PrintThere are many reasons why a mare may need surgical help delivering her foal.
In situations where a mare can’t deliver her foal, the only way to save the mare—and possibly the foal—may be to take the foal out surgically.
Margaret Mudge, VMD, assistant professor of equine emergency and critical care at Ohio State University, said that mares have a very short labor.
“This is quite different from most other species. Labor in the mare is very brief and explosive,” she said.
If the mare has a dystocia, there’s only a short window of time in which this can be safely corrected and still result in a live foal. After that, it becomes a matter of just trying to save the mare.
Cesarean sections fall into two categories: elective surgery and emergency surgery. Most are emergencies in which the mare has a dystocia, and the foal cannot be delivered vaginally. The only options left are a fetotomy (removing a dead foal through the birth canal in pieces) or a C-section.
Choosing A C-Section
If the mare has a known pre-existing condition, an elective C-section might be scheduled. Mare owners should be aware of any abnormalities, which are usually discovered during a breeding soundness exam.
Pelvic abnormalities are one example—such as a previous fracture that healed but left the pelvic area altered—or a tumor mass like melanoma growths in the pelvic area, or excessive scarring.
A mare might have a recto-vaginal tear from a previous foaling that was repaired but left the birth canal very narrow, or she might have a cervical injury. The owner might be lucky enough to get her in foal again but not want the risk of re-tearing a cervical laceration during another foaling. A cervical injury would reduce the mare’s chances of getting in foal again.
If there is any marked limitation in the size of the pelvic canal, this might require a C-section delivery of the foal. In these instances the mare owner needs to be working closely with a veterinarian to monitor the readiness of the mare for foaling. The foal has a much better chance of survival if the mare is actually in labor at the time of the surgery.
“The mare will have a good prognosis, no matter what, with an elective C-section. The foal, however, will have a much better prognosis if she has either started early labor—which would be ideal—or is at least very ready, and labor can then be induced,” said Mudge.
A mare’s readiness can be tracked by checking the milk electrolytes and watching the changes.
“Several reports indicate that if done properly, we can get up to 90 percent foal survival with elective C-sections, in the right circumstances. This does not include surgeries in mares that are acutely colicky and the owner feels we should take the foal out because she’s near term. Success rates are not as high when the foal is taken too early,” said Mudge.
“This is very frustrating for us and difficult for owners to understand,” she added. “Just because the mare, in number of days of gestation, is near term, the foal may not be ready.”
Fetal maturation and readiness increases considerably when the mare is ready to start labor, during the last days or hours of gestation. To take the foal out even a few days ahead of this time period threatens his ability to survive outside the uterus. Foals are not as likely to survive as are premature human babies or calves taken out of the uterus prematurely.
