Let’s face it. Dieting is no fun, whether you’re a human or a horse! But as equine obesity becomes more prevalent, a strict weight-loss program can be a “necessary evil” to prevent your horse from developing related diseases, such as laminitis or insulin resistance. In a controlled research setting, horses following a strict dietary protocol have successfully lost weight. But can owners replicate this tough love at their own barn?

Jennifer Gill, PhD, a graduate teaching assistant at North Carolina State University (NC State), and colleagues recently set out to determine the effectiveness of a 10% to 20% calorie restriction for weight loss in obese horses managed by their owners. Twenty-four client-owned horses—12 geldings and 12 mares—with body condition scores (BCS) of at least 6.5 (on a 9-point scale) participated in the 26-week study. Four NC State-owned geldings served as controls and did not have dietary restrictions.

Using requirements set forth in the National Research Council’s Nutrient Requirements of Horses (2007), the team formulated each horse’s ration to meet 80 to 90% of their digestible energy requirements and restricted horses’ dry matter intake to 1.25% to 1.5% of body weight. Because pastures in the area remained lush throughout the study, the team recommended that about half the owners restrict study horses’ pasture access by using a drylot, limiting turnout time, or using a grazing muzzle.

At the initial and final consultation, researchers measured horses’ heart girth, neck crest, body length, and height; calculated their weight; evaluated their BCS and cresty neck scores; and collected information on the animals’ exercise routine and current management practices