Diagnosing and treating umbilical and inguinal hernias in pigs
Tuesday, October 2, 2012
Hernias are fairly common in young pigs and may reduce the value of the pig at slaughter. Surgical correction is possible, but not recommended
by S. ERNEST SANFORD
Hernias involving the abdominal wall include umbilical, inguinal and scrotal. These hernias are among the most common developmental defects in swine. Umbilical hernias are also called by the common name "belly ruptures."
Inguinal hernias
Inguinal hernia is an inherited condition. It may not be noticed at birth but can become more obvious some weeks later. The incidence can double between birth and five weeks of age. Inguinal hernias occur almost exclusively in males and become more apparent after castration. In males, they usually extend down into the scrotum. Holding the piglet by the forelegs and gently shaking generally causes even a very small hernia to become more apparent and confirm the diagnosis. Scrotal hernias are, of course, entirely restricted to males and give specific definition to the condition rather than the more general term "inguinal hernia."
It can affect one, usually the left, or both inguinal canals. The testicles normally descend into the scrotum via the inguinal canals by the time of birth. The inguinal canals start to close behind the descending testicles 14-16 days before birth, after the testicles have passed through the external inguinal ring and have started their descent down the inguinal canals.
Inguinal hernias occur if the inguinal ring is very large or if the structures surrounding the canal are weak, allowing the abdominal contents to be forced into the inguinal canal by increased intra-abdominal pressure at or after birth.
Correction. Surgical repair of an inguinal hernia can be performed by your veterinarian, but is not recommended, and this surgery is seldom practiced today in commercial units.
Umbilical hernias ("belly ruptures")
Unlike inguinal, umbilical hernias occur in both sexes, though not equally. Umbilical hernias are estimated to be more than one per cent in females and 0.6 per cent in males. Umbilical hernias are secondary to failure of the normal closure of the abdominal ring after birth and result in protrusion of the intestines through the abdominal wall to form the "ball-like" lump called the "belly rupture" or hernia.
Hernias reduce the value of a pig at slaughter, where they are severely discounted. Morbidity is variable, but mortality is negligible except for large hernias which can increase mortality during the growing period. The prevalence of umbilical hernias is estimated to be between 0.4 and 6.7 per cent in commercial swine herds.
There are several purported reasons why the abdominal ring fails to close off after birth, among which are genetics, bacterial infections ascending the umbilical cord and environmental conditions of the neonatal pig.
The genetic influence over umbilical hernia is not entirely clear. If one exists, it is complex and not due to a simple inheritance of a few genes. A "familial" tendency has been observed for this condition. Excessive traction on the umbilical cord or clamping or cutting the umbilical cord too close to the abdominal wall can also lead to umbilical hernia. Bacterial infection of the umbilicus (navel) has, in recent years, attracted researchers to investigate it as a cause or a prelude to umbilical hernias. Ascending bacterial infections from the open umbilical cord can lead to umbilical abscesses and systemic infections such as septicemia (bacterial infections or "blood poisoning" going to multiple organs via the blood) and arthritis ("joint ill"). It is hypothesized that if the umbilical clot, seen at the umbilicus after birth, becomes infected it can lead to abscessation of the umbilicus at that spot, setting the stage for an umbilical hernia later.
Veterinarians at the Carthage Veterinary Services (CVS) clinic in Carthage, Ill., investigated bacterial infections of the umbilical cord and found that 28 per cent of neonatal pigs, at 26 to 48 hours after birth, had ascending bacterial infections of the umbilical cord. A large number of different aerobic bacterial pathogens contributed to the infections in the umbilical cord with E. coli, Staphylococcus hyicus, the "greasy pig disease" bacterium, and Enterococcus spp. being the most common.
Multiple bacterial infections were common in the neonatal umbilical cord. The CVS researchers found that the presence of even one bacterium increased the chances of a high umbilical cord score, which correlates with development later of an umbilical hernia. Each additional bacterium in the umbilical cord further increases the risk of development of hernias.
The CVS researchers further investigated whether antibiotic treatment at birth would reduce the level of bacterial infection of the navel cord. They found that treatment within six hours of birth with five-milligram injections of ceftiofur crystalline-free acid (Excede) resulted in a significant reduction in navel infections at weaning. Furthermore, at 16 weeks of age there was a significantly lower incidence of umbilical hernias in pigs treated with the antibiotic versus those not so treated.
Correction. Small hernias can be pushed back into the abdomen early in life, allowing the abdominal ring additional time to close. Your veterinarian can place an Elastrator ring close to the abdominal wall after the hernia has been pushed back into the abdomen to close off the abdominal ring. Surgical correction is also possible, but not recommended, and is not usually performed in our commercial herds. Attention should be paid to pigs with large hernias, so they do not become a welfare problem. BP
S. Ernest Sanford, DVM, Dip. Path., Diplomate ACVP, is a swine specialist with Boehringer Ingelheim Vetmedica (Canada) in Burlington. Email: ernest.sanford@boehringer-ingelheim.com