‘The feed room is where performance truly begins’: Vet explains the art and science of feeding performance horses
Fine-tuning a horse’s diet to the specific demands of his work aids optimum results. Ed Busuttil MRCVS outlines the science behind sport horse nutrition in this exclusive feature for H&H subscribers
In the competitive world of horse sport, feeding performance horses for marginal gains can make all the difference. Nutrition and how we feed horses is one of the most influential – and sometimes misunderstood – factors in a horse’s performance and health, often interlinked with managing medical and musculoskeletal conditions.
Whether you’re preparing a dressage horse for precision work, conditioning a showjumper for power or building stamina in an eventer, feeding performance horses correctly can mean the difference between a horse that just about performs at the level expected and one that excels.
This feature explores how workload, energy sources and modern feeding science come together to create a diet that supports fitness, recovery and soundness in the sport horse.
Feeding performance horses is both an art and a science. Two horses doing the same job may metabolise feed very differently, influenced by temperament, genetics and training routine. The goal is always the same: to provide enough of the right kind of energy to support performance without compromising health, temperament or gut function.
Feeding performance horses for workload
A horse in light work – perhaps hacking and schooling a few days a week – will have very different energy requirements to one galloping cross-country or jumping in several classes at a show.
Light work – a horse who does occasional schooling and hacking can usually be maintained on quality forage, perhaps with a low-energy feed balancer or small ration of cubes.
Moderate work – those whose work includes regular jumping, novice-level eventing or mid-level dressage will need more digestible energy and protein for muscle maintenance and recovery.
Heavy work – an animal who competes at an advanced level, or those whose work is polo, Flat racing or endurance, requires higher energy density and careful electrolyte management to support intense exercise and sweat losses.
Intense work – these are the horses who compete in elite endurance and eventing, and jump racing.
Based on the National Research Council guidelines, the energy requirement for horses are:
- light work – 16.7MJ per 100 kg
- moderate work – 19.5MJ per 100 kg
- heavy work – 22.3MJ per 100 kg
- intense work– 28.9MJ per 100 kg
These guidelines do not take into account the age and breed of the horse, which is why consulting with an independent nutritionist to carry out an individualised plan for your horse is essential.
The key is to feed appropriately for the work done. Overfeeding concentrates to a horse in light work can lead to excitability or digestive upset, while underfeeding an athlete in full training will cause weight loss, muscle wastage and reduced performance, increasing the risk of injury as stride length shortens.
How horses burn energy
As a horse exercises, it burns fuel consumed from their diet to produce energy, mainly through the aerobic and anaerobic metabolism systems.
Aerobic metabolism uses oxygen to convert carbohydrates and fats into energy. It’s the horse’s main energy system for longer, steadier exercise, such as dressage training, hacking or endurance training. It is efficient and produces minimal by-products that cause fatigue.
Anaerobic metabolism comes into play when oxygen supply can’t keep up with demand during sprints, jumping rounds or the final centre line. The body relies on stored glycogen (a form of carbohydrate) within the muscles and liver and produces lactic acid when it is used, leading to fatigue if prolonged.
Most equestrian disciplines involve a blend of the two. Eventers, for example, rely on aerobic energy for dressage and stamina across phases, but also need anaerobic bursts for jumping and speed work. Understanding which system predominates helps determine what sort of energy your horse needs from its diet.
For sustained aerobic effort, such as that seen in endurance or extended schooling sessions, slow-release energy from fibre and fats is ideal. For short, explosive efforts, such as showjumping or racing, more rapidly available carbohydrates provide quick power.
Fuelling and feeding performance horses for different sports
Each sport demands a unique nutritional balance to support its predominant energy system.
- Dressage: controlled, rhythmic work mainly utilises aerobic pathways. Diets rich in quality forage and oil-based calories promote calm, sustained energy without excess fizz.
- Showjumping: combines stamina with short anaerobic bursts. Moderate starch levels, balanced with digestible fibre and oils, support both energy systems.
- Eventing: the true all-rounder. A blend of fibre, oil and controlled starch fuels endurance and speed phases alike. Careful feeding before and after event days is key.
- Endurance: almost entirely aerobic. High-fat, high-fibre diets improve fat metabolism and delay fatigue, while electrolytes and hydration strategies are vital.
- Racing: high-intensity sprinting relies on glycogen oxidation to generate energy. Whereas anaerobic metabolism supplies up to 600m or 30% of the energy during a race, aerobic metabolism powers the rest.
It is also important to remember that racehorses are generally still growing and maturing, requiring extra energy. The caveat to this is that excess provision will predispose growing horses of any discipline to increased developmental orthopaedic disease and gastric ulceration risk, which may have welfare implications.
The importance of water
Water is the most essential yet most often underestimated nutrient in the sport horse’s diet. A 500kg horse in light work may drink around 25–30 litres per day, but this can easily double or even triple during hard training or competition, especially in warm weather.
Fluid loss through sweat can be significant. A galloping horse may lose more than 10 litres per hour. Dehydration quickly impairs performance, concentration and recovery, while increasing the risk of impaction colic and tying-up.
Constant access to fresh, clean water is vital, both at home and when travelling. Horses can also receive a salt lick or measured daily salt in feed to encourage adequate drinking and maintain electrolyte balance. Monitoring drinking habits, urine output and skin elasticity offers useful clues to hydration status.
Where horses get energy from
Hydrolysable carbohydrates (starch and sugar)
Broken down in the small intestine into glucose, these fuel high-intensity work. However, when overfed, they can lead to digestive and behavioural problems – particularly equine gastric ulcer syndrome (EGUS).
Diets providing more than 2g of hydrolysable carbohydrates per kilogram of bodyweight per day markedly increase ulcer risk, as undigested starch ferments in the stomach, producing acid and gas.
The type of carbohydrate matters too, with feeds with a high glycaemic index, such as oats or corn, causing rapid spikes in blood glucose and insulin, which can make sharp horses sharper and may influence muscle metabolism and gastric stability. Note that a kilogram of oats and corn have approximately 600g and 700g of hydrolysable carbohydrates respectively.
Feeds with a lower glycaemic index, like rice bran, provide calories without the sharp sugar rush of cereals. It delivers steady, cool energy while helping maintain condition and topline, particularly valuable for horses prone to ulcers or excitability.
Fermentable carbohydrates (fibre)
Fibre is the cornerstone of every equine diet. Fibre from different types of forage, including hay, haylage, beet pulp and chaff is fermented in the hindgut into volatile fatty acids (VFAs), a slow-release energy source ideal for endurance and general work. Fibre also supports digestive motility and a healthy gut microbiome.
Replenishing the glycogen store after exercise is most efficiently done within the “glycogen window”, within one to two hours of anaerobic work. For every 1g of stored muscular glycogen, 3g of water is also required. Although hydrolysable carbohydrates can be a useful source of glycogen replenishment, fermentable carbohydrates such as soaked beet pulp provide the quickest refuelling without the subsequent energy spikes associated with hydrolysable carbohydrates.
Fats and oils
Fats are highly energy-dense (more than twice the energy of carbohydrates) and produce a calm, long-lasting energy source. Common oil options for horses include linseed, soya and rice bran.
Horses adapt to fat supplementation over several weeks, gradually improving their ability to both digest and use fat as a fuel. This is hugely beneficial for stamina and reducing lactic acid build-up.
The ratio of omega-3 (alpha-linoleic acid) to omega-6 (linoleic acid) is an important consideration, as omega-6 can be pro-inflammatory, as opposed to omega-3, which is anti-inflammatory.
The ratio of omega-3 to omega-6 is 1:6.5 and 4:1 in soya and linseed oil respectively, indicating that linseed oil is significantly less inflammatory, and soya oil may be pro-inflammatory.
The forage-to-concentrate ratio
Even elite equine athletes are grazing animals at heart. Forage must remain the foundation of the diet, for both digestive health and mental wellbeing.
Horses should receive at least 1.5% of bodyweight in dry matter daily (around 7.5kg for a 500kg horse). Most sport horses thrive on a 70:30 forage-to-concentrate ratio, though top performers with very high calorie needs may require a little more concentrate.
Reducing forage too much increases the risk of gastric ulcers, colic and stereotypical behaviours, such as weaving or crib-biting. High-quality hay or haylage, ideally analysed for nutrient content, ensures consistent energy and protein intake. Soaking and steaming hay may reduce protein content by approximately 30% and 40% respectively.
Feed sensitivities
Feed allergies, intolerances and sensitivities can affect performance. Signs include dull coat, poor condition, recurring skin irritation or digestive upset.
Blood tests and skin testing can now detect immune reactions to specific ingredients such as soy, molasses, linseed or alfalfa. While these tests can be informative, a controlled elimination diet may still be required.
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