More than half of 300 horses involved in a study at at the Virginia-Maryland Regional College of Veterinary Medicine (VMRCVM) and the College of Agriculture and Life Sciences at Virginia Tech were found to be overweight or obese. The researchers also found that generous grain diets weren’t the issue in these cases of apparently overzealous eaters; rather, they found pasture grasses, hay, and inactivity were more to blame for the problem.

The researchers examined a sample population of 300 horses from 114 farms and found that 51% could be classified as overweight or obese per the Henneke body condition scoring system. The last research published on the incidence of equine obesity was the USDA’s 1998 National Animal Health Monitoring System study, which is based on an on-farm survey of horse owners across the country. These results indicated that 5% of the nation’s horses were overweight.

However, Craig Thatcher, DVM, PhD, a professor of Clinical Nutrition at VMRCVM said, “We believed that the incidence of obesity was much greater than this. We were seeing a large number of obese horses in our practice, particularly obese horses experiencing laminitis.”

Owners of the horses participating in the current study provided details about the animals’ diets, revealing that excess grain, commonly implicated as a cause of obesity, was not a primary factor in the horses’ weight gain