Nutrition for Optimum Equine Performance
By University of Guelph /The Horse

Feeding a balanced diet and ensuring nutrient replacement after exercise are imperative to keep horses performing well at an upper level of competition.

Don Kapper, PAS, shared equine nutrition and management knowledge during a recent visit to University of Guelph, in Ontario, Canada. He discussed the importance of understanding gut function and nutrient absorption in order to understand the importance of nutrient replacement.

He also addressed how to assess body condition and topline evaluation scores, as well as the importance of providing good quality protein as a source of amino acids to avoid deficiencies that can negatively affect topline muscles, tendons, hooves, and overall health. Finally, he spoke on the role of electrolytes in avoiding dehydration and keeping athletes bouncing back into top form for the next day of competition.

Here's a breakdown of Kapper's key points from each section.

Gut Function

An 1,100-pound horse will eat for up to 18 hours a day consuming 2.0% to 2.5 % of their body weight per day in dry forage (about 22 to 28 pounds). “Horses are designed to be continuous grazers,” Kapper explained.

While doing this, they will produce 25 to 30 gallons of saliva, significantly reducing the chances of acid irritating the gut and improving nutrient absorption and overall gut health. Horses only produce saliva when they chew, so feeding free-choice forage increases saliva production, one of the best buffers for the horses’ digestive system and the most effective way to reduce the chance of ulcers and impaction colic.

Horses are designed to graze throughout the day.

Kapper offered another benefit of continuous grazing by comparing the small intestine to sausage casing: “When it is full it is almost impossible to twist.” Going without eating for several hours at a time can be a factor in colic resulting from a twisted intestine.

The horse’s stomach is relatively small and food only stays there for around 15 minutes, while acids begin to break it down. It takes 30 to 90 minutes for the ingesta (ingested feed) to move through the next 90 feet of small intestine at a rate of one to three feet per minute. The small intestine is the primary location that amino acids, fatty acids, major and trace minerals, and vitamins are absorbed.

After the small intestine, the ingesta reaches the hind gut, which makes up 62% of their digestive system and functions with a microbial population breaking down the fiber in forages (which should make up 50% to 90% of a mature horse’s diet) by fermentation.

Knowing what nutrients are in your forage is important so you can factor in what concentrates and/or supplements hour horse might require to meet his daily dietary needs.

“If you don’t know what nutrients are in your forage, you are guessing at what needs to be added,” Kapper said. “If you don’t know what nutrients your horse needs every day, you are guessing at everything.”

Kapper also reminded attendees that concentrates usually should not exceed 50%, by weight, of the average mature horse’s total diet per day (some high-performance horses, however, might require a higher percentage of grain or concentrate to obtain the energy they need) , or exceed around five pounds in one feeding for an average-sized horse. This practice will help avoid digestive upset.

He also emphasized the importance of good forage to meet the nutritional needs, optimize digestive health, and improve the overall well-being of your horse. Free-choice forage will also facilitate the best mental state, he said.

Visual Assessment

Decreased performance will occur before you see visual changes in your horse that could indicate an unbalanced or deficient diet. Visual changes that should put up red flags include loss of muscle over the topline, a decline in hoof and hair quality, a loss of appetite, and general unthriftiness.

Checking your horse’s body condition score (or BCS) on a monthly basis provides a good visual indicator for achieving optimal caloric intake, with an ideal BCS typically being between 5 and 6 on a scale of 1 to 9. However, some horses at an ideal body weight can still be deficient in nutrients required to build and support the muscles necessary to perform athletic tasks.

TES Grades
Grade A—The horse has ideal muscle development’. The back, loin, and croup are full and well-rounded. The topline muscles are well-developed and blend smoothly into his ribs. The horse should be able to perform work requiring the use of all of these muscles.

Grade B—The back area is concave (sunken) between the vertebrae and the top of the ribs. You might have trouble fitting this horse with a saddle. The muscle atrophy in this area could cause back soreness when worked, which can negatively impact a horse’s attitude and performance. The loin muscles are well-developed and are the same height as the spinal processes (i.e. you cannot see or palpate the spinal processes).

Grade C—The back and loin areas are both concave between the vertebrae and the ribs. The spinal processes in the loin area are higher than the muscles beside them and can easily be seen and palpated. The atrophied muscles in the back and loin areas weaken the horse, and the length of time they are able to work and perform will be compromised, causing them to tire easily. Muscling over the croup and hindquarters are well-developed and rounded.

Grade D—All three areas of the topline are concave. The croup appears pointed at the top since the vertebrae and hip bones are higher than the muscles in-between them. In severely affected horses, the width of their stifle is narrower than the width of their point of hip. These horses will lack the strength and stamina to perform and the muscle atrophy will cause discomfort when worked.

Topline evaluation scoring (or TES) is graded from A to D (see descriptions at left) and looks at the muscles on the horse’s back, loin, and croup. Muscle loss is a solid indicator of a deficiency of amino acids, the building blocks of crude protein. Muscles contain 73% protein and the first limiting amino acid will determine how much ‘all’ of the other amino acids in their diet can be utilized. The easiest and first place to visualize a horse losing muscle mass, when a deficient amino acid diet is fed, is in their back area; the second is their loin; and third is their croup area.

Role of Protein and Amino Acids

Horses need all 10 essential amino acids—arginine, histidine, isoleucine, leucine, lysine (involved in growth and development), methionine (for hoof and hair quality), phenylalanine, threonine (involved in tissue repair), tryptophan, and valine—provided to horses on a daily basis. There are also 12 non-essential amino acids that horses can create themselves in adequate amounts. In order for crude protein to be synthesized, all the essential amino acids must be present in adequate amounts. If one amino acid runs out, it limits protein synthesis for the rest of the amino acids.

During the process of conditioning, horses’ muscles are broken down during exercise and before they repair and rebuild. Kapper drew the parallel of weight trainers reaching for their whey protein shake after a workout: A horse can benefit greatly from having 4 to 10 ounces of branch-chain amino acids replaced within 45 minutes of a workout. Whey is the best quality protein (amino acid) source, followed by soybean. Research has also shown that a lack of amino acids in the diet can affect the utilization of minerals in the diet, potentially causing skeletal and soft tissue problems.

What the Hooves Can Tell You about the Diet

Nutrients Found in the Hoof
Protein/Amino Acids (95%)
Fat/Oils (3 %)
Carotene (Vitamin A)
Alpha-Tocopherol (Vitamin E)
When 98% of the hoof is made up of the top two nutrients listed at left, begin working with those and work your way down the list for a systematic way to address hoof quality problems that could be nutrition related. Too many times we hear about individuals beginning with Number 10 (biotin) and work their way up the list.

For example, Slow growth can result from inadequate amino acids, while poor expansion and contraction with a cracking hoof wall can result from inadequate oils in the hoof. Poor-quality lamina can result from a diet deficient in the amino acids methionine and cysteine. In a calcium deficient diet, the middle of the hoof wall can break down and crumble. Sand cracks in the outer hoof wall can be an indicator of a lack of biotin.

Calorie Sources to Fuel Muscle Function

Choosing the right horse for the work you want to do is important, but so is choosing the right fuel for your horse to perform to his potential.

Carbohydrates and fats give horses the energy they need to perform.

Carbohydrates—Soluble carbohydrates (found abundantly in cereal grains like oats, corn, barley, and wheat) are the starches and sugars horses need to provide the glycogen (a complex carbohydrate that’s broken down into glucose, or sugar, molecules whenever they are needed by the body) for intense work. Kapper used a Quarter Horse sprinter fueling his bulky fast-twitch muscles as an example: Glycogen produced from carbohydrates are utilized when the sprinter’s heart rate exceeds 170 beats/minute, in anaerobic work. “The heart rate is the key to knowing what kind of fuel you should be using,” he said.

Fats and Oils—An Arabian used for pleasure riding, on the other hand, is a good example of a breed using long, lean slow-twitch muscles that burn fat in addition to glycogen for fuel, Kapper said. Vegetable oils can provide slow, long-term energy needed for low- to moderate-intensity, aerobic work.

Forage—Soft hay is generally more desirable for the performance horse because it has a higher nutrient content and is easier to digest. Over-mature hay cut later will have grown taller and have larger, courser stems. This hay will be higher in lignin, which makes it less palatable and lower in digestibility.

The Role of Electrolytes

Used correctly, supplemented electrolytes can delay the onset of fatigue by more than 22%, reduce muscle cramping, and improve the horse’s ability to bounce back and perform at the same level the next day. The amount of sweat produced in a workout will determine the amount of electrolytes which require replacing, and the demands are highest during hot and humid weather.

When correctly formulated, electrolytes can replace the ions lost in sweat. For performance purposes, the product should specify that it is a “performance” electrolyte on the label. The amounts of sodium, potassium, and chloride levels are usually provided in the labels ingredient list. But remember—not all electrolyte supplements are created equal. Higher quality electrolytes tend to be more palatable, while some others can be bitter, salty, and discourage consumption.

Before electrolytes can be absorbed they need to be broken down with water. Electrolytes can be administered in either feed or water, but the horse must continue to drink water for them to work properly. If water is not available or the horse does not drink after administering dry electrolytes, the horse will take water from its body and put it into their digestive system to break the powder down, which can actually have the opposite effect of the desired one and dehydrate the horse.

Use paste electrolytes with caution, Kapper advised, as some research from Michael Lindinger, PhD, suggests these can lay in the gut and pull water from the horse’s body, increasing dehydration, at the most critical time after exercise.

Additional factors affecting dehydration can include the trailer ride to the venue or a decrease in water and food intake from the stresses of being in a new location or from the water tasting different. Add the workload of the day on top of that and you can have a severely dehydrated horse on your hands.

Checking for dehydration can include the skin pinch test where the handler pinches the skin on the horses shoulder then checks that it flattens back down in one to one and a half seconds. The capillary refill test is another method, pressing on the horse’s gums and seeing the color return to pink in under one and a half seconds.

Take-Home Message

Kapper encouraged horse owners to be proactive in their feeding programs, and to know your horse’s ideal body weight and what nutrients are in your forage. These nutrients will vary with the type of forage (grass vs. legume) and its level of maturity (when it was cut). This will allow you to make informed decisions when choosing feed and/or balancers to make up the difference between what your horse is getting from its forage and what it needs.

Also, be sure to read the purpose statement on every feed tag and feed according to their feeding directions’ in order to fulfill nutrient requirements. Always choose a feed that is tailored to the individual needs of the horse (size, breed, age, workload, etc.) and feed according to the instructions. Kapper cautioned that “feeding less than recommended amounts/day, means you have chosen the wrong feed and it could result in nutritional deficiencies.”

Stay observant if your horse’s performance declines and be quick to pick up on the visual clues that the diet might need rebalancing

Nutrition is the science of prevention. Understanding the role of nutrition and working with an equine nutritionist will put you on the road to optimal health and performance for your horse.