A major cause of infertility in mares is acute bacterial and fungal infections of the lining of the uterus called the endometrium, the disease is called endometritis. Common sense and several research papers show the problem has been over diagnosed in the past using culture as the only tool. The reason is it is near impossible to get into the uterus without contamination by normal bacterial flora in the vagina, cervix, and even the uterus normally may have some bacteria, particularly when in heat. This results in unnecessary treatments and lost breeding time in many cases. When faced with an infertile mare, a review of the mares history, a general exam, and then more specific diagnostic procedures like cytology and culture should be performed...more. This article is about proper diagnosis of endometritis through interpretation of cytology and culture results. Once diagnosed links to articles on treatment are provided.

Should we routinely monitor mares for infection that have no clinical signs of problems and no history suggestive of trouble? Some may be surprised by the question. There is no proof that when weighing the benefit vs costs that this is a cost-effective procedure and the answer rides principly on the cost of the breeding though your goals and resources also figure in. There is no doubt that occasionally you will uncover an occult problem that if diagnosed early will save you time and money. But what about the other 90% of the time where the cytology and culture are normal. And then there are the times that a inappropriate diagnosis is made leading you to unnecessary expense?

Routine cytology becomes more justified when the "cost per cover" is expensive in either time or money and/or the timing of the birth needs to be as early as possible. Culture and cytology is strongly indicated whenever a mare has not settled after two or three cycles and after an initial exam no other cause can be found...more.