Matching Horse Feed to Energy Needs
Knowing how horses respond to different feeds might help in designing a horse's diet to best meet their exercise needs. The energy demands of a horse entered in a barrel race differ from those of a horse on a long trail ride. One runs powerful yet brief dashes, the other needs to trek at a steady pace for many hours.
For horses, as well as for people, eating highly glycemic carbohydrates is ideal for fueling muscles working in vigorous bursts. Longer-term energy that drives activities requiring endurance is best derived from low glycemic carbohydrates because these enter the blood stream more slowly.
To identify sources of high and low glycemic carbohydrates for horses, researchers from California tested how various common feeds affect energy levels in quarter horse mares. The scientists measured the mares' blood glucose concentrations, which generally peaked one-and-a-half to two hours after eating. The study found that the rise in blood sugar varied considerably, depending upon what was eaten.
The biggest response in blood sugar levels came from eating sweet feed, corn or oats. Among the horse feeds tested, these three generated the highest glycemic values.
In comparison, the horses experienced a much lower blood sugar spike after eating beet pulp, alfalfa, rice bran or soy hulls. Lying in between these two ends of the glycemic spectrum were barley and wheat bran.
Depending upon what sort of activity your horse is involved in, selecting a feed with either a high or low glycemic response could be most appropriate your horse.
Anne V. Rodiek and Carolyn L. Stull. 2007. Glycemic Index of Ten Common Horse Feeds. Journal of Equine Veterinary Science. 27(5): 205-211.