blackcob
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I fully accept the limits of things like COI - to use Alec's example, it would appear on paper that deerhounds are far more genetically diverse and in more robust health than cockers, which we both know to not be the whole picture. However, it would be foolish to completely disregard it as a tool. Consistent loss of genetic diversity is a ticking time bomb for a breed and 17% is unsustainable - these are the levels in which proliferation of genetic disease occurs and inbreeding depression rears its head. For two apparently unrelated dogs to only have enough genetic material between them to result in almost the equivalent of a father/daughter mating is alarming for the future of the breed.
To use CT's examples the use of imported dogs is surely very important but unfortunately demonstrates one of the limitations of COI; very often fewer generations are used when calculating for imported dogs which can result in an artificially lowered figure - go back another generation or two and more related dogs appear.
I also concede the point that no-one would be breeding like this if the dogs weren't outwardly healthy and successful, and I've no doubt that the vast majority are! The risk comes from things diagnosed later in life, PRA and DCM come to mind for cockers, the latter with an average age at diagnosis of something like 7. A popular sire will have several hundred offspring on the ground by then and it's too late. IIRC similar has happened in other breeds, haemophilia in GSDs is a case in point (I am ready to be corrected by the GSD mafia!
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Those breeding for the show ring take a lot of flack for their breeding practices (and rightly so in a lot of cases, thinking of the physical exaggerations that have proliferated purely as a result of what is being rewarded in the ring, and loss of working ability) but in this instance they appear to be taking a far more long term approach to the genetic health of the breed.
To use CT's examples the use of imported dogs is surely very important but unfortunately demonstrates one of the limitations of COI; very often fewer generations are used when calculating for imported dogs which can result in an artificially lowered figure - go back another generation or two and more related dogs appear.
I also concede the point that no-one would be breeding like this if the dogs weren't outwardly healthy and successful, and I've no doubt that the vast majority are! The risk comes from things diagnosed later in life, PRA and DCM come to mind for cockers, the latter with an average age at diagnosis of something like 7. A popular sire will have several hundred offspring on the ground by then and it's too late. IIRC similar has happened in other breeds, haemophilia in GSDs is a case in point (I am ready to be corrected by the GSD mafia!
Those breeding for the show ring take a lot of flack for their breeding practices (and rightly so in a lot of cases, thinking of the physical exaggerations that have proliferated purely as a result of what is being rewarded in the ring, and loss of working ability) but in this instance they appear to be taking a far more long term approach to the genetic health of the breed.