Last Updated on November 10, 2020 by Allison Price
Horses are athletes who are superior. Physical adaptations have provided horses speed and stamina through evolution. In modern horses, selective breeding has narrowed and refined desirable athletic skills.
Some of the physiological adaptations include high aerobic largest energy. And large glycogen intramuscular stocks. Also, specific ratios between breeds of muscle fiber types. Splenic contraction to increase circulating red blood cells powerful gaits. And the ability to control heat stress by sweating.
The horse’s innate physical ability is remarkable. But, to achieve best performance in any equine sport… it is important to have a conditioning program. This program must enhance cardiovascular function, muscle capillary density, endurance and bone strength. Also, increased muscle mass, increased storage of energy substrates, and more efficient usage.
How Much Energy?
Energy isn’t exactly a nutrient. Instead, it is a measure of a feed’s ability to drive body functions. Nutritionists refer to dietary energy as kilocalories or megacalories of digestible energy. Digestible energy (DE) refers to the amount of horse-absorbed energy in the diet.
Based on the horse’s maintenance energy need, digestible energy needs are being calculated. Plus, the extra energy needed for exercise, such as running and jumping. Starch, fat, protein, and fiber are the major sources of nutrition in the diet. Both of these sources should be part of the diet of athletic horses. But for a great result, more on this later, you need to mix them in particular ratios.
Just how much energy does a performance horse need? A non-working, 1,100lb (500kg) Thoroughbred requires approximately 16 Mcal of DE per day. According to the Nutritional Requirements for Horses of the National Research Council (2007). Approximately 20 Mcal DE per day should be taken by horses during light work (one to three hours of riding per week). In this category, horses include “weekend warriors” or mounts for the recreational trail.
Horses with moderate work need approximately 23 Mcal DE per day. Horses in this group include show horses, polo ponies, and ranch horses. Horses in heavy labor need about 26 Mcal DE per day. That’s four to five hours of riding per week, with large portions spent at the canter or doing skill work. In this category, horses include low to mid-level eventers. Also, some racehorses, and horses that are usually seen. Finally, in very hard labor (six to 12 hours of work a week), horses need around 34 Mcal DE per day. These are racehorses, three-day elite eventers, and driving horses combined.
Let’s do some basic arithmetic. This is to understand why a performance horse does not prosper on forage (pasture or hay) alone. A timothy hay of medium quality provides around 0.8 Mcal DE per pound. He will need to eat 40 pounds (18kg) of hay a day. In order for our Thoroughbred racehorse to fulfill his DE requirements (say, 32 Mcal). Almost an unlikely scenario. For one, the horse is unable to eat the amount of hay.
In reality, he can’t even eat half of that amount. High forage intakes often result in the creation of a “hay belly”. Which in a high-performance horse is an undesirable trait.
The Need for Carbohydrates and Fats
Horses need water, protein, minerals, vitamins and most importantly, energy for success. Carbohydrates, fat, and proteins can supply energy. For energy, protein is being used rather inefficiently. It is possible to categorize carbohydrates by how they are being digested. The high levels of starch that enzymes digest in the stomach and small intestine… are present in grains such as oats, corn, and barley.
Cellulose, hemicellulose, pectin, and indigestible lignin are in forages and high-fiber by-products. From beet pulp that has the same digestible energy as oats to mature grass hay. Which can have 65-75 percent less digestible energy. These structural carbohydrates vary in energy level.
Microbes that can digest the fibrous structural components of roughage… that enzymes cannot digest populate the horse’s hindgut. Carbohydrates are being fermented by microbes. Structural carbohydrate fermentation in forage… may help meet the energy needs of adult horses. Volatile fatty acids are being produced when microbes digest structural carbohydrates.
To support a healthy hindgut, all horses need a small intake of roughage in their diet. 1 percent of their body weight is the smallest daily forage intake, but 1.5 percent is a more appropriate amount.
It is necessary to balance the high energy needs of hard-working performance horses. And to provide enough fiber. One of the most complex aspects of feeding horses is… preserving the successful fermentation of structural carbohydrates in the hindgut.
Rules for feeding horses
- Do not feed more than 5 lb. (2.27 kg) of concentrate in one meal (smaller meals are safer)
- Don’t change concentrates or hay right away
- Feed at the same time of each day
These rules are to help horses maintain a healthy hindgut.
Any of the soluble carbohydrates can avoid… enzymatic digestion in the stomach and small intestine. And transfer through the hindgut. When horses are taking large quantities of straight grains more than 3 lb. (1.4 kg) per meal. The type of starch is also essential.
In the foregut, the starch in various grains is being digested to various degrees. But corn starch is not digested efficiently by horses. And up to 70% of cracked maize starch can reach the hindgut. By steam-flaking, the digestion of corn starch can increase. So, one way to decrease the amount of starch entering the hindgut is by processing. Starch in the hindgut is a concern. Because horses fed large quantities of grain have major shifts in the pH of the hindgut. It becomes acidic.
This is the product of very rapid starch fermentation, creating large VFA concentrations. VFA is easily absorbed through the epithelium of the hindgut. And although they are being considered “weak” acids, they can still cause a drop in pH. The problem with starch fermentation in the hindgut is that… low pH is being preferred by lactic acid-producing anaerobes.
Also, lactic acid is a stronger acid than VFA. And the hindgut is not absorbed. Subclinical acidosis may be because of lower pH. And contribute to other more serious issues.
It is good for the hindgut to lessen the amount of starch in feed. By formulating it with high digestible sources of fiber. Beet pulp, soybean hulls, dehydrated alfalfa (lucerne). And almond hulls are the most digestible sources of fiber for food. Other fiber sources that are not as needed include oat hulls (a by-product of oatmeal milling). As well as peanut hulls. If fat is not added, feeds formulated with high fiber (greater than 10% crude fiber) can be lower energy feeds.
Fat has 2.25 times more energy than grain. So added fat in the feed will substitute starch and help sustain energy levels. Fat is often used in feed because it is being characterized as a source of “cool energy”. Research has shown that glycogen sparing is high in fat-adapted horses (fed from 5-12 weeks). Glycogen is the source of energy that drives about 80% of the exercise that horses conduct. This makes it possible to keep more glycogen in reserve.
The Need for Minerals
For the constant bone-remodeling phase in performance horses… calcium (Ca) and phosphorus (P) are essential. Both the quantities and the Ca: P ratio are important. 2:1 is the optimal ratio of Ca to P. When alfalfa hay is the primary source of forage, the ratios can be much higher, up to 7:1. And weaker bones can be a result of over long periods of time.
An inverted Ca:P ratio can be produced when horsemen feed plain oats. And either poor-quality hay or pasture. These can also have Ca: P ratios of 1:1. This is a serious concern that needs to be remedied. For calcium and phosphorus, commercial feeds are usually balanced. Thus, eliminating any guesswork in calcium and phosphorus levels consideration.
The National Research Council (NRC), in its Nutrient Requirements of Horses, Sixth Edition… recommends 0.1%-0.3% Mg for the maintenance. This is probably equal to 10-15 g per day. Based on at least 20 pounds (9 kg) of dry matter intake. Most feedstuffs will meet this. And commercial feeds have magnesium added to the formula.
Kentucky Equine Research (KER) has shown… that the demand for zinc in trained horses has increased. Since copper, zinc, and manganese compete for absorption… all three minerals in horse feed should increase. In sweat, electrolytes are gone and must have a substitute. Usually, forty to fifty grams of salt or one to two ounces would fulfill most horses’ needs. If the horse sweats, it should meet the criteria for an extra one or two ounces of electrolytes.
The Need for Vitamins
There will be a drop in B vitamin status in the tissues and blood. That is if horses do not have access to pasture and must rely on stored forage. During fermentation in the hindgut, B vitamins are being produced in large amounts. But they are not absorbed from that part of the digestive tract. Particularly when high-grain diets are being fed. And horses are under the pressures of training and displaying. Thiamin and riboflavin criteria dependent on body weight. And influenced by the stage of development and level of work have been published by the NRC.
In light exercise versus heavy exercise… the requirements for Thiamin rise from 30 to 62.5 mg in a 1100-lb (500-kg) horse. In the above-mentioned horse, riboflavin requirements ranged from 20-25 mg. Although requirements for niacin, biotin, folate, B12, B6… and pantothenic acid are not identified yet… these vitamins should be part in a well-balanced commercial feed for performance horses.
A, D, E and K vitamins should be part of the feed. As an essential antioxidant, Vitamin E deserves some special attention. Vitamin E is a part of a group of antioxidants… that can recycle each other by disabling reactive oxygen species (ROS). When horses exercise, these peroxides and oxides are being formed. They damage all cells. Including muscle cells and immunoglobulins, that they come into contact with.
Lipoic acid, glutathione peroxidase, vitamin C, and ubiquinone… are also other components of the system. This scheme provides muscle cells with defense and increases immunity. Except for vitamin E, the horse develops other “recycled” antioxidants. Selenium (Se) is one other restricting dietary nutrient important to the system.
Selenium is part of glutathione peroxidase. So, it is important to have enough amounts in the feed. Commercial feeds can, in general, produce about 0.3 mg / kg of Se.
Water and Electrolytes
Water and electrolytes are other significant nutritional factors for the performance horse. The average non-working horse size requires around 6-8 gallons (20-30L) per day of water. Regular exercises can increase water requirements. As sweating followed by evaporative cooling at the skin surface… is the primary means by which horses rid themselves of body heat excess.
The loss of sweat fluid can exceed 10 liters per hour of exercise in hot weather. As a result, a performance horse’s daily water needs could be 50-60 liters or more. Ensure that there’s always plenty of fresh water available. And take advantage of the need of the horse to drink after exercise.
Sweat, is also rich in electrolytes. Especially sodium, potassium, and chloride. Since most forages and grain concentrates are low in salt. High-performance horses will need some form of electrolyte supplementation. Particularly in the summer months. When there can be high losses of sweat electrolytes. Be mindful that not all supplements with electrolytes are being produced equal.
A lot of sugar (such as sucrose or dextrose). And only small quantities of real electrolytes are present in certain supplements. Popular table salt or a 50:50 mixture of table salt and “lite salt” (potassium chloride) may be used as an alternative. Feed up to 2 to 3 ounces a day. Split into morning and evening feeds.
Keep your performance horse ‘s diet within these guidelines. And he’ll have the nutritional resources to do anything you need him to do.
I’m Allison, born and raised in San Diego California, the earliest memory I have with horses was at my grandfather’s farm. I used to sit at the stable as a kid and hang out with my Papa while he was training the horses. When I was invited to watch a horse riding competition, I got so fascinated with riding!