Battle of the Bulge

By Lori K. Warren, PhD, PAS

You’ve heard the condemning statistics—
6 out of every 10 Americans are overweight. Unfortunately, horses are becoming increasingly pudgy, right along with their owners. While not quite at the level as the obesity epidemic in humans and pets, the number of overweight horses has been growing in recent years. And with excess body fat comes serious health risks, for horses and humans alike.

This article will discuss common factors that contribute to obesity in horses, the consequences of excess body fat, and feeding strategies for getting your horse back to a healthy weight.

How the Scales Get Tipped

Excess dietary energy, in the form of calories, combined with too little exercise, does for horses what it does for humans—creates chubby waists, thunder thighs and broadening rumps.

For some equines, it’s a bit easier to become overweight. Ponies, in particular, are prone to becoming fat, likely because their ancestors were adapted to very harsh conditions where survival depended on gaining maximum nutritive value out of very sparse, coarse forage. Certain breeds of horses also seem to have a predisposition towards being “easy keepers” (Quarter Horses, Paints, Appaloosas, Morgans, Pasos, Andalusians and various warmbloods, to name just a few).

Overfeeding is a sure way to produce weight gain. In some cases, horses are deliberately overfed in preparation for show or sale. Although this practice is less common than it once was, many owners and trainers believe that a little extra fat can hide a multitude of conformation problems.

More commonly, horses become chubby as a result of misplaced owner affection. Many of us get considerable satisfaction from making our horses happy, and one of the things that makes them happiest is food. Whether it’s providing frequent treats or succumbing to the guilt we feel at feeding time by slipping them a few handfuls of oats, the calories add up.

In other cases, the horse owner may not recognize (or be willing to admit) their horse is overweight. We all like to see our horses in good flesh, but it’s possible to provide too much of a good thing. In addition, people new to horse ownership might not have a good understanding of what their horse needs or an appreciation for the nutrients provided by different feeds. For example, not all horses need grains, pellets or sweet feed. And, despite the many benefits described for high-fat feeds, these calorie-packed rations are definitely not appropriate for the overweight individual.

Motivation for Weight Loss

Just as obesity is a problem for humans, carrying around excess body fat is also a serious health issue for horses. Extra pounds place an extra burden on virtually all of the horse’s organ systems.
Never is this more evident than when the horse exercises — breathing becomes labored, his heart works overtime to pump blood to the tissues, he breaks into a sweat with the slightest exertion, and he fatigues easily. Additional fat also provide a layer of insulation that, while beneficial for keeping warm in the winter, can contribute to less efficient cooling, heat stress and dehydration in warmer weather. Extra weight also means additional strain on feet, joints and limbs, worsening symptoms of arthritis or leading to an inactive lifestyle, which only perpetuates the problem.

An even greater concern in overweight horses is an increased risk of laminitis or founder. Emerging research has shown that the body’s fat stores produce hormone-like chemicals, known as adipokines, which create a chronic state of inflammation. This pro-inflammatory condition is a major contributor to cardiovascular disease in overweight humans. In horses, these adipokines are thought to negatively affect blood flow to the foot.

The adipokines produced by fat tissue are also thought to promote the development of insulin resistance in overweight horses, a condition similar to Type II diabetes in overweight humans. Because cells are resistant to the effects of insulin, the pancreas must secrete more in an effort to promote normal glucose uptake by cells. Many tissues in the horse’s body require glucose as the only fuel, including the laminae in the hoof. Although more research is needed, it is believed that reduced glucose uptake due to insulin resistance may eventually starve the hoof tissues, causing the death of cells and resulting in laminitis.

If the above does not provide sufficient motivation for tackling your horse’s weight problem, maybe a reduced life span will. Numerous studies have shown that obesity reduces longevity in humans, dogs and cats. Although a similar correlation has not been sought in horses, it seems reasonable that those extra pounds may also prematurely end your horse’s life. Fortunately, research in other animals has also shown that reducing weight, even by as little as 10 to 15%, can significantly reverse these effects, possibly rewarding you with a few more years to enjoy the companionship of your favorite equine.

Strategies for Weight Loss

There’s really only one way to correct obesity: your horse’s calorie intake must be less than his calorie expenditure. You can accomplish this either by decreasing the amount of feed or by increasing the amount of exercise. The best approach is to do both.

Exercising can be difficult and uncomfortable for a severely overweight horse, so you will have to increase the time and intensity of each bout of exercise very gradually. In the beginning, long stretches of trail riding at a walk 3 to 4 days per week might be enough. As your horse starts to slim down and get stronger, you can add in some trotting and cantering under saddle, on a longe line, or in a roundpen. The key is to make exercise a regular routine to encourage muscle development, which burns more calories than fat.

You can also try to increase your horse’s opportunity to self-exercise by providing a larger turnout field and a lively companion for motivation. If your horse is really obese, however, you might have to seek a paddock that is devoid of edible pasture or he might pack on the calories as quickly as he works them off. Alternatively, you can provide pasture turnout for shorter bouts of time, rather than fulltime, to encourage play instead of dining.

The other half of the equation is gaining control over and modifying the diet. First you want to decrease the amount of dietary energy your horse is taking in. Starches, sugars and fats found in grains are the principle culprits, as they are far more energy-dense than pasture forage or hay. Even beet pulp or soy hull based feeds contain more calories than hay. So, cutting back, or even eliminating the grain or feed your horse receives is a good first step.

In addition to calories, a feed—whether it be oats, sweet feed, pellets or an extruded ration—also supplies protein and a number of essential minerals and vitamins. Depriving your horse of these other essential nutrients in an effort to cut calories may do more harm than good. So, when we eliminate grain from the diet of an overweight horse, we need to find an alternative method of supplying these nutrients. One good option is a ration balancing pellet. A ration balancing pellet contains a potent source of protein, minerals and vitamins, but does not have all the caloriesfound in traditional feeds. These pellets are typically designed to be fed in amounts of 1 to 2 pounds per day. Not only do they supply your overweight horse with the essential nutrients that may be lacking in his forage, they are substantial enough and tasty enough to make your horse feel like he is still getting his rightly deserved meal when feeding time rolls around.

The biggest component of any horse’s diet should be forage, and this is no different for an overweight individual. However, there are differences in the calorie content of hays. Grass hays, such as Coastal or Tifton-85 bermudagrass, timothy or orchardgrass contain fewer calories per pound than legume hays, such as alfalfa, peanut, or alfalfa/grass mix hays.

As much as possible, try to feed a relatively coarse, stemmy grass hay that has been cut at a more mature stage than optimum. These hays typically have fewer leaves, bigger stems, andfully developed seed heads, all of which lower the calorie content. Hays of this type require more chewing and will occupy your horse for a longer period of time, thus staving off those inevitable hunger pangs. Although the goal is to select a more mature hay, it should still be of good quality (i.e., no weeds, mold or dust). This type of hay should be offered at a rate of 1.5 – 2.0% of your horse’s body weight and good quality drinking water should be available at all times.

To further prolong the time spent eating, and avoid those baleful glares from a horse “on a diet,” find ways to make your horse work harder for his meals. For example, you can place his hay inside two haynets, or even better, place a haynet inside a canvas hay bag. You might also consider feeding chopped straw in between hay meals. Straw is largely made up of indigestible fiber and provides little in the way of nutrients, but it will likely satisfy your horse’s munchinginstincts and help to convince him he’s not being sorely deprived.

Because it is harder to control intake, pasture turnout may have to be limited. In fact, many owners of chronically “easy keepers” find that their horses or ponies are only capable of maintaining a healthy physique when kept on a dry lot. For some people, it may seem cruel to deny their equine companion grazing time; but for horses with a weight problem, it is even more inhumane to allow them to succumb to the health issues associated with being overweight.

Free-exercise is an important component of a weight loss program; therefore, the horse should be housed in an area where they can have freedom of movement, but not free access to grazing. Grazing can still be allowed, but on a limited basis, such as pasture turnout for 1 to 2 hours per day. A grazing muzzle can also be used to further slow down intake. Based on the weight loss results seen, the horse may eventually earn longer periods of grazing time.

To gain the most control over the overweight horse’s diet, they will need to be fed individually. Dominant horses are often the ones with the weight problem and are very adept at bullying others for a greater share of the feed. You may be able to provide the forage portion of the diet in a group setting. But, separating horses when it comes time to supplement the diet with grains or other feeds is the only way to ensure the plump individual doesn’t get more than his fair share.

Don’t Give in to Guilt

The answer for overweight horses, alas, is the same as it is for us: eat less and exercise more. But, if it was that easy, nobody would be overweight. Helping your horse to slim down takes time and patience. It also requires a bit of self-control—probably more on the part of you, than your horse. Those big brown eyes (or vengeful looks) may guilt you into giving him that pity scoop of sweet feed, but try not to cave. Remember that your efforts will help your horse to lead a longer and healthier life.