Endocrinology

A Little Daily Exercise Does the Metabolic Trick for Overweight Horses

By Adam Marcus

The amount of fat a horse has is important for determining its risk for metabolic disease, but where the horse becomes fat is more important still. Accumulation of adipose tissue at the nuchal crest and the tailhead has been linked to insulin resistance.

Putting a horse on a diet can make them leaner, but a new study shows caloric restriction alone is insufficient if the goal is to reduce their risk for metabolic problems associated with weight. Without exercise, overweight equids are likely to slim down around their ribs but not in the spots most closely associated with insulin resistance, researchers have found.

The amount and nature of exercise required to generate gains appears to be modest: 20 minutes of trotting 5 days per week. Combined with an equally modest diet, the workouts led to significant changes in body morphology that researchers said could reduce a horse’s risk for insulin problems.

“Incorporating small amounts of daily exercise is going to be an essential component of maintaining a healthy fat mass and healthy body weight,” said Wendy Pearson, PhD, MSc, an associate professor of animal biosciences at the University of Guelph, in Ontario, Canada, who helped conduct the study.

For the study, which appears in a recent issue of BMC Veterinary Research, Dr. Pearson and her colleagues examined how diet, exercise, or a combination of the 2 approaches affected fat deposition in 32 horses. The animals were assigned to 1 of 4 groups during a 10-week period:

1. Full feeding of an individualized meal plan, plus 5 days per week of exercise (100 minutes total)
2. A restricted diet of 85% of energy requirements
3. Feed restriction plus exercise
4. Control group that ate their full amount of required energy but that didn’t exercise

Morphologic assessment included body weight, cresty neck score and measures of body condition at the neck, shoulder, tailhead, leg and other sites.

Animals in all 4 groups lost weight, and their overall body scores fell. But the only horses in whom the assessments showed improvements at the neck and tailhead were those that exercised regularly—and the effect was greatest for those on calorie restriction, too, the researchers reported.

For horses already diagnosed with a metabolic condition, exercise should be encouraged, but a high-fiber diet that is low in soluble carbohydrates is essential, Dr. Pearson said. For animals with laminitis, exercise may be impossible until they have lost sufficient weight to promote recovery from the episode.

Although Dr. Pearson is quick to acknowledge regular exercise carries an inconvenience factor for many owners who board their horses, she stressed the “really tangible health benefit” of doing so.

“It’s particularly important for horses going in the wrong direction—from overweight to obese or those trending toward insulin resistance,” she said. “You don’t need a lot of exercise. This is literally a horse trotting around in a paddock 5 days a week. And if you can also incorporate feed restriction as needed, that will accelerate the weight loss.” MeV

For more information:
Garland A, van Doorn DA, van den Boom R, et al. Morphometric changes in overweight horses following 10-week weight loss programs. BMC Vet Res 2025;21:596. doi.org/10.1186/s12917-025-05032-z
https://bmcvetres.biomedcentral.com/articles/10.1186/s12917-025-05032-z