A quantitative study of the histological morphology of the endometrium of normal and barren mares.

The density of uterine glands, height of surface epithelium, numbers of hemosiderin laden macrophages, inflammatory cells and layers of periglandular fibrosis were evaluated in uterine biopsies from 40 mares. These features were found to be highly variable in normal equine endometrium. Minor pathological changes appeared to be masked by this normal variability. Atrophy of uterine glands was recognized in mares which had been barren for more than three years. No significant differences were found between barren and normal mares in the height of epithelium, number of hemosiderin laden macrophages, inflammatory cells or layers of collagen surrounding glands in the superficial portion of endometrium. The number of layers of fibrosis surrounding glands in the deep part of lamina propria were found to be correlated with years of barrenness. This finding appears to have prognostic potential.