Vaginal cytology studies in the horse
Bader, H.; Genn, H.J.; Klug, E.; Martin, J.C.; Himmler, V.
Deutsche Tierärztliche Wochenschrift 85(6): 226-231
1978
ISSN/ISBN: 0341-6593 PMID: 350544 Document Number: 130803
Vaginal smears examinations were made from 26 pregnant mares at the end of pregnancy to estimate the time of parturition. Beginning one week before the calculated end of gestation smears from the vaginal wall were taken daily until onset of foaling. The relation of eosinophilic to cyanophilic cells was used as parameter. The percentage of cyanophilic cells increased within the last week of gestation, but one or two days before parturition decreased drastically, in 19 mares to or near zero, in two mares to 30%. These mares foaled within 12 hours after the cyanophilic drop. In the remaining 5 mares percentage of cyanophilic cells also dropped to zero but increased again. In these cases parturition occurred 36 to 52 hours after the minimum cyanophilic reaction. In a second phase of these studies smears were taken in 26 cycling mares with spontaneous or induced oestrus. In dioestrus the relation of eosinophilic to cyanophilic cells varied widely and it was not possible to evaluate a clear tendency. But in oestrus there was an evident and rapid rise of percentage of cyanophilic reaction, a maximum of 90 - 100% occurring close to clinically palpated ovulation.