What's your opinion on DM carriers - Page 4

Blitzen, Joanro:   that's assuming the experts are right so far and it is a simple recessive.

If it turns out not to be, ie  if it is eventually identifed as one of those inheritances subject to

selectional changes,  genetics not actually being as 'black & white' a scence as you

are trying to portray;   OR if we simply breed one dog to another where one is a carrier

and one is untested or gets a false negative result,  then there certainly seem to be 

opportunities for the "sins of the father" to recur in following generations.

We simply do not 100%  know yet;  hell, as someone already pointed out above, one

of the tests currently existing could be testing for a condition that does not even apply

to GSDs.   Yes we should use testing insofar as it is currently available;  but a 'clear'

result should only be used to INFORM mating decisions,  and not MAKE those

decisions for us.  Proceed without illusions, I think.

MH, I didn't say the breed would disappear. And I don't breed dogs with bad hips, and so far, have not produced dogs with bad hips. I'm not minimizing anything. What I said was, if you want to eliminate every dog that is not DM allele free so that all thats left to use for breeding are the "clear" , the gene pool is going to be tremendously reduced. Even OFA says not to over state the importance of the test. I feel like I'm talking to a brick wall, so, good luck, Mind Hunt with your breeding program.
So far, my dogs are healthy, and I'm not going to wait until a dog is dead and dissected to determine if their frozen contribution can be incorporated into the genepool. Edit to say, in addition to reducing the gene pool, eliminating all but tested clear dogs won't eliminate DM any more than breeding only HD free dogs will ever eliminate HD.

I too have my doubts about the accuracy of the test, but what bothers me more is the people I've run into who insist they'd NEVER breed a "carrier" are not saying that because they too have been following the test and have reason to doubt it, but because they have no clue how a simple recessive actually works.  These folks assume the test IS accurate and still insiste that a carrier is at risk for developing DM.  Um, no.  If it's truly a simple recessive, then that's what it is.  Breeding carrier to clear is absolutely fine.  Other breeds do this for other health problems (my BC friends talk about some eye thing).  So for those that tell me they won't breed a carrier or buy a puppy with a carrier parent, I ask why not because I think they are wrong to say that, but I want to know what their reasoning is and whether it's valid questioning of the test and our understanding of DM or because they think a carrier of a simple recessive is somehow affected.

good point VK but heard the same thing about HD a few years ago;  same with eyes recently,  so where does this leave us.??

To answer the OP's question.... I would breed to a DM "Carrier" male. But he would only be bred to a "clear" female. I beleive the DM test is a TOOL that should be part of the whole package when either eliminating or adding a dog to a breeding program. I would however not eliminate a dog just because it is a "carrier" or "at risk". I first and foremost want to see the dogs temperment, hip/elbow/back xrays, titles, and pedigree etc as well as DM test BEFORE I will consider the dog for a breeding dog. I personally would use an "at risk" male in a breeding program if he was the total package, but he would only be bred to "clear" females... on the other hand I would eliminate a "clear"  or "carrier" male from a breeding program if he was not the total package.

There are several breeders that I know of that DM test their breeding dogs.

Dr. Clemmens has a great article on DM...

http://wholisticpawsvet.com/articles/Degenerative_Myelopathy_German_Shepherd_Dogs.pdf 

 

BLITZEN,

Great posts.... thanks for taking the time to post all that information. I have done alot of reading and studying on DM.

BUNDISHEP,

Just wanted to comment.... it is German SHEPHERD... not Shepard. Sorry one of my pet peeves..lol.

For those of you who believe it's not right to even breed carriers, consider this. I have a corgi, which is one of the breeds that the test was developed for and so the test is considered scientifically sound. So far out of over 2000 tested corgis 52% are at risk, 37% are carriers and only 11% are clear. To not use carriers would decimate the breed pool.

"I'm not certain that the test is looking at the DM specific to GSDs. Can anyone verify this?"

No; the current test for DM does not test for the type of DM specific to GSD's, ergo, is not a reliable indication that a dog that tests clear will not develop that form of the condition.  I would still encourage people to have their dogs tested for non-GSD specific form as a means of avoiding it but caution that it should not give anyone a false sense of security.

In answer to the original question, yes, I would breed a carrier male to a clear female.

Nans, heard what "thing about HD"?  I don't follow?  HD is not a simple recessive and I've never seen anyone claim it to be.

I was wondering that too, VK.  What was said about HD? Eyes are another topic.

I agree with you 100% - if breeders aren't using the DM test or factoring the results into their breeding programs using the  facts of the mode of inheritence of a simple recessive because they think the test is of no value, than I would love to hear why they feel that way. For example, have they had actual experience with a clear or carrier that has been diagnosed with DM at autopsy.  Or are their opinions based only on anecdotal information?  The jury is still out for me but the test is not invasive or harmful to the dog so if I were breeding I'd would definietly test my breeding stock. No DNA test is 100% accurate and there are mutations, the reason that OFA will only issue clearance by parentage for one generation and there needs to be DNA submitted that will permanently identify that dog.

However, if the refusal to use carriers (and I'd take that one more step and say an at risk would not be out of the question for me - why not) bred to clears, is  because they don't understand the way a SIMPLE recessive gene is inherited and expressed then that needs to be addressed. There are no modifiers involved with DM, the gene is not sex linked.  Either the dog carries the gene dominantly or recessively or it doesn't. A carrier means that dog has no more chance of developing DM than does a normal......a carrier will not develop the disease and can only produce DM if bred to another dog that carries the gene. 

If that carrier bred to a clear produces another carrier, then that dog needs to be bred to a clear. Everyone who tests wants to use a clear anyway, don't they?  If that procedure is followed for a few generations, in theory, the gene is going to be gone, maybe not forever. If the breeder is the sort who doesn't want to stay involved with the dogs he or she has bred to help make sure all are tested and bred accordingly then testing for DM is not going to be something they are going to do anyway. If a carrier or an a risk is used for breeding, then the ethical breeder will want to place the resulting breeding prospects that have tested as carriers where they will be bred to clears. Breeding to eliminate the gene for DM is not a once and done thing, it's on going.

Yes, there's a chance it will "come back" in the future so, based on what we know today, there is probably no chance in the near future that any line will ever be considered 100% free of the gene; testing isn't going to end any time soon for those who feel it's valuable to their breeding programs. That can also apply to dogs today that are not being tested because there haven't been any carriers or at risks in their pedigree for a generation or more. That's a false assumption. No lines are DM free.

I find it ironic that temperament issues, unsound conformation, lack of endurance, etc are excused by breeders, yet some make a big deal over using carriers (or at risks). What's the difference?

I tested my breeding dog because 1) it was cheap 2) it was easy (cheek swab) 3) some breeders/owners of nice breeding females want to know the results, and 4) I personally was curious.  I cannot say with any certainty what my dog will or won't produce, but that is true for any disorder.  I try to keep tabs on his progeny (right now he only has one litter on the ground but has had 2 other breedings in the past few months), including one that I personally own and two that are owned by local friends.  It is important to me to know and I would never making breeding decisions based solely on the results of ONE test for ONE genetic disorder when I know there is some reasonable doubt about the validity of the test.  I do not know enough about DM to have my own opinion on whether the test is correct for GSDs or not, but I'm hoping the more people focus on this disease (including using the available tests), the more we can learn and develop a test that may give certain results.