The source of energy (or calories) provided in a horse’s diet has a direct impact on how well a horse competes in any discipline. Focused research in the past decade has vastly improved our understanding of energy utilization in horses. In fact, it has been a major driver in changing how we formulate our feeds and what ingredients we now include in our horse feeds.
Where Do Horses Get Energy in Their Diets?
Energy comes from multiple sources in a horse’s diet. This can be in the form of fiber (structural carbohydrates), sugar/starch (non-structural carbohydrates), fats, and protein.
As a reminder, forage provides most of a horse’s fiber. It will also provide the horse with some sugar/starch and protein. Generally, there is minimal fat in forage (2-3%). In addition to forage, a horse’s diet is usually supplemented with a horse feed that adds additional energy. This, too, can be in the form of fiber, sugar/starch and protein. Of these:
- Fiber is mostly utilized in the hindgut of the horse by the gut microbes, which convert fiber to volatile fatty acids (VFA). Acetate is the primary VFA used as energy by the horse.
- Sugar/starches are absorbed and converted to glucose. Glucose is the primary blood sugar used to power any horse. Excess glucose is converted to glycogen and stored in the muscles and liver.
- Fat is now known to be able to be utilized by the horse extremely well as an energy source.
- Protein is not normally not used as an energy source, except when horses are in starvation mode.
How Horses Use Energy
Every horse operates at an aerobic level of activity every day. Any sort of movement will require energy. For example, just the simple act of walking to a water trough will require the horse to operate at an aerobic level. When it comes to competition horses, disciplines that usually operate at a consistent aerobic level can include:
- Trail riding at a walk or short bouts of trotting.
- Low impact dressage.
- Endurance riding at a walk or short bouts of trotting.
When it comes to aerobic exercise, horses require oxygen to utilize the energy stored in their body. This allows the horse to convert either carbohydrates (sugar/starch) and/or fats to be used as fuel. It is important to remember when it comes to all competition horses, all will have some level of aerobic activity. For example, even the warmup before a race will have the horse working at an aerobic level of exercise.
This changes for the horse when they compete under an anaerobic level of activity. Here, a horse uses energy to power short bursts of intense activity. Disciplines that expose horses to anaerobic levels of activity include disciplines like:
- Polo
- Racing
- Barrel racing
- Eventing
During an anaerobic phase of activity, horses are not able to use oxygen to metabolize fats. Rather they use energy in the form of glucose; first, blood glucose and when that is depleted, they rely on glycogen that is stored in the muscles and liver. Glycogen is broken down into glucose, which, in turn, is the fuel the horse needs.
However, it is not uncommon for horses to deplete their glycogen stores after intense or longer duration bouts of activity. Here, you may notice your horse losing steam during a competition or performance. This is usually indicative of a horse that is depleting most of their glycogen reserves.
How to Optimize the Energy in a Competition Horse
As a reminder, when a horse is working under aerobic conditions, it can use both fats and glucose coming from dietary sugars/starches as energy to fuel them. Under anerobic conditions, once blood glucose levels are depleted, horses will then convert stored glycogen to glucose.
Research in horses has shown fat to be an excellent source of energy for competition horses. This is because, during the aerobic phase of exercise or an event (or even during warm up), horses can burn fat almost as efficiently as glucose. Thus, it will delay the use of glucose and subsequent glycogen. Allowing the horse to have more “fuel”, or energy, in their tank when they shift into an anerobic state can allow them to compete at a higher level for a longer period of time. Thus, for competition horses today, they are recommended to be on a higher fat diet. This does not mean that fat will completely replace the sugar/starch portion of a horse’s diet. Both are still very important to competition horses. However, due to the rise in metabolic conditions amongst horses, the amount of sugar/starch (NSC) that we feed has reduced.
It does require an adaptation period for horses to be able to efficiently use fat as fuel to sustain exercise. It takes a minimum of two weeks to begin to see a change in the horse’s energy levels during exercise when adding fat to the diet. During this time, the horse will begin creating more enzymes that can process fat quickly and more readily.
Take Home Message
With our greater understanding of equine metabolism and nutrition, fat is now a much-needed energy source for competition horses. This is because fat is used quite easily by the horse during aerobic levels of activity and is proving to be a determining factor in how well a horse performs.
There are many different types of horse feeds with higher levels of fat for competition horses. For example:
- Kalm Ultra® is a pelleted high fat (12%) horse feed for hard-keeping and competition horses.
- Resolve® is a high fat (10%) and high fiber (18%), lower NSC (17.5%) pelleted horse feed for hard-keeping and competition horses.
- Senior Sport™ is a high fat (10%), high fiber (18%), lower NSC (16.5%) textured horse feed for hard-keepers and competition horses.
- Kalm Performer® is a high fat (10%), but lower protein textured horse feed for hard-keeping and active horses that are consuming higher protein forages.
- Wholesome Blends® Performance is a high fat (10%), soy-free, textured horse feed for hard-keepers and competition horses.
How much fat and which horse feed to choose will obviously depend on your individual horse’s needs. If they are an easy or hard-keeper, if they are overweight, what discipline they are in, or any other factors all are important considerations when selecting the right feed. Thus, it is always recommended to speak with a nutrition expert to discuss your own horse’s needs. Please feel free to contact us with any questions and for help with a personalized feeding plan.
References
National Research Council. (2007). Nutrient requirement of horses. 6th rev. ed. National Academies Press.
