Understanding and Managing Equine Obesity

In theory, weight management—for both people and horses—is simple, said Tania Cubitt, PhD: Eat less, exercise more, and lose weight.

Nonetheless, obesity remains a problem for not only horses but the people who care for them as well. Approximately 70% of American adults are either overweight or obese, she reported, noting that recent studies in horses have found obesity in 32% to 62% of animals. So if the weight management concept is that simple, she asked, why isn't it working?

Cubitt, an equine nutritionist for Performance Horse Nutrition in Weiser, Idaho, presented a lecture on ways to manage equine obesity at the 2013 Alltech Symposium, held May 19-22 in Lexington, Ky.

Obesity has a number of causes, Cubitt said, ranging from genetics to improved forage quality (horses didn't evolve eating bright green grass, she noted; rather, they consumed sparse, high fiber forage) to a lack of exercise. And it's at the root of a number of serious health problems, including insulin resistance, chronic inflammation, oxidative stress, and possibly even a decreased life span.

In fact, she noted, obese horses often face more health challenges than very skinny ones. Considering that, managing and preventing obesity should be at the top of every horse owner's to do list, she said.

But one of the major problems contributing to equine obesity, Cubitt said, is the owners themselves.

"Owners significantly underestimate the weight, body condition score (BCS), and cresty neck score of the horse," she said. They also tend to have misconceptions on a number of important weight-related factors, including:

The horse's activity level. "People really overestimate how much work horses do," she said. If owners feed horses based upon how much work they think they're doing, compared to how much work horses actually carry out, chances are the animal is being overfed. Racehorses and upper level three-day eventers often have very high energy requirements due to their high activity level, Cubitt said, while trail and pleasure horses generally have much lower energy requirements.

"Nutritionists do not distinguish between disciplines when estimating a horse’s workload," Cubitt explained. "We group all exercise together. So while a top level dressage horse may work very hard within its discipline compared to a polo pony or race horse in training, its workload may actually be considered moderate. Horse owners need to understand this concept when determining their horses’ activity level." Not sure where your horse fits? Consider consulting with a veterinarian or equine nutritionist to find out.

A horse with a BCS of 5

Photo Courtesy Dr. Tania Cubitt

What a "5" on a 9-point body condition scale actually looks like. Cubitt showed attendees an image of a horse at a healthy weight with a BCS of 5 (at left). She then said if she showed the same image to many of her clients they'd respond that the horse needed to put on more weight. Cubitt said that a horse with a BCS of 5 (or "moderate"), as described by the current body condition scoring system, has a flat back with no crease or ridge, ribs that aren't visually distinguishable but easily felt, some fat around tail head that's beginning to feel spongy, withers that appear rounded over spinous processes; and shoulders and neck that blend smoothly into body. 

How much is actually being fed. From scoops to coffee cans to ice cream cups, owners have a wide range of "measurements" for how much their horses consume, Cuibtt said. But the only way to actually know how much you're providing to the horse is to weigh the feed. 

Feed types. For instance, Cubitt said, low carbohydrate feeds—while potentially beneficial for some overweight horses—don't equate to low calorie feeds. "Most low carb feeds need to be fed at three to four pounds (per day) to provide the appropriate minerals," she said, meaning an overweight horse might need to consume more calories than they need to obtain the vitamins and minerals they need. In most cases, overweight horses might benefit more from a ration balancer pellet, which can provide the amino acids, vitamins, and minerals a horse needs without the excess calories. If specific questions arise, a veterinarian or equine nutritionist can help guide you in the right direction for what might work best for your horse. 

What "just a handful" really means. In reality, "just a handful" probably amounts to a lot more than what many owners think it does. Cubitt gave an example: Say an owner feeds their horse "just a handful" of senior feed in the morning and another handful at night. Each handful probably weighs about a half of a pound, meaning the horse is consuming about a pound of feed per day, she said. Each pound of senior feed contains about 1.3 megacalories (each megacalorie contains 1,000 calories), so that horse would be consuming about 474 megacalories each year; that means that horse could gain about 47 pounds—and one body condition score—per year, from "just a handful" of feed, morning and night, Cubitt said.

Cubitt stressed the importance of owner education to correct these misconceptions, and offered some suggestions about what's needed to combat obesity.

Ideal feeds are those that contain low energy, low starch, and sugar concentrations to reduce calorie intake; adequate protein levels to prevent unwanted muscle loss; appropriate vitamin and mineral concentrations for required daily intake; and high fiber to maintain gut fill to help obese horses lose weight, Cubitt said.

She also provided the following management tips for owners of obese horses:

  • Maximize chewing time for the food overweight horses consume to mimic their natural feeding behavior. Consider using slow feeders for both forage and concentrate, she said.
  • Aim to feed about 1.2 to 1.5% of the horse's body weight daily in forage. Never feed less than 1%, she cautions, as this can lead to problems including hindgut dysfunction, gastric ulcer formation, and stereotypic behavior development.
  • Also in the forage department, Cubitt recommended obtaining forage with a low nutritional value for obese horses to reduce the amount of calories they consume; however, avoid feeding straw. Cubitt said it can be hard to tell which forages have a low nutritional value without getting them tested, but typically these hays are more "stemmy" and fibrous rather than a rich green color,. "It's important that horse owners make the distinction between nutritional value and quality," she stressed. "Bad quality is always the same: weeds, dust, mold, etc. Good quality is what is appropriate for your horse. Low nutrient hay may be excellent quality for your horse if he is overweight and laminitic but poor quality if you have a thin lactating broodmare."
  • Don't forget exercise. "There has to be a partnership between diet restriction and exercise," she said. If overweight horses are out of shape, start exercise slowly and gradually build it up.

Never try to reduce a horse's body weight by more than 1% per week, Cubitt said. Rather, aim to reduce it by 0.5% per week.

In closing, Cubitt suggested that we need a different perspective when it comes to viewing obesity. When most people hear the phrase "nutritionally mistreated," they think about the thin, starved, or emaciated horse, she said.

"But this can also be applied to obese horses," she said. "It's all about perception."

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.