Collie that won Westminster is son of double merle

[Dekka]

Originally Posted by OutlineACDs

Seeing as ACD's get their deafness from dalamatians I'd say this is absolutely true.

As a rule breeders don't breed deaf puppies, but its not looked down upon to breed a uni.

This is interesting. Deafness is an issue with JRTs. Most will not breed a known uni as a rule. Are good bloodlines so rare in ACD (I honestly have no idea..) that its a risk worth taking?

To me saying the litter has no deafness doesn't mean much. As if its recessive (which at the very least it would have to be) you would be highly unlikely to get deaf puppies unless the sire was a carrier or affected. However all those puppies are possible carriers..

The LHW do have a small enough gene pool that breeding known carriers (but not affected) of genetic based issues to clear dogs is quite common. So I am not against it, but these things need to be tracked.

Seren might be a carrier for an eye issue. One of her parents is a carrier. But as long as the people getting the puppies, or grand puppies KNOW that there is a potential issue its not a huge detriment to the breed. But if no one knows that their dog's great grandmother had X recessive issue then they might not be able to make good decision without all the data.

[Laurelin]

I was always under the impression that deafness was strongly correlated with pigmentation on the ear (specifically inside the inner ear but a lot of times the dogs with white on the visible part of the ear also had no pigmentation inside)

Paps and JRTs are extreme piebalds. Paps specifically have a requirement in their breed standard to have color over both eyes and ears and my assumption was it wasn't just a cosmetic standard but also to help avoid deafness.

The CHW sheltie I know that is deaf has partially white ears.

[OutlineACDs]

Originally Posted by Dekka

This is interesting. Deafness is an issue with JRTs. Most will not breed a known uni as a rule. Are good bloodlines so rare in ACD (I honestly have no idea..) that its a risk worth taking?

To me saying the litter has no deafness doesn't mean much. As if its recessive (which at the very least it would have to be) you would be highly unlikely to get deaf puppies unless the sire was a carrier or affected. However all those puppies are possible carriers..

The LHW do have a small enough gene pool that breeding known carriers (but not affected) of genetic based issues to clear dogs is quite common. So I am not against it, but these things need to be tracked.

Seren might be a carrier for an eye issue. One of her parents is a carrier. But as long as the people getting the puppies, or grand puppies KNOW that there is a potential issue its not a huge detriment to the breed. But if no one knows that their dog's great grandmother had X recessive issue then they might not be able to make good decision without all the data.

And.. I just lost a huge post. I dislike laptops.

Yes our gene pool is small. A lot of breeders neutered/spayed a large percentage of dogs when the genetic test for PRA came out. If a dog was rated a C (affected), the majority of breeders assumed no one would ever want to breed to it and went ahead an neutered them. We lost a lot of dogs when that happened.

Take into account OFA (I do hips and elbows), PRA genetic testing, CERF, BAER testing, then on top of that working ability and temperament and your choices can get limited.

I also can't report on any offspring out of my litter seeing as none of the puppies were ever bred. So I don't have anything further to add about that line. I try to keep up with research and other breeeders. I will say that people are usually up front and honest about what they are producing. Before I used that dog at stud I did ask if he has produced any deaf puppies, or uni's. I also asked my bitch's breeder about dogs behind her and did my pedigree research with OFA as well.

I'm not sure about the amount of white on ACD's having anything to do with deafness. I've seen heavily mottled dogs, and dogs with BIG splotches of white be full hearing and produce pups with full hearing. My two bitches that were uni's were both minimally to moderately speckled with no white on the ears. My male who is bilateral hearing has a big bentley (white mark on forehead), and he's moderately mottled on his sides and legs.

[Dekka]

I hate loosing posts too!

Thanks that was intersting. White is often believed to have a factor in deafness in JRTs. People are particularly interested in BAER tests on dogs with white ears. Though I know many an all white JRT (or all white ears) with normal hearing and a few that have fully pigmented ears who are uni.

[Greenmagick]

I know in danes, with harls and double merles, pigment is definitely an issue.

From http://www.deafdogs.org/faq/

What Causes Deafness in Dogs?

What causes a dog to lose its hearing? A lot of the same things that cause hearing loss in humans. Genetic defects can cause a dog to be born deaf; this is known as congenital deafness. A dog can also lose its hearing due to an ear infection, injury to the ear, or may experience gradual (or sudden) hearing loss due to old age. Exposure to loud noise can cause temporary or permanent hearing loss, as can certain drugs.

The most common cause of congenital deafness is pigment related. (There is some talk about a recessive gene as well, but most researchers do not believe this is the case.) Some dogs have white coats, but still have pigmented skin (Samoyeds, West Highland Terriers, and White German Shepherds fall into this category). Although they have white fur, they have black noses and eye rims (their fur is actually not pure white, but a very light buff color). Other dogs normally have colored coats, and white trim (this includes Dalmatians; the white is actually not their real coat color, the "spots" are). The "trim" comes from areas of unpigmented (pink) skin, which produces white hair. If there is unpigmented skin in the inner ear, the nerve endings atrophy and die off in the first few weeks of the puppy's life, resulting in deafness. Please note that you cannot tell the color of hairs in the inner ear by looking at any visible part of the dog's ears (including the hair around the ear canal). Although many dogs with white hair on their ears will be deaf, many deaf dogs have colored ears as well.

[Romy]

Originally Posted by Dekka

This is interesting. Deafness is an issue with JRTs. Most will not breed a known uni as a rule. Are good bloodlines so rare in ACD (I honestly have no idea..) that its a risk worth taking?

To me saying the litter has no deafness doesn't mean much. As if its recessive (which at the very least it would have to be) you would be highly unlikely to get deaf puppies unless the sire was a carrier or affected. However all those puppies are possible carriers..

The LHW do have a small enough gene pool that breeding known carriers (but not affected) of genetic based issues to clear dogs is quite common. So I am not against it, but these things need to be tracked.

Seren might be a carrier for an eye issue. One of her parents is a carrier. But as long as the people getting the puppies, or grand puppies KNOW that there is a potential issue its not a huge detriment to the breed. But if no one knows that their dog's great grandmother had X recessive issue then they might not be able to make good decision without all the data.

What about the instances cited where two deaf parents were bred to produce an all hearing litter? To me that says it may have more to do with the white pigment than a simple dominant or recessive gene.

There's a point early in the fetal development of all animals (except albino) where the pigment migrates off the neural crest. That's why almost every single kind of animal has a "default" coloration where they are darker along the spine and lighter on the belly. It also just happens that it is a good camouflage pattern, but that pattern exists mostly because that's how pigment migrates. The amount tapers off by the time it reaches the stomach.

When you have genes for white spotting, that migration is pretty random. That is why clones of spotted animals have completely different markings from each other and from the "parent". The distribution of the white spotting isn't controlled by any gene, it's just present due to a gene, and the actual pigment migration is kind of random and/or influenced by unknown conditions in the womb.

[Dekka]

Originally Posted by Romy

What about the instances cited where two deaf parents were bred to produce an all hearing litter? To me that says it may have more to do with the white pigment than a simple dominant or recessive gene.

.

Actually it doesn't say that to me. In order to test that one would need to clone deaf and hearing high white dogs to see if the clones (who as you mentioned would have different markings) were or were not deaf.

And looking at how many pigmented dogs have deafness and unpigmented dogs don't.. one can't say its more or less related to that. It could be that the whiteness is a by product of the genes that create the hearing issues.

Once one leaves pea plants genetics gets more complicated than a punnet square. You also get genes that are epistatic to others, incomplete and co dominance etc. Penetrance is also an issue with genotype to phenotype expression. It may indeed by a 'simple' genetic trait that is being masked, or imcompletely expressed due to other genes, that may have some bearing on white.

As an aside, you cannot get a true albino horse. You end up with a lethal white. Its not the being white that kills, or the lack of pigmentation.. its the other genetic factors that come along with that particular genotype that kill.

[elegy]

What I can't get past in all of this is that it's being done for a COLOR. Why on earth is there so much emphasis on merle when a merle dog is not going to be better or healthier or anything else vs a non-merle? Because it wins in the show ring? Because it's "prettier" and flashier?

Just one more illustration of what is wrong with the dog fancy these days. For too many people it has become not breeding toward a better dog but breeding toward what will win or what is the current fad or what is the most unique. Far too often to the detriment of the dogs.

[Beanie]

Originally Posted by elegy

What I can't get past in all of this is that it's being done for a COLOR.

Yup... that's why it makes me feel so ill. There's no advantage to a merle x merle breeding except "ohhh pretty puppies!"

[Miakoda]

Originally Posted by Lilavati

I haven't read the whole thread, but I keep thinking there's a very simple solution to deliberate merle X merle breedings, if only the AKC or the breed club would do it . . . any offspring of such a mating has a pet registration. Period. It's pups can't be registered.

Although there might still be accidental merle X merle breedings, it would put an end to people doing it on purpose.

Of course, that would require that the AKC do something . . .


As for spaying a bitch after such a breeding . . . I don't see a reason why one should be obliged to abort the whole litter, killing healthy puppies as well and lose the brood bitch. As much as I think the puppies from such a breeding should be only registrable as pets . . . I'll probably be flamed for this, but I think I'd just put down any double merles shortly after birth rather than kill the whole litter. It would be just as a merciful as an abort and saves the rest of the litter and the bitch's breeding capacity.

Lil, I'm proud that the American Dog Breeder's Association (ADBA) refused to register merle "APBTs". Of course merle "APBTs" just miraculously appeared in the mid/late 1990's (there's no historical evidence that merle APBTs ever existed), but people didn't want to see the continued ruining of double merle breedings.

However, there is a breeder in Mississippi who breeds litter after litter of merle "APBTs" and will argue you till your blue in the face that such creatures are a part of history, but just glance over her newspaper ad for outrageously priced mutts.