderated amounts is highly digestible. One benefit of adding fat in the diet is increasing the energy density of the diet without increasing the feed intake. This is especially important for performance horses, because it is difficult at times to increase feed intake. Horses require an adjustment time when feeding added fat. A side benefit from feeding added fat is the improvement in the hair coat shine.
In most situations, feeding forage is required. Horses have the capability to utilize forage such as pasture and hay which can provide a significant amount of energy for horses. When not on pasture, it is recommended to feed long stem hay free choice to keep the digestive tract healthy. As a rule of thumb, it is recommended that the amount of forage offered be at least 1% of the horses body weight.
To dilute the amount of starch in grain products, fiber sources such as soybean hulls, beet pulp, and dehydrated alfalfa meal are being used. Because these ingredients are quite digestible, the horse can utilize them as energy sources. Other ingredients such as rice hulls, oat hulls, peanut hulls, and straw have lower digestibility values, so they provide less energy to the horse.
The dietary protein need of the horse is dependent on the horse’s life stage. For example, growing and lactating mares have greater protein needs than a mature horse at maintenance. Horses over 18 years of age may require extra protein, because protein digestibility may decline with age. With increased exercise, it is thought that the protein needs increase. If feeding a properly balanced grain product, the performance horse’s protein need will be met with the increased feeding rate of the grain product. There is not a need to feed a higher crude protein grain product.
A grain product with 12-14% crude protein is usually sufficient for performance horses. Grain products with higher protein are usually unnecessary for the equine athlete. Excess protein can be converted to energy, but the process is inefficient. The process produces by-products that increase the ammonia smell in urine.
The performance horse requires a balanced supply of minerals for the maintenance of the skeleton, muscular contraction, and for energy utilization. Life-time mineral supplementation in the horse’s diet is essential because it can contribute to the overall soundness of the horse. With supplementation of specific minerals, there is reduction in the risk of angular limb deformity, bone spurs, OCD’s, DOD’s, and retained placentas. Also, overall health of the horse can be maintained.
It is important that horses receive mineral supplementation either in the grain product or free-choice. Most mineral products for horses contain inorganic mineral sources. For example, calcium carbonate is a source of calcium, dicalcium phosphate is a source of phosphorus, copper sulfate is a source of copper, and zinc sulfate is a source of zinc. Some mineral products contain chelated trace minerals. Chelated trace minerals are more biologically available to the animal.
After horses have experienced prolonged physical activity in a performance event, it is important to replenish nutrients lost from sweat by allowing the horse to drink water. Do not allow the horse to over consume water. In addition, dietary salt supplementation is important to replenish the sodium and chloride loses from sweat. Electrolyte supplementation may be needed to compensate for the potassium loss.
Vitamins are also important to supplement in the diet of performance horses. Typically, vitamins A, D, and E and sometimes K are supplemented. For horses that are stressed, B vitamins are occasionally supplemented in the grain product. Even though the bacteria in the cecum have the capability to produce vitamins for the horse, vitamins are typically supplemented to ensure the well being of the animal.
To understand the energy needs of a performance horse, there are a few points that need to be explained. For horses in the US, the measure of dietary energy is usually expressed as the term kilocalories. Digestible energy refers to the amount of energy in the diet that is utilized by the horse. Feed ingredients have an estimated digestible energy value. The digestible energy requirement for a horse is calculated based on the horse’s maintenance requirement of digestible energy plus the additional energy needed for exercise. The digestible energy requirement is calculated for a horse, then the amount of feed needed to meet the horse’s requirement is determined.
This example illustrates the amount of feed required to meet the energy requirements of a 1,000lb horse at maintenance, doing light work, moderate work, and heavy work. The hay is assumed to have 900 kilocalories digestible energy per pound and the grain product fed has 1,475 kilocalories per pound. Hay is being fed at 1% of body weight per day or 10 lb per day. The horse’s energy requirement increases dramatically from 15,000 kilocalories per day to 28,000 kilocalories per day as the horse goes from maintenance to a heavy work load. To meet the increased dietary energy demand, the feeding rate of the grain product increases from 4.1 lb to 12.9 lb per day.
Performance horses being fed a significant amount of grain should be carefully managed to prevent any digestive upsets and to maximize intake. Use only the highest quality grain products with high energy density. Feed horses grain three to four times per day at regular intervals. Hard working horses should not be fed within two hours before or for one to two hours after exercise. Typical daily feed intake of forage and grain is 1.5 to 2.5% of the horse’s body weight. Hard working horses may require 3% of their body weight.
In summary energy is the primary nutrient of concern for performance horses. Digestible energy requirements of horses are determined by calculating the energy need for maintenance based on the horse’s weight plus the energy needed based on the amount of work expended. The categories for work are light, moderate, and heavy or intense.
Performance horses should be fed a balanced high-energy grain product that provides protein, minerals and vitamins. It is important to provide sufficient water to hard working, sweating horses. Provide sufficient forage at a minimum rate of 1.0% of the body weight daily in the diet of the performance horse. Feed the horse’s daily grain in equal allotments three to four times per day at regular intervals.