Histological changes in the vaginal mucosa of the cow during the oestrous cycle, after ovariectomy and following exogenous oestradiol benzoate and progesterone treatment.

The histological structure of the anterior vaginal mucosa was studied using sequential biopsies in five normal cyclical Friesian cows and in four of the same cows after ovariectomy and exogenous progesterone and oestradiol benzoate. During oestrus the epithelium comprised a single layer of tall columnar, highly active, mucus-secreting cells, whereas during the luteal phase of the cycle it comprised several layers of low columnar, cuboidal or flattened epithelial cells. Exogenous oestradiol benzoate and progesterone administered separately produced little change in the low columnar and cuboidal epithelium observed after ovariectomy.