Fat is responsible for endurance. Recent university studies have shown that the addition of fat in commercial rations is a readily available, excellent source of energy for horses. Fat supplemented equine rations reduce the bulk and the amount of daily grain intake thus reducing the likelihood of complications from excessive grain intake. Several equine studies have also shown improvement in performance following fat supplementation of the diet. Unless a commercial ration is designed to be a hay replacer, fiber is usually considered undesirable because it is composed of the woody portion of the plant and is poorly digested.
Most horses obtain ample amounts of fiber from the forages they consume.
In general, the lower the quality of grain, the higher the fiber. The lighter the oats, the lower the digestibility. Oat hulls are very difficult to break down. We want to see the fiber portion of the grain ration as low as possible and provide the fiber needed through the hay portion of the horse's ration. More feed manufacturers are now guaranteeing levels of vitamins and minerals, and many states are now requiring more disclosure on the feed tag.