Inflammatory Lesions in the Oviducts and Its Relationship With Endometrial Inflammation and Ovarian Activity in Criollo Mares

The equine oviduct is considered as a reproductive organ with essential functions for early reproductive events. There is extensive literature on the pathology of the equine endometrium relating to reduced fertility, but in only few studies, the influence of alterations of the equine oviduct has been examined. The aim of this study was to investigate the incidence of inflammatory lesions in the oviduct and its association with endometrial inflammation and ovarian activity in mares. One hundred fifty Criollo mares were selected from a population of horses sent to slaughter at an abattoir. Internal reproductive tracts were recovered within 10 minutes after slaughter, and uterine and oviducts samples were collected, processed, stained with hematoxylin-eosin, and analyzed. From the total mares examined, 69.3% were considered cyclic, 18.7% in anestrus, and 12% in the transitional phase. No significant (P > .05) correlations coefficients were observed among the degree of inflammatory cells in oviduct and in endometrium from cyclic and noncyclic mares. Most studied mares had some degree of lymphocytic infiltration in the oviduct mucosa (64%). The incidence of neutrophilic and eosinophilic infiltration in oviducts occurred in 8% and 4% of the mares studied, respectively. Cyclicity did not influence the neutrophilic and eosinophilic infiltration (P > .05). The incidence of oviduct inflammation in Criollo mares is more frequent than previously reported in other breeds; however, the neutrophilic and eosinophilic infiltration is rare. Endometrial infiltration is not an oviduct infiltration cause and is possible to observe oviduct inflammation without endometrial inflammation.