Horses that aren’t working relatively hard are unlikely to need concentrate feeds high in starch, so reducing starch is a good idea as work levels decrease. | Photo: iStock

Q.I don’t ride as much during the winter as I do in the summer. To compensate for my horse’s reduced workload and prevent weight gain, I recently switched him from 4 pounds of performance feed a day to 4 pounds of a low-starch feed. Despite the switch, he’s gaining weight. Why is he gaining weight on a low-starch feed?

—Via e-mail

A.Horses that aren’t working relatively hard are unlikely to need concentrate feeds high in starch, so reducing starch is a good idea as work levels decrease. However, weight maintenance is a function of calories consumed versus calories burned. If calories consumed exceed those used the horse will gain weight. Conversely, if a horse’s caloric intake is less than the calories he uses, he will lose weight. There are many potential sources of calories in a ration other than starch, so decreasing starch intake might not decrease a horse’s overall calorie