You are called to see a mare who aborted a single foal that…
You are called to see a mare who aborted a single foal that appears to be 7 months gestation. Upon examination of the placenta the only abnormality you observe on the placenta is a large (10x15cm) focal area of thick tan mucoid exuduate at the base of the pregnant horn. There are no gross lesions seen on the fetus. Which of the following is the most likely cause of the abortion?