Introduction:

Its been almost 11 months and the big day is almost here.  Planning for success is the focus.  Problems with the birthing process are termed dystocia. It is relatively rare.  Dystocia can be catastrophic and costly through loss of the mare or her future fertility and/ or loss of the foal. The incidence of birthing problems varies between species and between maiden animals and those that are multiparous.  Parturition occurs more rapidly in mares than in other domestic species (minutes vs hours). In any species, but especially the mare, the sooner dystocia is detected and corrected, the less chance of catastrophic results.  Will discuss mares here with some relevant comments for cattle and small ruminants in the coming weeks as calving and kidding season generaly waits in the roaring fork valley until after March 1st..

The incidence of dystocias varies with different breeds. It ranges from 4-10% with a slightly higher incidence in maiden mares of all breeds. Because the foal is repositioning for delivery during stage one, most abnormal deliveries can not be detected prior to foaling. The exception to this is a breech or posterior presentation. Up until 5 months of gestation the foal can rotate from an anterior (head first) to a posterior position. After 5 months the position is fixed. Most dystocias are caused by abnormal fetal posture (right side up, upside down or sideways) or position (abnormal leg or head position). However, the first abnormality that could be seen is a premature placental separation or “red bag”. Instead of seeing the white colored amnion first, you see the red or reddish-brown velvety looking chorionic membrane. This requires immediate action by an attendant. You need to carefully cut a small hole in the membranes with scissors and then tear it open further to deliver the foal. Call the vet after cutting the sac, as there is a good chance the foal may still need treatment. If the entire membrane separates, the foal will be without oxygen until delivered. With any type of dystocia, the risk to the foal is lack of oxygen from a prolonged delivery.

Signs of Dystocia

In a normal foaling, the mare's uterine contractions cause the fluid-filled chorioallantoic sac to rupture ("breaking water"), after which the foal's front feet appear in the birth canal. Mares usually then lie down and begin contractions that expel the foal within about 15 minutes. Most mares pass the placenta within an hour after foaling; the placenta is considered retained if it has not passed within 3 hours. Save the placenta in a cool place for examination; do not allow access by dogs or other animals.

There are 3 important signs that foaling is not proceeding normally after breaking water. If you observe any of the following signs, call our office immediately, as veterinary assistance is required. Then get the mare up and walking, as this will slow the uterine contractions. If the mare is to be transported to an equine hospital, get your truck and trailer ready to go.

     1. More than 15 minutes have elapsed since the mare has broken water, but the foal has not yet been delivered.

     2. Only one leg is protruding from the vulva, and no more of the foal has appeared over the past

10- 15 minutes.

3. The mare has not broken water, but a crimson mass appears at the vulva. This is the entire placenta being passed with the foal. The placenta must be quickly cut open so foaling can proceed and the foal can breathe oxygen.

Common specific problems:

A common type of dystocia occurs when a front foot or the head is turned aside before the foal enters the birth canal, blocking the foal's passage. Signs of this may be obvious, subtle or sometimes impossible to detect. In this situation, an experienced "equine midwife" (a person who has assisted at many mare foalings or your vet) can be invaluable. If the dystocia is quickly detected and the diverted foot or head is redirected into the birth canal, the foaling proceeds normally. However, if the problem is not detected or corrected and the mare continues in her attempts to expel the foal, the dystocia becomes more dangerous for both mare and foal.

The second type of dystocia involves some abnormality, such as abnormal presentation of the foal (such as the back appearing at the birth canal), an abnormally large foal, a deformed foal, an abnormal birth canal (such as scarring or a bony abnormality), or some other abnormality in the mare (such as ventral hernia or uterine torsion).

Considerations in Correcting Dystocia

While a foal can remain alive for up to 60 minutes after the water breaks, the risk of cardiovascular compromise and death increases after 30 minutes. That said a significant number of dystocias are caused by an abnormal orcompromised foals.

We usually attempt to manually correct a dystocia for several minutes before considering another approach. These subsequent approaches depend on how long the dystocia has been present, whether or not the fetus is alive, the prognosis for the mare's survival, the prognosis for the mare's fertility, and the time it takes to accomplish the procedure.

We sometimes need to resort to short term general anesthia to facilitate delivery.  After rapid intravenous infusion of an anesthetic, the mare's hind legs are lifted using hobbles, rope and a traction devices. The foal can then be more easily repelled back into the uterus, repositioned and possibly delivered. If delivery is not possible additional measures will need to be underttaken.

If the fetus is already deceased, it may be necessary to surgically remove part of the dead fetus via (fetotomy) to allow passage through the birth canal.

If the fetus is alive Cesarean section involves removal of the foal through a surgical incision in the mare's abdomen. This is a major surgical procedure.

Important Points in Treatment After foaling and Dystocia;

Uterine care: It is extremely improtant that the placental membranes are passed completely within 4 hrs of foaling  Oxytocin may be given to help the uterus expel excess fluid and tissue debris. Some mares show mild colic after oxytocin injection. Intrauterine boluses or infusions may be used to remove inflammatory products and fight local infection.  Its a good idea to save the fetal membranes and placenta in a clean plastic bag in a cool place so that they can be examined by your veterinarian at a foal/mare check exam within the first 12-24 hrs.

Got a question or a topic on horse health for next week-Give us a call.  next week we'll discuss what to expect from the mare and foal in the first 24 hrs of life.

"Prior proper planning provides proper pony care"  :)

Chuck Maker DVM

Justine Stalnaker DVM

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Alpine Equine Hospital

970-379-7100 office

970-366-1320 emergency