Nutrition Primer

Many common terms come from the long experience of man with horse, and some perhaps should be applied to the modern experience of raising horses. One of them, where feeds are concerned, might be "penny wise and pound foolish."

Kenneth Kopp, DVM, manager of horse feed at the Central Atlantic cooperative Southern States Inc., said a serious mistake made by horse owners is basing nutrition strictly on the cost per bag of feed or bale of hay. A common problem is the "owners or managers who purchase the cheapest hay and try to make up the difference with grain concentrates," Kopp said. This logic is a losing battle for both horse and budget. Quality forage--hay and pasture--is the foundation of good health.

"The basic needs for a grain concentrate are for energy (calories) supplementation, and as a vehicle for vitamins and minerals," Kopp said.

To have a healthy horse, "we must first concentrate on a quality forage program," Kopp said. The horse is designed by nature to be a wandering herbivore. Because of their small stomachs, horses given the choice will graze slowly for about 20 hours a day. Man has taken this ideal environment away from many horses and domesticated them into a box stall with interval meals of poor-quality hay and grain.

"Most of the hay that I see being fed to horses is overmature--it's been harvested too late. The younger the plant, the better the nutrition," he said.

For hay producers and vendors there sometimes is an "inherent conflict of interest to cut hay early," Kopp added. As a hay field matures, more bales of hay can be produced, so it can be more profitable to cut mature plants. However, as maturity increases, quality decreases. In addition, hay producers are at the mercy of local weather patterns. Many times they have to let hay fields continue growing because of rain in the forecast.

Owners need to know the difference between young and mature forages.

"If a large seed head is apparent, the plant is nutritionally overmature--horses in the wild would never consume these plants. They would select the new, young plants," Kopp said.

One reason mature plants are less nutritious is fiber changes with the age of the plant. As a plant produces a seed head, the fiber quality changes to a protective fiber "lignin." This is similar to tree bark, and it has no nutritional value. Straw is a good example of lignin--it is high in fiber, primarily lignin, which cannot be fermented in the horse's hindgut. A majority of the hay being fed to horses is high in lignin and thus poor quality.

Hay can be analyzed for nutrient composition. This can be a useful tool for larger farms buying hay in quantity. For the average horse owner, it might be impractical to test every batch of hay. Nutritionists will evaluate the acid detergent fiber (ADF) levels along with other nutrients found on analysis to determine the quality of the forage. As a rule of thumb, lignin will be higher with an increased ADF value, noted Kopp. Visual inspection by the horse owner will show if the hay has large stems and numerous seed heads. If so, the forage will usually be highly lignified and considered poor quality.

The best investment in nutrition for horses is quality forage. This includes pasture management. Taking the time and money to have a soil test performed and following up with recommended fertilization and pasture management will benefit your horse on a daily basis.

"Placing the focus of your feed budget on the best hay and pasture will pay great dividends in the nutrition and health of your horses," Kopp said.

Grain Concentrates

If forages are the natural way to feed horses, why offer grain at all?

"Because of the way we have domesticated the horse and how we use horses, grain concentrates are used for supplemental energy (calories), vitamins, and minerals," Kopp said.

The entire feed ration for a horse has to be balanced. That means whoever is formulating the ration will refer to the minimum guidelines established by the National Research Council (NRC) for horses in varied lifestyles. Those are minimums, Kopp stressed, and often local nutritionists will alter these based on current research and field experience.

"Feed formulation is part science, and part art," Kopp said. "Nutritionists sometimes have to extrapolate information from research in other species and from hands-on experience. In an ideal world, all nutritionists would like to base their formulas only on proven research. Many times the Nobel Peace Prize Research is not available, but the basic science behind a certain formula recommendation is logical.

"How rations are altered from NRC guidelines is the 'art' of feeding horses," he added. "And that is the important difference from one feed to the next."

While most feeds provide materials that include protein, fat, and fiber, as well as other supplements, the quality and quantity of the individual components can vary greatly. Kopp noted that some states have extended the labeling requirements on feed bags to include more information, such as: calcium (minimum and maximum levels), phosphorus, selenium, zinc, copper, and vitamin A.

Some feed manufacturers have voluntarily increased the amount of information on feed bags and tags, Kopp said. A reputable feed company should provide a complete nutrient breakdown for the owner and veterinarian to examine. A feed manufacturer will not release their "proprietary" formula, but should give you the nutrient levels found in the feed so that an accurate comparison can be made. However, comparing feed tags only does not provide the "complete picture," Kopp warned.

"For example, with foal and broodmare diets, not only is the percent of protein important, but also the quantities of essential amino acids," he said. "Two feeds may have the same crude protein guarantee, but vastly differ in guaranteed levels of lysine and methionine. The quality of protein is based on the amino acids that make up that protein. You may be feeding the correct amount of protein, but lacking in certain critical amino acids."

Another misconception about protein within the horse industry is energy. Horsemen for years have equated higher protein feeds with higher energy (calories). From this false logic, many owners and trainers have insisted on higher protein feeds for performance horses. It is not true that higher protein feeds are always higher in calories.

"The mature performance horse does not require very many grams of protein per day," Kopp explained. "Excess protein is actually a load on the liver and kidneys because of increased ammonia and urea production. Horses that consume more protein than they require will have to drink more water to excrete urea through the urine. It also has been theorized that increased ammonia production could affect intestinal and muscle physiology."

Protein is mainly used for structural needs in the body. With a mature horse, the need for a high-protein feed is diminished because most growth is completed. This becomes even more important if owners are feeding higher protein forages like alfalfa and clover. Most performance horses will only require a grain concentrate of 10% protein to balance the ration with these high protein fiber sources. The growing horse, lactating mare, and the geriatric horse do need higher protein rations.

Another area of misunderstanding is the benefit of fat in the equine diet. While high-fat diets might be the horror of human health, increasing the fat in your horse's diet might improve performance and health. Horses get into trouble when they consume excess soluble carbohydrates (sugars), which can lead to colic, diarrhea, myositis, and laminitis, said Kopp.

"By feeding a higher fat ration to your horse, it will be consuming less soluble carbohydrates," Kopp said. "Higher fat rations have been proven to have nutritional benefits for many equine disciplines and lifestyles. Horses require fewer pounds of grain concentrate with higher fat rations."

Five pounds of higher fat ration has more calories than five pounds of a lower fat ration, so you can and should feed less, he added.

Crude fiber guarantees on feed tags can also be confusing--protein and fiber quality might not be apparent, Kopp noted.

"Fiber is essential for proper health and performance, but some fibers are better than others. It depends on how fermentable the fiber source is. Sugar beet pulp and soybean hulls are good fiber sources, whereas peanut and rice hulls have less nutritional value. The most economical way to provide quality fiber is through the hay and pasture. However, some fibers in grain concentrates can be useful if they are of good quality."

What Form To Feed

Kopp said the tradition-steeped horse industry has been slow to accept pelleted horse feeds, as opposed to textured sweet feeds. The pig is a monogastric (one-stomached animal) like the horse, and the swine industry primarily uses pelleted feeds.

"So, while the horse owners are insistent on sweet feeds, the horse's belly can't tell the difference," Kopp said.

There is little, if any, nutritional difference between textured feeds and pellets with the same components, but there are some management advantages to pellets. The pellets have a longer shelf life than textured feeds because of the cooking process and the moisture levels, Kopp said. Pellets flow better in the winter, and owners claim pellets attract fewer flies in the summer.

"If you are feeding horses outdoors, spilled pellets can be consumed off the ground, whereas spilled textured feed will only benefit the birds and rodents," Kopp said.

"We need more research on the digestibility of pelleted feeds versus textured feeds. Many owners feel they can feed fewer pounds of pellets versus a like sweet feed. I've heard owners exclaim, 'I never see a pellet pass through in the manure, but I do find some grain when I feed sweet feed.' It stands to reason that the smaller particle size of pellets and the heat added at manufacturing could influence digestibility of grain. Until this question is answered, what type of feed you choose is a matter of personal preference."

Some owners have accused pellets of causing horses to choke and colic. Kopp said horses choke not because of type of feed, but because they eat too fast.

"I have seen horses that were choked on sweet feed, hay, and even pasture grasses," Kopp said.

Feeding hay before any grain to stimulate salivation and slow down a hungry horse is a good management tip that has been shown to reduce the incidence of choke.

"With regard to colic, there is no evidence to support the statement that horses are more prone to colic while being fed pellets. In recent epidemiological studies there has been no difference in colic risk assessment comparing sweet feeds to pellets," Kopp said.

Not all pelleted feeds are created equal, he added. Just because a horse might colic or choke while on pelleted feed doesn't prove all pelleted feeds are risky. Many horses suffer colic while being fed sweet feed, yet owners don't condemn all sweet feeds.

"Horses are creatures of habit," Kopp said. "We know that any kind of feed change does increase the risk of colic. With good water and forage management, pelleted feeds are no more risk than comparable sweet feeds."

Another tradition that does not always serve the horse well is feeding by volume rather than weight. Managers can be puzzled when, after a new shipment, the horse begins to lose weight. But, Kopp said, it is important to realize that the density of the feed might have changed, and with it, the amount getting to the horse.

"It's not coffee cans of grain and flakes of hay that make pounds of horse, it's pounds of grain and pounds of hay that make pounds of horse," he said.

In the question of poundage, Kopp said, hay should exceed grain. "We never want the pounds of grain to exceed pounds of hay. That's a rule of thumb," he said. A rare exception might come for a high performance horse, like one on the racetrack.

Finally, Kopp advocated a more scientific approach to determining whether a horse is too fat or not fat enough, a beginning step in determining the feed balance. Again, tradition has sometimes won out over a more rational approach. Kopp recommends that managers learn how to do body condition scoring for their horses. As in other species, guidelines have been developed for feeling the body fat "at certain critical areas" on the animal. Taking those results the managers can develop a body score, determining the fat level of the horse. "You need to feed to body condition," Kopp said. "Just looking at them all the time, it can fool you, even for experienced horse owners."

About the Author

Jacalyn Carfagno

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