About 85% of anovulatory follicles luteinize and 15% remain as persistent anovulatory follicles. | Photo: Courtesy Dr. Patrick McCue

Veterinarians see a wide variety of ovarian abnormalities when evaluating broodmare reproductive tracts. Knowing what’s benign and what’s pathogenic–causing disease or damage–can help them best manage these mares.

At the 2017 American Association of Equine Practitioners convention, held Nov. 17-21 in San Antonio, Texas, Patrick McCue, DVM, PhD, Dipl. ACT, reviewed common and uncommon ovarian issues that veterinarians might encounter when performing transrectal ultrasound exams. McCue is the Iron Rose Ranch Chair in Equine Reproduction at Colorado State University’s Equine Reproduction Laboratory.

Common Ovarian Problems

Anovulatory follicles “Approximately 4% to 8% of large dominant follicles (those faster-growing that are next-up for ovulating) in a mare in estrus fail to ovulate,” said McCue. Of these anovulatory follicles, about 85% luteinize (transform into a structure that produces progesterone–the pregnancy-maintaining hormone) and 15% remain as persistent anovulatory follicles