I do not think that the full consequences of the MVD protocol was ever spelt out.........
1. If you have cavaliers that are clear of murmur at 2.5 years, they should not be used for breeding if their parents are not both at least 5 years old.
2. If either parent develops a murmur before they are 5 years old, the offspring should not be used for breeding even if they are free of murmur themselves at 2.5 years old or over.
The situation now can be that a nice puppy is whelped and used at stud at 1 year old. His heart is MVD clear.
By the time he is 2.5 years old he has produced quite a lot of litters and is Granddad to a few promising puppies. His heart is MVD clear.
At 4 years old he has sired a great many more litters, his children are producing well and so are his Grandchildren, so he is a multiple Great Granddad. A cardiology check shows he has developed a heart murmur.
Most of those many descendants would not have existed if the MVD protocols had been followed. None of them, even the offspring produced after he was 2.5 years old, should be bred from under the MVD protocols.
The protocols suggested by the Cardiologists had to be draconian if they were to make any difference, but they were accepted by the Cavalier Clubs without any real discussion with the breeders that were expected to implement them.
The responsible breeders checked the hearts but most still used underage dogs and ignored the MVD status of the Grandparents.
The majority ignored the whole idea of heart checks and did not bother about the breeding guidelines at all, except to indignantly point out that the breed had a MVD protocol to anybody that criticised irresponsible breeders.
Nobody, Cardiologist, Kennel Club or Cavalier Club took stock of the true situation and asked whether something else should be done, a mistake that we need to learn from.
Cavaliers......Faith, The Ginger Tank and Woody.
Japanese Chins.... Dandy, Benny, Bridgette and Hana.
Remembered with love......... Tommy Tuppence and Fonzi