The structure and radiographic analysis of the alimentary tract of the tammar wallaby, Macropus eugenii (Marsupialia) II. the intestines

The gross and radiographic anatomy of the intestinal tract of M. eugenii is described. A short duodenum is held in a relatively fixed position close to the cranial abdominal hypaxial musculature by the mesoduodenum. The remainder of the small intestine is loosely coiled caudal to the proximal compartment of the stomach, except for the terminal ileum which crosses the abdomen from the left, to open into the large intestine on the ileal papilla. A simple caecum lies with its base on the right side level with lumbar vertebrae 5 and 6. Its body and apex are mobile. The lumen of the caecum is confluent with the ascending colon which is situated adjacent to the dorsal right flank. Cranially, the ascending colon turns caudally to form the proximal colic flexure, then becomes tightly bound to the middle compartment of the stomach by a gastrocolic ligament. After this the large intestine forms loose coils until it straightens out in the caudally directed descending colon in the dorsal midline of the caudal abdomen. The intestinal tract terminates at the cloaca. Faecal pellet formation is first seen in the proximal colic flexure. The time taken from the administration of barium sulphate until none was visible in the intestinal tract was significantly shorter in animals fed lucerne hay than in those fed kangaroo pellets