Foals have a better chance of surviving dystocia if the mare is taken to an equine hospital as soon as the prolonged delivery is recognized, said Katherine Cole MacGillivray, VMD, Dipl. ACVIM, of Haygard Equine Medical Institute in Lexington, Ky., at the ACVIM Forum 2010 veterinary meeting held in Anaheim, Calif.

Dystocia is usually defined as stage-2 labor (delivery of the foal) that lasts more than 30 minutes. "It is considered an equine emergency. The outcome will have a profound effect on the foal's and mare's survival and the mare's reproductive and overall general health," said MacGillivray.

The causes of dystocia include angular limb deformities of the fetus, fetal size, malpositioning, inadequate uterine contractions, congenital deformities or anomalies, and placental abnormalities.

Veterinarians will employ several methods to resolve dystocia:

  • Assisted vaginal delivery (AVD)--the mare is conscious and the veterinarian provides manual assistance in the vaginal delivery of the foal;
  • Controlled vaginal delivery (CVD)--the mare is under general anesthesia and the veterinarian is in control of the delivery;
  • Caesarean section--the foal is surgically removed from the uterus; and
  • Fetotomy--removal of a dead fetus

In the past only 10-29% of foals survived a dystocia. "The bottom line is that there were not a lot of foals born alive from a dystocia," she said.

"But it seemed to us that our foal survival was a little higher (now) than what had been reported (in the past)," MacGillivray said, so she set out to determine whether that was true and why.

She found that over the course of two years, Haygard has handled 172 dystocia cases; 121 live foals were born and of those 88 were discharged from the hospital. "Our overall survival rate is about 50%," MacGillivray said.

Many of the foals were sick with problems such as neonatal encephalopathy (dummy foals), sepsis and rib fractures, and about 50% of the foals required resuscitation after delivery and received assisted ventilation and/or injectable medications.

But because veterinary staff and equipment were readily available, half the foals survived. According to MacGillivray, foals born alive now have a 70% chance of survival.

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About the Author

Marie Rosenthal, MS

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