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AKC/CHF Podcast on Genetic Testing Released

RodRussell

RodRussell

Well-known member
AKC/CHF Podcast on Genetic Testing Released

http://www.akcchf.org/news-events/multimedia/podcasts/the-basics-of-genetic-testing.html

"In this edition of Genome Barks we bring you and interview with Dr. Danika Bannasch, a veterinary geneticist with the University of California Davis School of Veterinary Medicine. An expert in genetic research and testing, Dr. Bannasch recently hosted a round table discussion on interpreting genetic test results and how to incorporate those results into a breeding program. In this podcast she discusses genetic test basics and how breeders should use genetic tests."
 
Thanks for the info -- looking forward to listening to this over the weekend. :)
 
I found it very interesting and important to note what was said about breeding affected dogs. She said and correct me if my interpretation is wrong, but to eliminate all affected dogs from breeding would have a worse effect and is not recommended. You can still breed but to a non carrier.

Even though we currently don't have a dna test for cm/sm, I think this is very relavant and goes along with why certain asymptomatic cavaliers with sm are recommended or still allowed in protocol for breeding. I hope with the publication of results and also in the future if there is a dna test for mvd, that the public understands that.

Any thoughts?

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Well, I wouldn't consider that the major point, but it is definitely a consideration. The problem is it doesn't really apply to cavaliers in the way she recommends. There is no way to determine if a cavalier is a 'carrier' of SM or MVD and all evidence is that almost every single CKCS, if not all, are carriers, so we are way past the point of rescuing the breed that way (as can still be done for Griffin Bruxellois, if breeders test and use protocols!). So you can't pick a 'non-carrier' to breed to. YOU HAVE TO TEST and use late onset breeding protocols. And that is the major problem with the majority of breeders: they don't, and the evidence is there that they don't. Most at best only check that a dog has no syrinx at 2.5 and evidence, as much as they don't want to hear it, is that they need to at least scan once more. Though some breeders try to blame the researchers, the genetic issue is what it is -- not wanting to pay for multiple scans or a cardiodologist or echocardiogram doesn't make the genetic issue go away, and multiple studies by multiple researchers in mixed geographies have been consistent on this issue now (despite what breeders claim in their own surveys... )! And researchers didn't make it up to vex breeders, they identified it as an issue that must be addressed in order to help breeders and the breed, or the breed is at the end of its road.

Cavalier breeders have no choice but to test by a specialist, and then retest as dogs age as the majority of cavaliers will have both these problems eventually, and aim for late onset dogs. Cost cannot be an excuse not to test and know what you are breeding into your dogs (or people should just get out of the breed) -- and too many still do not even test, or retest for SM at a later point, and are then in effect breeding at least one affected dog anyway, if not two. :( Simon Swift has noted that if any reasonable number breeders actually followed testing and protocol recommendations, there would have been at least some -- rather than NO -- improvement in hearts within the club breeders in the UK. The fact that there was no improvement in over a decade means hardly anyone tests or follows protocols -- despite what people say.

Breeding some dogs with small syrinxes and without clinical signs *as determined by a neurologist, not the breeder*, is part of the breeding protocol already for SM so this really isn't any big change in approach. It was already incorporated in years ago for the reasons stated in this podcast.

But ... the issue remains the majority of breeders not testing at all, not testing more than once at a young age, and/or not following breeding protocols. For all that breeders claim they are -- or tell you they are -- they aren't. It remains really hard for puppy buyers to find a single breeder in many regions who test and follow protocols. And the breed supplements from the clubs show how many breeders, including committee members and health reps, are breeding underage dogs routinely (whatever about whether any of them test their dogs).

Nonetheless I hope some of them will listen to the podcast.

PS: Would you want a puppy from an AxD litter if the odds are significantly increased that you will end up as you did so sadly with Ella? Is that risk going to be a price difference point in future? TSuch questions are going to be serious issues for puppy buyers and breeders. Maybe breeders will need to be people capable of keeping entire AxD litters to use only the As for future litters.
 
Karlin said:
Well, I wouldn't consider that the major point, but it is definitely a consideration. The problem is it doesn't really apply to cavaliers in the way she recommends. There is no way to determine if a cavalier is a 'carrier' of SM or MVD and all evidence is that almost every single CKCS, if not all, are carriers, so we are way past the point of rescuing the breed that way (as can still be done for Griffin Bruxellois, if breeders test and use protocols!). So you can't pick a 'non-carrier' to breed to. YOU HAVE TO TEST and use late onset breeding protocols. And that is the major problem with the majority of breeders: they don't, and the evidence is there that they don't. Most at best only check that a dog has no syrinx at 2.5 and evidence, as much as they don't want to hear it, is that they need to at least scan once more. Though some breeders try to blame the researchers, the genetic issue is what it is -- not wanting to pay for multiple scans or a cardiodologist or echocardiogram doesn't make the genetic issue go away, and multiple studies by multiple researchers in mixed geographies have been consistent on this issue now (despite what breeders claim in their own surveys... )! And researchers didn't make it up to vex breeders, they identified it as an issue that must be addressed in order to help breeders and the breed, or the breed is at the end of its road.

Cavalier breeders have no choice but to test by a specialist, and then retest as dogs age as the majority of cavaliers will have both these problems eventually, and aim for late onset dogs. Cost cannot be an excuse not to test and know what you are breeding into your dogs (or people should just get out of the breed) -- and too many still do not even test, or retest for SM at a later point, and are then in effect breeding at least one affected dog anyway, if not two. :( Simon Swift has noted that if any reasonable number breeders actually followed testing and protocol recommendations, there would have been at least some -- rather than NO -- improvement in hearts within the club breeders in the UK. The fact that there was no improvement in over a decade means hardly anyone tests or follows protocols -- despite what people say.

Breeding some dogs with small syrinxes and without clinical signs *as determined by a neurologist, not the breeder*, is part of the breeding protocol already for SM so this really isn't any big change in approach. It was already incorporated in years ago for the reasons stated in this podcast.

But ... the issue remains the majority of breeders not testing at all, not testing more than once at a young age, and/or not following breeding protocols. For all that breeders claim they are -- or tell you they are -- they aren't. It remains really hard for puppy buyers to find a single breeder in many regions who test and follow protocols. And the breed supplements from the clubs show how many breeders, including committee members and health reps, are breeding underage dogs routinely (whatever about whether any of them test their dogs).

Nonetheless I hope some of them will listen to the podcast.

PS: Would you want a puppy from an AxD litter if the odds are significantly increased that you will end up as you did so sadly with Ella? Is that risk going to be a price difference point in future? TSuch questions are going to be serious issues for puppy buyers and breeders. Maybe breeders will need to be people capable of keeping entire AxD litters to use only the As for future litters.
Click to expand...

Great post, Karlin!
 
Karlin said:
But ... the issue remains the majority of breeders not testing at all, not testing more than once at a young age, and/or not following breeding protocols. For all that breeders claim they are -- or tell you they are -- they aren't. It remains really hard for puppy buyers to find a single breeder in many regions who test and follow protocols. And the breed supplements from the clubs show how many breeders, including committee members and health reps, are breeding underage dogs routinely (whatever about whether any of them test their dogs). .
Click to expand...


In the UK over half of all the litters registered with the Kennel Club have at least one parent under 2.5 years.

For cavalier club members the figures are the same. Over half of their litters are from cavaliers that are under the health guideline age for both SM & MVD.

Even IF these cavaliers have been health checked, the tests would have been done too young to fit the health protocols that every Cavalier Club member signs up to.


Karlin said:
PS: Would you want a puppy from an AxD litter if the odds are significantly increased that you will end up as you did so sadly with Ella? Is that risk going to be a price difference point in future? TSuch questions are going to be serious issues for puppy buyers and breeders. Maybe breeders will need to be people capable of keeping entire AxD litters to use only the As for future litters.
Click to expand...

If I was looking for a family pet for my children or a companion in my old age then I would want to have the best chance possible that it would remain healthy.
I would not expect to be offered a puppy that was the deliberate consequence of a risky breeding without being fully informed what I was taking on, and why this puppy had been put at increased risk of a painful life.

I do accept that there is an argument for the need to maintain genetic diversity, although show breeders continuing use of close line breeding, & the queues to use the same underage popular sires, would suggest that for many of them diversity is more an excuse than a real concern.

So this is a big dilemma, and one of the reasons that some breeders do not want MRI results published. They will now have to be prepared to explain and justify their grading choices to the people that buy their puppies.
 
Margaret C said:
In the UK over half of all the litters registered with the Kennel Club have at least one parent under 2.5 years.

For cavalier club members the figures are the same. Over half of their litters are from cavaliers that are under the health guideline age for both SM & MVD.

Even IF these cavaliers have been health checked, the tests would have been done too young to fit the health protocols that every Cavalier Club member signs up to. ...
Click to expand...

That information is amazing, considering that many bitches are bred more than once. This would mean, perhaps, that they were under 2.5 years at the time of their second litters, too.
 
Margaret C said:
... I do accept that there is an argument for the need to maintain genetic diversity, although show breeders continuing use of close line breeding, & the queues to use the same underage popular sires, would suggest that for many of them diversity is more an excuse than a real concern. ...
Click to expand...

Excuses for not taking personal responsibility abound in the fancy.

According to the AKC, in the USA, breeders eliminate roughly 80% of their "potential" breeding stock right off the top, due to the dogs' non-compliance with the breeders' evaluation according to the cosemetic, structural, and temperament breed standards. These become the "placed" puppies offered to pet owners.

So, if they are going to carp about genetic diversity, they should start off by closely examining those faces they see in their mirrors.
 
Karlin said:
PS: Would you want a puppy from an AxD litter if the odds are significantly increased that you will end up as you did so sadly with Ella? Is that risk going to be a price difference point in future? TSuch questions are going to be serious issues for puppy buyers and breeders. Maybe breeders will need to be people capable of keeping entire AxD litters to use only the As for future litters.
Click to expand...

To answer your question, I would have to look at the whole breeding. If the D cavalier was 6 years old, they technically could have been an A scanned younger. I would want to know history and not just that mating. I have mentioned to someone that age of onset seems to me as a big factor, so I would want the grandparents history etc.

Let's not forget MVD. There are cavaliers that have pedigrees or some with clear hearts over 9 years old. According to :

http://cavalierhealth.com/mvdprotocol.htm

• The offspring were ten to twenty times more likely to be free of MVD murmurs if the sire's heart was clear of murmurs at ages nine to eleven years.

I don't know of many matings that old but all I know is when I buy a puppy, there will be many things I will consider and having multiple scans would be one of them.
 
Going through what I did with Ella, actually brought me in contact with some great breeders. I would be in contact with them when I get a puppy.
 
I actually don't want to bring Ella up. I know what Ella went through and I also see on here what Cavaliers with CM alone go through so I would appreciate not mentioning her in relation to this discussion.
 
Fine, though Anne, you bring her up regularly yourself in many kinds of discussions, especially ones like this, so it is hard for someone to know that you don't want her mentioned.

The point then is that someone who has gone through the trauma of dealing with an SM affected dog knows only too well how awful this is. If there is a 25% greater risk of producing SM puppies from an AxD litter -- would you buy one from a breeder? It is a question directly tied to your stressing that people need to understand breeders need to include D graded dogs. That is a fine point to make -- but in reality it means breeding dogs with a higher risk of pain, and someone will buy those puppies that go on to live a life with SM and may go through a serious case of SM. I have a moderate-pain dog and that is hard enough; thankfully so far the other two are low symptom but it is very stressful regardless of how affected a dog is as all can change in weeks or days.

Surely it is not fair to expect others to buy the AxD puppies while those of us with SM dogs -- and I have three -- only will choose AxA offspring?. Will AxD puppies be cheaper? Will breeders help fund their treatment if affected? Should breeders hang on to full litters and rescan and select the A dogs for future breeding?

Personally I'd only be ever taking a puppy from an AxA litter if I ever buy a cavalier puppy again.
 
Hi

Was the MVD breeding guideline a compromise at 2 1/2 if so why,and who settled at that age the breeders ,cardios who ? , and have I seen the age of 5 mentioned somewhere .

It is utterly disheartening for the future of the breed when you read that half of litters registered under age are by Cavalier Club members that is an absolute horrible fact and I bet some of those very same people are so critical of byb and puppy
farmers ,whether they have been breeding for centuries or more and know every molecule of their dogs to breed under 21/2
when MVD is the biggest killer should never ever be done.
 
Brian M said:
Was the MVD breeding guideline a compromise at 2 1/2 if so why,and who settled at that age the breeders ,cardios who ? , and have I seen the age of 5 mentioned somewhere ..
Click to expand...


I believe it was the cardiologists that first devised the MVD protocol. The quickest & surest way to breed out early onset MVD would be to only breed cavaliers over five years old & clear of murmur.

Because it was impractical to wait so long, a compromise was agreed. Parent cavaliers that were two and a half years old & murmur clear could be used, as long as their parents were five years or over and heart clear.


Brian M said:
It is utterly disheartening for the future of the breed when you read that half of litters registered under age are by Cavalier Club members that is an absolute horrible fact ,
Click to expand...


Just to make things clear that was not quite what I wrote which was.......

"For cavalier club members the figures are the same. Over half of their litters are from cavaliers that are under the health guideline age for both SM & MVD."

Cavalier Club members are not responsible for half the underage litters registered, but half the litters club members do produce have one parent that is too young.
 
Karlin said:
Fine, though Anne, you bring her up regularly yourself in many kinds of discussions, especially ones like this, so it is hard for someone to know that you don't want her mentioned.

The point then is that someone who has gone through the trauma of dealing with an SM affected dog knows only too well how awful this is. If there is a 25% greater risk of producing SM puppies from an AxD litter -- would you buy one from a breeder? It is a question directly tied to your stressing that people need to understand breeders need to include D graded dogs. That is a fine point to make -- but in reality it means breeding dogs with a higher risk of pain, and someone will buy those puppies that go on to live a life with SM and may go through a serious case of SM. I have a moderate-pain dog and that is hard enough; thankfully so far the other two are low symptom but it is very stressful regardless of how affected a dog is as all can change in weeks or days.

Surely it is not fair to expect others to buy the AxD puppies while those of us with SM dogs -- and I have three -- only will choose AxA offspring?. Will AxD puppies be cheaper? Will breeders help fund their treatment if affected? Should breeders hang on to full litters and rescan and select the A dogs for future breeding?

Personally I'd only be ever taking a puppy from an AxA litter if I ever buy a cavalier puppy again.
Click to expand...

The other elephant in the room is what happens to the cavaliers that breeders scan when they are found to have a syrinx?

Many small breeders have faced this and decided it is their responsibility to keep the affected cavaliers, but there is a limit to how many non-productive cavaliers can be kept, especially in the more commercial kennels.

There is good evidence that such dogs have been passed on to pet owners without the diagnosis being revealed (why else would a dog with a CC be given away for free?) or passed on to rescue services.
 
Brian M said:
... Was the MVD breeding guideline a compromise at 2 1/2 if so why,and who settled at that age the breeders ,cardios who ? , and have I seen the age of 5 mentioned somewhere ...
Click to expand...

I was at the symposium at which the MVD protocol was introduced to USA breeders in Atlanta in May 1998. The geneticist Lennart Swenson explained that the ideal protocol was to wait until the breeding stock was 5 years old and murmur-free (by auscultation). Because the drafters expected opposition to such a delay in the first mating, he said that if the breeding pair were at least 2.5 years old and murmur-free AND all four of their parents were at least 5 years old and murmur-free, then that protocol would be just as good.

I have a verbatim transcript of that symposium.

I believe a similar symposium was held in the UK in 1996, and that Prof. Swenson made an identical presentation.
 
Brian,

I posted a link to rods website on a previous thread about mvd protocol history. I know the UK has an over 5 list. I will say that france has a different scheme.

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The UK Club's over 5 list until recently accepted dogs that were declared clear by a vet and did not require a cardiologist clearance -- so a lot of the dogs on that list would have a question mark hanging over that 'clear' as a UK study has shown vets miss half of all early grade murmurs.
 
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