Neonatal foal death due to a congenital defect

Amanda Mansz

Animal Health Laboratory, University of Guelph, Guelph, ON.

AHL Newsletter 2022;26(3):23.

A full-term foal who survived only minutes after a difficult foaling was submitted to AHL for postmortem evaluation.  Opening the abdominal and thoracic cavity revealed the entire liver, large colon, cecum, and ileum/distal jejunum were displaced into the thoracic cavity.  The pelvic flexure of the large colon was located in the thoracic inlet (Fig. 1).  The lungs were displaced and compressed into the cranial dorsal thoracic cavity.  The heart was also displaced slightly cranially, but the pericardium remained intact.  It was determined that the abdominal organs shifted into the thoracic cavity through a 20 cm x 15 cm oval-shaped opening in the diaphragm, which extended from the sternal body wall to the ventral aspect of the esophageal/caval hiatus.  The opening was rimmed by a smooth fibrous surface (Fig. 1).

In horses, congenital diaphragmatic hernias are a rare developmental lesion associated with stillbirth, intermittent bowel obstruction, or occasionally, newborn colic.  In this case, the cause of the acute death shortly after birth can be attributed to the inability to inflate lungs due to massive compression by relocated abdominal organs and associated circulatory disturbances.  The diaphragmatic rent was considered congenital due the smooth fibrous contour of the edge of the opening (no tearing or hemorrhage), and not a result of trauma from the dystocia described in the history.   AHL

Figure 1. Diaphragmatic defect with abdominal organ herniation in a neonatal foal.  Edge of diaphragmatic defect (arrow).  Lungs and heart are not visible.