Severe iatrogenic trauma during foaling.
Keywords: iatrogenic, foaling, trauma, equineA nine year old Standardbred mare had an assisted foaling because of an apparent "hip lock". This was regarded by the author with circumspect because hip lock is rare in mares due to their large pelvic sizes compared to cattle*. It is perhaps more likely that the foal had unilateral or bilateral hock flexion i.e. "dog sitting" posture:
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Either of these postural abnormalities may have been resolved partially or completely during traction. The nature of assistance was unclear but non-human mechanical forces may have been involved.
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A live foal was extracted. However, the mare appeared to be partially paralyzed in her hind quarters and was unable to rise. Her heart rate was elevated at 80 beats per minute and later rose to 130 beats per minute despite treatment with an NSAID and fluids. The mares packed cell volume was 37% but may have remained high because of splenic contraction. Hemorrhage from the vulva lips was obvious, soaking the adjacent pasture (see inset). The owner elected to euthanize the mare.
The lower image shows some of the postmortem findings; extensive muscular and fibrous tissue necrosis within the vaginal wall. There was also subluxation of the mare's right sacroiliac joint. Severe coalescing vaginal and vulvar hematomas were also present.
Note: It is essential to determine the presentation, posture and position of a foal before traction is attempted. The foal should be repelled and posture should be corrected, preferably with copious lubrication. In most cases (unlike calves) the foal will be dead in prolonged cases of dystocia. It is difficult to repel a foal to correct malposture because epidural anesthesia is either unavailable or slow to take effect. In such cases, pulling out the mare's tongue will prevent closure of her epiglottis. Perhaps obviously, this will have no effect on myometrial contraction but will prevent the mare from straining voluntarily. This information is valuable to clients with pregnant mares because they will often provide assistance in foaling before the veterinarian arrives at the farm.
*The birth canal in a mature mare has a cross-sectional area of about 400 square cm; a cow about 280 square cm.
