Yes, you should use clear dogs if the condition shows as a straightforward simple autosomal recessive.     That is easy.    Such conditions must be very satisfying to breed out.

The problems come when conditions are polygenic, or if the condition has limited pentrance, when most are working in the dark, and by only using apparently 'clear' dogs (you may only have a small handful in a generation) this is where your genetic bottleneck comes in.  And you then  use only clear x clear dogs at your peril, as you lose your genetic diversity.

Jo

> Yes, you should use clear dogs if the condition shows as a straightforward simple autosomal recessive. 

Only once the number of carriers is negligible enough to not narrow the gene pool.  Too many people have the over simplistic view that only clear to clear should be used.  As long as the resulting mating does not produce affected offspring then the full range of av bailable liens should continue to be utilised to avoid bottlenecks.

With polygenic conditions we carry on as we do now with hip scoring, if all the generations are scored we can see the general pattern, compare littermates and what dogs produce to best use what we have to keep levels/effects to a minimum.

Be interesting to know which breeds have actually lowered their mean hip score over the years that scoring has been available.    I only say this as the mean in Flatcoats has been just about the same all the time.      We are lucky that we are one of the lowest scorers, so maybe breeds who started off with higher mean scores  have made a significant reduction ?     Any takers?

Jo

Well I posted a link to soem OFA data that compared over various periods the percentage of Excellents (under 5 total BVA system), and the percentage in teh Dysplastic ranges (over 25 BVA system), and this certainly shows improvement.
http://www.offa.org/hipstatbreed.html?view=2

I'm pretty sure that the BMS for Rhodesian Ridgebacks has come down from 13 to 11 in the last 15 years or so. We're lucky to be a pretty low scoring breed :)

Trouble with just looking at the mean score is it takes a lot of numbers to change an average the more numbers you have.

A comparison of the range of scores from one decade to the next should show fewer dogs with unacceptable scores as more generations are scored.

Those OFA stats I mentioned for example showed that in Flat coted Retrievers of 333 dogs tested before 1980 there were 9% in the excellent range and 3.6% in the dysplastic range, and that the 863 tested 03 - 04, 27.6% were excellent and those in the dysplastic range had gone down to 2.3%.

I hadn't looked at the OFA data, only the BVA.

Of course the more widely the tests are used,  the statistical significance of the results must improve as well, so maybe over the years the results are more meaningful by virtue of numbers.

Jo

It was interesting when TNS was found in collies from Australia and many of the collie people in UK felt that it was an 'Australian problem' yet when responsible breeders here in the UK started DNA testing it WAS found that dogs here were carriers.  Affected dogs aren't found as they die very young.  It was thought a few affected litters had been born some time ago but the problem wasn't identified then, just put down to 'fading puppy syndrome'.  It's clear though that dogs in Australia and New Zealand have their ancestors here in UK so it was inevitable that the problem existed here, but with a smaller gene pool it came to the fore sooner.  Line breeding here would make the incidents more likely eventually, there's at least one well used agility dog who's a carrier, just think if his progeny were to be bred to each other.  Now thankfully there's a DNA test and no more puppies have to die, but people need to test, and people need to be aware of it.  Interestingly I saw a pup advertised for sale recently with 'parents DNA tested for CEA, CL and TNS' - what it didn't say was the sire had come back a carrier.  I know owners of previous litters who haven't been informed that their pups have a 50/50 chance of being a TNS carrier - most don't even know what TNS is.

> Interestingly I saw a pup advertised for sale recently with 'parents DNA tested for CEA, CL and TNS' - what it didn't say was the sire had come back a carrier.  I know owners of previous litters who haven't been informed that their pups have a 50/50 chance of being a TNS carrier - most don't even know what TNS is.

But the parents status will be on the registration documents and the pups themselves unaffected (healthy).

The pups where one parent is a carrier will themselves need testing, nothing wrong with the breeding and certainly no puppies should be sold without endorsement so that people do not breed in ignorance.

With several conditions to test for your going to be super lucky if the dog is clear for everything.  It is knowing what to do with the results of tests to ensure no more AFFECTED offspring are produced that is the point.

The only way to prove that you do not have a problem in your breeding lines is to do the health tests that are available and have been known to affect your breed.
To say that some may be dangerous and involve anesthetic is a little outdated as most vets that do hips and elbows do not anesthetise these days, they use a strong sedative that is quickly removed from the body.
I do hips, elbows, eyes and heart. I think i would do the patella one if it becomes available as i have seen several in my breed have problems with luxating patella. I also do DNA profiling and DNA archiver with the AHT (stored for future research into diseases in my breed)
This gives me some idea what i have to deal with when breeding. It isnt perfect as they are not all DNA based tests, but it is what we have available and knowing your results allow you to breed with knowledge. Having a bad result doesnt have to mean removal from the breeding program, it means you are more restricted on where you can go and that you must have a stud dog that compensates for any failure or flaw.
I do think that if we do not utilise what health test available and a puppy placed in a home comes back with hip dysplasia, heart failure or eye conditions, then it wont be long before someone decides to sue the breeder for not ensuring they had done all they could to avoid the said health condition.

read my comments on the health board wish the k/c would help us who try more

dogs that are not going to be bred from, then i do not see too much point in mandatory heath testing.
a dog can have all the health testing advocated by the kc but still be a poor example of the breeed, poorly put together,skeletal faults, poor temperament etc and people still think it ok to breed from because it has passed the genetic tests. it goes far deeper than passing the various health tests out there in my view and that can only be done by breeders becoming much more selective and ruthless in their breeding programs, not every dog and bitch should be bred from  but some seem to think they should.