Morphologic and morphometric exploration of the ovarian follicles in the Nellore sheep (Ovis aries)

Ovary plays the dynamic role in the reproductive biology of female animals. With the aim to study the ovarian and follicular morphometry of Nellore sheep, both right and left ovaries were collected separately from the slaughter houses of Tirupati. For each of the specimens, gross parameters such as weight, length, width and thickness were recorded. Then they were processed and stained with H&E, Masson’s trichome, Verhoff’s and Gomori’s stains for histology and histomorphometry. The right ovary weighed (0.37±0.06g) more the left (0.30±0.03g). The length of the right ovary (1.020±0.12cm) was lower than the left (1.13±0.07cm) but the width of the right (0.93±0.10cm) was greater than the left (0.83±0.02cm). The diameter of ovarian follicles in the cortex was measured as primordial (29.74±1.30µm), primary (47.27±2.06µm), secondary or early antral (140.65±15.90µm), small vesicular or antral (584.43±23.9µm) and large vesicular/antral (1413.61±102.94µm) of ovary. In the large antral follicle, the thickness of granulosa cell layer was 80.08±1.43µm, theca interna 51.03±1.86µm, theca externa 41.02±0.92µm and the oocyte diameter was 118.9±3.64µm. These results will be helpful to manipulate ovarian functions in small ruminants.