If breeders follow the guidelines they will have to remove cavaliers with SM that is already causes pain, so the gene pool will become smaller, but this was recognised and the SM protocol allows the use of older cavaliers with SM, but no symptoms, to stop the gene pool from becoming too reduced.
Originally Posted by kurtz
The genetic bottleneck argument was sometimes put forward by the UK breeders, and the truth is that breeders are between what we in the UK call 'a rock and a hard place'
(1) Continue to breed without removing SM affected dogs and within a few more generations the breed will consist of dogs with such pain ridden lives that nobody will want to buy them, and animal welfare laws will eventually stop them from being bred.
(2) Remove early affected dogs, start to breed away from SM but face the risk that a smaller pool of breeding dogs will be vunerable to another inherited problem showing up.
Personally I would choose (2) as giving the breed the best possible option.
Cavaliers......Faith, The Ginger Tank and Woody.
Japanese Chins.... Dandy, Benny, Bridgette and Hana.
Remembered with love......... Tommy Tuppence and Fonzi