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:
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.