How to Manage Your Horse’s Weight

Discover contributing factors to weight gain in horses and how to trim down your overweight horse.

The Henneke Body Condition Scale helps horse owners assess the varying degrees of fat in their horses by rating six key conformation points: neck, withers, crease of back, tail head, ribs, and behind the shoulder. Mitchell Luo/UnSplash

Is your horse overweight? Would your vet think he is? What would your best horse pal say?

Excess weight can make horses’ everyday lives more difficult and lead to serious health complications–even death.

In this article, we’ll discuss why so many horses are fat and getting fatter, plus explain why their being overweight is so detrimental. Then we’ll help you determine whether your own horse is carrying extra weight, plus offer experts’ tips for trimming excess poundage and keeping it off.

Horsemen of every era have appreciated a handsome horse in good flesh, but the wise horseman of today knows that fat really isn’t “the best color.”

Why the Weight?
Horses evolved to be free-roaming grazers. In the wild, they’re able to survive on scarce pastures, storing excess weight during the summer in preparation for limited foliage in winter.

Yet, as domesticated animals, they often consume high-starch, high-concentrate grain feeds once or twice a day, with limited or no grazing access.

And that’s not even mentioning the high-sugar treats we owners love to feed them.

Before the 20th century, horses were primarily used as work animals; their jobs transporting humans or powering farm equipment ensured regular exercise. Today, we use horses primarily for recreation, and some are more accurately classified as “yard ornaments.”

Too much food, too little exercise – it’s the guaranteed formula for weight gain. As it turns out, though, there are a few other surprising factors contributing to our horses’ bulging sides.

The easy keeper. Some horses just don’t need many calories to maintain optimal body condition. Kentucky Equine Research, Inc., conducted a survey and found that owners who describe their horses as “easy keepers” tend to find it virtually impossible to reduce their horses’ weights by calorie restriction alone. Moreover, these owners assert they’re not dishing out high starch feeds.

While you may prefer the look of a chunky horse over an underweight horse, being overweight is a health issue you should avoid. pen_ash/Pixabay

Super-grass. Surprisingly, one of the primary weight-gain factors is vastly improved forage. Over the years, the nutritional content of forage has increased. As free-roaming grazers, horses thrived on sparse pastures and diverse forage. Today’s forage is limited in species, primarily consisting of those grasses and legumes best for maximizing nutrition. Plus, genetic technology has further boosted the nutrition value of these forages, meaning horses are getting pasture and hays that are higher in starch and carbs than ever before.

The time of day a horse grazes can make a difference, too. Rhonda Hoffman, PhD, PAS, associate professor of equine science at Middle Tennessee State University in Murfreesboro, explains that during photosynthesis, green plants produce glucose and other sugars, with oxygen as a byproduct in the presence of light. As a result, forage carbohydrates naturally rise throughout the morning and peak in the late afternoon due to continuous exposure to light. Plant carbs then decline overnight and into the early morning hours. That means horses that graze in the afternoon, as opposed to during the night or early morning, are likely to ingest two to four times as much sugar, starch, and fructans, and are therefore at a greater risk of obesity.

We like ’em plump. In many cases, we just prefer to see our horses carrying extra weight. For halter horses, especially, a “meatier” profile has traditionally been desirable. Emotionally, it’s pleasant to feel that you’re feeding your horse “plenty,” but in reality the extra calories aren’t doing him any favors.

Why Fat’s Bad
Excess poundage on your horse stresses almost all of his body systems. Specifically, a fat horse may suffer:

  • Increased stress on heart and lungs as they work overtime to deliver oxygen to his outsize body.
  • A tendency toward lethargy and becoming easily fatigued. Also, increased risk of injury due to poor conditioning. Overweight horses are more likely to stumble, take a misstep, or overextend a joint.
  • Greater strain on hooves, joints, muscles, and limbs, putting him at risk for ligament and tendon injuries and laminitis. Greater strain and concussion also can aggravate existing arthritis, or increase the risk of developing early arthritis.
  • Reduced reproductive efficiency, the result of metabolic and hormonal imbalances.
  • Impeded bone growth in young, growing horses; increased risk of developmental orthopedic complications, as cartilage expands before bones are fully developed.
  • Reduced performance ability, because extra weight limits a horse’s ability to move freely. Plus, if he’s overweight, he’s likely not as fit as he should be to perform at his full potential.
  • Reduced efficiency in regulating body temperature. This is especially problematic in hot, humid climates, where excessive layers of fat can prevent a horse’s body from cooling itself.
  • Increased risk of developing Cushing’s syndrome and equine metabolic syndrome or EMS (see “The Lowdown on EMS” at end of article).
  • Shorter life span, as any combination of these conditions take their toll.

Now What? OK, your horse is chubby. Now what? As with humans, the best approach is simple math: add exercise, subtract calories. Naturally, it’s not as simple as it sounds, but our tips will help you get started.(Always consult your vet before changing your horse’s diet and exercise routines.)

Kick the carbs. If your horse is doing mild-to-moderate work, he probably doesn’t need grain. High-quality forage (hay or pasture) plus a vitamin and mineral supplement are enough to meet his nutritional needs. Stick to grass hay, which is low in calories, rather than feeding alfalfa or a grass-alfalfa mix.

Horses need the satisfaction of chewing roughage without added calories. Dr. Hoffman notes you can also soak quality hay in water before feeding it, to substantially reduce starch and fructan contents.

If your horse maintains a high level of activity, he may need additional nutrition in the form of a low carb/starch grain mix (read the labels!), or corn oil or rice bran supplementation.

Feed solo. Cherry Hill, noted horsekeeping expert and author of numerous horse-management books, says that if you feed a group of horses in a community feeder, some will naturally get more than their recommended share of calories. If need be, move your overweight horse to a solo pen or paddock.

Limit grazing. Hill suggests turning a chubby horse out in an area without any vegetation, such as an arena or round pen, where he’ll be able to exercise freely without eating. If this isn’t an option for you (and your horse must be kept on pasture some of the time), try a grazing muzzle. Be sure to introduce the muzzle gradually, with supervision, and make sure your horse can drink while wearing it.Another option is to turn out at night only, when the carb, starch, and sugar contents of pasture forage are at their lowest.

Control your easy keeper’s turnout time to ensure he isn’t taking in extra calories and sugars. Stux/Pixabay

Get him movin’. If your horse isn’t on a regular exercise regimen, start one, building up his stamina in small increments. Slowly increase the time and intensity of his workouts, shooting for at least 30 minutes a day, if possible (half an hour a day is preferable to two hours once a week).

If you can’t ride on any given day, Hill suggests in-hand work, longeing, long-lining, ponying, time on a treadmill or a hot walker, or even swimming, if that’s an option for you. “The more you can increase your horse’s metabolic rate with regular exercise, the more calories he’ll burn, even when he’s standing still.”

Limit the goodies. It’s OK to give your horse a treat every so often, but giving him 20 horse cookies a day is not. Even apples and carrots are high in sugar and fructans, explains Dr. Hoffman, so although one a day may be fine, a bucketful is not.

A few more tips:

  • Be patient. Weight loss should be gradual. Too many changes too fast can cause a horse to become stressed, possibly causing a metabolic upset, which can lead to colic.
  • Track your horse’s progress using a weight tape. Contrary to assumption, weight tapes are remarkably accurate, and an excellent way to gauge a horse’s weight. This will help you make adjustments in his diet and exercise plans, as needed. For example, if your horse’s weight plateaus before he’s at his ideal weight, gradually reduce his feed rations again—and/or increase his activity.
  • Make sure your horse always has access to fresh, free-choice water and a salt block.Water will aid digestion, and if his activity is increased, he’ll need to drink more to replenish himself. Salt will encourage him to drink more, aid in temperature regulation via sweating, and help balance his overall diet and electrolytes.
  • Check pastures, round pens, paddocks, and arenas to make sure there’s nowhere your horse could be escaping to chow down on grass.
  • Even if your horse is low in the pecking order (and he’s fed in a group), regularly observe him eating to make sure he isn’t scarfing down his neighbor’s dinner, too.
  • Schedule regular visits with your vet to monitor your horse’s progress and to ensure his weight-loss program is healthy for his specific needs.
  • Don’t obsess over perfection. This is all about health.
Longeing your horse is an easy and effective way to exercise your horse and build your relationship with him. Schaeffer/UnSplash

The Lowdown on EMS
Equine metabolic syndrome (EMS) is a relatively new term to describe a disorder that’s not yet well understood. Indeed, EMS is often misdiagnosed as Cushing’s syndrome, hypothyroidism or insulin resistance syndrome.

Dr. Rhonda Hoffman, who researches carbohydrate metabolism and insulin sensitivity in horses suspected of having EMS, relates the disorder to Type 2 diabetes in humans.

“Type 2 diabetes is often associated with obesity, and typical warning signs include ‘insulin resistance.’ In which normal amounts of insulin fail to lower blood glucose levels.” She explains. “When this happens, the pancreas must produce more insulin to control blood glucose levels. Insulin stores fat, and thus insulin resistant people (or horses) are extremely efficient at storing fat–and therefore more likely to be obese.”

Researchers haven’t been able to determine whether a horse can be predisposed to insulin resistance, or why one may be become so—whether it rests on genetics, conditions during gestation, or environmental factors. But they do believe that insulin resistance indicates the onset of EMS. They also know foods high in starch and sugar cause significant spikes in blood glucose, and horses that consume such foods over a long period of time can become insulin resistant.

Another indication of EMS is obesity-associated laminitis. This type of laminitis is mild compared to the painful, disabling kind caused by gastro-intestinal failure. All laminitis stems from changed circulation in the laminae; in obese horses, insulin insensitivity appears to interfere with the endothelial tissue of the laminae, bringing on the disease. Unfortunately, there’s currently no medication to treat EMS (those used to manage Cushing’s proved ineffective). Experts agree the best way to manage EMS is through diet and exercise. For at-risk obese horses, cutting calories and increasing activity seem to be the best remedies.

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