Fuelling the Endurance Horse

A diet formulated for stamina and endurance can be quite different from that designed for power and speed.  We take a look at the theory behind fuelling for success over long distances.
The Right Balance

Achieving the correct dietary balance of energy (calories), protein, vitamins, minerals and water is of particular importance for the competition horse and can have a profound effect on the success of the endurance horse who, particularly at the top level, must perform for periods of up to 8 hours, or more, at a time.  The energy and nutrient requirements for this sustained effort are quite different from those of say, a racehorse running flat out over 6 furlongs and the duration of the competition itself means a horse must often eat and drink whilst “on the move” in order to maintain energy levels.
Fuel for Work

The horse obtains energy from three main dietary sources - fibre, starch (providing glucose) and oil - and then stores it in the muscles and liver, as glycogen, or intramuscularly and elsewhere, as fat.  These different fuel sources are then mobilised, as required, by the muscles to perform work and the type or intensity of the work dictates the fuel used.  At slower speeds - walk, trot and, with improved fitness, slow canter - the muscles use fat, glycogen or glucose in the presence of oxygen (aerobically) to fuel their work. 
As the speed and intensity of the work increases and heart rate exceeds 150bpm, the heart and lungs cannot provide enough oxygen for the muscles to use fuel in this way so they have to work without it (anaerobically).  This limits the fuel they can use to glycogen resulting in the production of lactic acid which, if not removed efficiently, can accumulate and cause fatigue.
Fibre Fuel

Horses have evolved to thrive on fibre from forage but increased work demands mean that forage alone is rarely sufficient for them to maintain satisfactory condition and perform to the levels expected.  We therefore supplement forage with additional sources of calories and other nutrients according to workload. 
Fibre remains a particularly useful source of energy for the endurance horse however, because its fermentation in the hindgut results in a slow release of its energy over a period of time.  This means that fuel provided by fibre is available for use hours after it was consumed by the horse, thus helping to keep him going for longer periods.  Fibre is also important for the healthy functioning of the digestive system and, importantly for the endurance horse, it acts as a reservoir for water and electrolytes in the hind gut, helping to maintain crucial hydration levels.
Not all Fibre Sources are Created Equal!

The source you use will vary according to the time of year as well as the energy demands of your horse.
This should always be clean, dry and sweet smelling but nutrient content may vary.  Coarser, stalkier hay is not very digestible and is less nutritious whilst softer, leafier hay will be more palatable, digestible and contain more nutrients.  Soaking hay helps reduce spore content and provides additional water.
This generally contains more nutrients on a dry matter basis than hay though the nutrients are more diluted as it can be 40 – 50% water.  This means that a higher weight of haylage must be fed to ensure the horse’s fibre requirements are met.
This is about 80% water so the nutrients are even more diluted than those in haylage.  Quality will vary but it is still an excellent feed source and helps increase fluid intake too.
Fed dried and chopped or as soaked cubes, this can provide good levels of energy (weight for weight similar to a low energy mix) plus additional vitamins and minerals and generally better quality protein than average hay.
Additional Fibre Sources
Soaked sugar beet pulp is an excellent way to add fibre to the diet and obviously helps fluid intake too.  It is increasingly included in compound feeds along with soya hulls which also have a “water holding” capacity.
Super Fibres
Fibre can be divided into various parts:

  • Lignin - the “woody” part which cannot be digested
  • Cellulose – fermented to release low levels of energy by bacteria in the hind gut
  • Hemicellulose and pectin – more easily digested by the horse and yielding more energy than cellulose

Ingredients that are high in hemicellulose and pectin include sugar beet pulp and soya hulls and it is these “super fibres” that are helping feed manufacturers to increase the proportion of energy in their feeds which is provided by fibre.  However this is still rarely sufficient for the elite endurance horse and further energy sources must be provided, including oil and cereals.
Too Much of a Good Thing

Alfalfa is a particularly popular feed for endurance horses since it is both a good source of digestible fibre and also rich in quality protein.  It does present a dilemma though, as you can have too much of a good thing!  If alfalfa is fed in large quantities (6 – 10kg) as the main energy source, the horse will be receiving more quality protein than he needs, especially if additional good quality forage or hard feed is fed. 
The excess can be used as fuel but the process is inefficient, producing body heat which the endurance horse can do without and its excretion involves the use of valuable water reserves and the production of urine with a high urea content.  More urine and high ammonia contamination are not good for the respiratory tract of the stabled horse so, whilst alfalfa represents an excellent ingredient in the endurance horse’s diet, its inclusion should be moderate rather than dominant.
Oil Energy

Oil is particularly concentrated and provides 2 ¼ times as many calories as carbohydrates (starch) from cereals, again in a slow release form.  What’s more, it is said to have a “glycogen sparing” effect, since it is used by the muscles at low work intensities allowing glycogen to be saved for times when they have to work anaerobically and can only use glycogen. 
This helps to improve stamina, essential for the endurance horse, whilst the slow release nature of energy from oil, like that of fibre, is non-heating and unlikely to cause excitable behaviour.  Oil must be provided in considerable quantities in the diet to make a significant energy contribution; if straight vegetable oil is fed, at least 250 – 500 ml per day is necessary which can present palatability problems and makes the use of a specially formulated high oil supplement, like Outshine, more appealing. 
More than Just Oil!

Outshine combines oils from soya and linseed to provide a balance of Omega 3 and 6 fatty acids thus avoiding the risk of an imbalance from feeding straight soya oil, for example, or boiled linseed.  The more oil that is included in the diet though, the greater the body’s requirement for antioxidants to deal with the free radicals produced during its metabolism.  Outshine contains additional antioxidants in the form of vitamins C and E, as well as selenium and zinc, to support the safe and efficient utilisation of the oil by the body and making its use preferable to feeding straight oil.
Brain Fuel

The energy provided by cereals is much more readily available to the horse than that from fibre, since it is digested by enzymes in the foregut and absorbed into the blood stream as glucose.  As well as being used by muscles during the intense work of, say, a sprint finish, glucose is the main source of fuel for the brain and other organs, so an exclusion of all starch and sugars from the diet is not necessarily a good thing.  What is important is the way the cereals are cooked in order to make their starch content as digestible as possible to the horse and maximise the chances of them being digested where they should be.  It is the passing of undigested cereals in to the hind gut which can lead to digestive or metabolic upsets.
Superb Package

All-Round Endurance Mix provides the perfect blend of energy sources for the endurance horse with fibre from alfalfa and super fibres, including sugar beet pulp and soya hulls.  The oil content is an outstanding 10% and the micronised cereals it contains are meticulously cooked to make them as digestible as possible and maximise the chance of them being digested in the foregut, where they should be. 
The “fast release” energy they provide meets the requirements of anaerobic respiration during short bursts of fast work as well as providing a readily available source of essential glucose for brain and organ function.  Sustained performance is supported by the high specification vitamins and minerals, including Bioplexes™ and important antioxidants whilst Yea Sacc
® yeast culture stimulates fibre digesting bacteria and helps promote gut health.

Protein is of particular importance to any performance horse since it provides the building blocks of muscle tissue.  It comprises a number of amino acids, some of which can be manufactured by the horse and some which have to be provided in the diet.  It is the proportion of these “essential” amino acids in a protein source which determines its quality and, as with so many things in life, quality is just as important as quantity.  Some protein is provided by traditional forages but specially formulated compound feeds aim to provide an optimum balance of amino acids to help muscle development and function, as well as support tissue development and repair. 

A broad spectrum of vitamins and minerals are essential to ensure the healthy functioning of body systems, with particular importance laid on the inclusion of chelated minerals and anti-oxidants.  Chelated minerals (Bioplexes®) are more easily absorbed by the horse’s body than some other common mineral sources, benefiting tissue integrity, immune status and overall health, whilst antioxidants help protect the body from the effects of free radicals resulting from increased work levels.
Antioxidants, such as vitamin E and selenium, are particularly important when increased quantities of oil are fed, to help ensure its efficient utilisation.  As a guide, for every 100ml of oil added to the diet an additional 100 IU of vitamin E are required; specially formulated compound feeds, like All-Round Endurance Mix, or high oil supplements, like Outshine, are formulated to account for this.

Free choice access to clean water and salt is essential in any feed regime, especially for prolonged endurance exercise where dehydration leads to decreased blood volume and blood flow to muscles, resulting in poor muscular performance, fatigue and exhaustion.  Essential body salts including sodium, potassium, chloride and, in lesser amounts, magnesium and calcium, are lost in sweat and their replacement is essential through the addition of electrolytes to wet feed or water.  These are best administered whenever a horse has sweated to ensure their rapid replenishment by the horse’s body thus minimising the risk of fatigue and aiding recovery.
Advanced Electrolyte Formulation

Aqua-Aide is scientifically formulated and contains key salts, including potassium chloride and magnesium, in addition to the commonly included sodium chloride, plus sufficient dextrose for optimum absorption.  It is designed to be administered according to length and intensity of work done and can be fed ad hoc (whenever the horse sweats), on an ongoing basis or before, during and after competition days.  Its highly palatable formulation can be administered in water or wet (sloppy) feed.

  • Some horses may take time to adapt to drinking water containing electrolytes so, when introducing Aqua-Aide for the first time, provide a source of water without the electrolyte to avoid the risk of the horse not drinking.

  • When administering Aqua-Aide in the feed, ensure the feed is wet and sloppy and that the horse has access to plenty of fresh drinking water.

  • Electrolytes given with insufficient fluid could increase the risk of dehydration.

Complete Picture

Condition is as important in the endurance horse as it is for all performance horses, with the aim being a fit, lean, muscular horse not a thin one.  Feeding the right balance of energy and other nutrients to fuel the horse’s workload and maintenance requirements should achieve this.  Considered by some as out dated, the “traditional” approach of supplementing forage with small volumes of a highly digestible, concentrated source of additional nutrients (compound feed) continues to make sense. 
It leaves more of the horse’s limited appetite for forage consumption, benefiting both physiological and psychological well-being and giving for a happy, and hopefully, successful endurance horse.  All Baileys competition feeds are formulated to ensure an optimum balance of essential nutrients when fed at recommended levels.  They provide a blend of energy sources but offer the choice of an emphasis on different energy types according to your horse’s temperament or preference. 
Essential nutrition

For those whose calorie requirements are met by forage or who require only reduced amounts of hard feed, say during early fitness training, a balancer like Lo-Cal or Performance Balancer will ensure that levels of essential protein, vitamins and minerals can be maintained without additional calories.  The role of nutrition in healing and recovery should also not be under estimated so a balancer can be useful during periods of “down time” too.