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The Obesity Problem

Horse owners’ misconceptions about what, when and how much to feed are behind this pervasive situation.

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Equine nutritional problems are often the fault of horse owners who dole out improper ration sizes or oversupplement, experts say.

These practices, experts say, are opposite of how a horse’s digestive system normally processes food.

Horses are grazing animals designed to eat small amounts throughout the day and periodically nap in 15- to 20-minute intervals. Equine stomachs constantly produce acid regardless of the presence of food, which can lead to ulcers and behavioral problems as the animals chew and eat in an effort to produce saliva.

“Saliva is a natural antacid,” says Juliet M. Getty, Ph.D., of Getty Equine Nutrition LLC in Bayfield, Colo. “Horses will eat whatever they can to produce saliva, including manure and their wooden stalls. Providing high-quality hay at all times allows the horse to self-regulate food intake and reduces its stress.”

A common owner misconception is that a horse will become overweight if hay is provided at all times, says Dr. Getty, who wrote the book “Feed Your Horse Like a Horse” and founded GettyEquineNutrition.com, a consultation service.

An empty stomach may cause stress, increasing the hormone cortisol, which raises insulin levels and makes fat impossible to burn. A horse previously fed only at meal times understands after about a week that its access to hay hasn’t decreased. At that point, they’ll eat only when needed, Getty says.

“Obesity is the most pervasive problem with equine nutrition,” says Teresa Burns, DVM, Dipl. ACVIM, a clinical instructor in equine field services at Ohio State University. “Horses are being fed too many calories, and it is causing obesity, predisposing them to laminitis, colic and diabetes.”

Some owners are wary of allowing too much pasture time because they think their horses will injure themselves or each other, Dr. Burns says. Less time in the pasture often means less grazing and less exercise, she says.

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“We have come to realize that horses do better without starch [cereal grains and oats],” Getty says. “The oats were once used for energy because horses were worked more than they are in general today. Now a high-quality grass hay and alfalfa hay mix with mineral supplements is the best diet for the average, healthy, non-pregnant or lactating broodmares.”

Reading commercial feed labels is the best way to resolve oversupplementing and overfeeding, says Carey Williams, Ph.D., an equine extension specialist at Rutgers University.

“If clients are feeding their horses low-quality hay, then supplements are needed,” Dr. Williams says. “If a horse is being fed a manufacturer diet that says it is complete, nothing more needs to be added. Often, owners mix different grains together and just mess up what the companies have created. Horses can be fed too many micronutrients. Sometimes they’re being fed at two to four times in excess, which can be toxic.”

Equine veterinarians and nutritionists say primary care practitioners should assign a body conditioning score each time they examine a horse.

“The equine industry needs to promote assessing how each animal is doing nutritionally,” says David Galligan, VMD, MBA, of the University of Pennsylvania’s New Bolton Center. “As in human medicine, nutrition is a key welfare issue. Especially with the down economy, owners could be using [lower quality] feeds to save money.

“Nutrition sets the whole basis for health. Underfed horses are susceptible to disease, while overfed horses can increase their disease risk.”

Coffee cans and scoops are often used to measure food, a routine that is unreliable and does nothing to promote good equine health.

“Owners often feed by volume or eyeballing, which isn’t a good practice since neither is an accurate measurement,” Dr. Galligan says. “Feeds have different weights because they have different densities. The crude protein percentage can change depending on the percent of feed the horse consumes. If the horse eats less than the amount fed, it will have a lower density rate.
“If the horse’s ribs can’t be seen or palpated, it is overweight. Feeding horses properly is a spectrum of balances. If owners account for nutrients instead of weight of the food, the horse will have a better chance of proper nutrition.”

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Square Bales are Best

Rolled hay, or round bales, is sometimes fed as a more economical food for horses, according to Burns, but it’s a bad idea for multiple reasons.

“Inflammatory airway disease or heaves, a form of asthma, can happen in horses that eat round bales,” Burns says. “These large round bales house mold spores and can even lead to botulism. The horses are standing in these bales and inhaling everything that was growing inside these bales, with the center being the worst part.

“Small square bales are better, but it’s faster and cheaper to feed the large bales, which is a big mistake.”

Talking with the owner about a horse’s diet and exercise level can reduce nutritional problems, experts say.

Eric Davis, DVM, MS, Dipl. ACVS, Dipl. ACVIM, is director of field services for the Humane Society Veterinary Medical Association.

“When I examine horses on Indian reservations, they look great,” Dr. Davis says. “The reservation horses are largely in good health because they live the way horses are meant to live. It’s a problem sometimes to get the best quality forage, depending in the region. Some areas may be too humid or too dry, while others are selenium deficient for growing optimal hay, but providing an ample supply of clean water and the best quality hay possible is really the basis to good horse nutrition. Minimal supplements are needed for the average horse.”

Obese Horses

When obesity is diagnosed in a horse, dieting isn’t necessary, according to Getty.

“Overweight horses, just like those of a preferred weight, should have hay available at all times,” Getty says. “What an owner should do is eliminate starches. Non-structural carbohydrates should be less than 12 percent in foods in order to be safe to feed free-choice and reduce insulin levels.”

Veterinarians say well-meaning owners sometimes don’t believe that quality hay and the six classes of nutrients—water, fat, carbohydrates, protein, vitamins and minerals—are all their horse needs. This leads to the inaccurate matching of feed to the needs of a horse.

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“Ninety percent of feeds have 10 percent molasses in it,” Rutgers’ Williams says. “I tell clients to keep molasses in less than the first four ingredients on their feed labels.

“A rule of thumb in feeding horses is that they should eat 2 to 2.5 percent their body weight in a day, but some breeds only need 1.5 percent of their body weight in food a day. Owners often think their horse is more active than it actually is, too, which leads them to believe they need a different type of feed.”

As horses age, their ability to absorb calcium decreases, but their ability to masticate the food is the greater issue, experts say.

“Older horses can lose teeth or get flat mouth, which is an obstacle to eating,” Williams says. “Horses lacking teeth will roll the hay into a ball in their mouth—called quids. They’re unable to adequately masticate the food, then spit it out. Veterinarians need to recommend feeding hay cubes and adding water to the hay cubes so the horses can swallow it.” 

Grade Every Exam

A recent study conducted by the University of Nottingham in England found that 1 in 5 leisure horses was overweight or obese.

Equine experts suggest using a Henneke Body Conditioning Score of 1 to 9 during examinations. A score of 4 or 5 is ideal, while 7, 8 or 9 is considered obese.

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