Tips for Keeping Mares in Foal (AAEP 2012)

Proper and timely intervention can mean the difference between a live foal and a lost one. And while most equine pregnancies proceed without incident, an estimated 12.9% of mares lose their foals between 40 days of gestation and the estimated foaling date. These mares could potentially benefit from such intervention.

"In some cases, by the time a breeder or equine veterinarian recognizes the mare is showing signs of premature birth, any assistance is likely insufficient, resulting in a weak foal unlikely to survive," said Kristina Lu, VMD, Dipl. ACT, of Hagyard Equine Medical Institute, in Lexington, Ky. Timing and approach is critical, and she described approaches during her presentation at the 2012 American Associations of Equine Practitioners' Convention, held Dec 1-5 in Anaheim, Calif.

One-third of all stillbirths and deaths within 24 hours of birth are due to infections of the fetoplacental unit, she noted. Other causes of death include bacterial infections, complications during birth, congenital anomalies (e.g., contracted foals--those that are extremely upright or buckled forward at the pasterns, fetlocks, and/or knees), premature placental separation, and twins.

"What these data tell us is that if we can manage infection and inflammation in pregnant mares, we are targeting approximately one-third of the problem," Lu noted.

If Lu suspects or diagnoses an infection, she treats the mare with pentoxifylline to reduce inflammation, administers antibiotics to fight infection, and also administers the synthetic hormone altrenogest to help the mare maintain pregnancy.

Other options that veterinarians should consider on a case-by-case basis for maintaining pregnancy include using tocolytic drugs to suppress uterine contractility, nasal oxygen delivered to the mare to increase oxygen delivery to the foal, and a technique called cervical cerclage, which involves tying a suture around the cervix to prevent bacteria from reaching the uterus through the vagina and cervix. Veterinarians use the latter technique only sparingly at present, and they must remove the suture prior to foaling.

In broodmares that have aborted repeatedly for unknown reasons, Lu suggested giving acupuncture a try.

"There are actually numerous studies that support acupuncture (use) in pregnancy," Lu said. "In women, a small study showed that 11 of 12 women treated via acupuncture for preterm labor successfully delivered to term."

While veterinarians have come a long way in developing techniques to help mares stay in foal, "we as practitioners rarely fully understand the mechanisms of impending preterm birth of our equine patients," lamented Lu at the conclusion of her presentation.

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.