Diagnosis and treatment of equine ascending placentitis: compilation of 17 case reports

Elisabeth Hemberg¹Jane Morrell^2*

• ¹Haddebo Seminstation, Sweden, Hjortkvarn, Sweden
• ²Swedish University of Agricultural Sciences, Uppsala, Sweden

Placentitis (inflammation of the placenta) most commonly occurs during the last trimester of pregnancy, frequently due to bacterial entrance via the vulva. The outcome of the pregnancy, i.e. prevention of abortion or the birth of a compromised foal, depends on when treatment is initiated, appropriate medication, and surgical correction of the vulva to ensure an effective seal. In this study in the period 2012-2024, 17 mares were referred to the clinic, presenting with signs of placentitis, most commonly premature udder activity and/or discharge from the vulva. All mares maintained the pregnancy after treatment, ultimately producing a live foal that survived. The earliest cases were mares with the most pronounced clinical signs; these mares received treatment with a poor perfusion into the placenta and delivered septicaemic foals. The remaining foals born showed only minor clinical signs or appeared healthy. For later cases, treatment with drugs providing good uterine perfusion continued until foaling, included trimethoprim sulfate twice a day and acetyl salicylic acid, a COX 1 anti-inflammatory drug, twice a day, administered until parturition, if necessary. In addition, for 16 mares, a vulvoplasty (Caslick´s operation) was performed, or was extended if the mare had already been operated on.