By Lauren Lamb
An umbilical hernia is a defect in the horse’s ventral body wall at the location of the umbilicus. The umbilicus is the equivalent of our belly button. The umbilicus is where the umbilical cord attaches to the foal while it is developing in the mare’s uterus. The umbilical cord is made up of a vein, two arteries and the urachus. The umbilical vein and artery carry blood to and from the fetus as it is developing in the uterus. The urachus is a tube that connects to the fetus’ bladder and carries urine from the developing fetus.
Umbilical hernias are seen in foals between the ages of birth and three months of age. The hernia bump seen on the bottom of the abdomen is made up of skin, subcutaneous tissue, peritoneum (lining of the abdomen) and a piece of the gastrointestinal tract.
Questions concerning umbilical hernias frequently asked by owners:
- How does an umbilical hernia develop?
- Are they genetic?
- How can I prevent an umbilical hernia?
Some evidence shows umbilical hernias may have a genetic component; however, the genetic influence is most likely mild. This means breeding a mare and/or stud that had an umbilical hernia when they were foals will not result in an offspring with an umbilical hernia. The flip side of the coin is also true; crossing a mare and stud with no history of umbilical hernias will not result in a foal without an umbilical hernia.
Some have a strong belief that foaling behavior of the mare immediately after delivery can have an influence on whether a foal will develop an umbilical hernia. The natural behavior of a mare following delivery of her foal is to remain lying down until the foal starts to move and becomes more active. This may take several minutes for the foal to become active. Once the foal becomes active, the mare will stand up and break the umbilical cord about one inch from the foal’s navel. When a mare stands prematurely, the risk of an umbilical hernia forming can be increased. The most common reason for a mare to stand prematurely is human intervention. When humans try to rush into the stall to assist the foal or mare, the mare will become nervous and stand up too early.
An umbilical infection can lead to an umbilical hernia. The post foaling care of the umbilicus can influence whether or not a foal will develop an umbilical infection. The umbilicus should be dipped in dilute Nolvasan solution or betadine solution two to three times a day for the first three days of life. An umbilical infection is likely to occur if the umbilicus is not dipped in an antiseptic solution for the first three days after birth.
The size of an umbilical hernia is measured in fingers, aka the number of fingers that will fit in the hernia. A small hernia is less than three fingers in size. A large hernia is anything bigger than three fingers in size. The hernia should not be painful on palpation, nor should there be any heat or swelling around the hernia. When you place your fingers in the hernia, the contents of the hernia should be easily reduced (pushed back into the abdomen). A veterinarian should be contacted as soon as possible if you notice any heat, swelling, pain on palpation or you cannot reduce the hernia. A veterinarian should also be contacted as soon as possible if a horse with an umbilical hernia starts to colic. All these clinical signs are evidence that a portion of the intestine is stuck within the hernia. When the intestine is stuck within the hernia, the blood supply to the intestine can be compromised, which will result in the intestine becoming necrotic—dead. The hernia should be checked daily to ensure none of the previously mentioned clinical signs have developed.
Several treatment options are available for hernias. One conservative treatment option for small hernias (less than three fingers), is to reduce the hernia one to three times a day. By reducing the hernia you allow the hernia ring (defect in the body wall) to heal close. When the foal reaches four months of age, there is little chance that the hernia will heal with conservative therapy. Any foal that is greater than four months of age with an umbilical hernia will need a surgery to repair the hernia.
An umbilical hernia has two surgical repair options—both require general anesthesia and can be performed in a clean stall or a surgery room. A hernia repair performed in a surgery room has lower complication rate following surgery.
The first surgical option is called the closed technique. With the closed technique, the abdominal cavity is not opened, but the skin and subcutaneous tissue are opened. The hernia is repaired by placing large sutures across the abdominal defect. The closed technique decreases the risk of an infection occurring within the abdomen, but it increases the risk that a portion of the intestine is sutured to the body wall. The closed technique is usually used in cases were the surgery is performed in a stall within the barn. In this location, there is higher environmental contamination compared to a surgery room.
The open technique is the second option. With the open technique the abdominal cavity is opened and large sutures are placed across the defect to close the hernia. With the open technique, the risk of the intestine being sutured to the abdominal wall are significantly decreased. The open technique should be performed in a surgery room.
Following surgery, foals are kept on stall rest with no hand walking for two weeks and then turnout in a small paddock or trap for an additional two weeks. After four weeks, foals are allowed to go back to regular turnout and exercise.
Umbilical hernias are abdominal wall defects that are commonly seen in foals. The cause of an umbilical hernia is not completely understood; however, both genetics and husbandry practice can contribute to a horse developing an umbilical hernia. Surgery is not always required to repair umbilical hernias unless the foal is over four months of age. At this age surgery is needed to repair the hernia. Following surgery, foals had a good prognosis.