Large animal masses
Hernias
The most common hernias are umbilical and inguinal.
Umbilical hernias
Umbilical hernias can occur due to a genetic predisposition, an umbilical infection, or, more rarely, umbilical trauma. Occasionally body wall trauma will lead to an “umbilical” hernia and incisional hernias often include the umbilical region. We will focus on the neonatal ones.
Most umbilical hernias are reducible and a hernia ring is palpable. Quarterhorse fillies are genetically predisposed as are certain lines of Holsteins and pigs. If you do not see signs of infection, it is worth coaching your client about the likely heritability, particularly in those groups. Many simple hernias in foals will resolve over the first two months of life; it is worth waiting until the foal is weaned before considering hernia repair. Hernias have not been reported to resolve as often in cattle and swine.
In many calves, the hernia develops because an umbilical infection precludes normal closure. Infection can develop in any of the umbilical structures (arteries, vein or urachus). These are also generally reducible but may have purulent discharge and/or heat and pain associated. Umbilical abscesses without an associated hernia can be treated as regular abscesses. Otherwise, the infection is removed en bloc (as a closed unit) at the time of hernia repair.
If a hernia develops due to trauma, it is essential to wait until a hernia ring (composed of fibrous tissue) develops prior to attempting repair; this usually takes about 60 days.
Exception: if the intestines are “stuck” in the hernia and the hernia is not reducible, this is an emergency.
Inguinal hernias
Inguinal hernias present quite differently depending upon the age of the patient. Adult horses with inguinal hernia are emergencies and often require surgery to remove the intestines from the hernia; The intestines can become devitalized quite quickly.
Foals and calves with inguinal hernias are typically not an emergency. The intestines slide around and can be shoved back into the abdomen (but quickly slide back out). These usually resolve on their own over time. However, it is possible for the intestines to become stuck in the hernia. These cases do require emergency surgery.
Adult bulls with hernias are typically not an emergency. These are associated with large fat pads in the inguinal ring that protect the intestines.
