Comparison of three methods of sampling for endometrial cytology in the mare

Objective: This prospective study aims to compare three different sampling techniques for the collection of endometrial cytological specimens in the mare: the guarded culture swab, the uterine cytobrush and the low volume uterine flush. Material and methods: The study po pulation consisted of six healthy Standardbred mares in dioestrus. In each mare an acute endometritis was induced by performing a lowvolume uterine flush 6 days after ovulation using a sterile isotonic solution (lactated Ringer’s solution or ViGroTM Complete Flush Solution). Two days after initiating inflammation, samples were collected from each mare using the three compared techniques: the double guarded cotton swab, the uterine cytobrush and the low volume uterine flush. The cytological evaluation of the samples was based on following criteria: the quality and cellularity of the samples and the number of neu trophils recovered. Results: The uterine cytobrush yielded slides of significantly (p = 0.02) better quality than the low volume uterine flush. There was no significant difference between the cytobrush and the double guarded swab technique for the quality. There was no difference between techniques in the number of endometrial cells (p = 0.55) and neutrophils recovered (p = 0.28). Conclusion and clinical relevance: Endometrial cytology is a practical method for the diagnosis of acute endometrial inflammation in the mare. Since no difference in the number of neutrophils was found between the three techniques, the choice of the sampling method should be based on other factors such as practicability, costs and disadvantages of each technique.