Metabolism of glucose is little understood in the ruminant animal. It has been demonstrated that little or no carbohydrate passes into the intestinal tract of adult ruminants on an all roughage ration (Heald 1951). Soluble carbohydrates of roughages are fermented to volatile fatty acids in the rumen. Available data show that 70% of total cellulose digestion occurs in the rumen and 30% in the cecum and large intestine with little or no cellulose digestion occurring in the small intestine (Hale, et al. 1947 and Gray 1951). The end products of cellulose digestion are the volatile fatty acids and not glucose. It has been estimated that up to 80% of the metabolizable energy of the feed is provided by the volatile fatty acids (McClymont, 1952). On an all roughage ration the source of blood glucose must, therefore, be from propionic acid which is liberally produced by rumen fermentation
