Exfoliative vaginal cytology during the oestrous cycle of the cow, after ovariectomy, and after exogenous progesterone and oestradiol-17 beta.

Vaginal exfoliative cytology was studied in five normal cyclical Friesian cows over 10 oestrous cycles each. Oestrus was assessed by the use of KaMaR heat mount detectors, whilst progesterone concentrations were measured in the peripheral blood using radioimmunoassay. Apart from oestrus, the exfoliative cytology was not consistent in appearance and did not appear to be influenced directly by the changes in endogenous ovarian steroid hormones. Four of the cows were subsequently ovariectomized and the vaginal exfoliative cytology monitored before and after the administration of 2 g of progesterone in a slow release vehicle and, following a rest period, after the administration of 12.5 mg oestradiol benzoate in oil. Peripheral progesterone and oestradiol-17 beta concentrations were measured in the peripheral plasma. Although the total number of epithelial cells increased after both hormone treatments no specific changes were observed.