An umbilical hernia occurs when there is a defect in the body wall surrounding the umbilicus (belly button or navel). This defect is a consequence of failure of the body wall to fuse in that region during development in the uterus. In many foals, the umbilical hernia is quite small (1 “finger” or less in diameter) and will often close or become negligible as the foal grows. Other times, the umbilical hernia is simply too large for the foal to outgrow. If the defect is large enough, intestines can slide through the defect and into the hernia sac.
When this occurs, the intestine is at risk of becoming entrapped and causing the foal to colic significantly. For this reason, these larger or persistent umbilical hernias are surgically repaired. The body wall is reconstructed with sutures and the excessive skin (hernia sac) removed. In colts this can be done at the same time of gelding, if desired to save the horse from additional anesthesia.