Feeding Horses for Competitions:
From Racing to Dressage
Sarah L. Ralston, VMD, Ph.D., dACVN, Department of
Animal Science, School of Environmental and Biological Sciences, Rutgers University
Fact Sheet #934 - Reviewed 2004
Feeding performance horses during conditioning has already been
addressed in a previous fact sheet (FS752, 1994). Emphasis should be
placed on provision of the best quality forage available free choice and
feeding only as much grain or concentrates as needed to maintain desired
body condition. Addition of fats (vegetable, corn or canola oils) may be
beneficial, especially if the horse is having problems maintaining
weight or with chronic tying up. Edible oils however, should be
introduced slowly and comprise no more than 10% of the total ration
(usually 1–2 cups per day). It takes at least three weeks for a horse to
adjust to a high-fat diet. Free-choice salt and water are the only other
real requirements. Vitamin/mineral supplements should not be necessary
if a balanced ration is fed and, if used, selected carefully to prevent
Ingestion of concentrates, forages, water, and electrolytes however,
have immediate effects on a horse’s metabolism and potentially its
performance. There have been relatively few studies that directly
correlate feed management on the day of performance and subsequent
exercise-related variables. However, there are sufficient data to
suggest that the type of performance expected of a horse (aerobic versus
anaerobic, short duration versus long) can be influenced by nutritional
management on the day of competition. In this fact sheet recommendations
are given for feeding horses on the day of competition for various types
Feeding for Short-Term, Anaerobic Performances
(Racing and Other Speed Events)
Short-term, anaerobic performance is that in which the horse is asked
to expend maximal anaerobic effort for less than three minutes. This
includes events such as Thoroughbred and Quarterhorse flat-racing and
rodeo/gymkhana speed events (barrel racing, pole bending, calf roping,
etc.). Glucose and glycogen are the major sources of energy used, though
free fatty acids may be utilized during the warm up periods, sparing
glucose and glycogen for the main effort.
During this type of exertion glucose and glycogen are the predominant
sources of energy used by the working muscles. Depletion of glycogen and
glucose, leading to fatigue, are the most common problems. The animal’s
metabolism does not have time to mobilize body stores of energy, fluids,
and electrolytes during the actual performance. Therefore emphasis
should be placed obtaining maximum glucose and glycogen availability
immediately before the event.
Body weight is another major consideration. Sweat losses are minimal,
and gastrointestinal water content is not mobilized to replace losses
during the actual competition. In race-type treadmill training,
increased time to fatigue with furosemide (Lasix) was apparently due
solely to decreased weight due to urinary losses (Hinchcliff et al,
1993). When urinary water losses were added back prior to exercise,
there was no difference in furosemide-treated horses' performance from
saline-treated controls. High forage intake will also increase gut fill
and therefore body weight.
Low blood pH also contributes to the onset of fatigue in exercising
horses. Anaerobic utilization of glycogen and glucose produces lactic
acid, which accumulates in the blood, lowering the pH. A meal of grain
will also reduce blood pH by different mechanisms for up to four hours
after feeding (Lewis, 1995).
The goal for competition-day feeding therefore should be to minimize
weight, maintain optimal but not excessive hydration, and promote
increased availability of glucose and glycogen.
If properly conditioned for the event,
the horse should not need
extra energy intake before the race. Indeed, a 16-hour fast prior to
racing may actually optimize energy utilization. Horses fasted for 16
hours then subjected to a prolonged warm up followed by intense exercise
had the highest muscle glycogen, plasma glucose, and free fatty acids at
the end of exercise relative to when the horses were fed 1 kg corn at 1,
3, or 5 hours prior to exercise (Lawrence et al; 1995, Stull and Rodiek,
1993). If fed at all, a normal ration of concentrates without added
electrolytes should be offered at least five hours or more before the
competition. If warm time is very short, a small (1 to 2 lbs.) meal of
sweet feed 1–2 hours before the race will result in high blood glucose
and insulin. This will maximize anaerobic energy substrate (glucose,
glycogen) availability during the race but may inhibit fat utilization.
Blood pH will also be slightly reduced, so this may not be the best
strategy for horses prone to rhabdomyolysis (tying up). Not offering hay
on the day of the race may reduce gut fill slightly but it will also
increase the duration and magnitude of the reduction in blood pH
associated with a meal of grain or concentrates (Meyer 1996a,b; Ralston,
Unpublished data, 1993-1995).
Electrolyte supplementation before the race will stimulate greater water
intake and therefore gastrointestinal weight. Since sweat losses are
minimal during these events, electrolyte supplementation should not be
needed until after the race, if at all. However, it is not advisable to
withhold access to water for prolonged periods of time since even
moderate dehydration may decrease exercise tolerance. It would be better
to allow the horse free-choice water, even if fasted, to permit optimal
While the horse is being cooled out after the race, it is advisable to
offer small amounts (0.5-1 gallon) of warm water at frequent intervals
until the horse is no longer thirsty. Do not allow free-choice access,
especially to cold water. Electrolytes should not be added to the water,
as that may reduce intake. After the horse has “cooled out” from the
race (heart and respiration rates normal and no longer sweating), it
should be offered free choice hay. Feeding small (1– 2 lbs.) amounts of
grain hourly for the next 6-8 hours may enhance replenishment of
glycogen stores. If the normal grain intake is more than doubled by this
technique, however, there may be an increased risk of colic or
Bicarbonate administration (up to 1 lb. sodium bicarbonate/1000 lb.
horse in 1 gallon of water by nasogastric tube) may reduce the metabolic
acidosis induced by intense anaerobic efforts. However, especially at
the higher doses tested, bicarbonate administration caused persistently
low blood potassium and calcium, which may be more detrimental to
performance than moderate metabolic acidosis (Frey et al, 1995; Lewis,
1995). Administration of bicarbonate in any form is illegal in most
racing jurisdictions and is not recommended.
Vitamin supplementation on the day of competition has not been reported
to be of benefit in horses fed balanced rations.
Feeding During Long-Term, Aerobic Performances
(Endurance, Dressage, Horse Shows)
Long-term, aerobic performance is that in which the work is primarily
aerobic and lasts for more than one hour. This includes endurance,
competitive trail riding, dressage, three-day events (riding and
driving), and horse shows in which horses are entered in multiple
classes and often are worked hard before entering the ring. These
animals are working primarily on an aerobic basis, generating huge heat
loads and sweat losses. These athletes rely heavily on free fatty acids
from large intestinal fermentation of forage and mobilization of body
fat stores as energy sources. Glycogen and glucose stores are not of as
great a concern as in short-duration, anaerobic work, though they are
Maintenance of hydration, optimal mobilization and utilization of
body energy stores (fats) and fatty acids from the gastrointestinal
system, and electrolyte balance are the main goals for this type of
work, especially in multi-day or endur-ance-type events.
For these horses, feeding large amounts of grain
with limited access to
hay may increase the risk of metabolic failure, especially for endurance
type competitions (Ralston, 1988). A meal of grain will cause insulin
release, which inhibits the mobilization and utilization of fats. High
circulating insulin will also drive glucose into the working muscle
cells more quickly. It has been reported to cause hypoglycemia (low
blood glucose) after 1 to 2 hours of moderate aerobic exercise (Lawrence
et al, 1995). The night before an event hay should be offered free to
maximize intestinal reservoirs of energy, water and electrolytes and the
normal amount of grain or concentrates offered. If grain or other forms
of concentrates are offered the morning of or during competition, they
should be low fat (<5%) and supplemented with an electrolyte mix
formulated specifically for equine athletes. The amount of electrolytes
given will depend on anticipated heat, humidity, and duration of the
exercise, usually 1–4 ounces will suffice.
Electrolytes will stimulate thirst and increase water intake within 3–4
hours of dosing. If top dressed on the concentrates, however, they may
reduce intake, so they may need to be force fed. Grain, especially sweet
feeds, should not be fed less than four or five hours before the
competition starts unless the competitor plans to feed small amounts
(0.5–1 lb. per feeding) of these feeds frequently (at one- to two-hour
intervals) during actual competition.
Supplementation with electrolytes every 2 hours during competition will
help maintain electrolyte status (Ralston and Larsen, 1989; Schott et
al, 1997). However the amounts needed are controversial and vary
dramatically with climatic conditions, terrain, and fitness of the
horse. A general rule of thumb is to give 30 to 90 g per hour of work.
However, concentrated electrolyte solutions should not be force fed to
horses that are dehydrated as this potentially will compound the
dehydration by drawing body water into the gastrointestinal system and
cause abdominal malaise. Horses should be encouraged to drink at every
opportunity, though rapid ingestion of large amounts of cold water
should be avoided if the horse is not going to immediately continue to
work. Placing a small amount of sodium chloride on the gums of a horse
may also encourage drinking.
In high heat and humidity, high-protein forages such as alfalfa probably
should be restricted, since the protein used for energy releases a
higher metabolic heat increment than does starch or fatty acids (Lewis,
1995). However, mashes made of soaked hay cubes or bran to which
electrolytes are added are excellent ways to get the horse to ingest
more fluid and electrolytes. Though alfalfa cubes and bran are both
fairly high in protein (about 16%), if fed in restricted amounts (1 lb.
cubes, ¼ to ½ lb. bran) the increased water and electrolyte intake plus
provision of readily fermentable fiber sources will outweigh the
detriments of high protein. Many competitors add apples or carrots to
mashes to enhance palatability. Fats and oils should not be supplemented
during competition since they will delay gastric emptying and may impede
absorption of electrolytes.
While forage/roughage intake should be emphasized, dry hays may compound
dehydration problems, especially in horses at multi-day events, if the
horses were accustomed to being on lush pasture at home. Soaking hay in
water may alleviate this potential problem during competitions.
Administering fluids by nasogastric tube may be beneficial in cases of
severe losses during multiple-day competitions (if allowed by the
competition rules). If at all possible, the horses should be allowed to
graze as much as possible.
Most horses performing prolonged, aerobic work have high blood pH and
minimal accumulation of acid in blood. Lactate accumulation is not a
problem if the horses are properly conditioned. Therefore,
administration of sodium bicarbonate is strictly contradicted before,
during, or after competition.
After competition is completed, offering free-choice hay
soaked in water, small amounts of grain (0.5–1 lb.) at frequent
intervals (every 1-2 hours for up to 8 hours) and additional
electrolytes will hasten the horse’s recovery. Do not offer grain or
concentrates until the horse has been cooled off and its heart rate is
back to normal. This is especially important in multi-day events.
Though vitamin supplementation has not been investigated in this type
of competition, prolonged stress such as 12 hours of transport resulted
in below normal plasma vitamin C relative to non-transported horses
(Baucus et al, 1990). Though horses do not normally require dietary
ascorbic acid, during periods of prolonged stress (>12 hours), addition
of 10 grams of vitamin C twice a day during the competition will not
hurt and may help.
Knowledge of the predominant nutritional concerns for a given type of
competition will aid in the selection of feeds and supplements for the
day of competition. For example, electrolyte supplementation is critical
in endurance horses on the day of performance but is probably not
necessary and may be contraindicated for the Thoroughbred racehorse.
Fasting racehorses up to 16 hours before the competition may improve
energy substrate availability whereas horses performing prolonged
aerobic work need intestinal sources of nutrients (e.g., hay offered
free choice the night before and morning of competition) to maintain
adequate energy, fluid, and electrolyte status.
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plasma variables in endurance exercised horses. Equine Veterinary
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JH, Brady AH, Cooper SR. 1995. Effects of warming up, racing and sodium
bicarbonate in Standardbred horses. Journal of Equine Veterinary
Hinchcliff KW, McKeever KH,
Muir WW, Sams R. 1993. Effect of furosemide and weight carriage on
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gastrointestinal fill in horses, Part 1. Equine Practice
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endurance competition. Equine Athlete 10:40–44.
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