Histo-morphology of genitalia in crossbred dairy cows with kinked cervix

Abstract

The study was conducted on genitalia collected from 100 dairy cows/heifers from the Meat Technology Unit, Mannuthy. The animals brought for slaughter at Meat Technology Unit, Mannuthy were from herds of five different farms (University and Government Undertaking farms) in Kerala state. This included six animals culled on account of factors other than infertility with normal reproductive system (control group) and the remaining animals with a known history of infertility. In total, seven animals showed kinked cervix condition. Cervix was evaluated morphometrically and histologically. Grossly, the cervix was hard, kinked and S-shaped, with a mean length of 9.64 ± 1.19 cm. Average number of annular rings in the cervical canal was 4.14 ± 0.26 with an average diameter of 1.74 ± 0.18 cm. At the external os, diameter of the cervix was less, while at the uterine end, diameter was more. The opening of each cervical ring showed a misalignment instead of a straight line. Histologically, the cervix was lined by simple columnar epithelium with signs of degeneration and desquamation. However, the submucosal layer was extensively infiltrated by collagen fibres. In uterus, there was a significant difference in the number of endometrial glands and height of the glandular epithelial cells which was less when compared to the control group. Muscular layer outer to connective tissue layer was thin and uneven. Alterations of the glandular structures negatively influence the viability of spermatozoa due to the lack of secretory products. This fibrous, collagen rich kinked cervix limits the smooth deposition of the semen into the uterus during artificial insemination and the insufficiently dilated cervix affects its contractibility leading to dystocia and subfertility.