Scanning electron microscopic study of ovary and oviduct of crossbred dairy cows with ovarian hypoplasia

Abstract

Hypoplasia of ovary is one of the major causes of infertility in dairy cattle, which is characterized by absence of oestrus cycle, affecting livestock productivity and economics to a great extent. This study was conducted on the female genitalia collected from 100 dairy cows/heifers from the Meat Technology Unit, Mannuthy which included six animals culled on account of factors other than infertility with normal genitalia (control group) and remaining animals with a known history of infertility. Two animals of 22 months and 24 months of age showed bilateral ovarian hypoplasia. The history revealed that the animals were healthy, but had not shown oestrus. Grossly ovaries of the first animal appeared as pink-coloured, small, wrinkled, flattened, elongated structures without any follicles or CL. Second animal showed inactive, small, flat, streak-like left ovary without any cyclical structures. But the right ovary showed a single large corpus haemorrhagicum on the caudal end. Then ovarian tissue was fixed in 2 percent gluteraldehyde in 0.1 M phosphate buffer at pH 7.3. Under scanning electron microscopy, the ovary exhibited an uneven surface with clefts and grooves. The surface cells lost their normal appearance without any microvilli. Large round smooth germ cells were also observed on the ovarian surface. In the oviduct, the mucosa was lined by nonciliated cells having rounded surface interspersed among shrunken cells. The epithelial cell surface was covered with bulbous processes. Ciliated cells were not observed in the present study. Ovarian abnormality is reported to be the main cause of altered morphology of the surface epithelial cells and change in the ultrastructure of oviductal mucosa.

Keywords

• ovarian hypoplasia
• scanning electron microscopy
• dairy cows