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white factor dogs


Leigha
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I have heard people speculate that sheep react differently to a white dog. Others see no difference. I wonder if the white dog's similarity in appearance to a wolf might make sheep (or shepherds) edgy?

attachicon.gifarctic-wolf.jpg attachicon.gifChiannaFredCarter.jpg

 

There are top-class handlers who aren't prejudiced against dogs with a lot of white. Some dogs with a great deal of white have won the Supreme. I know some good handlers that like a lot of white because they feel it settles the sheep.

 

Wolves come in all shades from quite white to quite black, so I doubt that's an issue! :D

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The argument I've always heard is that sheep won't respect a white dog because _______________ (insert reason here, but usually because they look like sheep). That usual reason doesn't make sense to me because there are plenty of breeds of sheep who aren't white, livestock guardian dogs that aren't white, and white headed dogs whom no one would say can't move sheep because of the color of their heads, which is pretty much the first thing the sheep will see as the dog approaches them.

 

But the reasoning is that the sheep won't respect a white dog and therefore will tend to challenge it, which in turns causes the dog to lose confidence. Wash, rinse, repeat. I haven't experienced that with my own white dog, but who knows? The belief came from somewhere and probably has a kernel of truth, perhaps based on the experiences of one or more individuals at some time in the past.

 

There's at least one very well known handler who thinks red dogs just don't hold up as well (physically).

 

But for every naysayer, there's probably someone who's had a different experience.

 

As for my white dog, when he had just turned three I threw him in at Edgeworth (600-yard outrun) when Kat (my other open dog at the time, besides Twist) came up lame. He made the outrun, but the sheep had drifted down the hill face and so he passed behind them on the other side of the ridge. At Edgeworth the set out is far enough away that's it's really difficult to see what's happening (I've told the story of Kat passing across the entire top end of the field with me not seeing her), and you just have to count on the dog to do the job. Well, I could see Pip once he came out from behind the ridge, where he had passed behind the sheep without seeing them and so went on to the set out pens. Because I could see his bright white self, I was able to redirect him on to his sheep and bring them on down the field. Of course, that's not an argument for having a white dog, but white is pretty easy to see at a distance. Just don't ask me to find him if he's moving away from me and it's foggy. :lol:

 

Having had a lot of experience setting out with Pip I can honestly say that very few dogs mistake him for a sheep, but there has been the occasional dog that will just keep looking at him and if it had a thought bubble over its head it might be thinking something like "It smells like a dog, but kind of looks like a sheep. WTF?" But the vast majority of dogs go right on past him to pick up their sheep without a second glance.

 

J.

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OK, so having read all the archives for hours, here's what I've concluded.

 

Please let me know if anyone disagrees with this and why?

 

1. White factoring is usually indicated by white extending up the hind legs from the paws to above the hocks or having any white on the sides or back of the dog.

 

2. A BC could be white factored but NOT meet the above criteria and one would only know with DNA testing or if the dog was bred to a white factored dog and produced mostly white puppies.

 

3. A white factored dog with a dark head is not neccesarily any more prone to health problems, including hearing or blindness, than non-white factored dogs.

 

4. Dogs with mostly black bodies and are NOT white factored but have lot's of white extending over eyes and/or ears DO have a predispsition for hearing and eye problems including blindness and/or deafness.

 

5. Breeding two merle dogs together will produce a higher incidence of puppies born with either hearing problems, eye problems or both.

 

6. Breeding two white factored dogs together with dark heads will produce dogs just as healthy as breeding two non-white factored dogs together.

 

7. Breeding two dog that are NOT white factored but both have white extending over their eyes and/or ears will produce puppies with a higher incidence of hearing and/or eye problems.

 

8. White on the head, shoulders and/or front legs does NOT indicate white factoring.

 

9. BC's should be bred based on working ability and NOT color. This means breeders should NOT show prejudice against breeding two white factored dogs together, all other considerations being equal.

 

10. Breeding two dogs together BOTH with white extending over their ears and/or eyes, even if the dogs are well matched based on working ability, should be discouraged.

 

11. Breeding two merle dogs together should be highly discouraged.

 

Whew!

 

Bonnie

 

 

 

 

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I don't have time to answer all your points, but I want to note that white headed dogs don't necessarily have a predisposition for hearing problems. There appears to be a correlation between white ears and possible deafness, but you can't necessarily tell that by looking because the lack of pigmentation of the hair cells in question is related to the hairs of the inner ear. One can assume that a dog with a white head/white ears would have white hairs inside the ears (although it's not a guarantee), but one can't assume that a dog with dark ears doesn't have white hairs inside the ears. There have been plenty of very dark dogs who are deaf. As far as I know, causation of deafness by the presence of white heads/ears has not been scientifically proven, beyond the idea that deafness associated with white ears is likely the result of lack of pigmentation in the cells of the inner ear. I believe at this point it is seen simply a correlation (i.e., white head/ears doesn't automatically cause deafness, nor does it mark a particular likelihood statistically that a dog will be deaf <--someone can correct me on this latter point if there is actually some sort of scientic statistics regarding percentage of dogs with white heads/ears who are also likely to be deaf).

 

I've never heard of any eye/sight issues associated with white headed dogs, only with double merles (who often appear with a lot of white on them, but the genetics of double merle are quite different from the genetics of a white head and just because the MM dog can have eye problems--at the worst this would include having no eyes--white headed dogs do not have any of those same eye problems that are associated with a doube merle).

 

The "hidden merle" is a very real possibility, but I don't think too many people have encountered "hidden white factors." Again, I have no data to support that, but most white factored dogs are fairly obvious, and because you aren't running to risk of some of the terrible health issues that can be associated with double merle, there's no compelling reason to search for a hidden white factor (do they even have a genetic test?) because the worst you'll get breeding white factored dogs together is dogs with a lot of white on them..

 

Again, the genetics of white factoring and white headed are different. One does not correspond to the other. White factored dogs, all the way up to and including fully white dogs are no more prone to health problems than their non-white-factored counterparts. White headed dogs might have the possibility of a greater chance of deafness, but as I said above, as far as I know there are no actual statistics to indicate the risk of deafness associated with a white head/ears.

 

J.

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11. Breeding two merle dogs together should be highly discouraged.

 

Whew!

 

Bonnie

 

More than "highly discouraged" I think it's totally irresponsible to accept the very significant risk of deformed/defective pups just in order to produce a color (any color). It's my belief that any registry should refuse to register pups from a double-merle breeding because of the high likelihood of both eye and ear issues (blindness and deafness).

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I have heard that a dog can be white factored for head, white factored for body, or both. I have also heard that if I didn't want all white (give or take), to breed my white factored (for body, not head) dog to a dark bitch. He did have one split face puppy, when bred to a very dark bitch, and the split face is deaf in her black ear. I've looked as far down her black ear as she'll let me and have seen no white hairs, but the BAER test for that ear was a total flat line. She is about 50/50 BW. Both her parents have Arthur Allen's Spot in their pedigrees at about the same line. She looks very much like AA Spot's dad Gilchrist Spot. She can be a very good working dog, but erratic in her biddability, which will take me back up the boards to Donald's latest addendum to "Instrument repair".

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Big mistake people make is looking at a litter of pups with split faces and assuming the pups with white will be the ones with hearing loss. The white faces just indicate a genetic predisposition for a failure of migration of stem cells. The darkest pup in the litter can be deaf while the white headed pup can have normal hearing. That's why the entire litter should be BAER tested.

 

I have a dog that went deaf in one ear. His biddability became erratic precisely because of his hearing loss. Your dog might not be disobeying you. Sound does funny things to dogs with normal hearing. Your dog may not be able to hear you well enough to follow commands under many conditions.

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5. Breeding two merle dogs together will produce a higher incidence of puppies born with either hearing problems, eye problems or both.

 

This is true, but unless I'm mistaken (and I'm pretty sure I'm right about this) it is only true of the pups that are homozygous, that is, if they've received 2 copies of the merle allele. These dogs are otherwise known as double merles, written as MM.

 

Merle to merle matings will produce, statistically, 25% solid color pups (i.e. black & white, red & white, etc.), 50% merle pups and 25% double merles. It is these double merles that are highly likely to have vision and/or hearing impairments.

 

(These statistics would change if a double merle were bred to a solid color dog, in which case 100% of the pups would be heterozygous merles, i.e. Mm. I read of a double merle rough Collie that's being used at stud to produce all merle litters. If he were ever -- doG forbid -- bred to a merle, the litter would be statistically be 50% MM amd 50% Mm.

 

Therefore, your #5 point leads the the #11 recommendation. IMO, it is unethical to ever breed merle to merle. There is nothing "better" about the heterozygous merles produced and the homozygous ones are either culled at birth or go on to lead (imo) incomplete lives as handicapped dogs.

 

The "hidden merle" is a very real possibility

 

While there are such things as "hidden" merles, more often referred to as "cryptic" or "phantom" merles, merles don't just crop up out of the blue. One of that dog's parents was merle. So, yes, if you breed an apparently solid colored offspring of a merle to another solid dog, there's a very small chance that you could get merle puppies. And that dog would have a small area of merle on it somewhere that has gone unnoticed, usually blending into the line between color & white, or with ticking or something similar. This would be consistent in all litters. An unintended merle to merle breeding could be prevented by a test breeding to a solid dog, although it's possible, but rare, for a merle to produce no merle puppies in one litter.

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The article on hearing loss was a correlation study between hearing loss and various phenotypes (looks). There was some correlation between excessive white on the head, 1 blue eye, and 2 blue eys with hearing loss. This does not demonstrate cause and affect.

 

I'll post a link to the article later (I have to go now) and some comments from Mark Neff on the likely genetics of this (I asked him about this).

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Here is the link I promised

Prevalence of Unilateral and Bilateral Deafness in Border Collies and Association with Phenotype

********************************************************************************************************************

Mark Neff's comments were there is a gene which controls the production of a protein that produces color in hair and then there are genes that control where the lack of pigementation will occur. These two things lead to incomplete correlation between deafness and coat coloration.

 

 

 

Here is the background section from an article on deafness in another breed which sumarizes what is known about deafenss in several breeds. In this the authors discuss a follow-up study in Border Collies (reference 12) where excessive white on the head did not correlate to deafness; I have not found free access to the entire reference 12, only the abstract.

Prevalence of congenital hereditary sensorineural deafness in Australian Cattle Dogs and associations with coat characteristics and sex

 

Background

Congenital hereditary sensorineural deafness (CHSD) is a common form of deafness in dogs and has been reported in over 80 breeds, including the Dalmatian, Bull Terrier, Border Collie and Australian Cattle Dog [1]. This form of deafness can be identified in pups from about six weeks of age, and should be differentiated from sensorineural deafness due to degeneration of the auditory pathway, which usually occurs later in life, and from conductive deafness associated with aural pathology or chronic infection. Congenital hereditary sensorineural deafness can affect one or both ears, and is an all or nothing phenotype in the affected ear [1]. Bilaterally deaf pups are often identified by breeders without clinical testing, but unilateral deafness is difficult to detect without brainstem auditory evoked response (BAER) testing [2].

 

Congenital hereditary sensorineural deafness appears to have a variable relationship with pigmentation in different dog breeds. In breeds with solid coloured coats, such as the Doberman and Shropshire Terrier, CHSD is not associated with pigmentation and the causative lesion has been described as cochlear neuroepithelial degeneration [3,4]. In other breeds, such as the Dalmatian and Bull Terrier, CHSD is associated with a lack of coat and iris pigmentation, which is associated with absence of melanocytes in these tissues. In this latter form of deafness, there is degeneration of the stria vascularis of the cochlea during the first four weeks of life [5,6] and an absence of melanocytes in the stria of affected dogs [5,6].

 

Mode of inheritance

While for many years, the mode of inheritance of CHSD has been uncertain in many breeds including the Australian Cattle Dog, results from a recent study support CHSD being inherited as an autosomal recessive trait with incomplete penetrance in the Australian Stumpy-tail Cattle Dog [7]. In that study, the deafness phenotype was associated with red-based coat colour and possibly speckling, leading to the suggestion that genes for these coat characteristics may form a tightly linked gene cluster with the gene variant associated with this form of deafness. There is evidence that this gene cluster is on CFA10[7]. In contrast, a variety of inheritance mechanisms have been suggested for the Dalmatian, mainly involving the interaction of several genes [8-10].

 

Association of CHSD with lack of pigmentation

In several dog breeds, lack of pigmentation, rather than a specific base coat colour, has been associated with CHSD. In a study of 2,597 Border Collies, prevalence of deafness was higher in dogs with merle coat pigmentation, excessive white on the head, or blue eyes [11]. However, this contrasts with findings from a later study, where the prevalence of CHSD was not increased in Border Collies with increased white head patches [12]. In many studies in Dalmatians, the prevalence of CHSD was higher in dogs with blue eyes [1,8,9,13-16], and further, the prevalence of CHSD in Dalmatians was lower in dogs with pigmented patches in addition to pigmented spotting [1,8,13,14,16]. This may also be consistent with a recent study in the Australian Stumpy-tail Cattle Dog, a breed related to the Australian Cattle Dog, where speckled marking of the coat was weakly associated with deafness [7]. Speckled coats show an even distribution of white and red or white and black hairs [7]. To date, no study has been published investigating possible associations between CHSD and speckled or mottled coat pattern, or between CHSD and pigmented head or body patches in the Australian Cattle Dog. The only study conducted in Australian Cattle Dogs included 293 dogs, and found no significant difference in the prevalences of CHSD by coat colour (blue, red, blue and tan, or blue and black and tan) [1].

 

Association with sex

Relationships between CHSD and sex have not been observed in Australian Cattle Dogs, Australian Stumpy-tail Cattle Dogs, Border Collies, Bull Terriers, and in some studies in Dalmatians [1,7,8,11]. In contrast, in other studies in Dalmatians, females were more likely to have CHSD [14,15,17]. In one study, while there was a higher prevalence of CHSD in female Dalmatians, there was also a higher prevalence of heterochromia iridis (HI) in the females compared with males [17]. Heterochromia iridis, an incomplete pigmentation of the iridial stroma, is independently associated with CHSD [17], so this finding also supports a relationship between pigment gene expression and gender. However, in another study, despite a higher prevalence of deafness in females, HI was more common in males [14]. No mechanism for this possible sex predisposition has been proposed.

 

The link has the entire article with references.

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Here is what I can find on reference 12. Note that excessive white on the head was not listed in the phenotypes that correlated to deafness. Since two of the authors of this follow-up study were part of the first study, presumably they would have looked at head coloration.

 

 

I suspect (an untested hypothesis) that when any pup in the litter has 1 or 2 blue eyes, a merle coat, or excessive white on the head; any of the pups in the litter are at increased risk of deafness (not just the pups with these phenotypes). This hypothesis would fit with the incomplete or inconsistent correlation between deafness and coat color within the same individual pup in a litter.

 

 

Prevalence, heritability and genetic correlations of congenital sensorineural deafness and pigmentation phenotypes in the Border Collie

 

De Risio L, Lewis T, Freeman J, de Stefani A, Matiasek L, Blott S.

 

Abstract

The objectives of this study were to estimate prevalence, heritability and genetic correlations of congenital sensorineural deafness (CSD) and pigmentation phenotypes in the Border Collie. Entire litters of Border Collies that presented to the Animal Health Trust (1994-2008) for assessment of hearing status by brain stem auditory evoked response (BAER) at 4-10 weeks of age were included. Heritability and genetic correlations were estimated using residual maximum likelihood (REML). Of 4143 puppies that met the inclusion criteria, 97.6% had normal hearing status, 2.0% were unilaterally deaf and 0.4% were bilaterally deaf. Heritability of deafness as a trichotomous trait (normal/unilaterally deaf/bilaterally deaf) was estimated at 0.42 using multivariate analysis. Genetic correlations of deafness with iris colour and merle coat colour were 0.58 and 0.26, respectively. These results indicate that there is a significant genetic effect on CSD in Border Collies and that some of the genes determining deafness also influence pigmentation phenotypes.

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Thanks so much for your input all and I think we have shed some light on this very confusing topic and helped me at least, come to some basic understanding of white factoring.

 

I'm still up for edits.........:~) Hope I got it close to right this time.

 

Here's is the amended White Factor faq's:

 

1. White factoring is usually indicated by white extending up the hind legs from the paws to above the hocks or having any white on the sides or back of the dog.

 

2. A BC could be white factored but NOT meet the above criteria and one would only know with DNA testing or if the dog was bred to a white factored dog and produced mostly white puppies.

 

3. A white factored dog with a dark head is not neccesarily any more prone to health problems, including hearing and/or blindness, than non-white factored dogs.

 

4. Dogs with mostly black bodies and are NOT white factored but have lot's of white extending over eyes and/or ears MAY have a predispsition for hearing

problems and/or deafness, although this predisposition is not conclusive.

 

5. Breeding two merle dogs together will produce a higher incidence of puppies born with either hearing problems, eye problems or both.

 

6. Breeding two white factored dogs together with dark heads will produce dogs just as healthy as breeding two non-white factored dogs together, although the puppies will have more white on their bodies than if two non-white factored dogs were bred together.

 

7. Breeding two dog that are NOT white factored but both have white extending over their eyes and/or ears MAY produce puppies with a higher incidence of hearing problems and/or deafness.

 

8. White on the head, shoulders and/or front legs does NOT indicate white factoring.

 

9. BC's should be bred based on working ability and NOT color. This means breeders should NOT show prejudice against breeding two white factored dogs together, all other considerations being equal.

 

10. Breeding two dogs together BOTH with white extending over their ears and/or eyes, even if the dogs are well matched based on working ability, should be discouraged.

 

11. Breeding two merle dogs together should be NEVER be done and WiLL produce puppies with hearing and/or eyesight problems.

 

12. Because a correlation between head pigmentation and deafness is not firmly established, the only way to know if a puppy has hearing problems is with BAER testing.

 

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The ABCA Health & Genetics Committee has no recommendations against breeding white factored dogs or dogs with excessive white on the heads since there is no conclusive scientific evidence to support making such a recommendation (see wyndrunhr's #10).

 

Mark Billadeau

ABCA Health & Genetics Committee Chair

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I think Mark's most recent post sums it up nicely.

As I said in an earlier post, you can also breed two dark dogs, or two dark-headed dogs, and get deaf puppies, so I'm not sure why you keep focusing on dark heads being okay and light heads not....

 

The only color-based breeding virtually guaranteed to cause genetic defects is merle-merle.

 

J.

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I wasn't even aware of the term "white factored" until I came on here. I'm reasonably clued up on the no-nos of breeding healthwise (although have no intention of breeding myself) and it's seemed a non-issue to me.

 

From my non scientific study perspective, looking round at the many hundreds of BCs I see regularly, a large proportion seem to be white factored, just as a large proportion aren't. I shall continue my sampling to test my initial hypothesis since I obviously haven't examined each and every dog closely.

 

Given that a lot of breeding seems to happen without much (or any) thought, if there were health issues in question I guess that they would be more common than they are, but there are very few congentially deaf dogs that I know of, though I do accept that the number I see will be skewed by the fact that most people wouldn't choose to do agility with a deaf dog.

 

The proportion of dogs with white heads and/or so much white on the body that they would be called white dogs is also relatively small when compared with the high proportion of white factored dogs.

 

So in practice it seems to me that the only reason for a prejudice against white factored dogs in breeding is a colour bias against an increased risk of puppies with a lot of white on them - and we know what we think about breeding for colour (or lack of it).

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5. Breeding two merle dogs together will produce a higher incidence of puppies born with either hearing problems, eye problems or both.

...

11. Breeding two merle dogs together should be NEVER be done and WiLL produce puppies with hearing and/or eyesight problems.

 

Wyndrunhr, while I don't disagree with either of these points, I'm not sure what they have to do with white factoring and don't believe they belong in a list of information about white factored dogs.

 

The excessive white produced in merle to merle matings is completely unrelated to normal white factoring, as it's a separate genetic issue altogether.

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Since we're on the topic of white factoring, has anyone ever heard of or had experience with something called a "white dog thrower" or something referred to as a "lethal white factor" that is not the lethal white assiciated with double merle dogs?

Many years ago, I was gifted an imported BC bitch that was supposed to become the foundation of a breeding program. Someone else imported her from Scotland, bred at the time to a Scottish dog. The person who initially purchased her whelped the litter and then sold her on.

The bitch was white factored. I don't know if the sire of that litter was or not. There was one puppy in that first litter of five that was almost entirely white, just one very small black spot in its rump, and it was congenitally, bilaterally deaf.

I bred this bitch to my blue merle male, who was not white factored. There were two mostly white merle pups in that litter of 5. Although they looked like double merles, they were not, and AFAIK, their hearing was fine, though unilateral deafness may have been possible. There was also a monorchid black & white, non-white factored pup in the litter.

The bitch was bred one last time to a well known open trial dog, who IIRC was also white factored. Another litter of 5 with an almost entirely white puppy. I think only one but it might have been 2. No hearing problems that I was aware of, but again, unilateral deafness may not have been noticed or reported.

I never bred her again and the next bitch I got -- a fantastic working dog from stellar lines -- turned out to be severely dysplastic. The merle dog was bred one other time with no white puppies produced but one CEA pup, so that was the end of his breeding career, as well.

That was the end of my trying to become a breeder. :blink:

But back to the first bitch. I don't remember who it was who told me that there were some dogs that were "white dog throwers" that consistently threw white puppies regardless of external white factoring, and that many of these white pups would have a "lethal white factor" that could produce deafness and other health problems.

This was before the age of the internet, and I wasn't able to get any further information. Years later I did attempt again to find out more, but wasn't very successful. No references to "white dog throwers" and the only "lethal white factor" I came across referred either to homozygous merles or a syndrome in horses or chinchillas.

So, I'm curious to know if anyone else has any knowledge of either of these terms in regards to dogs, BCs in particular.

Thanks.

ETA: The bitch was black & white. Not even overly marked white, just the white running up inside the back legs.

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See post 63 above for the source.

 

OK so

 

"Entire litters of Border Collies that presented to the Animal Health Trust (1994-2008) for assessment of hearing status "

 

But what was the source of those litters? How representative of the UK BC/WSD population as a whole were they?

 

Not very, I would guess, since only a minority of those producing pups would bother to have them tested by the AHT, or at all. Most likely limited to show breeders, some sport breeders and some responsible working breeders, I would think.

 

There is a huge population of dogs that never come under such scrutiny and whose breeding is unrecorded.

 

It's a problem getting accurate results, I know.

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The crux of the issue you bring up is, was congenital deafness present in the gene pool before the development of show bred border collies and do the popular UK show lines (not purely Aussie show lines) carry the genes at a higher rate than working lines?

 

 

I suspect the answer is the rates are the same because congenital deafness was present prior to the development of UK show lines which ultimately come from UK working lines and Aussie show lines. In this scenario one way show lines could have a higher rate of congenital deafness is if carriers were also popular sires. Is there any evidence that popular "show" sires are producing deaf pups?

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