Changes in the Mare Oviduct Across Different Seasons Throughout the Year.

At present, oviductal pathologies and their influence on mare fertility have not been clearly determined. Checking changes throughout the year in the oviductal structure may be relevant to understand the influence on the appearance of problems in oviductal functionality and, thus, the impact on fertility, which is the objective of this work. The oviducts of 56 mares were examined. Their anatomy, permeability, oviductal cellularity and the presence of pathologies were assessed to establish the correlations between the time of the year and each of these parameters. We cannot conclude whether there is a correlation between oviductal permeability or the presence of pathologies and season. Also, we did not find a relationship between oviductal permeability and the presence of pathologies; in fact, most of the oviducts analysed were permeable throughout the year (88.13%), and only 5.93% showed partial permeability, while 5.93% were not permeable. Regarding pathologies, 7.62% of the oviducts presented adhesions, with an increased incidence during anoestrus and the spring transitional period, while 23.72% of the oviducts presented paraoviductal cysts and 41.52% presented paraovarian cysts. The incidence of oviductal thickening was observed only during the reproductive season (14.7%). Regarding oviductal cellularity, it´s correlated (0.236) with the ovarian activity observed throughout the year.