Energy Sources for Different Disciplines
For optimum performance, horses require energy from a multitude of sources. A combination of fibre, starch, and fat is generally the best way to fuel performance, and the ratio of these sources provided in the diet will depend on the type of work that is required from the horse.
Structural carbohydrates in the form of pasture, hay, chaff and fibre products are essential components of the equine diet. Each horse requires a minimum of 1.5% of their body weight in forage daily to maintain optimum digestive health. Horses have a highly developed hindgut that houses billions of bacteria and protozoa capable of fermenting large quantities of fibre. The end products of fibre fermentation can be used as energy sources throughout the day because fermentation continues long after a meal has been eaten.
Since proper gut function is essential to the health and well-being of the horse, fibre-rich forage should be considered the foundation of any feeding program. Pasture and grass type hays are ideal for making up the bulk of forage requirements, and the inclusion of lucerne at smaller amounts has fantastic benefits to working horses. Lucerne is higher in energy and protein than most grass type forages, and the higher calcium it contains increases buffering qualities against gastric ulcers. Lucerne should be a part of the diet for all harder working horses such as racing and upper level eventing and show jumping.
Grain and Concentrate Feeds
Grains and other dietary components provide energy through non-structural carbohydrates, which gives the faster release energy needed for racing, jumping and hardworking horses. The starch in grains is converted to blood glucose when digested and is the first form of energy the horse uses. Remaining glucose not utilised initially, is converted to glycogen and stored in the horse’s muscle and liver for use when next required.
Glucose is one of the major energy sources that provides horses with fast release energy for work, and the amount of glucose available to the horse at the start of exercise is relative to the last meal the horse consumed.
Starch is an essential energy source for any horses where fast paced work is required, particularly racing. It is important that glycogen stores are replenished after each period of exertion, to ensure stores are at adequate levels for the next heavy work period or race. Remaining glycogen levels can make a significant difference to how a horse finishes a race.
Despite the obvious benefits of starch as an energy source, it is important that it is fed correctly to avoid digestive conditions. To reduce the risk of gastric ulcers and hindgut acidosis, grains that have been processed through heat and pressure are recommended, such as steam flaking or pelletising, as well as keeping meal sizes to 2.5kgs and below.
Performance horses prone to tying up or with behavioural conditions would benefit from a decreased starch diet with fat and fibre used as the predominant energy source.
Similar to fibre, fat is a slow release energy source that has numerous benefits to working horses. It is a highly dense form of energy, containing 2.5x the energy as the same amount of oats. This makes it great for weight gain and fussy horses that can't eat large volumes.
Because it provides slow release energy it can help to improve stamina for horses working for long periods through a process called glycogen sparing. Research has shown that when a horse’s body is adapted to a high fat diet, it learns to mobilise and utilise fat more efficiently. This means the body will switch to burning fat more readily, and spare muscle and liver glycogen for use in high intensity exercise. This is particularly important during long distance (endurance) exercise. It is important to be aware that it takes 14 – 30 days to adapt the digestive system to a diet high in fat and a minimum of 30 days to switch on the metabolic processes to utilise fat as an energy source in preference to glycogen. It takes 3 – 4 months for muscles to produce aerobic energy at optimum levels using fat. This means fat will need to be introduced to the horse's diet at least 3 months prior to an extended workout or endurance race to achieve optimum results.
Fat also has an important role to play in race horse diets as it can assist with exercise efficiency and recovery. Feeding stabilised rice bran (KER Equi-Jewel) has shown to reduce heart rate and lactate accumulation during work.
Fat is also ideal for replacing part of the grain ration for sensitive horses such as ones suffering from tying up, laminitis or digestive conditions such as gastric ulcers
While every discipline requires a combination of each of the three energy sources, adopting the correct ratio depends on the individual horse and the work asked of them. Where fast paced work such as racing, jumping and some aspects of dressage require glucose and glycogen from grain, long distance work requires more slow release energy sources such as fibre and fat.
Useful articles on this topic can be found at below:
Please don’t hesitate to get in touch with myself or your local NRM and McMillan Equine representative with any questions or for more information on any aspect of your horses’ nutrition.
Luisa Wood, Equine Nutritionist