You are both right on this one I think -- a bit of both replies.
It's not that mating of top quality dogs who've been extensively health tested can't produce unhealthy pups, but the health testing should still be done. And buyers of puppies should be made aware by the breeder of what health testing has been done.
That's very well said and yes, agree fully. Buyers also need to be aware of what to ask about, thus the post on looking for a breeder and what to ask in the Library section
, and websites like
www.cavaliercampaign.com and
www.cavaliermatters.com.
Unfortunately early onset wouldn't necessarily indicate poor breeding practice and the problem is larger -- decades of mediocre to poor breeding practice by many breeders (some due to lack of knowledge about the science behind what might happen, but some just indifference to inward health and the long term implications of their breeding choices, if outwardly they saw nothing or avoided seeing anything, won in the show ring,and made money off puppies). Now we have a narrowing of gene pools that means -- very sadly, as the researchers have found -- that there doesn't seem to be a single line anywhere in the world that does not have the malformation, does not have the possibility of producing SM, and does not carry the genes for the disease.
I do think an owner of an affected dog should start from the point of view of discussing the issue with the breeder, finding out after the fact if it wasn't (ideally)done before, if the parents were MRId at all, and seeing how they can work with the breeder on the case of the individual puppy. Scans can go to research where they can help the future of the breed, which may prove some small comfort to the owner of an affected dog (one positive, powerful step they can take).
Breeders that refuse to scan, and knowingly use dogs that have been diagnosed with a significant degree of SM, who lie about knowing they have produced SM, and lie about knowing that some of their well known dogs are producing it -- in other words, those that focus on themselves, their show ribbons and their pockets, rather than being responsible to the breed, other breeders, and the families who buy their puppies -- they deserve excoriation and exposure. This is the most severe animal cruelty and deliberate fraud.