Thirty-five of the 49 mares that underwent hysteroscopic hydrotubation became pregnant after treatment. | Photo: Courtesy Dr. Stephanie Walbornn

Uterine tube, or oviduct, obstruction in mares, though rare, can cause subfertility. Diagnosing the condition is difficult; therefore, veterinarians typically do so by exclusion, said Stephanie Walbornn, DVM, Dipl. ACT. In other words, they suspect uterine tube obstruction after ruling out other causes for a mare’s subfertility using conventional diagnostic techniques.

While veterinarians have several methods for treating presumed uterine tube obstruction in mares, it’s been unclear how they affect future fertility. So Walbornn, of Rood & Riddle Equine Hospital in Wellington, Florida, compared pregnancy rates after practitioners performed two treatment methods for suspected uterine tube obstruction. She presented her findings at the 2018 American Association of Equine Practitioners Convention, held Dec. 1-5 in San Francisco, California.

The uterine tubes serve as reservoirs for deposited sperm, are the site of fertilization, and nourish the oocyte (egg) and embryo. If a mare is subfertile in the absence of ovarian and uterine abnormalities, and despite good reproductive management and stallion sperm quality, said Walbornn, veterinarians might suspect uterine tube pathology (disease or damage). Based on previous studies, mares become increasingly susceptible to this condition as they age, she added