This is a unique form of bacterial placentitis affecting late gestation mares that causes abortion, stillbirth, or foals born alive but compromised. This form of placentitis was first diagnosed in central Kentucky in the 1980s and has also been reported in other areas of the United States and abroad.

The number of nocardioform placentitis cases fluctuates from year to year. How mares become affected has still not been determined. Nocardioform placentitis is typically a sporadic occurrence on the farm, however, and there is no evidence affected mares pose a risk to other mares in their herd.

Mares experiencing nocardioform placentitis breed back normally and are not at an increased risk for reoccurrence in subsequent pregnancies. While the number of cases has increased this year, incidence within the overall population of mares is very low (less than 1% of abortions reported)