Karlin said:
Breeding for conformation (appearance) actually helps PRESERVE breed health because it sets standards, including those of health...
The very nature of purebred dogs means ALL purebreds have some health issues because they come from limited gene pools so if you want a purebred you are already supporting a philosophy of restricted breeding.
What does "breeding for diversity" mean? I thought i read about this somewhere on cavaliertalk, maybe it was another forum; i thought that reputable breeders attempt to breed for diversity, but i'm not sure what that means. I think I've read (on an SM discussion list) that over time, cavalier breeding has become ever more narrow and restricted in terms of the standards of appearance, as well as health; and i read an abstract of an article by Clare Rusbridge in which she wrote that narrowing the gene pool in order to breed out MVD likely contributed to the increase in incidence of SM (though i could be misunderstanding that). On the SM discussion list, i think that there were some who have been around a long time who were saying that in an earlier era, show quality cavaliers were more diverse in their appearance, and that the sought after type has been narrowed as time goes by. Is there general agreement about that, or is it controversial?
The thing about good breeders breeding for conformation is that those are the breeders who stay informed about health issues through their clubs and competitions, and are the ones who will respond to issues like MVD and SM.
That sure does make sense. I just think i've read somewhere that good reputable breeders, or some of them, have become committed to 'breeding for diversity' in the interest of improving the health of the breed, but i don't know what that means in terms of selecting breeding dogs.
In the case of good breeders, if inbreeding/line breeding narrows the gene pool, increasing the likelihood that genes of health problems can brought out in offspring, and there are a whole number of different selection criteria a breeder can use in choosing which dogs to breed together, health criteria and appearance criteria, several of each, would it be safer and increasing the chances of good health to minimize the the number of traits the breeder is trying to achieve in the offspring--would that preserve more genetic diversity? Or does it not matter how many different characteristics a breeder tries to achieve in the offspring, to the health of the animals and the breed?
Is this all a matter of speculation anyway? quite a complex subject.
SM MAY be related to selecting for a certain head but that is then more due to using ONLY a restricted number of winning sires over and over. But that doesn't explain why such numbers of cavaliers, just as many from unknown background, are presenting with SM. It clearly is only a possible contributing factor for certain lines, not the sole source of the problem. Clare Rusbridge, the leading authority on CKCS SM, doesn't think it is even a significant element.
Is it that the data that some interested parties are collecting (xrays and MRIs associated with different head types) is not as suggestive as those collecting it believe for some reason?
Basically, with purebreds, you either want your dog to look like a proper breed example or you don't care if they drift away until they start looking, as many byb/puppy mill cavaliers do, like they are crossbred with terriers, beagles, springers, etc. This causes all sorts of problems in and of themselves.
It's certainly an issue that for some people seems to present an ethical dilemma. But i get the impression this hasn't really been studied, there haven't been any systematic comparisons of purebred v mutts (not just crossbreeds but heinz 57s) to get an idea if there is any substantial health difference. The generalization that mutts are healthier than purebreds isn't really based on any proof (is that true?), but does make sense theoretically, in terms of restricted gene pools. It's an interesting subject to me, as i never was interested in having a purebred dog, i had known many in my life of course, but found my own mutts to be the best of dogs, cute, beautiful, friendly, sweet and smart, so didn't see the point in having a purebred--until i met a cavalier.
If people want genetic diversity, then it is better to choose one of the millions of needy crossbreeds in every shelter in n every country rather than support BYBs and puppy mills in demolishing a breed by disregarding both health or conformation.
I think that a lot of byb's do a lot of inbreeding--carelessly and crudely--just using one sire and one or two dams over and over, i don't think it's necessarily true that byb's use diversity. My impression was that some very highly ethical breeders advocated "breeding for diversity," even breed clubs had taken this position--but i'm not sure where i was reading this. Am i remembering wrong?
A white faced cavalier like any type of mismarking can always appear in any breeder's lines and is not a problem, simply an interesting variation in markings that would keep the dog from being shown -- if it otherwise was of show quality (very few dogs are of show quality).
This was one of the things i read in a mail group discussion, that there once was more diversity in the markings of cavaliers being shown than now. Why would that be, if it's true?
