Gross Morphological and Scanning Electron Microscopic Study of Abomasum of Sheep (Ovis aries) during Pre-natal Life

Background: The enzymatic digestion occurs in the abomasum of sheep. A systematic comprehensive study on the embryogenesis of abomasums of sheep is lacking due to availability of sporadic information in current literature. So the current research was designed to explain the detail gross ontogenic occurrences along with scanning electron microscopic study of abomasum in sheep. Methods: From the local slaughter house, 12 healthy sheep foeti of non-descript breed were gathered and grouped into Group I (early pregnancy), Group II (mid pregnancy) and Group III (late pregnancy) having 04 foeti in every group. The abdomen of the foetus was incised and opened. The stomach was exposed and the gross observations were recorded. Then tissue samples from the abomasum were processed for scanning electron microscopic study. Result: The abomasums assumed comma shape at the gestational age of 32 to 48 days. At 67 days of foetus, the external constriction between fundus and pylorus of the abomasum was observed distinctly. In foeti of 32 to 48 days age, it was present between 13th rib and 1st lumbar vertebra. This topography changed to 8th rib and 3rd lumbar vertebra by 121 days of foetal age. The outline of the abomasal folds were noted first at 32 days of age. The height of the abomasal folds in fundus was larger than pylorus. The appearance of gastric pits on the mucosal surface was first observed at 63 days of gestation through scanning electron microscope.