Feeding is something that can significantly influence a horse’s health and performance, but it isn’t rocket science. Common sense and moderation go a long way—so does a good hay analysis and recognizing your horse’s energy needs and ability to utilize feed.
A competition horse in heavy training has more precise and different nutritional needs than a leisure horse in light use, but the basic principles apply to all horses. With fairly simple feeding, you can usually get far when the basics are in place. One of the most important starting points for finding a suitable, correct diet is determining the horse’s energy needs according to its intended use. If the energy requirement is assessed far above the true need, there is a risk that the horse will gain weight. Excess weight and weight gain predispose horses to many different diseases. If, on the other hand, the estimate is far too low, the horse may lose weight, muscle development will be hindered, and stamina and performance will decline. In general, owners overestimate their horses’ workload and training demands, and therefore also their energy requirements. In addition to the amount of exercise and training, it is useful to evaluate the intensity of the work.
- Light exercise: Most movement is walking and trotting, totaling a few hours per week.
- Moderate exercise: 3–5 hours per week, mostly trotting, but also walking and cantering, plus some more demanding training or coaching.
- Heavy exercise: 4–5 hours per week of trotting, cantering, and more intensive training or coaching.
- Very heavy training: 6–12 hours per week of effective base training plus anaerobic endurance or speed work.
Most horses fall into the first three categories. Horses doing light to moderate work do not differ much in energy requirements from a horse fed for maintenance, which surprises many. On the other hand, high-performing sport horses may need as much as twice the energy of horses at rest. Energy requirements are also influenced by breed, age, metabolism, and the amount and quality of training.
Carbohydrates are the horse’s primary energy source
A horse’s basic diet always consists of forage—hay. A horse gets energy from carbohydrates and fats. These are absorbed in the small intestine. Carbohydrates include starch, sugars, cellulose, and other fibers, which are broken down into glucose before absorption. Carbohydrates are also divided into non-structural (such as sugars and starch) and structural (such as cellulose). Structural carbohydrates contain fiber and are one of the most important components for ensuring optimal hindgut function. In addition to energy, carbohydrates are needed for growth, muscle work, metabolism, and the nervous system. If a horse eats large amounts of concentrate or is sensitive to carbohydrates, starch intake should be monitored. Undigested starch can acidify the gut, increasing the risk of digestive problems. Non-structural carbohydrates (NSCs) come from sugars and starches, mainly from grains.
Fiber digestion and fermentation take place in the large intestine. This process produces volatile fatty acids, which are absorbed into the horse’s circulation. The share of energy coming from fatty acids is comparable to the forage-to-concentrate ratio: the more forage in the diet, the greater the share of energy derived from fatty acids. When grazing, a horse receives a large portion of energy from glucose because grass contains a lot of sugar. Most horses doing heavy work need non-structural carbohydrates (NSCs) to maintain stamina. Even for these horses, however, it is important to monitor total sugar and starch intake and feed only as much as the horse needs based on age and training intensity.
Billions of beneficial microbes live in the horse’s large intestine. They digest fiber and produce volatile fatty acids used by the body as an energy source. Fiber helps maintain proper hindgut pH balance and significantly reduces the risk of colic. Hay is what horses are designed to eat, and it should always be fed at a minimum of 1% of the animal’s body weight per day. Especially with a sport horse doing heavy work, it is worth investing in a hay analysis, which provides accurate nutrient levels and helps determine which nutrients should be added to the diet. High-quality fats are an easy—and often safer—way to increase energy in a performance horse’s diet than adding large quantities of grain.
Remember water and salt
These nutrients are often given less attention, but fresh, clean water and adequate salt are extremely important for all animals—especially horses in training. In hot weather during exercise, horses can sweat as much as 10–15 liters per hour. In addition, horse sweat contains more electrolytes than what circulates in the body, unlike humans. This means that giving only water to a sweating horse dilutes the body’s electrolyte concentration. Because electrolytes are needed to maintain fluid balance and each cell’s electrical activity, they are extremely important for performance. Under normal conditions, when only small amounts of sweat are produced, a salt lick or loose salt, alongside hay and grain, is sufficient. Prolonged and heavy sweating also requires replenishing potassium, sodium, and chloride.
Adequate protein intake
Increasing energy in the horse’s diet is primarily done through carbohydrates or fats. Although protein—and more specifically certain amino acids—is required for growth, muscle development, and maintaining body systems, protein is a fairly inefficient energy source. Horses need essential amino acids, the most important being lysine, methionine, and threonine. Horses in light work can often meet their protein needs from high-quality hay or grass. Horses in moderate to heavy work have higher protein needs, which can be supplemented with grains, concentrates, or alfalfa. Protein should not be fed in excess, because eliminating the surplus burdens the body and predisposes the horse to weight gain. If a horse’s urine has a strong ammonia smell, it can be a sign that the horse is receiving too much protein. On the other hand, insufficient protein intake prevents, among other things, muscle development, which is particularly essential for sport horses.
Stress management
Many sport horses may experience stress in their lives, and tolerance to stress varies greatly between individuals. Stress can affect the horse’s digestive system, but also the musculoskeletal system. A sport horse’s limbs and hooves are subjected to considerable strain and impact. Providing joint-specific nutrients such as glucosamine and chondroitin sulfate, as well as hoof nutrients such as organic zinc and biotin, can help protect joints and hooves from damage. Vitamin E and organic selenium act as antioxidants and are very important components of a sport horse’s diet. Antioxidants help combat muscle damage caused by free radicals associated with exercise and metabolism. Organic trace minerals are not only important for joint and hoof well-being, but also essential for normal nervous system function and immune health. Stress from training, travel, competing, new environments, and other factors can affect the gut microbiome and cause digestive disturbances. In addition, large amounts of concentrates—sometimes needed for stamina—can predispose horses to digestive issues. Pre- and probiotics that support gut function can help minimize digestive upsets and safeguard intestinal function. The key to feeding horses—whether doing lighter or heavier work—is moderation and nutrient balance. Use common sense and observe your horse’s behavior and any changes in it.
