Evaluation of the cytology of uterus, vagina, and clitoris as predictors of uterine condition in the mare

Detection of venereal disease and acute or chronic endometritis can be achieved by cytological examination. The presence of significant numbers of neutrophils in the uterine smear is the best indication for equine endometritis. Uterine function may be evaluated by examining clitoral or vaginal smears. In this study, 20 nonpregnant mares were selected and their reproductive functions were evaluated by rectal palpation. The levels of progesterone were measured by radioimmunoassay (RIA). Cytological smears were prepared from clitoris, vagina, and uterus. A wet swab was applied to the clitoral fossa and the collected material transferred to a microscope slide. Vaginal samples were collected using 30 cm wet swabs. Uterine samples were collected from uterine lavage fluid. There was no significant difference (P≥0.05) between cell densities in the estrus phase (p4<1 ng/ml) compared with the interval between estrus phases (p4>1 ng/ml). Significant differences (P<0.05) were noted in epithelial cell, lymphocyte, and neutrophil densities between diestrus phase (p4≥3.5 ng/ml) and other phases (p4<3.5 ng/ml). Epithelial, neutrophil, and lymphocyte densities were significantly different between clitoral, vaginal and uterine smears (P<0.05). There were significant differences in epithelial cells and neutrophils of vaginal and uterine smears in mares affected by metritis compared with repeat breeder and normal mares. We concluded that the clitoral cytology of mares could not predict uterine physiology but evaluation of vaginal cytology showed more appropriate potential. However, further study is needed to assess vaginal cytology in comparison with other methods for evaluating uterine reproductive physiology.