This is my perspective on this. I think there's still a gap in communication on the uses of MRIing and the notion of 'clear' dogs and what the 2.5 age indication means on the breeding protocol. And the extreme urgency of the SM problem right now. This gap really needs to be directly addressed and clarified by the researchers I think as it has become (or been allowed to become) a centrepiece of misunderstanding.
First, the 2.5 age is ONLY there, as Dr Rusbridge states on the protocol, because it matches the heart protocol (so dogs shouldn't be bred before then *anyway*) but also allows for a good period of time in which to look for symptoms. In general dogs that show symptoms before age 3 are going to have more severe forms of SM. But in most cases, severe forms are *almost always related* to severity of malformation/herniation so to say that dogs needn't be MRId because symptoms can show up any time is to ignore the fact that 1) symptoms are often subtle anyway that breeders and pet owners miss them entirely (not to mention vets); AND 2) that the key issue for the vast majority of dogs especially in terms of passing this along to offspring is NOT symptoms but the severity of the SM/malformation/herniation. I do not know a single researcher or neurologist who disagrees with this point. Indeed I believe that shortly a statement will be issued from a range of the neurologists warning as to the urgent need to MRI and follow the breeding protocol. They are very concerned now for the future of the breed and the lack of take-up of MRI schemes (I know Dr Dewey has become increasingly worried that this indicates there's no interest from breeders to address the problem and follow the breeding protocol and that he has been very disheartened that almost no breeders have taken up his low cost MRI scheme. I expect other neurologists are about to become far more vocal about the issue and that, at last, it will stop being seen by so many, very mistakenly, as somehow the quirky view of one UK neurologist).
Also, the protocol does NOT give an all clear for breeding to a dog that has say, a severe malformation and severe herniation but no symptoms -- there are levels of acceptability and the assumption is , as with MVD, people weigh up the implications of a diagnosis (eg a low-murmur dog at age 8 is a better choice of ancestor than a high murmur dog hence the value of tracking status over generations). I know from talking directly to both Dr Rusbridge and Penny Knowler, as well as from communications with other leading neurologists in this area, that what is very important is not to breed a dog with severe features regardless of its symptom free state unless there are compelling reasons to do so. All indications at this point are that this does get progressively worse in the breed and the likelihood is that, while the given stud or bitch may be asymptomatic, its offspring stand a good chance of getting a combination of the severe malformation and the other elements that will cause symptoms, and then passing these more severe combinations genetically on to the next generation.
In addition I know from general correspondence with a number of researchers (without knowing the actual breeders/lines involved because the researchers across the board are totally protective of identities and observing confidentiality), that these researchers have been truly shocked that dogs and lines that they KNOW from research work to have severe SM remain in very active breeding programmes around the world. These are dogs that were breeder-submitted for the research programmes or whose direct offspring have been diagnosed with very severe SM and breeders know the status of the dog. The fact that not only are people finding reasons not to MRI but actually keeping known, affected dogs (some very symptomatic I am told!) in leading breeding programmes where they are producing hundreds of puppies has deeply shocked many of the geneticists and neurologists involved with the research on this breed.
Hence I do think there is going to be a direct appeal on the extreme urgency of the situation from a united front of senior neurologists to the breed clubs internationally on this issue. The scientists are at this point calling the situation as they see it: they do not have investments in dogs, lines, shows, or stud fees nor are they involved in the breed club politics and no vested interest to argue that dogs should be scanned. They just see a breed that is getting to the end of its genetic tether and they do not understand why people do not want to save the breed, particularly when this is such a horrifically painful condition for an affected dog to live with (as human sufferers can confirm, and have, on some of the SM dog lists).
With what authority can I speak to such things? I have been in contact with many of those on the research side in recent months because I am researching a piece on this for one of the major international science publications, mainly because the genetic angle is so interesting -- the genome scan and possibility of identifying polygenetic markers for a condition that requires numerous genes to combine in certain ways to produce it) is out at the cutting edge of genetic research and has HUGE implications for human illness so the human medical world is very interested in this work, as are geneticists generally.
It would be sad to see this breed disappear entirely because the breed clubs have failed to inform breeders of how serious the issue is. The leadership needs to come from the breed clubs, as it is hard for individual breeders to take decisions where they are then ostracised (as is definitely happening; I get a lot of pprivate email to this effect) and wade through the existing research to try and understand what is really going on. A key reason I had for setting up the SM Infosite --
www.sm.cavaliertalk.com -- was to get neutral info on research and the latest thinking out to anyone interested as there was so much rumour and misunderstanding about the growing body of research and evidence.
Perhaps people will become more persuaded when the Ohio research is written up, and Dr Dewey's two upcoming papers are published, and a new piece of work from Dr Rusbridge, which is going into one of the leading international vet journals -- but I fear how far this will continue to have progressed given that publication timetables mean this could be a year or two from now. We can already see the shift in visibility -- and one assumes, the increasing severity in the cases -- of SM that have emerged in just the past year or two so imagine the effect of two more years of no action...
I am in the process of preparing an interview with the leading geneticist on his SM work and perspective for the Infosite and will let people know when that is to appear. I think it is really important that people begin to see how general the view is that this an enormous and urgent problem for breeders. He, btw, was of the view that the condition was SO urgent a year ago that breeders should not be breeeding ANY dogs except totally clear to totally clear. Dr Rusbridge realised that was not possible with the narrow breed gene pool and the MVD problems so took that into consideration with the more flexible protocol.
As an afterthought: Mr Skerritt believes a dog can be diagnosed at 6 months as in his experience the malformation is visible at that point. Other neurologists feel about age 1 is a good baseline point to watch for progression. But certainly observing the state of the malformation and herniation at that point is enough to base future breeding decisions on. From then on, a diagnosed dog can be watched for symptoms rather than re-MRI'd. Hopefully within a couple of years there will be some genetic tests which help refine understanding of which dogs are best to breed. And as noted there's some possibility of using ultrasound (however this does not reveal too much at this point but an experienced neurologist could do a basic diagnosis using it) and the hope that newer MRI techniques such aas the one that also measures the flow of the cerbrospinal fluid will help predict which dogs are likely to go on and have severe symptoms.
Apologies for the length of the post but there were several points to address there. In general I think the issue lies with the breed clubs and health clubs and the way in which they champion this, not individual breeders who must be finding the situation even more confusing than it actually is because there is just no leadership on nthis problem at all and no attempt to give supportive guidance. Eeven the info on SM on the club websites is mostly months out of date and I don't know any that have posted the revisde breeding protocols, with most never posting the initial protocol.
Meanwhile most dogs continue to be misdiagnosed with allergies or disk problems and scratching at shoulders and neck is dismissed as dislike of a style of collar or harness or skin allergies or mites. Or people think because the dog doesn't scratch it can't have SM even though Dr Dewey sees the scratching in only about 40% of cases. So I really strongly believe many who are guessing their dogs have no symptoms actually have symptomatic dogs and just guessing at status based on symptoms is meaningless.
