Comparative analysis between the cytobrush and low-volume uterine flush techniques for endometrial cytology in clinically normal postpartum crossbred dairy cows

This study compared two frequently employed techniques for the collection of endometrial and inflammatory cells and characterized postpartum endometrial cytology (EC) of clinically normal postpartum crossbred dairy cows in dairy farming system in Southwestern Brazil. Thirty-four crossbred, clinically healthy dairy cows with normal delivery and puerperium, complete uterine involution and without any treatment were monitored until 42 days in milk (DIM). All cows were evaluated by complete clinical and gynecological examinations at days 0, 7, 14, 21, 28, and 42 DIM. The gynecological examinations were done by transrectal palpation, ultrasonography, vaginoscopy, evaluation of the vaginal mucus and EC by using the cytobrush (CB) and low-volume uterine flush (LVF) techniques. The agreement (Kappa statistic) between the two technicians was good for CB (86%) and LVF (80.3%) for the counting of the percentage of neutrophils. The average number of neutrophils was significantly higher throughout the experiment for LVF, but a reduced percentage of neutrophils were observed during the postpartum period for both techniques. The amount of macrophages, lymphocytes, and eosinophils were not affected during postpartum and there was no significant difference relative to these cells when the two techniques were compared. There were significant differences in the percentage of cows with subclinical endometritis only at d28 by CB (22.2%) and LVF (59.3%).