Eosinophils in equine uterine cytology and histology specimens

In a review of specimens from 80 mares with concurrently collected endometrial biopsy and cytology preparations, eosinophils were found in 33 specimens from 27 mares. In 22 of 27 mares, there were conditions predisposing to pneumovagina, which presumably led to pneumouterus. Thirty-two of the 80 mares also had conditions predisposing to pneumovagina but no eosinophils in the uterine specimens. Experimental introduction of air into the uterus of 3 mares resulted in eosinophils in their uterine specimens.