“…Changes of the type described in the vagina of calves have been reported extensively for several other animal species, such as rodents (LONG and EVANS, 1922;BIGGERS, 1953;BERN, ALFERT and BLAIR, 1957;DEANESLY, 1966;KIMURA, BASU and NANDI, 1967; LADINSKY, GRUCHOW and PECKHAM, 1968), pigs (DONE and HEARD, 1968;KURZ, NAIRN, NELSON, CHRISTENSEN and MIROCHA, 1969) and the cow (COLE, 1930). The changes reported after the administration of estrogens appear to be similar to those found in estrus (ALLEN, 1922;ALLEN and DOISY, 1923;ZUCKERMAN, 1940;TRIBBY, 1943;HUGGINS, JENSEN and STOCK CLEVE-LAND, 1954;BARKER and WALKER, 1966;THRASHER, CLARK and CLARKE, 1967). The estrogenic effect reported in the literature consists of a proliferation to squamous epithelium with or without keratinization, whereas the layer of mucous cells partly disappears, and partly changes into tall secretory cells.…”