Nicki
Moderator
I think the latest estimate is that 70% of Cavaliers are born with CM, which they have from birth but which obviously develops as the puppy grows. The foetal tissue research at the Royal Veterinary College is trying to find out exactly when and why it starts developing in unborn and newly-born puppies. Since not all that 70% have problems caused by their CM, I presume that it is the degree and position of the malformation which causes pain. CM doesn't necessarily lead on to SM, but it is rare for a dog with SM not to have CM as well.
Kate, Oliver and Aled
Thanks Kate, you beat me to it!!
There will be an update on the foetal tissue research at the CAVALIER HEALTH DAY 20th November 2010 at the Royal Veterinary College - more details on http://www.thecavalierclub.co.uk/start.html
This will be well worth attending - some fantastic speakers.