Conventional wisdom says that umbilical hernias are inheritable,
and a dog with a hernia should not be bred. Conventional wisdom,
however, does not differentiate between "true hernias" where
there is a defect in the body wall, and "delayed closures",
where a small bit of omentum slips out of the area before the
umbilicus closes. In 26 years of dealing with breeders and
reproduction, I do not have any evidence that "delayed closures"
are inheritable. "True hernias" are indeed highly inheritable.
They generally have a thick cartilage edge with an irregular,
more or less circular shape. They may extend up into the
diaphragm, causing a communication between the thoracic (chest)
cavity and the abdominal cavity. These are very difficult to
repair surgically because there is a great deal of tissue
missing and the tissue is hard and inflexible. They often
require the use of a mesh implant to close the defect. These
hernias can be related to other midline defects such as heart
abnormalities and cleft palates. "Delayed