Vaginal lumen cytology and peripheral sex hormone concentrations at different vaginal orifice statuses in the female greater Grasscutter

Abstract

This study aimed to characterise the oestrous cycle of the female greater grasscutter (Thryonomys swinderianus) through investigating the pattern of exfoliated vaginal epithelia cells and peripheral sex hormone profiles in two different vaginal orifice status (open and close) displayed by the animal. Vaginal smears and blood samples were collected every other day from 12 non pregnantgrasscutterdoes for 7 days regardless of the vaginal orifice status. The cells in the smear were classified into parabasal, intermediate, superficial and metoestrus epithelial cell. Blood plasmawas assayed for estradiol (E₂) and progesterone (P₄) hormones. Irrespective of the vaginal status, intermediate cells were predominant with 54% and 56.7% for open and close vagina orifice, respectively. Superficial cells were15 % in open vagina status as against 9 % in the close vagina status. E₂ concentration was significantly higher (P ˂ 0.05) in the open vagina status (6.75 vs 3.91 ng/ml) whereas P4 concentration was similar in both statuses. In conclusion, the similarity in the occurrence of vaginal lumen cells at open and close status indicated that the grasscutter could be an induced ovulator while the higher E₂ concentration in the open vagina status could mean higher sexual receptivity at this stage.

Keywords: Greater grasscutter; induced ovulator; sex hormones; vaginal cytology