199P.A. Harris COMPARISON OF THE DIGESTIBLE ENERGY (DE) AND NET ENERGY (NE) SYSTEMS FOR THE HORSE

The horse can be described as a monogastric herbivore or a non-ruminant herbivore which is suited to the digestion and utilization of high fiber diets due to continual microbial fermentation primarily within the hindgut (cecum and colon). Domestication, and an increasing demand for horses to perform under circumstances that require energy intakes above those able to be provided by their more ‘natural ’ diet of fresh forage, has resulted in the inclusion, in particular, of cereal grains and their by-products as well as supplemental fat in many horse diets. Such additions may be made in the form of the raw material or processed raw material or a manufactured compound feed. The upper part of the gastrointes-tinal tract has a relatively small capacity and the horse has digestive and metabolic limitations to high grain (high soluble carbohydrate) diets. Large grain meals may overwhelm the digestive capacity of the stomach and small intestine leading to the rapid fermentation of the grain carbohydrate in the hindgut. This may result in one of a number of disorders including colic, diarrhea and laminitis. Providing the right amount of energy from the appropriate sources without compromisin