COMPARATIVE GROSS AND MICROSCOPIC ANATOMY OF THE OMASUM OF THE SHEEP AND GOAT.

The gross and light microscopic features of the omasal wall and the digital and scanning electron microscopic morphology of the mucosal surface of primary laminae were studied and compared betwen sheep and goat. There was only little difference between the gross and microscopic anatomy of the omasum the sheep and goat. The omasum in both species was bean-shaped and pinkish to grayish in color. It has greater and lesser curvatures, body and neck. It was small and lay on the right side of the median plane. Inside were numerous laminae of different orders: primary (largest), secondary and tertiary (smallest). The laminae were arranged in 1,3,2,3,1,3,2 . . . pattern. Primary and secondary laminae were more numerous in the sheep (9.9 ± 0.9; 10.3 ± 1.6) than in the goat (9.1 ± 0.7; 9.4 ± 1.7) (P<0.05). Tertiary laminae, however, were more abundant in the goat (16.8 ± 2.9) than in the sheep (14.1 ± 2.5) (P<0.05). From without inward, the wall of the omasum in both species consisted of tunica serosa, muscularis, submucosa and mucosa. The mucosa, of the laminae, was studded with many conical and few dome-shaped papillae. Similar papillae were demonstrated with the use of digital and scanning electron microscope. Papillae appeared more plentiful in the sheep than in the goat. The present findings, hopefully, will contribute in understanding the role of the omasum in small ruminant digestion. [ABSTRACT FROM AUTHOR]