For individualised advise and products available for endurance riders and horse enthusiasts central Vic, please contact Caohmin Holistics for Horse and Rider via email caohmin_quarabs@yahoo.com.au
For a customised feed plan please contact Carol Layton www.balancedequine.com.au
other useful links
www.becfeedsolutions.com.au
www.nutragrow.com
www.energreennutrition.com.au
www.bulknutrients.com.au
TECHNICAL BULLETIN
FEEDING THE ENDURANCE HORSE
By Scott O’Brien
Nutritionist
Ridley AgriProducts Pty Ltd
FEEDING THE ENDURANCE HORSE
By Scott O’Brien
Nutritionist
Ridley AgriProducts Pty Ltd
tables and figures have been removed to save space - for full article refer to www.ker.com
A. INTRODUCTION
The competitive endurance horse is the epitome of equine athleticism. The completion rates,
winning times and distances covered by endurance horses are testimony to the equine’s athletic
ability and a credit to their training and management by endurance riders. Proper nutrition is
paramount to obtaining peak performance from endurance horses and over recent years there has
been a great deal of research into this area. This has greatly improved our understanding as how to
manage and feed these horses.
Most endurance horses are Arabian or Arabian derivatives as the natural physique of these
horses is ideally suited to endurance. However many other breeds have competed successfully and
should not be discounted as potential long distance mounts particularly if they are well conformed
with a good attitude.
The fit endurance horse has a lean and wiry appearance. They should be maintained in
condition score 2.5 to 3.0 for optimum performance and this would typically mean bodyweights
about 380 to 480 kg.
In terms of equine sports, endurance riding offers great potential for nutrition to influence
competitive performance. The reasons for this are (1) that the endurance horse spends a great deal
of time working (from four to eight hours for an 80 km ride), (2) the endurance horse has an
opportunity to be rested and fed both on track and at veterinary checks during the ride, and (3) the
speeds at which endurance horses compete mean that the horse primarily uses aerobic pathways for
energy metabolism. This reliance on aerobic metabolism means that more storage fuels are
available to the animal as energy sources and these can partially be replenished while the horse is
working.
This technical bulletin is intended to improve your understanding of horse nutrition and
allow you to design feeding programmes for endurance horses to achieve peak performance. It
deals specifically with endurance horses that are mature horses performing work. For information
on nutrition in other classes of horses there are technical bulletins for stud horses and recreational
horses. To better understand horse nutrition it is first necessary to review the digestive system of
the horse and its capability to digest feed.
B. THE DIGESTIVE SYSTEM OF THE HORSE
The digestive system of the horse is quite unique when compared to other types of livestock.
Figure 1 is a diagrammatic representation of the equine digestive system.
The digestive system can be broken down into two functional parts: the foregut and the
hindgut. The foregut is comprised of a small, simple stomach followed by a long, narrow small
intestine. The foregut functions in a manner similar to that of monogastric species such as pigs and
it is here that enzymatic breakdown of ingested feed occurs. The stomach and small intestine are
where most of the protein, fat, vitamins, minerals and about half of the soluble carbohydrates are
digested and absorbed. The hindgut is comprised of the caecum and the colon. The hindgut
functions in a manner similar to the rumen of cattle in that it is a large, voluminous organ which
contains billions of bacteria and protozoa which ferment fibre and the remaining soluble
carbohydrates into volatile fatty acids which are then absorbed into the bloodstream and utilised as
a source of energy by the horse.
The horse is therefore classified as a hindgut fermenter or non-ruminant herbivore and is
somewhere between a ruminant and a monogastric in its utilisation of feedstuffs.
The Practical Implications of the Equine Digestive System
As we have seen the horse has a small stomach and cannot tolerate too much feed at one
time. Horses also have a fast rate of food passage through the stomach and the small intestine due
to the relatively small size of these two organs. Table 1 shows the relative rates that feeds pass
through various areas of the digestive tract.
Area of Digestive Tract
Retention Time
Stomach 30 minutes
Small Intestine 1 to 6 hours
Hindgut 48 to 60 hours
Table 1. The Rates of Feed Passage through the Equine Digestive Tract
Ingested feed in horses is firstly exposed to enzymatic breakdown in the stomach and small
intestine fermentation in the hindgut. This means that soluble sugars and digestible proteins are
well utilised and there is good absorption of glucose and amino acids in the foregut.
From this brief review of the equine digestive system, it can be seen that horses have
evolved over millions of years for the continual intake of high fibre as occurs in the situation where
horses are grazing pasture. The horse is not ideally suited to large meals of concentrated feed.
However with endurance horses performing considerable work and expending large
amounts of energy, it becomes necessary to supplement pasture with energy in the form of either
concentrated high starch feeds or fat in the form of vegetable oil. When feeding starch in the
formof grain or pellets, it is important to remember that feed management should be carefully
managed to ensure good performance and prevent problems.
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Why is feed management crucial when feeding concentrated feed?
When horses are fed large meals of high starch feed, much of the starch is digested in the
foregut. Any remaining starch that is not digested passes quickly down to the hindgut. The
consequences of large amounts of starch in the hindgut are that it is fermented to lactic acid that
lowers pH (increases acidity) in the hindgut. This pH drop in the hindgut can cause the death of
certain bacteria that then release endotoxins that can result in colic, colitis and various degrees of
laminitis.
Practical methods of minimising problems
• Feed adequate levels of fibre – all horses should be fed an absolute minimum of 1% of
body weight per day of good quality hay. This is usually not a problem in endurance horses that
have access to grazing.
• Introduce grain rations gradually over a two week period.
• Feed frequent small amounts - ideally horses should not be fed more than 2kg of grain
per meal. Most endurance horses are commonly fed only relatively small amounts of grain (up to 3
kilograms). When horses are fed in excess of 2 kilograms of hard feed per day it should ideally be
divided into two feeds.
• Feed by weight and not volume - feedstuffs vary greatly in both energy and density. If
you feed by volume you run the risk of either over feeding or under feeding your horse.
• Use feeds that are processed in order to increase starch digestion in the foregut – the
digestibility of starch in the foregut can be greatly increased by the use of processing methods such
as pelleting, steam-flaking, expanding and extrusion.
C. NUTRIENT REQUIREMENTS OF HORSES
To remain healthy and perform to their optimum potential, it is essential that endurance
horses be provided with the required amounts of energy, protein, minerals, vitamins and water.
A good balance of nutrients is also critical as the appetite of the horse is principally
controlled by its requirements for energy. When a horse has consumed sufficient energy, it stops
eating, regardless of whether other nutrient requirements have been met.
The nutrient requirements of each individual horse depend on the physiological condition at
the time. The horse requires nutrients for maintenance, i.e. to maintain weight and fuel body
processes such as grazing and breathing. In addition to these the endurance horse will require
additional nutrients to meet the additional requirements of work.
The following is a summary of the important nutrients for endurance horses:
1. Energy
Given that endurance horses cannot compete until five years of age they are mature and
have no additional requirements for growth. The endurance horse therefore has energy requirements
for both maintenance and work. This energy can be derived from feed in three main types (fibre,
starch and fat). These fractions are digested in the gastrointestinal tract and stored in the body as
fuel in various forms. This fuel can be stored as muscle and liver glycogen, intramuscular and
adipose fat, all of which can be used to augment the feed taken in during the ride to provide energy
for muscle contraction. When required these different fuels are mobilised and used by contracting
muscles to lever the horse’s mass to cover the ground.
Fibre from pasture and roughage sources is a very important energy source to the horse.
Horses are hindgut fermenters which means they are able to utilise plant fibre. Bacteria in the
hindgut ferment fibre into volatile fatty acids (VFA’s) that are absorbed and taken to the liver where
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they are converted to glucose and stored as liver glycogen or fat. The digestion of fibre is a slow
process so fibre can contribute energy to the horse during the ride long after a meal has been eaten.
All fibre sources are not equal and fibre consists of many different fractions. Lignin is
indigestible and is unable to be utilized by horses, cellulose can be utilized by fermentation in the
hindgut but does not yield a lot of energy. Hemicellulose and pectin are two fibre sources that are
well digested by the horse and yield more energy than other fibre fractions. Sugar Beet Pulp and
soybean hulls are two ingredients that are commonly termed “super fibre” due to the fact that they
are low in lignin and high in digestible fibres such as hemicellulose and pectin.
It is absolutely vital to the endurance horse that it has a healthy gut. Under normal
circumstances the gastrointestinal tract is continually moving food through. During exercise much
of the blood supply to the gut is diverted away to the muscles and the skin. Dehydration due to
heavy sweating also causes a decrease in blood volume and electrolyte imbalances. All of these can
result in slowing of the gut, which can lead to colic and even death.
Research has shown there are two advantages in having a high fibre diet. Firstly the high
water holding capacity of fibre results in an increase in water intake. The water and electrolytes
held in the hindgut can then be drawn upon by the horse to help prevent dehydration and electrolyte
imbalances, which are the key cause of metabolic problems in endurance horses. Secondly the
presence of fibre in the gut will ensure that some blood flow to the gut remains during exercise.
Starch from cereal grains is commonly fed to endurance horses to increase the energy level
in the diet since horses can rarely maintain condition on energy from fibre alone. Starch is digested
in the small intestine to glucose, which is absorbed and can then be used directly or stored as
glycogen or fat. The digestion of starch stimulates the storage of glycogen by raising insulin levels.
The rate of increase and the level of blood glucose after a meal is often termed “glycemic response”
and has important applications in the feeding of endurance horses.
Fat from vegetable oil is a rich energy source for the endurance horse and oil contains 2.25
times as much energy per weight as cereal grain. Fat is extremely well digested in the small
intestine and has no risk of the problems that can occur with cereal grains if they are not fed
properly. Fat is digested in the small intestine to fatty acids, which can be metabolised directly or
stored as body fat.
The feeding of fat to the long distance horse is particularly attractive, as research has shown
that fat supplemented horses were better able to mobilise body fat reserves as an energy source
therefore spared muscle and liver glycogen thus delaying the onset of fatigue. Fat is extremely
energy dense and reduces the amount of total feed required to maintain condition in horses that
exhibit depressed appetite.
Dietary energy is expressed in Megajoules of Digestible Energy per kilogram of feed
(DEMJ/kg). There are equations that can estimate the Maintenance DE requirement and the
additional requirements for work. An example of these values is presented in Tables 2 and 4. Table
2 shows that the nutrient content of the diet does not change dramatically if extra feed is consumed
to meet the demands of work. In many cases horses will not increase their intake to compensate and
the diet must be further concentrated in order to meet the demands of training. It is impossible in
horses that have access to grazing to determine total intake. The only way of determining the
nutritional status is to monitor body condition score.
Energy expenditure will depend on many factors. The Usual Intake Limit refers to the energy provided by a typical endurance ration assuming 2kg of high
energy hard feed, 500mls vegetable oil, 2kg lucerne hay/chaff and access to pasture. The Daily Appetite limit refers to the energy provided by a ration assuming 5kg of high energy hard feed,
750mls vegetable oil and 6kg lucerne hay/chaff.
When energy is fed in excess of requirements it results in weight gain. In situations where a
horse’s energy requirements are not met, poor performance and weight loss will result. The astute
endurance rider will carefully monitor bodyweight or body condition score and adjust feed
allocations accordingly. Recent research has shown the importance of maintaining body condition
score in the appropriate range (2.5 to 3.0) for endurance horses to ensure better completion rates.
(For more information consult the technical bulletin: The Importance of Body Condition Score in
Endurance Horses)
2. Protein
Protein is made up of individual amino acids linked together and it is for these amino acids
that the animal has a specific requirement. As can be seen in Table 2 the protein requirements for
endurance horses are quite low and are easily met by the feeds that are commonly fed to endurance
horses. If protein intake exceeds the requirement then the excess can be used as a source of energy.
In this process the amino acids are broken down by the liver, generating metabolic heat and the
resulting nitrogen is excreted in the urine as ammonia.
Excessive protein intake should be avoided in endurance horses for several reasons:
• Water requirements increase with higher protein as the horse tries to excrete the ammonia
and hydration is vital to performance
• Levels of ammonia and urea in the blood can lead to disturbances in gut function.
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• High protein leads to an increase in metabolic heat and reduce the efficiency that a horse
can cool itself
3. Minerals
Minerals can be classified into:
Major Minerals are those required in large amounts (grams per day) by the animals.
Minerals are found in all feedstuffs but are commonly not present in adequate quantities or the
correct ratio and supplementation is necessary. Table 6 highlights the importance of the major
minerals and the recommended levels that they are required.
Electrolytes are minerals that disassociate in solution into charged ions. They are all major
minerals in that they are required in large amounts. Horses have evolved a highly efficient
sweating mechanism to cool their body when exercising. The sweat output of horses depends on
temperature and humidity and the duration and intensity of work
Sweat loss is in the range of 4 to 10 litres per hour:
- 10 litres per day Light Training
- 20 litres per day Medium Training
- 40+ litres per day 80km Endurance Ride
The electrolytes that are lost in sweat and must be replaced are Sodium, Chloride,
Potassium, and small amounts of Calcium and Magnesium.
Electrolyte Conc. In Sweat
(grams/litre)
Total loss in 15 litres of sweat
Sodium Na+ 2.8 42.0
Chloride Cl- 5.3 79.5
Potassium K+ 1.4 21.0
Calcium Ca2+ 0.12 1.80
Magnesium Mg2+ 0.05 0.75
For horses on a mainly hay or pasture diet, the potassium requirement is usually met but
sodium and chloride intake is often inadequate. Most hard feeds contain added salt and will
contribute sodium and chloride. A simple strategy is to include 30 to 60 grams (1 to 2 tablespoons)
of table salt mixed in with the daily feed depending on the workload. Feed intake will be affected at
higher levels so it may need to be divided into several feeds. The use of a high quality electrolyte
supplement designed for endurance a horse, according to the directions is recommended for several
days prior, during and several days after competition events. Avoid electrolytes that contain
bicarbonate or citrate as they can predispose to alkalosis.
Trace Minerals are required in very small amounts but play vitally important roles in many
body functions. Deficiencies and excesses of trace minerals can be harmful to horses and trace
mineral supplements should be used with care. Table 7 highlights the importance of the trace
minerals and the recommended levels that they are required.
4. Vitamins
Vitamins are complex substances that play important roles in growth, reproduction and
health.
Essential vitamins are those that cannot be synthesised by the horse and must be provided
in the diet. The essential vitamins are A, D3 and E are found in quite high levels in forages that are
commonly fed to horses so additional supplementation is rarely necessary. Vitamin E however is
becoming increasingly more important and supplementation is recommended particularly in hard
working horses.
Non-essential vitamins (B group, K and C) are derived from common feedstuffs and
synthesised by micro flora in the large intestine in amounts that are generally satisfactory. There
may be circumstances however in hard working or stressed horses where supplementation can be
beneficial.
5. Water
Water is often the forgotten nutrient but is essential to maintain body functions and replace
losses in urine, dung and from the lungs and skin. A supply of clean, fresh, cool water should be
available to horses at all times. The requirements depend on duration and intensity of work. Up to
60 litres of fluid can be present in the hindgut, and this reservoir of fluid can be drawn upon during
rides. Fibre has a high water holding capacity; therefore diets that are high in fibre increase the size
of the fluid reservoir within the gut and are therefore highly beneficial to endurance horses
Maintenance, cool weather 4 to 5 litres per 100kg of bodyweight daily
18 to 23 litres per day for a 450kg horse
Hard exercise, hot weather 10 to 15 litres per 100kg of bodyweight daily
45 to 68 litres per day for a 450kg horse
D. NUTRITIONAL VALUE OF FEEDSTUFFS
The principal feed for horses in Australia is grazing from either native or improved pasture.
The highly seasonal climate in Australia means that the nutritional value of pasture varies markedly
throughout the year. During certain times of the year or when work is performed the grazed pasture contains
insufficient energy. The answer to this is to supplement with energy in the form of cereal grains of
fat. When increasing energy in this way it is important to retain the correct ratio of all other
nutrients to energy in order to minimise nutritional problems.
Cereal Grains – cereal grains are all relatively high in energy due to the high starch
content. They only contain moderate levels of protein and are low in calcium and high in
phosphorus. Oats are the safest grain for horses because they are higher in fibre. They are highly
palatable and can be fed whole or crimped. Barley is higher in energy than oats and is quite
palatable. Barley is a hard grain and should be processed before feeding either by rolling, pelleting
or steam flaking in order to increase the digestibility. Corn is a very high energy grain and is used
to increase energy levels in the diet. Corn also benefits from being processed.
Protein Meal – protein meals are used to increase the protein in horse rations. As we have
seen they have little role to play in the diet of endurance horses. Black Sunflower Seeds are a
palatable high fat energy source but are also high in protein.
Forages – hay, chaff and grazing forms a most important part of the endurance horses
ration. Lucerne Hay/Chaff is highly palatable roughage that is readily accepted with little wastage.
It is however not ideal as the sole source of forage as it is high in protein and calcium. The theory is
that diets too high in calcium can depress the ability of the horse to mobilise calcium body reserves
during a ride an increase the risk of thumps (synchronous diaphragmatic flutter) Cereal Hay/Chaff
may be less palatable and is lower in energy but has a better protein and calcium level for
endurance horses. A blend of white and green chaff is an ideal mix. Pasture is extremely variable
depending upon the composition of the pasture and the conditions under which it is grown.
Miscellaneous – Bran is a byproduct from the flour milling industry and is commonly fed
to horses as it is readily available. It can be a useful feed in endurance horse programs when it is
dampened to make a “wet mash” which make a good feed for use at vet checks. The use of too
much bran can cause an imbalance in the ration as it is low in calcium and high in phosphorus.
Molasses is a byproduct from the sugar industry and is low in protein but is moderately high in
energy as it contains approximately 40% sugar. The use of molasses mixed in water to help promote
water intake and mask the taste and smell of different water will also provide potassium and some
calcium and help with electrolyte balance. Vegetable Oil is a highly concentrated form of energy
but provides no other nutrients except for energy.
E. EXERCISE PHYSIOLOGY
There are two pathways by which the horse can utilise stored fuels. The first is aerobic
metabolism whereby fat and/or glucose and/or glycogen can be utilised in the presence of oxygen.
The second is anaerobic metabolism that occurs in the absence of oxygen and only glucose and/or
glycogen can be utilised. The type of metabolism that occurs depends primarily on the speed of
work and the type of muscle fibres recruited.
At the walk fat stores are primarily used aerobically, when trotting fat stores and glycogen
are used aerobically and at a canter fat cannot be mobilised rapidly enough and only glycogen is
utilised aerobically. Eventually at a fast enough speed the respiratory and cardiovascular system
cannot deliver enough oxygen to allow fuels to be utilised aerobically and glycogen is utilised
anaerobic ally with a resultant lactic acid accumulation and rapid onset of fatigue. As the speed
increases the glycogen utilisation increases until there is a dramatic shift to glycogen utilisation as
the horse crosses the anaerobic threshold. Obviously the speed at which this occurs depends on
factors such as terrain, environmental conditions etc.
The reason for the change in the usage of fuel is the recruitment of different muscle types.
The horse has three types of muscle fibre: Type I, Type IIA and Type IIB. Type I and
IIA fibres have a high aerobic capacity whereas Type IIB fibres rely very heavily anaerobic energy
generation. Different breeds of horses have different percentages of muscle fibre types. The Arabian
has a high proportion of Type I and Type IIA fibres and is ideally suited to endurance.
Endurance horses perform almost exclusively in the aerobic zone and only during very fast
work and steep hill work would anaerobic metabolism be employed. Fatigue in endurance horses in
most cases is therefore a result of the depletion of glycogen and fat stores rather than lactic acid
accumulation. The stores in the body of a conditioned endurance horse are quite substantial and
explain the remarkable feats of stamina we observe.
Fat reserves in a horse are by far the most extensive. It is highly
beneficial to condition endurance horses to utilise fat reserves by feeding fat in the diet and
conditioning appropriately, thereby sparing muscle and liver glycogen and delaying the onset of
fatigue. It also highlights once again the importance of body condition score. Horses that are too
lean will not have the fat reserves on which to depend during competition.
The ideal hard feed for an endurance horse
is one that:
• contains a blend of energy from fat, fibre and starch
• is low in protein (12% or less)
• contains a moderate but not excessive amount of starch to increase energy and help boost
glycogen reserves
• contains between 6 and 10 % fat (rations with higher fat are often the cause of palatability
problems)
• contains a high level of good quality fibre
• is designed to provide a balance of minerals and vitamins at a feeding rate that suits
endurance horses. Most endurance horses are able to be maintained on hard feed levels of less than
3 kg per day.
E. FEEDING STRATEGY AND HINTS
General Recommendations
• For endurance horses the most important recommendation is to feed a high fibre diet.
This fibre can provide large quantities of energy to the working horse and has several other
advantages that have already been discussed. Ideally horses could be fed exclusively on good
quality pasture and supplemented with minerals, vitamins and electrolytes where appropriate.
However most horses require some sort of supplementation in order to maintain condition under the
rigours of an endurance season. If selecting hay then a high quality grass hay or mixed
grass/legume hay would be the ideal choice.
• Feed a high fat diet. This will ensure the utilisation of fat rather than glycogen. High fat
feeds or top dressing with vegetable oil can be used. Fat feeding is most beneficial for horses with
low feed intake as the volume of feed can be reduced but energy maintained. One cup (250 ml) of
vegetable oil per day is equivalent to 600 grams or a 1 litre dipper of barley and should be readily
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accepted by horses. Higher rates can be fed where additional energy is required but palatability can
be a problem at high rates.
• Supplement with electrolytes
• Maintain body condition in the desired range and feed according to the work level
• Supplement with trace minerals and vitamins. Endurance horses have high
requirements due to their heavy workload. Many trace minerals such as chromium and selenium
have proven benefits. Similarly some of the vitamins such as Vitamin E and Vitamin C have a role
to play in improving the performance of the endurance horse.
• Ensure water is fresh, clean, cool and available. Hydration is critical to endurance
horses and horses need to be trained to drink at every opportunity.
Leading up to a ride
• Reduce training intensity and frequency to ensure glycogen reserves are full. For horses
prone to tying up grain will also need to be reduced. On rest days all horses should be provided
rations with grain reduced by at least one third.
• Electrolyte loading is commonly practiced by endurance riders with their horses. Doses
of electrolytes in a non-working horse are rapidly excreted and can cause water loss due to high
urine output. Standard doses of electrolytes should be used. A dose of electrolytes within one hour
of ride start may help stimulate thirst on the first leg.
• Maintain forage intake. If the horse is not routinely fed hay and will be at the ride it is a
good idea to introduce a small amount of hay for 1 to 2 days prior to the ride.
• Make a Travel Plan. Travelling can be quite stressful. Allow for rest stops on long trips
and offer the horse water as well as hay or grazing during stops. Horses should not be fed hard feed
for at least 6 hours prior to travel. Allow adequate recovery time from the trip.
At the ride before competition
• Ensure the horse is completely hydrated and has an adequate reserve of electrolytes.
Making sure that a horse is drinking and supplementing with electrolytes will ensure this. For
horses that do not drink well consider taking water from home or try “sweetening” the water with
molasses, vanilla essence or apple juice.
• If a horse is to be given a hard feed it should preferably be at least 6 hours before
ride start. This will ensure that high insulin levels do not impact negatively on performance.
• Provide free choice access to water and grass or hay up until ride start to ensure the
horse has a hindgut full of fibre and reserves of water, electrolytes and energy.
During the Ride and at Vet Checks
• Allow horses to drink at every opportunity on track
• Allowing horses to graze occasionally on track will help improve gut sounds
• At vet checks the first priority is to have the horse rehydrate itself. Offer both plain
water and water sweetened with molasses as the horses preference may change.
• After the horse has begun to rehydrate itself then it can be offered some feed.
Strategies to maximise water intake include the use of “wet feeds”. These feeds are easily eaten
by a tired horse and reduce the need for salivation. Examples are:
- dampened, sweetened chaff with added electrolytes. Small amounts of grain may be useful in
tempting the horse but large feeds of grain should not be used. Treats such as carrots or apples can
also be used.
- wet bran mash or soaked pellets are highly palatable
- hay dampened by wrapping in a wet hessian bag and left for up to 6 hours is highly palatable and
helps to replenish lost fluids.
• Electrolytes if being dosed should be given after a horse has drunk and eaten as they
can discourage intake for a short period
After the ride
• At the completion of the ride the horse should be fed as at the vet check but can also
be fed a usual hard feed. An important point to remember is that the horse will often consume
large quantities of water and feed and the rider should make sure that the horse does not run out.
• Electrolytes are most important in the recovery period and high doses should be given
for 2 days after the ride.
• Rest and recovery is important for the longevity of endurance horses. It can take up to
72 hours to replenish the glycogen reserves that have been depleted. Over this time horses should
be fed up to 50 % more than usual and then tapered off to normal levels.
Spelling horses between seasons
The aim with spelled horses is to maintain bodyweight and health during the rest period.
Spelled horses will generally have access to pasture. The level of feeding necessary will depend
upon the condition of the pasture. On good quality pasture no additional energy will be required
but the use of a high quality mineral supplement will assist where deficiencies occur. Where
pasture quality and quantity are reduced then feeding of hay and a balanced hard feed will ensure
that spelled horses do not lose too much condition. As a general rule horses in this category should
receive a maximum of 0.5% of their bodyweight in hard feed per day (0.5kg of feed per 100kg
bodyweight)
Feed management hints
• The feeder is as important as the feed - the person who feeds the horse should closely
observe the horse for change in appetite, monitor the condition of the horse and adjust the horse’s
feeding regime accordingly.
• Horses have individual tastes - horses have personal likes and dislikes and this should be
taken into account when feeding but always remember to provide a balanced diet. The ration
should be modified to suit individual horses requirements.
• Use only quality feedstuffs - feeds should be free of weeds, dust and mould.
• Feed a horse according to its needs - an adequate ration will ensure that a horse looks
good, maintains bodyweight and is willing to work. An underfed horse will look poor, lose
bodyweight and lack vitality. An overfed horse will gain bodyweight and may express excess
energy as ‘fizzy’ behaviour.
• Feed small meals often and at regular times - horses are creatures of habit and
appreciate a regular feeding routine.
• Observe dung for changes - check the amount, consistency, smell and colour of the dung
as an indicator of digestive function and hydration status. Any deviation from normal may indicate
digestive upsets.
• Regularly review feed programme - seek the help of experienced equine nutritionists.www.ker.com
• Follow a health program – keep up to date with worming, teeth and vaccination
schedules.
G. COMMON PROBLEMS
Poor quality or shelly feet
Poor quality feet can be the downfall of an otherwise good endurance horse. The old saying
“No Hoof – No Horse” is no truer than in the sport of endurance. There are many “hoof foods” on
the market based on the vitamin Biotin with or without extra ingredients such as methionine, zinc
etc. These products can improve the quality of some horses feet but do not work in all cases. The
products that provide the correct dose of 15mg of biotin per day are expensive and need to be used
for at least nine months in order to grow a new foot.
Fizzy or Overly Nervous Horses
These horses can be their own worst enemy in endurance. They often expend a lot of
nervous energy and go a bit too hard early on and deplete their energy reserves. Quite often this is a
temperament issue but nutritionally there are a couple of things that are worth a try such as :
- the use of a “calming supplement” containing Thiamine (Vitamin B1)
- eliminate oats from the ration and feed processed feeds
- divide the hard feed into two feeds per day
- the use of oil to replace energy from starch
- ensure adequate electrolytes are provided
- feed according to workload (do not overfeed)
Tying-Up or Equine Rhabdomyolysis
Tying-up is a complicated condition and recent research has expanded our knowledge, but
there is still much more to be determined. Some horses have a genetic predisposition to tying-up
and these horses need to be managed carefully. Other horses can tie-up as a result of poor feed
management. If you have a horse that ties-up seek professional help from a veterinarian and
nutritionist. They will consider many options such as :
- eliminate oats from the ration and feed processed feeds
- divide the hard feed into two feeds per day
- the use of oil to replace energy from starch
- ensure adequate electrolytes are provided
- reduce feed on rest days. Feed after work not in anticipation of work
- Vitamin E, Vitamin C, Selenium, Chromium
Depressed Appetite
Many endurance horses, especially those that run towards the front of the field will train off
and exhibit signs of depressed appetite. This typically occurs after longer, hard training or
competitions. For these horses, experiment and find a feed that they like. Consider a pre-race and
post-race booster of B Vitamins to combat stress and help appetite and an antioxidant supplement
of Vitamin E and Selenium.
Horses that are hard to put weight on
The consequences of horses that are too lean and difficult to put on weight are fully
explained in the technical bulletin: The Importance of Body Condition Score in Endurance
Horses. In simple terms these horses need to consume more energy and expend less. Fat in the form
of vegetable oil will increase the energy in the diet and it may also be necessary to feed horses more
than the owner is used to. Remember that horse are all individuals and what works for one may not
necessarily work for another. A reduction in training intensity or complete spell is often the only
way to regain lost condition on notorious poor-doers.
H. FEEDS AND SUPPLEMENTS
Ridley AgriProducts and Kentucky Equine Research manufacture and distribute a range
of high quality horses feeds and supplements. These products are scientifically formulated by
experienced equine nutritionists to ensure that they provide a complete nutritional solution for
optimum performance. Commercially prepared horse feeds are an economical and simple feeding
solution. However, it is important that horse owners take care to select the feed product most suited
to their horses needs and also follow the manufacturers feeding recommendations.
www.ker.com
by Dr. John Kohnke BVSc RDA
www.kohnkesown.com
Horses used in endurance sport competition undergo extended training programs in preparation for competition. Endurance horses are
highly trained and time spent training for competition requires the highest daily energy demand of any equine athlete. They must be fed to
be responsive and energetic without being hard to control or ‘above’ themselves. Many horses are given only limited access to grazing,
often to reduce the risk of injury and because of the need to control their diets. Endurance competition can also drain a horse’s body
reserves over a full season of competition, as the stress of travelling and regular competition can often have an adverse effect on body
condition, recovery and ultimate performance.
A well balanced diet, formulated to meet the specific needs of each individual horse is essential for health, maximum endurance,
fitness, maintenance of condition, and optimum response to training.
Regular teeth care is important to remove sharp edges on the large grinding cheek teeth once every 6 months during training, and when a
horse is first brought into training, as well as routine worming to control internal parasites is essential.
ENDURANCE HORSES – Overall Requirements
Many advances in the scientific and practical feeding of endurance horses have been made over the last two decades. Rations now
include more fat to reduce the bulk of the ration a horse has to consume to meet the energy needs for long distance exercise. Most upper
level competition horses are stabled and fed grain based feeds, with less reliance on pasture as a nutritional base for their diet. Horses
are trained for 2-3 years or longer to prepare for long distance competition, so that a ration formulated to meet exercise demands and
ensure long term soundness is paramount to continued success. A well cared for and trained endurance horse is able to compete over
thousands of kilometres in organised rides over a period of years.
The majority of endurance horses are small framed, hardy horses often based on part or pure Arabian bloodlines. Many of these horses
naturally have a reduced capacity for bulky feeds, with limits on appetite imposed by the stress of extended exercise in preparation for
competition. In many cases, the diet has to be manipulated to ensure each horse can consume an adequate volume to meet its
requirements.
Specific Nutritional Needs of the Endurance Horse
Endurance horses have the following special nutritional needs
Limited intake of bulk to maintain low gut weight, requiring an energy dense ration based on
high energy grains and fat with adequate high quality fibre for digestion.
Intake of high quality protein to maintain muscle mass and repair, whilst avoiding hindgut heat production from excess protein.
Avoid protein overload - less ammonia smell in the stable.
Adequate fat as an energy boost, as well as Omega 3:Omega 6 balance to maintain muscle function and skin condition
High quality fibre for efficient fermentation and water holding capacity in the hindgut.
Provision of adequate, but not excessive, calcium during training to maintain bone strength, with balanced phosphorus and range of
trace-minerals for bone and joint repair, and metabolic function.
A range of vitamins, including Vitamin A for tendon strength, Vitamin D for bone.
strength, Vitamin E and selenium for muscle strength and stamina and B-group Vitamins to maintain the appetite, metabolic
function and offset stress of long distance exercise.
Adequate intake of electrolytes, especially sodium, potassium and magnesium to maintain muscle/nerve function and fluid balance.
Access at all times to a supply of fresh, clean water to replace sweat and other losses. Avoid dehydration and risk of heat stress.
Opportunity for access to green pasture to maintain appetite and willingness and drain airways with head down grazing.
SPECIFIC NUTRITIONAL NEEDS FOR ENDURANCE HORSES
Endurance Horse - Body weight 400-450kg Condition Score 2-2½
NUTRIENT
REQUIREMENT/SOURCES/GUIDELINES
ENERGY
Daily Requirement in training 130-150MJ DE, 100km ride 210 MJ DE, heavy rider 250MJ DE.
40-50% grain to 40-45% roughage. Feed bulk limited by hard work and small frame size - usually
consume 10-11kg daily. Traditionally oats as 30-40% base, with corn, barley and oil as major energy
sources, more oil and corn for longer distance rides or in smaller framed horses.
PROTEIN Require 10-12% crude protein, up to 12-14% in early training, 0.32-0.35% lysine. Above 1 cup daily of
oil or on minimal lucerne diets, add extra 3-5% high quality protein such as soyabean or canola meal.
An extra 2% protein for 2-3 meals after competition to help muscle and bone repair.
ROUGHAGE Upper level competition 45-50% grain : 50-55% roughage, lower level 40% grain, 60% roughage.
Minimum roughage 1% body weight, but for endurance may limit to 0.5-0.75% to reduce gut weight but
still retain hindgut water reserves. Dampen hay to reduce dust and respiratory allergies.
Minerals: Mature horse, heavy sweat loss of calcium requires replacement 2.5Ca:1 P. Iron for aerobic
muscle enzymes, selenium for muscle strength, chromium for muscle bulk and glycogen sparing effect.
Electrolytes: Speeds below 450m/m but extended duration, sweat loss 40-60L during ride. Salt 40-60g,
with heavy sweat electrolyte mix double the dose rate and rehydration fluid after exercise.
Vitamins: Increased Vitamin E for stamina, muscle strength and as an anti oxidant in an oil
supplemented diet. Vitamin B-Group for appetite.
WATER Daily consumption: - Cool weather 25-30 litres
Extended work and hot weather 30-40 litres
Heavy sweat loss 50 – 80 litres daily.
COMMON FEED RELATED PROBLEMS
The majority of problems in endurance horses, other than lameness, are metabolic conditions, such as tying-up, loss of appetite due to
stress and long term training, dehydration during heavy training with sweat and fluid losses, and poor recovery after hard competition.
“Tying-Up” (Set Fast)
High energy rations in excess of exercise need, particularly when they are still fed on light work or rest days, or if training is interrupted
by travelling prior to competition, increase the risk of ‘tying-up’ when normal exercise resumes. Fillies and mares tend to be more prone
to tying-up, especially if they have a nervous temperament and are fed a ration based on oats as a major energy source. An endurance
horse may tie-up when the blood becomes depleted in calcium, potassium, magnesium and chloride by heavy sweat loss or when
dehydrated and exhausted during a long or hard ride.
The overall risk of tying up in these horses can be significantly reduced by cutting the amount of oats to one third or less, and
substituting with either rolled barley, extruded feed or rice pellets as the primary energy source. On rest or light workdays, reduce the
amount of grain to one third on the evening feed prior to the rest day and make up the bulk with good quality roughage as hay.
Reintroduce the grain over 2 days once full training is recommenced. For more information refer to Facsheet No 2.
Depressed Appetite
The high physical demands of endurance training can lead to fatigue and disinterest in food as the appetite is depressed. Many horses
will begin to leave feed when subjected to hard or intense exercise or following competition especially after traveling over long distances
to a ride. As a horse gains aerobic fitness during training, it will require less energy for an equivalent amount of exercise, and therefore
may not voluntarily consume the same amount of feed that it needs in early training.
Small framed horses, such as Arabians, may not be able to physically consume a large bulk of feed. Therefore substitution of oats as a
major energy source with more energy dense grains such as corn or steam-rolled barley and oil can help to significantly reduce the bulk
of the ration, whilst retaining energy intake and balance of roughage for efficient digestion and water retention in the hindgut.
There are a number of other underlying causes of poor appetite, picky eating and loss of appetite. Low grade irritation due to gastric acid
“heartburn” when agitated by relocation and stress of ride preparation, or travelled over long distances on an empty stomach. Ulceration
of the stomach and small intestine lining is a common cause of loss of appetite in horses in heavy training on high grain diets, or horses
on minimal roughage diets with little or no access to pasture.
Recent research indicated that dosing with highly concentrated electrolyte mixes, liquids or pastes prior to and during a ride can
increase the risk of gastric irritation and ulceration.
Dehydration
Many competitive horses are prone to dehydration and ‘tucking up’ in the belly when travelling to and from competition, particularly
those with a ‘nervy’ disposition that sweat freely, or sweat heavily when training during hot or humid weather. Loss of fluid and body
salts through sweating can result in reduced stamina, poor recovery after a competitive ride and drying out of the coat.
A routine daily supplement of (60-80g) salt and mixed electrolytes such as Cell-Salts (1 scoopful with 1 scoopful of salt) will help
increase fluid intake and replace body salts lost during exercise and travelling in sweating horses. Additional supplementation with an
oral rehydration fluid will also be of benefit to a dehydrated horse, but care must be taken to avoid concentrated salt mixes or pastes
without adequate water during a ride or at a rest point.
Maintaining Muscle Bulk
Training increases the strength and ‘fitness’ of muscles. In horses that are given long slow distance exercise, the bulk and ‘roundness’ of
the rump and croup muscles decreases as fat and retained fluids within the muscle structures are reduced. This often corresponds to a
loss of condition as a horse improves in fitness and reaches a suitable competitive condition score with less subcutaneous fat.
The trace mineral chromium has been observed in a number of human and animal studies to increase the muscle to fat ratio and help
maintain muscle bulk and utilisation of carbohydrates as an energy source.
A daily supplement of 5mg of chromium in conjunction with other minerals and vitamins combined with a diet containing 12-14%
protein is recommended to help maintain muscle mass in hard working horses, as in Marathon Endurance. Other supplements, such as
Muscle XL, provide high quality protein, Vitamin E and organic zinc to help maintain adequate muscle mass and strength in hard
working horses.
‘Cow-pat Droppings’ and Grain in the Manure
Many horses in upper level competition that are stabled and have restricted or no access to grazing, and minimal roughage intake on high
grain diets, develop ‘cow pat’ droppings and pass whole grain in their manure. Some of these horses also suffer from sore feet, crumbly
white lines and broken-away hoof edges.
The overload of excess grain, particularly where large amounts are given to meet energy demand, can result in hindgut acidosis with
increased bowel motility and in some cases, onset of low grade laminitis (founder), and a scratchy, shortened stride and ‘sore feet’.
Reducing the amount of grain to 1½-2kg per feed and providing adequate roughage will help to reduce hindgut acid build-up.
Special Considerations relating to Feeding Endurance Horses
Minerals
Adequate intake of a wide range of minerals is required by the hard working Endurance horse.
Recent studies have indicated that calcium turnover in bone is increased dramatically when a horse is exercised for more than 16km per
day. The rate of calcium deposition in bone was increased by up to 20% when long distance exercise was given, triggering reduced
calcium excretion in the urine and increased body retention of calcium.
Excessive calcium intake during training, particularly from high amounts of alfalfa hay, can cause suppression of parathyroid
gland function, which normally controls mobilisation of calcium stores from the bones to maintain blood calcium levels. During
competition in excess of four hours duration, sweat loss lowers blood calcium, which is not replenished by parathyroid hormone
action. Low blood calcium causes a high risk of ‘tying up’ and the “thumps” during competition.
Recent recommendations suggest that minimal lucerne hay not exceeding 3kg daily, should be provided during training, and meadow
hay and pasture should be used as the main roughage source. In the 2-3 days prior to competition, the amount of lucerne hay can be
increased to provide a reserve of calcium and water for use during the ride. This feeding method will maintain parathyroid action, which
will be activated once blood calcium decreases during long distance competition. The amount of supplementary calcium and phosphorus
added to the diet should only be sufficient to balance the ration to meet daily requirements, usually 25-30g as a supplement.
Supplementation with additional but not excessive calcium to maintain bone strength and replace sweat losses, selenium and
Vitamin E for muscle function, aerobic metabolism and efficient utilisation of fat added diets, and Vitamin A to maintain tendon
strength are widely used to ensure an animal can perform and remain fit and sound over extended training periods and longer
competitive seasons. Fluid and electrolyte replacement is essential to combat the large sweat losses, and maintain vitality and
performance, but avoid large doses of electrolyte solutions or pastes as “top-ups” during a ride without adequate water intake.
Vitamins
Studies have indicated that when large amounts of energy are metabolised, particularly where increased levels of fat are provided, extra
Vitamin E and B-Group vitamins are required. It has been reported that up to 5000IU of Vitamin E is supplemented daily to top
Endurance horses. Conservative doses of 1000 – 2000IU, such as in Cell-E Premium or Marathon Endurance are considered to be of
practical benefit to maximise stamina and muscle function in Endurance horses during training.
Preparation for Endurance Competition
Endurance horses utilise their muscle energy stores very efficiently through aerobic (oxygen) metabolic pathways. The extended
duration of exercise results in depletion of over 50% of their muscle glycogen energy stores during a standard 80-100km ride. Although
energy is not diverted for growth, as all competitive endurance horses are mature, adequate energy must be provided for exercise, tissue
repair and to maintain body condition during extended training.
In heavy training, feeding extra fat in the diet of endurance horses helps conserve muscle glycogen and reduce the rate of glycogen
depletion, thus maintaining glycogen reserves for faster finishes at the end of the ride.
Many successful endurance horses are maintained on relatively small amounts of 3-4kg of grain each day, particularly those that have
access to pasture, as they are more settled and tend to do better. Endurance horses also seem to be more sensitive to over-supply of
energy in grains, particularly the Arabian breeds, with increased risk of tying up and unsettled behaviour.
The use of 4-5% by weight of vegetable oil (usually 2-3 cups daily) added to the ration to provide a highly digestible, dense form of
energy to replace some of the grain is particularly suited to long distance aerobic exercise in endurance horses. It also helps to reduce
the volume of the concentrate feed that needs to be consumed, eliminates dust in the ration and helps to conserve muscle glycogen.
Theoretically, it would be an advantage in endurance competition to minimise gut fill and hence body weight and ‘load’ carried in the
lead up to a long distance ride. A lighter horse will expend less energy over a long distance and be less likely to fatigue early during
competitive rides. However, concentrating the diet by reducing hay intake can increase the risk of metabolic problems such as tying up
and colic, as well as dehydration because of reduced hindgut water reserve normally held in the fibrous roughage. There are a number of
modifications to a ration that can be made, taking care not to cause refusal by radical changes in the proportion or type of feeds.
1. For the last 3-4 days before a ride, provide an additional 500-750g grain mix, with protein meal and oil concentrate mixed in a
50:50 blend of cereal and alfalfa chaff to help retain hindgut water reserve in the fibrous structure. Good quality lucerne hay for
extra protein, calcium and natural salts can also be fed to appetite as overnight roughage.
2. Supplement with an electrolyte mix made up of 2 tablespoons of salt (providing sodium and chloride), 2-3 tablespoons (40-60g)
of an electrolyte mix (e.g. Cell-Salts) on the two evenings prior to a ride to encourage fluid uptake and replace salts lost during
taper-off training and travelling. Ensure adequate water is available at all times and feed dampened feeds, including hay,
to increase fluid intake.
If a horse is dehydrated or ‘pinched-up’ in the skin or ‘tucked up’ in the belly, feed the hay should be soaked in water. A wet
bran mash at the rate of 1 litre of bran per 100kg body weight can be offered at 72 hours prior to the ride if the horse’s
droppings are pebbly and dried out.
3. On the two evenings before the ride, increase the Vitamin E from the standard 1000 IU daily to 2000 IU daily. Some riders
increase the amount of Vitamin E to 5000iu daily in the last 7 days before a ride, but the horse must be routinely supplemented
with at least 1000iu daily for 2-3 weeks before a pre-ride high dose is given. Many riders give a supplement of 10-20g Vitamin
C, and a range of oral B-group vitamins about 15-24 hours before the ride to aid the appetite during the ride.
If the horse becomes dehydrated in the 24-36 hours before the ride, administer a rehydration fluid always providing water to
drink as well. Avoid administering saline drenches unless under veterinary supervision as strong saline (hypertonic solutions)
can increase the risk of gastric irritation and the degree of dehydration and bowel motility leading to low grade diarrhoea and
further fluid loss in some cases.
4. At about 5-6 hours before a long ride (no closer), offer a sweetened soaked mixture of 2kg crushed corn (or preferably cooked
or extruded corn, barley or race) or steam rolled barley (including 1 cupful of oil if the horse is currently being given oil for
energy), 500g chaff or chopped hay and half a biscuit (about 1kg) of lucerne hay.
5. Up to the time of the ride, provide 1-2 kg dampened good quality mixed hay in a haynet for the horse to consume at its leisure.
Always provide water to drink until the start of the ride.
Studies have suggested that offering 500g of sweetened grain mix 10 minutes before starting a ride, and doing the same just before
leaving each check point, may slow the onset of fatigue.
During a Ride
A thirsty horse should be ‘topped up’ with fluid by allowing it to drink at creeks, dams or other fresh, clean water sources during the
ride. This will not cause gut discomfort and colic if the horse continues exercising immediately following the drink.
Studies indicate that encouraging a horse to drink at rivers, creeks or other cool, clean water sources will significantly improve its
chances of successfully completing a ride.
Many riders carry 1 or 2 syringes of a rehydration fluid in their saddle bags. They administer a dose over the tongue to assist in
electrolyte and fluid replacement prior to allowing a horse to drink on the ride. Some riders mix 1 scoopful of electrolyte mix in honey
and glycerine to form a paste and carry it for oral dosing in the same way. However, very concentrated pastes must be avoided if water
intake is limited. The horse must be allowed to drink at least 4-6 litres of water after electrolytes are given in this way.
At Each Vet Check
The primary need of an endurance horse resting at a check point is fluid and electrolytes initially, rather than trying to tempt it to eat a
feed.
Ensure that the horse is cooled-out as quickly as possible after unsaddling, particularly if it is puffing and panting in humid
weather. This will help to lower the body temperature and ensure a faster heart rate recovery.
Administer a rehydration fluid over the tongue, and provide 2-4 litres of cool water (chill taken off) initially, and then after 10 minutes,
administer another dose of rehydration fluid and offer a full bucket of water to drink, along with dampened feed,
Studies have shown that it is unwise to feed a large amount of carbohydrate based energy feed, such as a high grain mix, at a vet
check rest period. The digestion and uptake of large amounts of carbohydrates will depress the metabolism of body and gut fat
as the energy source and result in earlier fatigue due to glycogen depletion once the ride is resumed. However, feeding a limited
amount of 500g of grain mix about 10 minutes before resuming a ride may actually help to delay the onset of fatigue.
After the Ride
After cooling out, offer electrolytes, such as a rehydration fluid over the tongue, followed by small amounts of water to drink initially.
Once the horse has settled down and is ready to eat, provide 1½-2kg of a dampened feed consisting of 60% chaff with added protein to
aid muscle recovery, (eg 60g Muscle-XL) and 40% crushed grain or pellets. Mix a standard dose of electrolytes into the feed.
The gut is less active after exhausting exercise, so it is best to provide 500-700g (about 1-2 litres in bulk) of feed at 30 minute intervals,
rather than encouraging the horse to eat its fill if it is hungry. Giving large amounts of food immediately after a ride can result in colic.
Once the horse has regained its appetite and gut motility is restored, feeding up to 1½kg of the standard concentrate used in training at 3-
4 hourly intervals, mixed with an equal volume of lucerne chaff, will help replenish energy stores. A total of up to 5kg of grain with 5-
7% oil added can be given as 3-4 small feeds during the first 18 hours to help restore glycogen stores in the muscles. Each meal should
contain 14-16% protein, boosted by adding 200g (1 cupful) soyabean meal to the standard concentrate feed to replace damaged muscle
protein. To replace electrolyte loss in sweat, add a dose of a salt mix. Ensure the horse is rested overnight if possible before long
distance travel.
Ideally, double the normal doses of electrolytes should be continued for 2-3 days after each ride, with free access to water at all times to
restore gut fluid and electrolyte reserves. Dampened good quality hay should be provided ad-lib, or access to pasture after the first 24
hours to help replenish fluid levels in the hindgut.
