Looking for a reputable breeder, need help!

[mum24dog]

Elitist and self righteous, well yes when certain topics arise.

 

And yes, it seems true that regular posters are hobbyists or part timers but I never get the sense that they believe that what their dogs do is all the breed needs to be able to do. They understand the true potential as long as the breed isn't dumbed down or distorted for whatever reason.

 

The notion of uniformity is a red herring when it comes to these dogs. A cattle dog is not a sheep dog, a lowland small field dog is not a fell dog, and an open range dog is something else again. Some maybe able to cross over but uniform they ain't.

[Debbie Meier]

If you want to see how many Border Collies are linebred, the pedigrees of National Finals competitors are available on the USBCHA website.

 

 

 

Not many. There's no need to.

sire and dam, which is what is displayed isn't going to help you determine the COI nor how closely line bred the dogs are.

 

Without thoroughly researching the individuals that were at finals I don't think you can honestly say not many. Seems that there would be more then just a few that have more then one common ancestor with in the first 3-4-5 generations on their pedigree giving them a decent COI (8-12%)

 

I think we are seeing COI's going down on average since few are doing close up line-breeding, but that also brings in the question of drift and if that has something to do with the increase of certain defects that we are seeing as the carrier rates have spread out of certain families to now influence most families.

[juliepoudrier]

The thing with outcrosses is that you have no way to predict if you'll end up with that unlucky combination for polygenic diseases.

 

Linebreeding can concentrate good and bad genes, and of course anything that's a simple recessive, deleterious or not, will likely appear sooner or later.

 

I honestly don't care what any one person's definition is of "real" work is. I know the work I do with my dogs and that I will potentially do with my dogs and I know what kind of working dog I like, so that's really what matters to me.

 

I would buy a pup from someone who line breeds if I like the dogs that are produced, and I wouldn't buy a dog from someone who has a gazillion litters all the time. Aside from the question of when the producing dogs are actually proving themselves by doing "real work," I'd have to wonder why the need to produce so many. I doubt there's anyone in this country with so much work that they have to produce dozens of puppies every year. But that's just me. YMMV.

 

J.

[red russel]

"Line breeding can concentrate good and bad genes, and of course anything that's a simple recessive, deleterious or not, will likely appear sooner or later."

 

I LOVE the word deleterious and think it not used nearly often enough. Thank you Julie! I just started giggling with joy when I saw it in your post. Made me happy.

 

dave

[Gloria Atwater]

I believe I can say with near certainty that I've never used "deleterious" in a sentence. I must remedy this.

~ Gloria

[Gideon's girl]

Yes, you have.

[Mark Billadeau]

So often I read the argument that line breeding must be okay since that is how breeds were developed. One flaw in this argument is that when breeds were developed the level of genetic diversity was greater than it is now, meaning the likelihood of mating two dogs carrying the same genetic mutation was less than it is now.

 

Teun C. van den Dool provides us with a very good analysis of COIs from the ISDS database. I have attached one of the graphs from his work: STATISTICS FROM THE STUD BOOKS

 

Note the increasing COIs from the early days of the ISDS. Teun also notes

 

A CI of 7% is certainly low considering the small genetic diversity in the current population (effectively the genomes of 8 dogs).

The genetic diversity on our gene pool essentially comes from 8 dogs!

 

 

One should also note that there are many datapoints (each data point represents a littter) where the COI is very high. Tuen discusses examples of line-breeding with very high COIs from Winston Cap which yielded good (Winston Cap like dogs) and very bad (genetic diseases) results showing that even the breeders of yore could not always get the desired results from line breeding because one cannot control which copies of the genes will be passed on.

 

The second plot from Tuen highlights the issue with loss of genetic diversity. It is a plot showing the precentage of ISDS dogs that do not have Winston Cap genetics. We better hope that Winston Cap did not carry genetic mutations that adversely impact our gene pool.

 

Just imagine what would happen to the genetic diversity in our gene pool if a dog from one of the litters with COIs >50% were to win the International. We can predict the results from the plot for Winston Cap.