How common is it for pups to be born with hernia's and is there anything you can do about them?

Here is a link to a useful article on the subject, which differntiates between true Hernia (serious) and a late closure (minor aesthetic blemish). http://www.showdogsupersite.com/kenlclub/breedvet/umbilical.html

One of my cavaliers has had a small umbilical hernia since birth (now nearly 7) which is frequently checked out. It has never caused a problem and is never expected to. I was under the impression from the vets it was not uncommon. Treatment has never been suggested because it is unlikely to become a problem.