Well I have VERY lengthy views on DM after a TON of research into the subject.. here is what we tell people and other breeders alike on the subject of DM DM- Ok, well Im going to say Im sorry in advance on writing a book here on information on DM. Its a VERY hot topic with a lot of breeders in the US (still being totally ignored by show breeders in Europe at this time) But A LOT of the info out there is seriously flawed and there are A LOT of misinformed people. Ok - First off. What is DM? Degenerative myelopathy (DM) is a progressive disease of the spinal cord in older dogs. The disease has an insidious onset typically between 8 and 14 years of age. Pembroke Welsh corgis are one breed that is at higher risk for DM due to their longer spinal cords and a genetic predisposition in the breed for the condition. What causes DM? DM, like most degenerative conditions has a wide variety of causes and triggers. Genetics of course play a role, with injury, exercise, overall health and nutrition also being key factors. Recent research has identified a mutation in a gene that confers a greatly increased risk of developing the disease. This mutation does not have a simple Positive or Negative test result that can be easily assigned to each dog. Instead the genetic test result gives us a break down of At Risk to Develop DM, Carrier, and Clear These three results break down to the following. At Risk dogs have two copies of the gene thought to develop the DM gene. They are at potential risk, but that in no way means they will get DM. It means they have the potential to develop DM if combined with outside factors. Carrier means that while the dog caries one copy of the genetic mutation to develop DM they themselves will most likely never have the condition themselves, but they could potentially pass this gene on to their offspring. Clear means the dog does not contain two copies of the gene BUT still may be at risk if outside factors present. Currently in the US 52% of all Corgis are DM At Risk. 37% are Carrier, and only 11% are Clear. Meaning that a HUGE majority of corgis are at risk for this condition but only a TINY number of those will ever actually develop DM, and most of those will be due to outside factors combined with genetics. OFA recently updated their DM breeding guide to read The “A” (mutated) allele appears to be very common in some breeds. In these breeds, an overly aggressive breeding program to eliminate dogs testing A/A or A/N might be devastating to the breed as a whole because it would eliminate a large fraction of the high quality dogs that would otherwise contribute desirable qualities to the breed. (An interesting note on this gene that is linked to DM in corgis. This same gene appears in up to 90% of Fox Terriers at risk or Carrier) yet there has never been a single case of DM reported within that breed, which lives a very long time Basically DM testing is very flawed still! We dearly wish we could get a simple test that says Yes, this dog WILL have this condition, or NO this dog will not ever develop this condition. But that is no where near the test we currently have for DM. The test results now can say that a Dog most likely will not have DM as long as no outside factors come into play (DM Clear dogs have been known to still develop DM under those conditions) and DM At Risk dogs (making up the largest portion of the corgi breed) will most likely NOT have DM as long as no outside factors come into play. Of all Corgis (regardless of test results) less than 2% total will ever develop DM. Which in itself is a fact that MOST people ignore or do not realize. So our take on DM testing! -- DM testing has a long way to go to be a real tool in a breeding program. Dogs have been reported who have developed DM even when they have been tested as Carrier or Normal/Clear. These diagnoses of DM were confirmed by necropsy and examination of the spinal cord. In one case, the dog had a different mutation at the SOD1 locus, which confirms that more than one form of DM exists, and more than one gene is involved. It should for sure be a consideration and lines with known genetically linked DM cases should never be bred. As OFA states, breeders who decide to exclude anything but DM clear dogs in their programs will destroy the corgi breed entirely by doing so. DM testing is important, but at the same time, its one of MANY factors that good breeders should take into consideration. It is not a MAJOR factor. I have spoken to many breeders over the last two years on the topic of DM....I have been offered the chance to own several DM clear puppies (one was from vWD positive parents (a HUGE genetic condition that should never be bred, but was because the parents happened to be DM clear) Another breeder offered me a DM clear male puppy with a mostly white ear (of course this is only a cosmetic fault, but should still be considered pet quality only, not offered with breeder rights as this is a fault) A different breeder offered a Fluffy DM clear puppy online for Full AKC, again, this is a fault and should not be used for breeding. DM Clear is fast being the #1 concern with breeders, and its absolutely silly for that to be the truth! There are SO many factors that breeders should be considering in combination with DM test results, but that they are ignoring instead in favor of getting a DM clear result. Our goal as breeders is to produce the total package. Outstanding health, amazing temperament, super longevity, intelligence, and beauty! The perfect puppy to be a family member or the star of the show ring. A great farm companion or a buddy on your every adventure! We do DM testing on our corgis, and are working towards DM clear test results simply because even if the risk is barely there, every step we make in the right direction is important. Our lines are vWD clear by parentage, and are from lines with excellent genetic health, and NO genetically linked DM or ANY other DM for that matter.
Posted on: Wed, 19 Nov 2014 07:31:32 +0000
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