The Ultimate Equine Athlete: Nutrition and Supplementation

It is possible for an upper level equine athlete to compete solely on hay, some concentrate, salt and water. A superior individual with proper management and training would perform very well, but there is always that question of the "extra edge". At this level of competition, so much time, effort and money has already been invested that the human component wants to find the "extra edge" to win. The horse does not care if it wins. It will perform to the best of its training and capacity. It is in our human nature for us to want success. If we can just find the magic that gives our equine athlete an edge, why not use it? Nutritional manipulation by feed and supplementation is a way. Whether it pushes a nose over the wire first, creates a perfect reining pattern, or the quickest and cleanest Grand Prix course, humans will go to any length to obtain the best result.

Depending on the type of high level activity, the horse will be utilizing energy aerobically (endurance) or anaerobically (440-yd race), but most will use a combination of the two. In order to get the most efficient utilization of energy for the highest performance, a horse needs to be equipped metabolically to mobilize the energy in muscle that is in the form of glucose and glycogen. Learning how to appropriately feed your equine athlete that will allow the maximum storage of energy (glucose and glycogen), which can be readily utilized during competition, is the goal of the trainer.

Fueling the Exercise
It makes no difference if your horse is at the racetrack, on the XC course, or climbing a mountain after 80 km; he is a mammal, and all mammals utilize carbohydrates as energy sources. We tend to think of carbohydrates for horses as the grains or concentrates we feed them; however these are just the sugars and starches that can be quickly digested. Forage provides up to 80% of the carbohydrates in a horse's diet - compare that to the overall total carbohydrate in a human diet, which is close to only 30 - 40%. The hindgut can ferment much of the cellulitic material to VFA (volatile fatty acids) and starches which are utilized as immediate energy. A mammal, especially a herbivore such as the horse, will not normally utilize protein or fat as an energy source during work unless carbohydrate is unavailable or limiting.

When the horse consumes carbohydrates from forage or concentrates, they are immobilized immediately for energy, stored as glycogen for later energy needs or converted to fat for long-term energy storage. Protein and fats when consumed follow different metabolic pathways. Feeding fat is "hot" right now. There are many formulations manufactured by feed companies specifically tailored to higher levels of fat compared to sugars and starches. Under normal feeding conditions, the horse would consume approximately 3% of its diet as fat. This is to insure it gets the essential fatty acids it needs, not for fuel. However, if a horse puts on weight as fat, not as muscle, it can be broken down to fuel body processes, including providing energy as Volatile Fatty Acids. Fats DO seem to provide a sparing effect on glycogen stores, allowing them to last longer in the muscle. Endurance racers and eventers have taken to feeding high levels of fats in their horses' diets.

Short-term feeding of fat, i.e. a few weeks before a big event or race, does not, at this point, seem to have any positive effects on energy utilization or the horse's performance. However, long-term feeding of at least 10-20% fat as part of the total diet MAY stimulate some enzyme systems in muscle cells, inducing the use of fat as an energy source instead of glycogen. This may lead to improved performance, as the horse has more glycogen reserves to call on when needed in intense aerobic competition. Still, even in this high-fat feeding situation, muscle cells seem to use available glucose in the muscle cells first (carbohydrates), before switching to fat utilization.

Fat is a cheap energy source to feed. It generates three times as much energy as carbohydrates on a gram for gram basis during aerobic activity (such as endurance, dressage, parts of eventing, etc.). Feeding fats can benefit performance animals in low intensity, low or long term speed events.

Feeding protein as energy seems to be an ongoing discussion amongst nutritionists. While protein is necessary for the formation and maintenance of all tissues and organs, and the muscles are almost entirely proteins, the horse is designed by nature to eat a low protein diet and allow hindgut microorganisms to provide what plants cannot. It is true that you need protein to build and maintain muscle mass during intense training, so it is natural that horses in heavy training (who are often young and still growing) would need and utilize higher levels of protein in the diet. It is usual to feed 12-14% rather than 8-11% Crude Protein to these animals.

High performance horses should have a good lean body mass with defined musculature and have fat reserves covering the ribs, spine, and on the neck and hindquarters. The hindquarters should not appear caved in, nor should the animal appear "tucked up" or "herringutted" along the abdomen. This is an indication of protein deficiency in the diet and either the animal cannot put on muscle mass, or is utilizing its muscles and breaking them down to provide a source of protein for metabolism.

So, we still feed carbohydrates, fat and protein to our upper level competitors, but in varying and usually higher amounts than the rest of the equine population (with the exception of lactating mares). This enables them to perform more efficiently. Now, how do we now feed for extra high performance? What supplements can we add to get that extra "edge" to put him over the top?

Speed Events
If the horse is very fit, metabolic demands during competition that require prolong bursts of high speeds and/or prolonging speed are relatively simple. Only carbohydrates can be metabolized fast enough to provide the energy needed for raw speed. As a secondary backup, the horse during the speed burst will rely on stored levels of high-energy compounds such as Adenosine Triphosphate (ATP) and Creatinine Phosphate (CrP). These compounds are metabolically costly to replace, so you want to keep glucose and stored glycogen levels high in these horses' muscles. In addition to a diet of high quality hay, quality concentrates, fresh water, salt and essential vitamins and minerals, what can a racehorse receive to get that extra "edge"?

There is nothing to get the "edge" if he does not get proper consistent training, the sound base diet stated above, and above all, the animal initially must be sound in limbs and wind. There is no magic potion that can correct what is wrong in the first place. However, there are a number of supplements that are legal and utilized by owners and trainers of horses to perform at speed. There are many differences of opinions as to their efficacy.

Supplementation with extra Vitamins and Minerals, and DMG (Dimethylglycine) which have anti-oxidant properties is usually a given in the racehorse industry. Selenium levels should be monitored closely and not overfed, as the horse is very sensitive to selenium toxicity. Overfeeding Vitamin E and Vitamin A and C can not hurt, and may prevent oxidative damage or prevent an episode of tying up. Extra alfalfa (legumes) could be fed as well as extra magnesium.

Added B vitamins are a good supplement for all horses in intensive training. They are essential to the utilization of all types of food, especially carbohydrates. Any type of stress increases the need for B vitamins. Horses that are confined, denied access to fresh grazing and fed high grain diets will benefit from added B complex vitamins, especially Thiamin (B1). The integrity of the digestive system is not compromised and the horse is perkier and performs well. Racehorses are often confined for 23 hours/day and fed high concentrate diets.

Another supplement routinely given to racehorses, but illegal in harness racing, is Bicarbonate of Soda, routinely called "milkshaking". You can test if a horse has had a milkshake or not, but the supplementation does seem to improve performance. Why feed bicarbonate (baking soda)? When muscles work for a period at high speed, the interior of each muscle cell becomes highly acidic. Under these conditions, energy generating pathways that produce ATP will begin to fail, the muscles tire, and lactic acid builds up within them.

However, adding bicarbonate to the diet does not change the pH inside the muscle cells, it changes it only in the blood. We still don't know exactly the metabolic methods that bicarbonate enables muscles to conserve glycogen. With intense speed, blood pH will rise, which seems to encourage acidity to leave the muscle cell, where it can be neutralized. This leaves energy-generating pathways untouched and performing within each muscle cell as efficiently as possible.

A lot of bicarbonate must be given, and within 2 or less hours of a race. 25 or 30 tablespoons of baking soda is not palatable, so it is mixed in water to resemble a milkshake and tubed into the horse's stomach. Hence the nickname of "milkshaking a horse".

Citrate loading is another way to get the same effect as bicarbonate loading. Citrate is a pre-cursor of bicarbonate, and the horse's body metabolizes it to bicarbonate. It will take over 2.5 times the amount of citrate to have the same effect on muscle tissues as bicarbonate. This means that the horse needs 50 to 60 tablespoons of citrate mixed and tubed into its stomach before a race.

It will show up as positive for milkshaking at harness tracks, but some trainers take the chance! If you decide to add bicarbonate or citrate to the horse's regimen, and it is legal in its sport, then have a qualified person such as a veterinarian administer the stomach tube. Horses are notoriously sensitive to having anything shoved up their nostrils, usually struggle a bit, and could easily aspirate the heavy substance into its lungs, or damage esophageal tissue.

Carbohydrate loading is beneficial to horses competing in all high level events that demand speed and endurance, just as in human athletes. Carbohydrate loading is done with the intention of increasing muscle glycogen stores (stored fuel) before an event. A horse can store glycogen in this manner similar to a human athlete. You can simply feed your horse a higher level of a readily digestible carbohydrate starting at least 4 days before an event. Usually, depending upon the individual horse and the type of race, you would increase the grain portion of its diet from 10-20%. Remember to always keep ample forage and water in front of him when doing so. Timing at least one of these extra grain feedings after a workout and complete cool-down appears to enhance the storage of extra glycogen in muscle tissue. It is true that extra grain (concentrates) will increase body heat, but not by any significant amount if judicially spread over feedings. Also, increase the grain levels up to the day of the event, but not that day. Any heat generation will have dissipated and not compromise the horse's performance. There are also many carbohydrate formulations manufactured that are advertised for carbohydrate boosting. These are usually palatable powders that are formulated to add in the normal concentrate diet. They do not in any way increase the total bulk of the diet. Some products have feeding guidelines with them, others do not. Pick one with guidelines. Always feed a bit less than the maximum to a smaller horse than a larger horse, or you are just wasting the supplement. A smaller horse has less muscle to store glycogen.

A good carbohydrate supplement powder should contain a mix of sugars. You need to get a sustained boost in blood sugar, which triggers insulin release from the pancreas. This signals that more sugar is needed and blood sugar is drawn into the muscles for more energy. Short-chained sugar molecules such as maltose, dextrose, and sucrose will cause a rapid blood sugar rise.

Longer chained molecules such as the dextrans will cause a very slow but sustained blood sugar rise. Utilizing a powdered product in your training which has a mixture of both types and is your best purchase. Since adding over 10% of grain or concentrate mix to a diet may sometimes lead to digestive disturbances or laminitis, it is wise to stick with the formulated products commercially available. They are so highly digestible, that the probability of reaching the large intestine to precipitate any problems is nil if used as recommended.

These carbohydrate powders should be feed 2-3 days before an event, with at least one supplemental feeding after a workout and cool-down. Horses that utilize both speed and endurance in their performances such as reining, eventers, hunter jumpers, etc., would benefit more by feeding these supplements over a longer period, such as a week to 10 days, but only every other day. Horses that utilize bursts of speed with endurance seem to utilize glycogen stores more efficiently when fed extra carbohydrates in this manner. As your horse thunders down the backstretch, hormones trigger the muscles and blood to increase insulin and release stored glycogen for the extra fuel it needs immediately. The horse will always utilize a carbohydrate source as extra energy first, and this type of feeding may just give him the "edge" to get his nose over the wire first. Lots of fresh water, a B vitamin supplement and added chromium will also enhance carbohydrate loading.

There are many people who argue that added fat to the diet would perform just as well, especially those in endurance events. I will discuss fat as a supplement next time as many new supplements are sprouting on the market every week with added fat as energy sources. However, racehorses at extreme speed to not have the time to metabolize fat stores from intramuscular storage.

Chromium enhances the uptake of glucose by both muscle and fat tissues. It also allows fatty acids to be liberated from fat storage during hard work as added energy sources (mainly in endurance activities) and stabilizes blood glucose levels. If blood glucose levels are stable your horse will not experience energy peaks and valleys followed by sudden exhaustion. Chromium is always critical to proper function of insulin by the body and is needed daily in trace amounts. Some horses are borderline insulin deficient, but don't really exhibit symptoms, except by being a little more "tired" or having a longer time recovering after an intense workout. If you have blood tests performed on your horse and this proves to be the case, added chromium at 1.3-2.0 mg/day should help to stabilize blood sugar levels and recovery rates, thereby increasing overall performance.

DMG (Dimthethylglycine) or TMG (Trimethylglycine) are often added to carbohydrate or chromium supplements as "performance boosters". They appear to increase the horse's fitness during initial stages of their training.

However, in horses on a high plane of fitness and competition, there is no evidence that added DMG and TMG increase performance any more. They do have anti-oxidant properties that can prevent tying up in initial stages of training, but are not really needed at peak levels of fitness. If it is added to the supplement you buy, there is no harm in feeding them, but be aware that they perform better with horses starting training.

Next week we'll discuss the uses of individual supplements, vitamins, minerals and food additives.

Read Part II!

Eve-KarenRejman is a Dairy Biochemist and Equine Nutritionist living in rural Poland, Maine.
She can be reached at Feedemwell@icqmail0.com.