Macroscopic and Microscopic Development of the Stomach in Hamdani Crossbred Sheep Fetuses (Ovis aries)

The ruminant stomach is a critical digestive department in terms of converting low-quality feed into high nutrient-value substances. In these animals, there is a compound stomach structure with 4 compartments. Understanding the developmental structure of the stomach at macroscopic and microscopic levels is especially important in terms of nutrition. Türkiye can be considered one of the leading countries in the world in terms of sheep breeding. Our study aimed to investigate macroscopically and microscopically the developmental structures of the stomach of Hamdani crossbred sheep fetuses collected at different gestation periods. For this purpose, a total of 15 fetuses, 5 fetuses each from 3 different periods of pregnancy, were included in the study. The stomachs of the fetuses were dissected simultaneously and their topographic and macroscopic features were determined. After routine histological procedures, the stomachs separated from the body cavities were stained with Hematoxylin & Eosin and Masson Trichrome stains. As a result of the study, macroscopic and microscopic information about fetal development of the stomach was obtained. It was revealed macroscopically and microscopically that the rumen was the largest part of the stomach until the middle of the 2nd period of gestation, and that the abomasum grew rapidly at the end of this period and showed similar characteristics to the adult sheep stomach. The data of the study will contribute to macroscopic, microscopic, and ultrasonographic studies on the stomach in ruminant animals.