This is the protrusion of abdominal contents (mesentery or intestinal tract), through a defect in the abdominal wall, the skin remaining intact.
Size of the lesion depends on the extent of the defect and the amount of intestine or other content incvolved. Hernias may be congenital (umbilical hernias), or acquired such as traumatic, inguinal and scrotal hernias, and rupture of the prepubic tendon.
Hernias are likely to be rare in the animals selected for the live export process. They are mentioned because they may resemble haematomas, ruptured urethra, abscesses and preparturient oedema.
A hernia may present as a soft, elastic reducible swelling except when trapped gut is being strangulated or acute rupture causes haemorrhage and oedema. Umbilical hernias occur in the ventral abdomen, the result of the umbilical ring failing to close after birth. The sharp edge of the umbilical ring can be palpated. Traumatic hernias occur in the ventral or lateral abdomen and are the result of trauma from a horn or a fall. Acute and severe hernias may be associated with pain and distress. Hernia associated with rupture of the prepubic tendon occurs in older cows generally in late pregnancy due to failure of stretched and thinned abdominal muscles. Scrotal hernias involve herniation of abdominal content through the inguinal canal of males. The scrotum is unusually enlarged and strangulation is a real risk. Close external and internal (rectal) palpation may assist in confirming the diagnosis.
Surgical and bandaging options are available but are unlikely to be practical or successful within the constraints of the export process. Animals in distress should be euthanased or sent for emergency slaughter. Pregnant animals with severe abdominal or pre-pubic herniation may be induced to abort or calve with corticosteroids (dexamethasone) and prostaglandins (cloprostanol, dinoprost trometamolin) and should be assisted as necessary at dleivery.
Low stress animal handling, well designed facilities and careful selection of animals prevent this and many other problems in the live export process.