BC Deafness

[juliepoudrier]

One explanation for breeding might simply be that the dog was bred before it went deaf. Not everyone is open about such issues in dogs, so if the owner of a dog doesn't know that adult-onset deafness occurs in a line, even sporadically, it's entirely possible to breed a dog before you know that deafness is an issue.

 

Not making excuses, but just pointing out a scenario where an dog who goes deaf as an adult might already have been bred.

 

J.

[Laurae]

Sorry, but WHY would you breed a deaf dog? Even uilaterally? It is a major hinderance when working at a distance.

 

A friend has recently encoutered this in his dog. The dog's work is going downhill with his hearing. The dog watches the handler for instructions when his 'bad' ear is towards the handler. I cannot imagine a 4-5 year old dog working so well with a hearing problem that it would be irrestible to breed to/from. I have just become aware of how prevelant this is in the breed and how many people still breed affected dogs.

 

If as evidence shows it is a recessive then there will be non affected carriers and knowing this then it would be like breeding dogs that are carriers of CEA but like CEA why breed an affected? I am sure there are equal or better dogs out there that are NOT affected.

 

Timely subject and one that needs openness, thank you Kathy for bringing it up.

 

Have you read the entire thread, Pam?

[nancyp]

I didnt read that he was wanting breed? Just wanting info , which is why people ask I think.

[Pam Wolf]

The question was posed about breeding an affected dog that is my response

[Jim Nashed]

Actually if you referring to my question, iwas asking whether my dogs new unilateral deafness could be due to Early onset deafness or is it more indicative of something else. No breeding plans now that he is deaf in his right. The other question is if he has EOD affecting his right sided deafness will he be deaf in his left soon too and if so when. His BAER showed good left sided hearing now. Just trying to guess his future.

 

Jim

[sjones]

I just took Wisp in today at the UW Minnesoata for a BAER test. I have been suspecting that she has limited hearing for awhile and decided after this years trialing season to go ahead and have her tested. The vet said she has limited hearing in the left ear(the ear I suspected) and decreased hearing in the right. That would explain our problems on the drive, now I know she wasn't just blowing me off. So ends her trialing career, but she can still help do chores around the farm.

As to Pams response on why would anyone breed a deaf, even a uni dog. I don't think anyone would do it on purpose, at least I hope not. I will share my personal story about this. I bought Belle as an 8 week old puppy back in 1999. She was an easy dog to train, on and off sheep. I spent quite a bit of time at trials looking for a male that I thought would compliment her and hopefully add some strenght to areas I felt she was lacking in. I found a well bred male to breed her to and in 2003 Belle had 2 pups. Since there were only 2 in the litter I kept both girls, Floss and Wisp. I can't remember exactly when I started noticing a difference in Belle's work, but I'm guessing at about age 3 1/2 or 4 years is when it became apparent she was almost totally deaf. So I had her, Floss and Wisp spayed. So if I'd known that Belle would become deaf at a young age, I would't have bred her at all, but many times with the late onset deafness you don't know until its too late. I did take responsibility and had all 3 spayed. I don't regret having Floss and Wisp, I have learned much from them and even muddled my way into the open class with both.

A few years back I sent some swabs in to a hearing study that was being done at a university in Canada, but never heard anything back from it. Does anyone know what happened with that study?

 

Samantha

[juliepoudrier]

Hi Jim,

What did the BAER tester say regarding his hearing? I know a BAER test is pretty limited in that it can tell if the dog hears in a particular ear or not, but it can't give you any real quantitative information on how much a dog hears in the "abnormal" ear(s). If you have a baseline test when he had normal hearing, then you can compare the two and perhaps get an idea of how much loss, but even that would be a guess.

 

The reason I ask if you asked your testing vet is because the people who do BAER tests are the ones most likely to be able to answer your question. My guess would be that if he hasn't gone deaf in the other ear yet, he may well not ever go deaf in that ear (at least until old age strikes), but I don't have a lot of experience with deafness issues, so I'm just guessing.

 

J.

[KathyF]

Jim-

 

From what I was told these dogs will progress to complete deafness. That was very sad news for me to hear. They couldn't tell me how quickly as it seems that each dog will progress at a different rate.

 

Kathy

[Jim Nashed]

Kathy , that is not great news obviously but I guess you can never tell the future with certainty. It does seem strange that the dogs would loose hearing first in one ear than the next but what you said is what I assumed.

 

Julie, the BAER test found him to be completely deaf on the right but he scored well on the left and seems to have hearing on the left. You can not quantify the amount but it was read as a " normal" result. There certainly are other causesnof deafness too. He recently was found to be strongly positive for his Lyme titer just before his BAER too. He is much less lethrgic and sore since antibiotics too. Lyme's can affect hearing in humans but I don't think in dogs so much, but we also have Rocky Mtn Spotted fever in our area too. I did ask the vet doing the test but they were not 100 percent familiar with EOD, except that it exists as a cause of deafness in BCs.

 

Again no breeding in his future but one can never be certain if his deafnss is genetic or acquired with out a gene test. I am planning on sending a swab though of his DNA for Dr. Neff study.

 

Jim

[Pearse]

At this point I personally would not have the dog altered because we could have a genetic test and clarity of the genetics of this disease within the lifetime of the dog which could enable a great working dog to be bred in such a way to not produce affected pups. But I personally would not breed the dog.

 

I disagree with Mark on this. Unless the dog is truly exceptional (ie: in the top 0.1% of working dogs), I see no reason to breed a dog that is homozygous for a deleterious mutation that has a profound negative effect on the ability of the dog to work.

 

A deaf dog can't work effectively.

 

A dog that is deaf because it carries a recessive mutation (and all the available evidence points at a recessive mutation in at least one gene being a major factor in this) will ALWAYS contribute a copy of the mutated gene to ALL of its progeny, regardless of whether the other parent is affected or not, thereby increasing the frequency of the deleterious mutation in the population. Furthermore, since at this point we have know way of detecting carriers, breeding an affected dog risks producing a litter where 50% of the pups will go deaf. I can't see any good reason to breed that dog when there are so many other good dogs available. The only reason would be if that dog was so exceptional in every other way that losing those genetics would be a major loss to the breed (and I would argue that we know so little about the heritability of working ability that even that argument is a weak one).

 

DNA test or not, I don't see a good reason to breed a dog you know is affected with this condition.

 

Pearse

[Pam Wolf]

Thank you Samantha. I can fully understand not knowing when the problem arises at an older age. But as the original question was posed it seemed someone was asking about breeding a known affected dog.

 

And as Pearce reiterated. A deaf dog cannot work effectively. Back in the day that would have been enough to not breed him/her.

 

This is a good case for breeding older dogs once proven.

[Denise Wall]

I think it's appropriate to evaluate the specifics of each genetic disease in the specific breed before making sweeping breeding recommendations or restrictions. In this case, it would be important to obtain reliable data on the affected and carrier rate within the population. Once the DNA test is out, and the incidence of the gene is known, then breeding recommendations could be considered based on the prevalence, severity of the problem as a health concern (i.e., I would not consider EOD as severe a problem as idiopathic epilepsy), the value of the particular dog otherwise in the gene pool, and the ability to control breeding of progeny so the incidence of the gene is not significantly increased in the overall gene pool (i.e., a worthy affected dog is bred carefully, to a limited number of appropriate mates and the progeny tested and followed).

 

I'm not talking about a broad recommendation to breed an affected dog as much as you want as long as it's bred to a DNA clear dog. I'm talking about careful breeding to keep valuable genetics in the breed. As in the approach for CEA, "breeding through the problem" in order to not lose the valuable contribution of certain dogs or lines.

[Pearse]

I think it's appropriate to evaluate the specifics of each genetic disease in the specific breed before making sweeping breeding recommendations or restrictions. In this case, it would be important to obtain reliable data on the affected and carrier rate within the population. Once the DNA test is out, and the incidence of the gene is known, then breeding recommendations could be considered based on the prevalence, severity of the problem as a health concern (i.e., I would not consider EOD as severe a problem as idiopathic epilepsy), the value of the particular dog otherwise in the gene pool, and the ability to control breeding of progeny so the incidence of the gene is not significantly increased in the overall gene pool (i.e., a worthy affected dog is bred carefully, to a limited number of appropriate mates and the progeny tested and followed).

 

I'm not talking about a broad recommendation to breed an affected dog as much as you want as long as it's bred to a DNA clear dog. I'm talking about careful breeding to keep valuable genetics in the breed. As in the approach for CEA, "breeding through the problem" in order to not lose the valuable contribution of certain dogs or lines.

 

 

 

All very valid points, but regardless of the gene frequency in the population, why would one knowingly increase the frequency by breeding a litter of pups, every one of which is going to be a carrier, at the very least?

 

The only reason to do so is when that particular sire or dam can contribute something to the breed that no other dog can. That is almost never the case. So, to my mind, there is almost never a good reason to breed a dog with a known genetic condition, where we are almost certain that a major contributor is an autosomal recessive mutation, and where that condition severely limits the working ability of that dog and any others who inherit the condition.

 

Furthermore, the true gene frequency in the population may never be known because it's unlikely that the research necessary to determine that will be done. So, it seems to me that the most prudent course is to do all we can to prevent any increase in the gene frequency by not breeding dogs known to be deaf, unless there are extraordinary reasons to do so.

 

Pearse

[Denise Wall]

Pearse, I think we are in general agreement in that we both feel the dog must be extraordinary to make the breeding worth it. All dogs can contribute something to the gene pool that no other dog can because they are all individuals. Whether what they can contribute is good enough is another argument. There is no "all other things being equal" scenario because the genetics and expression of working traits is so complex. If the unique combination a dog can contribute is of enough value to the breed, the progeny can be carefully selected and bred on to lose the gene in two generations. (I realize you know all of this but let's just look at it anyway.) For example, assuming there's one main EOD gene, when a carrier is bred to a DNA clear, statistically, there will be 50% carriers. If all one cares about is EOD, the pups can be tested and a DNA clear one kept, assuming there are enough of them for a clear and statistics bear out. The rest of the pups that are carriers can be neutered. Then, if the clear selected pup is breedworthy in other ways, the line can continue without the EOD gene. The same thing can be accomplished when breeding an affected dog, except all of the first generation would be carrier. A limited number, say one that trained out the best, could be kept intact and bred to a DNA clear mate. Then the same process as with the carrier x clear mating above is carried out. Just because the other dogs produced are not being bred it doesn't decrease their usefulness or value as working dogs in their lifetimes and no affected pups would be produced.

 

Alternately, in the first example, If a carrier is bred to a clear, the pups could all be followed and the best one chosen for breeding, neutering the others. If the best worker tests out to be a carrier, the process can be repeated until the result is a DNA clear to carry on the good and unique characteristics of that line. The problem has been bred through while retaining the good traits. It's not so different from breeding the affected dog. Either way, it must be done knowledgeably and responsibly with regard to the number of times the dog is bred and how the progeny are chosen and bred on.

 

However, the biggest argument I can think of for why we should go to all this trouble to keep these various individuals and their unique combination of characteristics in the gene pool despite genetic diseases is just look back and think of all the outstanding dogs and lines we *wouldn't* have if they hadn't been accidentally bred, not knowing their problem(s). I believe every dog I've had for the last two decades goes back to a dog that might be excluded if their DNA status had been known for various genetic diseases in the breed. Though there were affected dogs produced along the way, there were also many that resulted, mostly accidentally, as successful "breed throughs" of the problem. Now we can refine that. Why not do it with care and knowledge?

[Pearse]

If the unique combination a dog can contribute is of enough value to the breed, the progeny can be carefully selected and bred on to lose the gene in two generations. (I realize you know all of this but let's just look at it anyway.).

 

There's the first problem I have with the argument. The majority of dogs being bred do not improve the breed. The reasons they are being bred are financial or because the owner wants a pup from their favorite dog. So, right away the argument "only breed a dog if it is exceptional and deaf" fails most of the time. If we could rely upon people to make truly objective and altruistic decisions, then fine, I buy into this argument. But, we can't. Lots of people who either don't know better, or do know better but like most of us can rationalize anything, will convince themselves that their average stockdog is exceptional and worth breeding despite whatever maladies it has.

 

For example, assuming there's one main EOD gene, when a carrier is bred to a DNA clear, statistically, there will be 50% carriers. If all one cares about is EOD, the pups can be tested and a DNA clear one kept, assuming there are enough of them for a clear and statistics bear out. The rest of the pups that are carriers can be neutered. Then, if the clear selected pup is breedworthy in other ways, the line can continue without the EOD gene. The same thing can be accomplished when breeding an affected dog, except all of the first generation would be carrier. A limited number, say one that trained out the best, could be kept intact and bred to a DNA clear mate. Then the same process as with the carrier x clear mating above is carried out. Just because the other dogs produced are not being bred it doesn't decrease their usefulness or value as working dogs in their lifetimes and no affected pups would be produced.

 

Except, that is not the way things work in the real world either. Most breeders will not cull (and by cull, I mean kill) the affected or carrier pups that they don't mean to keep. Almost no one will sell a pup with a spay/neuter contract (especially if the stated reason is for health defects meaning the pups will not sell), and it's doubtful if those contracts are worth the paper they are printed on in the first place. There may be some highly ethical breeders who really care about improving the breed who would take the necessary steps to prevent affected or carrier pups from reproducing, but they would be in the minority. Therefore, assume that 80% - 90% of carriers would enter the population unaltered.

 

The estimated incidence for CEA in the Border Collie population is 2.5%. The estimated carrier rate is 25%. That pretty much means that every breeding should require DNA testing of both parents to make sure you aren't going to have affected pups because you have a 1:8 chance (0.25 x 0.25) that any given breeding will produce some affected pups.

 

We don't know what the carrier and affected rates for EOD are yet, but anectdotally I don't know anyone who has a dog with CEA, but I know at least five people with dogs with early onset deafness, and I don't know that many people. To me, that argues for an abundance of caution until we have a better handle on this.

 

 

 

However, the biggest argument I can think of for why we should go to all this trouble to keep these various individuals and their unique combination of characteristics in the gene pool despite genetic diseases is just look back and think of all the outstanding dogs and lines we *wouldn't* have if they hadn't been accidentally bred, not knowing their problem(s). I believe every dog I've had for the last two decades goes back to a dog that might be excluded if their DNA status had been known for various genetic diseases in the breed. Though there were affected dogs produced along the way, there were also many that resulted, mostly accidentally, as successful "breed throughs" of the problem. Now we can refine that. Why not do it with care and knowledge?

 

I'm not convinced by this argument either. While it may be true that, in the past, dogs who had undiagnosed genetic problems (or problems that were diagnosed but for which the genetic basis was unknown) and those dogs went on to great things and produced great lines, now that we understand and, in some cases, can test for genetic problems, those same lines can be perpetuated using unaffected siblings, parents, or other close relatives.

 

Not to nitpick, but at this point in time the argument over testing for EOD is moot. There is no genetic test. The genetics have not been elucidated. We don't know how many genes are involved. We can't test progeny. So, to my mind, the only prudent course at this point is to not breed deaf dogs.

 

Pearse

 

 

 

[Mark Billadeau]

Pearse,

 

You should note that I did not say go ahead and breed the deaf dog; I said I would not alter the dog at this point. I am not advocating breeding deaf dogs.

 

Based upon your limited statistics of EOD dogs, either the affected/carrier rates are higher than CEA or the dogs you know are from lines that have a higher carrier rate than other lines. Eliminating a large number of dogs could have detrimental affects on our gene pool (or specific lines) of working dogs.

 

Altering EOD dogs (especially the females) will have limited effect on reducing the carrier/affected rates since most will have been bred at least once prior to going deaf. Once identified these dogs should not be bred (without knowledge of the genetics of EOD) AND this information should be shared with those who have dogs from these lines.

 

Mark

[Pam Wolf]

Pearse, while I agree with most of your points, there are many people willing to buy pups with genetic disorders. Unfortunately this just helps promote the breeding of these dogs. If the sellers can't sell the pups then they will stop breeding (or at least slack off breeding) but like with puppymills, as long as people will buy they will produce.

 

We can progeny test, but breeding from suspect lines should wait til the dog is 4-5 years of age (or older with it's own set of problems) which should catch most of the affecteds. Baer testing on pups is not effecient for EOD. But if people held off breeding for a couple of years then not only would deafness be showing as an affect on the work, but testing would be able to show EOD.

 

And openness about which dogs are affected would help all. Do not attach stigma to the dogs or their breeders often the breeders did not know at the time. And sometimes accidental breedings do occure. Responsible breeders will be open as long as they are not flayed for doing so.

[Mark Billadeau]

those same lines can be perpetuated using unaffected siblings, parents, or other close relatives.

How is an unaffected sibling as good as the affected GREAT working dog when it comes to the genetics of the work? These two siblings did not receive the exact same genes. Unless the sibling has the same working ability and traits is it really a good genetic substitute for the affected sibling?

 

Mark

[nancyp]

Quote by Pam

We can progeny test, but breeding from suspect lines should wait til the dog is 4-5 years of age (or older with it's own set of problems) which should catch most of the affecteds. Baer testing on pups is not effecient for EOD. But if people held off breeding for a couple of years then not only would deafness be showing as an affect on the work, but testing would be able to show EOD.

 

 

I dont agree, We know SO little right now about EOD and the only way to know 100% sure it is early onset and not deafness at birth is to test. We are just getting into the 3-5 year olds KNOWN to be hearing at birth, But to make sure, Early testing is a important tool for this study.JMHO

[nancyp]

Altering EOD dogs (especially the females) will have limited effect on reducing the carrier/affected rates since most will have been bred at least once prior to going deaf. Once identified these dogs should not be bred (without knowledge of the genetics of EOD) AND this information should be shared with those who have dogs from these lines.

 

Mark

 

Why the females, if this is a gene carried by BOTH, then the male is JUST as important, is it not?

 

Oh I read it wrong Sorry Mark, I think you were saying JUST altering the female will not be enough.

[Mark Billadeau]

What I was referring to was the fact that it's easier on males than females to wait until 6+ years to see if it develops before breeding.

[Pam Wolf]

Nancy I did not say baer testing on pups was not necessary, but that is is NOT effective for discovering

EOD.

 

I know of dogs that were puppy tested and at 4 years of age are now deaf. That is good evidence of EOD. By virtue of the puppy testing it is known that the dog has EOD the pupppy test was normal hearing. Therefore early testing is not effective for predicting EOD.

[juliepoudrier]

Nancy I did not say baer testing on pups was not necessary, but that is is NOT effective for discovering

EOD.

 

I know of dogs that were puppy tested and at 4 years of age are now deaf. That is good evidence of EOD. By virtue of the puppy testing it is known that the dog has EOD the pupppy test was normal hearing. Therefore early testing is not effective for predicting EOD.

Did someone say it was effective for determining EOD? I don't think I've read that here. Obviously the value of BAER testing of puppies is to have a baseline, as you note. But I really don't understand where this argument about BAER testing came from--I don't think anyone said BAER testing was predictive of EOD.

 

J.

[Laurae]

Did someone say it was effective for determining EOD? I don't think I've read that here. Obviously the value of BAER testing of puppies is to have a baseline, as you note. But I really don't understand where this argument about BAER testing came from--I don't think anyone said BAER testing was predictive of EOD.

 

J.

 

Exactly!