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Thread: Did you know there is more than one definition of CM?

  1. #1

    Default Did you know there is more than one definition of CM?

    In a new study, three definitions of Chiari-like malformation are compared in asymptomatic dogs.
    http://www.cavalierhealth.org/sm2.ht..._non-CKCS_dogs
    Rod Russell

  2. #2

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    You mean sometimes some dogs have less bone than others? I'm not having a go at you Rod (honest Injun) it's just that I'm so fed up with new pronouncements on SM related matters that are basically common sense.

    I can quite see a forthcoming study saying did you know that some syrinxes are larger than others. Long hard day, I'm off for some alcohol.
    Sheena Stevens

  3. #3
    Join Date
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    Actually this is a fascinating piece if research and should be read by all. In laymans terms - two of the markers used to define CM in Cavaliers (indentation and impaction) are also found in unaffected breeds, so may not actually be relevant. Furthermore these two markers could be altered by head position when scanned- and also that bracychephaly increased the chance of those two possibly irrelevant markers.
    The point is that "unaffected dogs" lacked any degree of herniation. In other words, that herniation which is NOT graded under the BVA/KC scheme should be the defining feature of CM. So when they rewrite the grading system they can also add PSOM & VD or is that too much to ask.
    Last edited by bridgette; 10-17-2014 at 12:01 PM.
    Bridgette Evans
    Svena CKCS

  4. #4

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    Well, I'd like to throw in one of my obsessions in to this mix.

    Everything - genes, chromosomes, haplotypes, etcetera - stems from the joining together of sperm and egg. So therefore everything depends on the reproductive organs. Leaving aside anomalies of insufficient diet, accidents, infections, etc. it is vital that breeders pay attention to the reproductive health of their animals. But there seems to be a disregard amongst breeders for those male dogs whose testicles don't descend fully. And a lot of breeders don't seem to appreciate that in any mammal the body parts are mirrored in both sexes, although genes cause different development. So ovaries equal testicles.

    Therefore, if in a litter there are males with only one testicle, there are likely to be females with inadequate ovaries. The one testicle or failure of complete descent is known to be caused by a recessive on both sides. In over 20 years of breeding I have seen very little interest by breeders in endeavouring to rid their lines of this recessive, and even less knowledge of the fact that ovaries can also be affected - and unless specific questions are asked, no information is usually given as to whether a stud dog has ever sired this condition in a litter. It tends to be regarded as more of an irritation, something that's accepted and the pup sold as a pet.

    It is worth pointing out that both testicles and ovaries play a part in proper bone development, growth and replacement of bone through the life of the animal. Inadequate ovaries lead to smaller litters and less likelihood of being able to maintain a successful pregnancy.
    Sheena Stevens

  5. #5

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    Here is the current definition of Chiari-like malformation, as far as I know:

    "In dogs, CM is characterized by herniation of the cerebellum and medulla into or through the foramen magnum (FM). Overcrowding of the caudal cranial fossa has been demonstrated in Cavalier King Charles Spaniels (CKCS) where there is a mismatch between caudal cranial fossa volume and brain parenchyma within leading to cerebellar herniation, medullary kinking, obstruction of the dorsal craniocervical subarachnoid space, and alteration of cerebrospinal fluid (CSF) flow." From: "Chiari-Like Malformation and Syringomyelia in American Brussels Griffon Dogs"
    Rod Russell

  6. #6
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    trouble is a blanket description (for CM) is being used for all breeds, however, there is no account for what is found to be "normal" for a specific breed.
    Bridgette Evans
    Svena CKCS

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