Passage of digesta through the intestines of the sheep

Abstract

In studies on the rate of passage of food through the alimentary tract of the ruminant, most workers have examined the gut as a whole or have differentiated only between the reticulo-rumen and the remainder of the gut (Balch, 1950; Castle, 1956a, b ;Blaxter, Graham & Wainman, 1956).This is no doubt due to the emphasis rightly placed on digestion in the reticulo-rumen, which usually holds about 70"/0 of the total gut contents.It is generally accepted that passage of digesta through the intestines is fairly rapid compared with passage through the reticulo-rumen, and that once digesta leave the stomach they are propelled by peristaltic contractions.Although the volatile fatty acids absorbed from the compartments of the stomach satisfy most of the energy requirements of ruminants, most nitrogenous compounds other than ammonia, lipids other than volatile fatty acids, vitamins and a little carbohydrate are absorbed from the small intestine, and both small and large intestines share in the absorption of large amounts of water and minerals; in addition a small amount of organic matter is digested in the large intestine (Boyne, Campbell, Davidson &