Feeding Racehorses

Feeding Racehorses

– by B.Lynne Hoff, B.Sc.Pharm, President Sunglade Ranch

In an effort to summarize and simplify some of the information available to racehorse owners about the care and feeding of their equine charges, I have researched many interesting articles available on the internet. A lot of the information I will address is from a group called The Kentucky Equine Research Staff and their interesting and informative articles can be found online under EquineNews.

I will attempt to address feed requirements, common misconceptions and health issues in a simple, concise manner. I will list types of nutrients and their sources, the advantages and disadvantages of each source and finally to make some recommendations that I feel will give the racehorse the very best nutrition in the most bioavailable form while keeping a protocol of simplifying the program and cost-saving for the stable owner. In this day and age of thousands of supplements and complete feeds and millions of dollars of advertising, it is easy to get involved in spending too much time and money trying to do the very best for our equine athletes.

When you think of basic nutrition, you should think energy…but not just energy but the type of energy. A product may contain alot of nutrients in terms of energy density or gross energy but may not be in a form that is easily available to the animal (ie) Digestible Energy (DE). For example, corn and oat straw have exactly the same gross energy, but everyone knows that a horse will grow fat on corn but waste away on oat straw. That is because corn is far more digestible (available to the horse) than straw.

Classes of Nutrients:
1. Carbohydrates
2. Pro
3. Fat
These nutrients are supplied in different forms of feed that have varying DE and also can produce toxins as a by product of metabolism.


The bulk of a racehorse’s feed consists of different types of carbohydrates:
The cornerstone of a feeding program should be FIBER. Fiber rich clean forage such as timothy or oaten hay should be offered at the rate of 15 to 20 lbs per day. My horses do not do well on straight grass hay. I offer a good alfalfa mix. The experts suggest a racehorse can have about 2 to 4 lbs of alfalfa daily mixed with their grass hay. That would be about a 20 % alfalfa mix. I use a 35% mix
but have also noticed some “scurf” on my horses’ coats that may be related to too much alfalfa. The advantage of a fiber rich diet is that fibre is digested both in the fore and hindgut. The horse has a huge capacity in the hindgut to digest fiber and so fiber fermentation, unlike starch (grains) fermentation, can be used as energy sources throughout the day because they keep being supplied long after a meal has been eaten. Beet pulp is an excellent source of highly digestible fiber and has a DE content similar to oats…..without the starch. Because a fiber rich diet keeps moving through the horses’ gut, it protects the equine athlete from gastric ulcers and colic. Small concentrated meals such as complete feeds do not offer that protection and leave the gut empty and prone to acidosis.The “nitro” in a horse’s diet is generally STARCH.

Traditionally, straight cereal grains such as oats, corn and barley supply starch which like sugar from molasses, when digested, results in a direct rise in blood glucose and insulin, two of the most important fators involved in glyogen synthesis. Glycogen is the major fuel used in the muscle of a racehorse during high intensity training and competing. The problem with starch IS the rapid rise of blood sugar which also tails off rapidly and can result in a blood sugar “crash”. So there is a limit to how much grain a racehorse’s diet should contain. Starch should be digested in the small intestine but too much grain can result in overflow into the cecum and colon, resulting in acidosis which can kill off microbial populations and cause colic, anorexia, ulcers and stereotypical behaviours such as wood-chewing and weaving. Typically, no more than 5 lbs of grain should be fed in one meal.
Sugar from such sources as molasses also causes a rapid rise in blood sugar and insulin. High blood sugar is also related to behavioural problems in most species including horses.

The building blocks for bone and muscle are amino acids supplied by protein metabolism

Protein is supplied by most forages and are the building blocks for equine athletes. Extra protein can be used as a source of energy as well but the resulting amino acids are broken down by the liver and the nitrogen is excreted as ammonia. Excessive protein should be avoided as (a) water requirements increase and (b) blood urea levels increase which can cause intestinal disturbances. Also, increased ammonia in the blood can cause nerve irritability and other metabolic disturbances. Increased ammonia in the urine can lead to respiratory problems from stall odor. It is interesting to note that most “complete feed” manufacturers recommend increased protein levels for senior horses.One of the most important energy sources that is often overlooked in horse nutrition is fat
Glycogen from starch and sugar is stored in the muscle and liver and is the predominant fuel used in a race. However, fat is stored in the adipose tissue and to a lessor degree in the muscle and is very important to supply calories for lower intensity training, endurance and to meet the racehorse’s maintenance energy requirement. Fat is very digestable, particularly vegetable oils. Once adapted, (built up slowly) a horse can digest up to 90% of it’s oil ration even up to 2 1/2 cups per day. Vegetable oil has about 2 1/2 times Digestable Energy (DE) than corn and 3 times the DE of oats. It is very safe and will not cause hind gut disturbances as it will not ferment back there.

Vitamins and minerals facilitate the proper use of nutrients
Nutrients supply the energy and vitamins and minerals supply the tools to use it. Many vitamins and minerals are found naturally in good forage. However, land is being depleted with the steady use of chemicals including fertilizer and foodstuffs for both humans and animals are no longer the quality they once were. To ensure proper vitamin and mineral balances are maintained, a high quality feed supplement should be used. This supplement should contain pure ingredients in a bioavailable form without sugar, artificial flavors and fillers.

Probiotics replenish the “good bugs” in the gut and enable optimal digestion
A good probiotic supplement must be stabilized to be effective and contain a wide spectrum of species in the correct balance to be effective.

A word about “Complete Feeds” or “Sweet Feeds”

There has been a shift away from feeding straight forage and cereal grains to feeding “complete feeds” that supposedly are formulated specifically for different types of horses. I feel strongly that these types of products can be misleading as to content labeling, take decision making away from the handler, and make it impossible to custom feed your equine individual. For example, it is my understanding the complete feed manufactures are allowed to label their product with a guaranteed analysis that is the sum of the raw ingredients used to make that feed. THEN the feed is heat treated to “granulate” or “extrude”, etc. What happens to most vitamins when they are heated?

Also, “complete feeds” or “sweet feeds” are heavy in sugar and starch which can cause blood sugar spiking. They are usually meant to be fed at 12 to 15 pounds a day, so unless you are feeding to that level, the few vitamins and minerals that are left will not be in sufficient quantity to be useful. And concentrated small meals promote digestive and behavioural problems.

My Recommendations for Racehorse Diets

(divided into at least two meals). Keeping it simple and cost effective!
1.  Free choice clean 10-20 % alfalfa/timothy hay offered in slow feed nets. Averaging 15 to 25 lbs daily.
2.  Beet pulp either dry or moistened 5 to 10 lbs daily
3.  Grain (oats, corn, barley) 5 to 10 lbs daily
4.  Fat (oil such as canola, corn, soy) 1/2 to 2 cups daily
5.  Free choice trace mineralized salt with iodine
6.  BioEquine horse feed supplement 1 to 2 scoops once daily as top dressing on grainSpecial considerations:

  • Joint supplementation. The proper levels of vitamin C, copper, maganese, zinc and silica encourage natural joint fluid production. All these are supplied by BioEquine and I do not use any additional products for joints in my reining and cutting horses. However, many owners like to supplement with other products such as glucosamine. If you do, choose Glucosamine HCL over Glucosamine Sulfate. It is absorbed better. And it should be fed at 6,000 to 10,000mg/day. Some studies have shown that a combination of glucosamine and chondroitin seem to work best. The chondroitin dosage should be fed at 1,200 to 5,000mg/day. MSM is an anti -inflammatory but needs to be at a dosage of 20,000mg/day to be effective for arthritis. Check the dosages on “joint mixes”. Most of the time, they are too low.
  • Equine Therapy. For those of us who ride our horses on a regular basis, it is easy to tell when they are a little “off”. Ideally, a young horse should start into their training with teeth, feet and stride correct. I have found an amazing therapy team (Sig and Kevin) at www.bluequine.com
  • “Tying Up” in thoroughbreds is different than in quarter horses. In quarter horses, a change in diet by decreasing starch (grain) and increasing fat usually can control the situation. The situation is the same in thoroughbreds but there also seems to be a strong genetic connection. Generally, thoroughbreds prone to typing up should not get more than 5 pounds of grain daily and should not be layed off the same as others in training.