Ascending placentitis in the mare

Ascending placentitis in the mare, which affects 3 to 7% of pregnancies, is a common cause of abortion, premature birth and delivery of compromised foals (Troedsson, 2003; LeBlanc, 2010). Since the infection ascends from the caudal genital tract, the first and most distinct lesions are seen near the caudal pole area of the allantochorion adjacent to the cervix. The symptoms are not always obvious or will be exhibited only at a later stage of the disease process, which renders timely adequate treatment difficult. Moreover, experimental models of placentitis in the mare are difficult to maintain and double-blind, controlled studies are scarce, making it hard to formulate clear science-based advice. In this paper, the diagnosis is discussed on the basis of the symptoms, the ultrasound examinations and the endocrinological parameters, and the therapeutic and prognostic considerations are evaluated.