Fetal mummification in a mare

A single mummified fetus was removed from the uterus of a 23-year-old mare that had been bred approximately 30 months previously. The mare had received supplemental progestin therapy for approximately 150 days after ovulation. This case represents the longest recorded occurrence of fetal mummification in the mare. Progestion administration may have contributed to the initial retention of the fetus in the uterus.