Horses get fat the same way humans do: overeating and lack of exercise, says Kenneth Kopp, DVM, technical services veterinarian for Arenus in St. Louis, Mo.
“Equine obesity is rampant,” Dr. Kopp says. “Obesity may increase the risk of many maladies such as laminitis, developmental orthopedic disease, arthritis and several metabolic disorders.
“It is well-known that surplus body fat can tilt the animal toward a pro-inflammatory state as well as contribute to metabolic disorders such as insulin resistance.”
Today’s equine diet is similar to the American human diet: too many soluble carbohydrates.
“Veterinarians should communicate with owners to make sure that the grain ration being fed is what the horse actually needs and is fed in proper amounts,” he says. “Vets could assist owners by suggesting they weigh their animal’s total ration instead of just offering coffee cans or scoops of grain and flakes of hay.”
In some areas of the country, good forage is scarce or hay is hard to get and expensive. Owners may need to feed more grain. Improved seed technologies have created maximized-gain pastures with more carbohydrates than native grass to better fatten cattle.
“Wild grasses are generally not as high in carbohydrates as our modern, improved grasses and legumes,” Kopp says. “When owners have lush carbohydrate-rich pastures, veterinarians might recommend that horses wear a grazing muzzle or limit grazing time to control carbohydrate intake.
“Veterinarians might advise owners to try spreading out the horse’s paddock and pasture hay so he has to walk from pile to pile. Put the hay opposite from the water so he has to walk back and forth. Some barns are installing walkers, making exercise part of a total board plan.”
Adjust Caloric Intake
Some obese horses are like house pets in that they receive very little consistent exercise. Other horses may be stallbound because of injury. It is crucial for the veterinarian to help adjust total caloric intake based on current needs.
“We want today’s horse to look a certain way, to perform a certain way,” Kopp says. “Often this may require owners to feed grain for additional calories. Horses are designed to consume forages, and every effort should be made to minimize calories from grain. When grain is needed for supplemental calories, higher fat rations provide a safer source as these rations are inherently lower in carbohydrates.
“Many horses can be maintained on forages alone provided they are offered low-calorie supplements that balance vitamins, minerals and amino acids. Today there are several low-inclusion supplements that provide balanced nutrition without significantly increasing caloric intake and these are useful tools in feeding obese horses.”
Kopp, who has specialized in equine nutrition since 1991, suggests that veterinarians educate owners about body condition scoring, which can be learned from local extension offices or universities. Charting body condition scores can help prevent obesity by providing weekly adjustments to equine rations.
Arenus is a division of Novus Nutrition Brands, a Novus International Co. dedicated to improving the health, performance and longevity of horses and companion animals.
Just as human obesity burdens the health-care system, equine obesity creates much work for the practitioner, says Gabriele Sutton, owner of KAM Animal Services in Ontario, Canada. Along with a high fat/high fiber feed, she recommends that a client-centered veterinarian stay involved in the horse’s nutrition, even joining forces with a nutritionist.
Sutton says many horses, especially Warmbloods, quarter horses, Andalusians and ponies, have “blueprint to become overweight.”
Robert Eustace, BVSc Cert EO Cert FP FRCVS, director of The Laminitis Clinic in Dauntsey, England, agrees.
“Some breeds have a different carbohydrate metabolism than others,” he says. “Thoroughbreds are much less efficient at absorbing nutrients from their diets than native ponies, cobs and Warmbloods, whose ‘thrifty’ gene seems to enable them to survive in times of little food. They run easier to fat when food is plentiful.”
Overweight horses have fat deposits on the crests of their necks, over the loins, tailhead and around the sheath or udder.
“I like to be able to feel a horse’s ribs easily, yet not be able to see them,” Dr. Eustace says.
“Several factors can make feeding a horse more difficult than it need be. One pressure is from friends to try the latest fad in feed. Another factor is the ridiculous and damaging tendency of most show judges to only award rosettes to animals that are grossly overweight.”
Starvation or too drastic a reduction in feed can lead to hyperlipidemia, Eustace says.
“If the energy level of the diet is suddenly reduced, the animal will mobilize fat reserves to provide the missing energy,” he says. “In cases of hyperlipidemia, the mobilization gets out of control with excessive quantities of liquid fat being released into the bloodstream. Hyperlipidemia is often fatal.”
Eating Like a Horse
“As scientists and horse owners ourselves, we know that horses really enjoy eating,” says Mary Beth Gordon, DVM, of Purina Mills in St. Louis. “They bang on the stall door, wanting more if you just give them a handful of food. So we developed our WellSolve to offer a larger portion, extending a horse’s mealtime, while helping to keep insulin levels balanced and prevent weight gain.”
John Sylvester, Ph.D., of Buckeye Nutrition in Dalton, Ohio, says research shows that consistently providing high sugar and starch diets keeps blood insulin levels elevated, which is linked to conditions such as insulin resistance, laminitis and behavior problems.
Sylvester cites equine obesity studies at Virginia Tech University, the Equine Studies Group in England and the University of Pennsylvania’s New Bolton Center as being instrumental in Buckeye’s development of proper feed.
“If your clients use a texturized or pelleted feed, they should know the starch and sugar content,” Sylvester advises. Inappropriate energy intake can lead to excess weight.
He says weanlings, yearlings and working horses alike all need the best forage you can provide. Depending on their growth and work rates, balance the hay with the best grain or a fat supplement (if calories are needed), as well as a ration balancer that gives them vitamins and amino acids.
“Many owners overfeed their animals,” he says. “Most horses don’t need all that extra energy. Not maintaining a good body weight can lead to all kinds of problems, such as obese mares having foaling difficulties.”
Bill Vandergrift, Ph.D., president of EquiVision Inc. of Versailles, Ky., takes it a step further.
“The dams of foals not necessarily genetically predisposed to obesity need to be maintained in a moderate body condition during pregnancy,” he says. “This sets the basic metabolism of the horse before it is ever born. When in the foal, weanling and yearling stage of its life, the horse needs to be managed in a manner that promotes skeletal growth more than growth of body mass.
“Unfortunately, this is contrary to the way certain individual horses will be managed in order to compete successfully, for example, in halter futurity classes.”
A Role for Supplements
Doug Herthel, DVM, of Alamo Pintado Equine Medical Center in Los Olivos, Calif., says it is often difficult for the clinically obese horse to lose weight. He has found success by reducing calories and starches, and developing Platinum Performance, a supplement that fills nutrient gaps by providing a source of essential fatty acids, antioxidants, essential amino acids, vitamins and trace minerals.
“Omega 3-fatty acids help insulin drive the glucose into the membrane,” Dr. Herthel says. “They also increase insulin receptor sensitivity and reduce systemic inflammation, which helps decrease disease and aging.”
Chronium and magnesium are critical in glucose metabolism. Carnitine transports the fatty acids into the mitochondria.
Nutrition is a large part of Herthel’s practice. “The good effects are accumulative,” he says. “We use fewer antibiotics and other drugs. Animals recover faster. We are also able to prevent disease through proper diet. Humans and horses are very similar in that way.”
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