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UMBILICAL HERNIAS Let me start off by saying that 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. There is NO EVIDENCE that "Delayed Closures", which is MOST COMMONLY called "Umbilical Hernia", are Inheritable. "Delayed Closures" are exactly that, a delayed closure. There is an area in the abdominal wall where the great vessels of the umbilical cord exit the body of the fetus to derive nutrition and oxygen from the placenta. After birth, these vessels close and shrink up. There is left behind a small area in the midline where the vessels formerly escaped the body. The nature of this structure is a linear slit in the midline, lined with normal connective tissue. Omentum is a kind of slippery thin sheet of tissue which is present in the abdomen. It provides several services to the abdominal organs. It has blood vessels traveling through it to the intestine. Its surfaces produce serous fluid which lubricates the abdominal organs and makes it possible for them to slide against each other without rubbing. It carries lymph nodes for the abdomen, and is a major depot for fat storage. It partially contains the small intestine, and supports them in a kind of "plastic bag". As the puppy puts on weight, it is possible for a bit of the Omentum to protrude through the umbilical slit. As the normal process of closing of the umbilicus proceeds, it is possible for this bit of tissue to be trapped. Thus causing a "Delayed Closure" AND look of a Umbilical Hernia, thus the association with the phrase. In this case, the normal intestine becomes strangulated in the process of closure. No Delayed Closure can ever close completely, simply because there is something sticking through it. It closes tightly around the Omentum, trapping it outside in a absolutely firm, unchanging "bubble". There are no worries that a bitch with a delayed closure and trapped Omentum bubble will show any sign of problem in carrying a litter or whelping. There are also no worries that one of these bitches will produce puppies with hernias. There are no harmful side effects or pain associated with this condition. It is very common, and the major cause is tugging of the umbilical cord after birth. It can also be caused by the clamps on the umbilical cord after a birth via c-section. "True Hernias", however, are a true defect and can make no progress in closing, ever. They must always be surgically repaired. They generally have a thick cartilage edge with a irregular, circular shape. They may extend up into the diaphragm, causing a communication between the chest cavity and the abdominal cavity. Because "True Hernias" are Relatively Rare, most breeders have never seen one. |
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