Puppy buyer guide
Increasingly, puppy buyers are interested in finding breeders who follow the SM breeding guidelines, MRI their breeding dogs, and use the least-affected or unaffected dogs to try to breed away from syringomyelia. Initial results are very encouraging; however, the current recommended breeding advice remains experimental. A two year project is underway in the UK, which will use results from the international genome project, to refine breeding recommendations.
Because this is a new area of concern, buyers generally are not sure what certificates they should be looking for, or the questions they should be asking of prospective breeders. To help puppy buyers who have syringomyelia as a concern, this section explains the rationale behind the breeding guidelines, the MRI grading scheme, what a grading certificate will look like, and what to ask a breeder when looking for puppies.
Puppy buyers will want to first find a breeder also following the decade-old MVD and ask to see the cardiologist certificates and age of breeding dogs, to prove it. Learn more about the protocol, and what certificates look like, here.
What are the breeding guidelines?
Current breeding recommendations were issued in February 2007, after being agreed upon by neurologists and researchers who attended the International Conference on Syringomyelia, London, November 2006. These recommendations were made using current information and in response to CKCS breeder requests for guidelines. It has yet to be proven if this guide is appropriate. The aim of these recommendations is to reduce the incidence of symptomatic syringomyelia (SM) in the breed, not to create litters of puppies guaranteed not to have SM as the chance of producing an affected dog cannot be predicted without knowing the inheritance. You can view more detail on the guidelines here. The guidelines closely follow the reasoning behind the well-established mitral valve disease (MVD) breeding guidelines. MVD also is an apparently polygenetic, widespread and progressive condition in the breed with unknown inheritance. By breeding dogs that are heart clear and at least 2.5 years with parents heart clear until at last age 5, breeders who follow the guidelines have significantly lowered the chance of early onset heart disease. Most international breed clubs advocate CKCS breeders follow the MVD breeding guidelines. The SM guidelines are designed to dovetail with the MVD guidelines (hence the age of 2.5 years).
How does the MRI grading scheme work?
Neurologists who participate in the grading scheme will issue a certificate when a dog is MRId. The certificate indicates whether or not the dog has a Chiari-like malformation; whether the dog has one or more syrinxes and their size ('dilation') and location (by vertebrae); and whether other associated conditions are present, such as hydrocephalus or PSOM (ear disease). A grade from A-F is assigned to the dog dependent on whether it is older than 2.5 years, has a syrinx or not, and if so, the size and whether the dog is symptomatic. This is the grading table:
|GRADE||AGE (Years)||SYRINGOMYELIA||BREED TO|
|A||Over 2.5||Absent or less than 2mm central canal dilatation in the C2-C4 region only||A, C, D|
|C||Under 2.5||Absent||A and re-scan after age 2.5|
|D||Over 2.5||Present but Asymptomatic||A|
|E||Under 2.5||Present but Asymptomatic||Do not breed|
|F||Any||Present and Symptomatic||Do not breed|
Do they know if it works?
Initial results have indicated that dogs with good grades tend to have siblings or other closely related dogs with similarly good grades, suggesting there are familial clusters of good genes. In addition, some early breeding results, mostly coming from Dutch breeders, indicate that while AxA crossings may produce a small number of affected dogs, most offspring are A dogs, whereas D crossings produced no As and large clusters of Ds and Fs. Some initial results were reported at the International SM Symposium in Rugby, UK. More results are needed for a clearer statistical picture to begin to emerge.
What should I ask a breeder?
If you wish to find a breeder who is using the breeding recommendations for SM, the starting point is of course, to ask them if they are MRI scanning their breeding stock. If yes, then ask the grade of the parents, and ask to see the neurologist's certificate. The certificate will have the name of the practice and should contain either blanks or checkboxes next to the elements the dog was assessed for (these will probably be hydrocephalus, dilated ventricles, malformation, presence of syrinx, cerebellar herniation). There will also be a space for the dog's grade. The certificate will be signed and dated by the neurologist or neurosurgeon. It may also be time-stamped with the practice stamp.
Ideally, both parents should be A dogs. If not, ask the breeder what qualities the non-A dog had that were felt to be important for the breeding. At this time, there are not enough A dogs identified for all matings to be AxA but the breeder should still be following the table above when choosing a mate for the A dog, and should be able to explain the choice of parents. Ask how many of their dogs they have scanned and whether scans have been done on related dogs and the results (ideally, a puppy buyer should be seeking parents with more good scans in related dogs). Ask if they know the status of offspring from previous litters. Ask whether there have been any symptomatic dogs that they know of in their lines or related lines.
And of course, ask to see the cardiologist's certificates on the heart status of the parent dogs. too. This is a very important health protocol and a buyer wants the best hearts possible as well.
Are puppies from scanned litters more expensive?
They may be, but at this time most scanning breeders add only a modest increase on the price, if anything. Keep in mind that MRIs are expensive even on the few available low cost schemes, and breeders will likely try to recoup some of this cost.
Are there lists of scanning breeders?
It would be helpful if there were, but at this time there aren't. Finding scanning breeders can be difficult, but keep asking is the number is growing. The health representative to a local, regional or national club might be a good place to start.