Effects of Removing the Rumen, Reticulum, Omasum, and Proximal Third of the Abomasum on Digestion and Blood Changes in Calves

Summary Experiments were carried out with calves which had their forestomachs, upper one-third of abomasum with vagi, and spleen surgically removed. Some aspects of the nutrition, physiology of digestion, and levels of blood constituents were studied. Voluntary feed intake was found to be affected by stomach growth, anorexia, and scouring. Diets high in fiber stimulated the rumination cycle. Rate of passage of food was similar to that of simple-stomached animals. Results indicate that the decrease in blood sugar concentration which occurs in normal calves is independent of rumen development, dietary changes, or increased levels of volatile fatty acids in the functional rumen or in the blood. Changes in postprandial acetone body and volatile fatty acid levels were noted. The significance of these findings and the possible relationship between these factors are discussed.