Inguinal hernia is the most common cause of groin swelling in the young foal.

The inguinal canal is the connection between the abdominal cavity (the space surrounding the abdominal organs) and the inside of the pouch of the scrotum. This canal is defined and bounded by heavy ligaments within the groin, which make up the inguinal ring. The inguinal ring is a conduit for the vessels, nerves and spermatic cord that run to the testicles. Testicular descent from the abdomen into the scrotum (which normally happens before birth) requires passage through the inguinal ring. In normal male foals, the testicles have already descended into the scrotum by birth.

In some cases though, the inguinal ring is larger than normal. This is more common in some breeds (gaited breeds and Warmbloods). In that case, an inguinal hernia could develop, meaning that the intestine or other abdominal contents migrates through the inguinal ring into the scrotum, causing abnormal swelling.

Although rare, there is a risk that bowel could become entrapped in the inguinal ring, causing a life-threatening emergency. This is why it is important to have your vet diagnose and treat swelling in this area and determine the best treatment plan.

In some cases, inguinal hernia in the foal can be treated conservatively, by pushing the herniated intestine back through the ring until the rings close down. In other cases, surgery to close the inguinal rings is the best choice.