Page 29 - NM Spring 2019

“8-12% of foaling’s will have some sort of difficulty.”
When Things Don’t Go As Expected
As mentioned, dystocias occur in approximately 8-12% of all foalings. Most commonly, they occur with a maiden mare delivering her first foal, but can occur with any mare, any time. The most common cause of dystocia is an abnormal alignment of the foal in the birth canal. Either a malposition
or malalignment will prevent normal passage of the foal, thus requiring intervention. There are three primary goals with ANY dystocia: save the life of the mare, save the life of the foal, and preserve the fertility of the mare for future use. Time is of the essence to achieve these three goals as statistics show that each 10-minute interval increase in labor time (stage 2) beyond 30 minutes, results in a 10% increase in the risk of failure of survival of
the foal. Have an emergency plan in place for foaling season, that includes a conversation before your mare is in labor between the mare owner, foaling staff, and the veterinarian.
Dystocias are often classified into groupings of mild, moderate, and severe based on the threat to both the fetus and mare and difficulty in correcting. Mild dystocias can often be corrected by the foaling attendant, if properly trained, while moderate to severe dystocias often require more skilled intervention, and more hands to
get the job done. Mild causes of dystocia include elbow lock, upside-down foal, backwards foal, uterine inertia, and redbag (premature placental separation) delivery. Moderate dystocias are
often flexural in nature such as front legs flexed at knee and neck flexed ventrally. Presentation
of the muzzle below the brim of the pelvis and “hip lock” are considered moderate as well. The more severe causes, such as front legs flexed
at shoulder, neck flexed to side, muzzle not reachable, “breech” position, transverse position, and twins entering birth canal simultaneously, can become disastrous for both the mare and foal quickly and are often extremely difficult to correct.
So, when should we be suspicious of a problem? Since delivery of the foal should be completed within about 20 minutes, any lack
of progress toward delivery in that time frame should raise a red flag. Occasionally, delivery will be unfolding quite normally and all at once progress will stop, or the mare can become painful acutely which is abnormal and should also be a cause for concern. The most evident indicator of a dystocia is if something besides the front feet and nose are presenting. In reality, even if you have no idea what the problem is, but know things aren’t going as planned, a call to your veterinarian is warranted.
Veterinary intervention is almost always required for severe dystocias and, depending
on the skill level of the foaling team, even for some mild and moderate causes. Veterinary intervention typically becomes necessary when more manipulation of the fetus is required. Your veterinarian likely will sedate the mare and give an epidural injection to help prevent the mare from straining. This allows for a longer window of time to manipulate the fetus without the mare pushing against you. Occasionally, the dystocia is so complicated that surgical intervention is required to achieve the goals of a live mare, live foal, and future breeding soundness.
Most dystocias occur despite our best efforts and are not preventable. Redbag deliveries, however, are one of the causes that we may
be able to prevent, or at least be prepared for ahead of time. Premature placental separation occurs secondary to placental infections, fescue toxicity, or stress. Only 1-2% of all births result in a “redbag” however this placental separation accounts for 5-10% of all causes of abortion, stillbirth, and perinatal death. Chronic placental separation can be present during gestation and
is able to be identified ultrasonographically, however it can also be an acute situation culminating during labor. Instead of the placental membranes rupturing in order as listed above
and essentially coming out inside-out, the entire placenta breaks loose from its uterine attachments and comes out right side out and intact with
the cervical star visible rather than ruptured. If a “redbag”, so called for its brick red and velvety appearance, is encountered during foaling, the placenta should be opened with a sharp knife or scissors immediately. This premature detachment rapidly decreases the oxygen supply to the fetus and can result in a dead foal if not corrected. Having an ultrasound exam at the 5th month of gestation is a good screening test to look for the indicators of impending placentitis and regular ultrasound examinations may be required for
at risk mares. Additionally, moving pregnant mares off of fescue pasture 60-90 days before the expected foaling date helps prevent fescue induced premature placental separation.
Foaling season is certainly “the most wonderful (and sleep deprived) time of the year”, yet it can have its problems too. Being prepared for the worst, and knowing what is normal versus abnormal, can save not only your mare and her arriving foal, but future foals as well. While we cannot prevent most causes of dystocia, early intervention is paramount to increase the chances of a successful outcome in the midst of disaster. Remember, it is always the right decision to call your veterinarian for foaling complications, even if you are not sure if what you have encountered is normal or not. Your veterinarian should be an integral part of your foaling season plan and is there to be a source of information and support during this exciting time.
Megan Petty, DVM is an associate equine veterinarian at Tularosa Equine Clinic
in Tularosa, NM. Dr. Petty is a general
equine practitioner with a special interest in reproduction, internal medicine, and race horses. She is passionate about educating horse owners and spending time with her husband Bryan, and their dogs Maverick and Ray, on their breeding farm Creekside Farm near Bent, NM.
During stage 1 of labor, the foal is doing some serious rearranging in utero and the mare may appear uncomfortable or colicky.
Stage 2 of labor consists of the actual birthing of the foal.
Stage 3 labor involves the passage of the placenta after the foal is born.