As horse owners may know, horse obesity has become a growing problem. An obese or overweight horse is at risk for a host of health problems such as arthritis, heart disease, insulin resistance and laminitis.

In a recent two-year-long study, researchers at the Animal Health Trust in Newmarket, England, recruited 72 owners of horses and ponies. Owners were instructed to estimate their horse’s or pony’s body condition score (BCS) based on a modified version of the Carroll and Huntington scoring system, which analyzed the equid’s fat coversion​ on a scale ranging from zero (very thin) to six (very fat). If the animals ranked as five or six, they were deemed obese. 

About 31 percent of horses and ponies who participated in the study were considered obese. More specifically, animals ages 5 to 20 were more likely to be obese than horses and ponies younger than 5. It is worth pointing out that due to imperfect methods of calculating how much fat is on a horse’s body, owners tend to underestimate body condition scores.

In the study, about 6 percent of horses received supplemental feed aside from forage, but that percentage changed depending on the season: 91 percent received grains or concentrates in the winter and 79 percent did in the summer.

Causes of weight gain
What are the mechanisms behind this weight gain? One of the main explanations revolves around seasonal weight consistency. In the wild, horses were designed to eat large amounts of grass during the summer when forage was plentiful, and afterward convert it to fat. They would store the energy as fat during the winter, when there is no grass growth. Generally, a wild horse would lose weight over the cold months and become quite thin by spring, ready to put weight back on. Thus, horses’ metabolisms are designed around this annual fluctuation in weight. 

However, today most horses don’t lose much weight in the winter, even though their metabolic mechanisms are still in place. When their bodies gear up for the “lean” season, it often never arrives, so they only add weight. It is not surprising then that horses with native genes suffer from obesity and laminitis, which is a crippling disease that affects the hooves.

What’s more, weight gain is worsened by “resting” horses – those that have retired or are otherwise out of work. Lack of exercise stores excessive weight in an animal. 

Risk of laminitis
The more a horse weighs, the higher its risk of laminitis. In the English study, about 21 percent of obese horses and ponies had a history of laminitis compared to only 13 percent of those that were in good or underweight condition. About 16 percent of the horses that participated in the study reportedly had suffered at least one previous episode of laminitis.

Horse care
It is crucial to monitor a horse’s physical health on a weekly basis. Check the animal’s crest, loins and hind. A condition score can be given to different places on the horse’s body to track weight, including the pelvis, loins, ribs and neck. 

Regular exercise and proper feeding amounts are critical to curbing the equine obesity problem. Giving your horse high quality horse products can help ensure the animal receives the nutrients it needs without overfeeding.