Labrador COI's

[newf]

This one in particular: http://www.instituteofcaninebiology.org ... -dont-know
seems appropriate!

Don't know anything about this stuff but that was interesting to get a little about what I don't know.

[Nickheref]

One thought that always crops up in my mind is non native species that have been introduced - say grey squirrels, muntjac and canada geese. As far as I am aware these all came about from small releases of individuals on an initial single location (Woburn for 2 species at least). Also the initial release was a relatively small group of individuals and yet against the odds they have thrived and spread throughout the country. Surely according to COI philosophy they should have become so inbred that they were unable to colonise the country so succesfully and would have died out in a few generations.
I think there is a colony of black rats (might have been a vole)on a small Scottish island that it is believed from genetic tests are all descended from a single pregnant female who washed up. (I am trawling my memory on this one but am sure I have read something about it). Again they should not be thriving as they have all come about from brother to sister matings.

[Judy]

The only difference is natural selection rather than us selecting the mate. Plus the poor doers will die off very quickly whereas we nurture them all regardless and may sometimes use a poor doer if it has qualities we are looking for or the breeder is ignorant, nature wouldn't.

[kennel maiden]

Yes, Galapagos Islands was a good case in point too, with very successful 'in-breeding'.

[Nickheref]

True but in a quick reading of the link it refers to wild animals having an average COI of less than 1% whereas with these it must be off the scale! So from where I sit the problem is a combination of
1 Hidden genetic issues
2 Breeding from substandard animals along the "she not that good but has a brilliant pedigree so I thought I would take a litter from her" philosophy.

As the rats etc seem to demonstrate that if your stock is very sound genetically you may be better off line breeding than bringing in rogue genes merely to lower the COI! This was I think Naj's and Dawnrazor's point, ie stockmanship and being ruthless in selection of breeding stock.
Just playing devil's advocate!

[Naj]

Even with close line breeding the old kennels used to outcross every 5th generation but this would have been a much truer outcross to new blood than you are able to do today with such close links across lines. As a matter of interest there is a herd of cattle that is totally inbred after it was left behind on a remote island in the Pentland Firth when the crofters left back in the 40s/50s. It's been studied for many years now.

Naj

[Nickheref]

Completely agree Naj, my point being that COI should be well down the list of factors affecting choice of breeding stock. If every dog is outcrossed at every mating it becomes hard to get a real outcross as you say. Hence my belief that line bred families have a real place in breeding dogs and should not be stigmatised as lazy or poor breeding, when I purchased a bitch to bring in to my breeding programme (sounds grand but isn't really) I went for a line bred bitch, who had a fairly high COI, of a different family for that purpose. She still had to prove she was good enough before I would have a litter from her. The COI of the litter will be lower than either of the parents but my choices were not made purely on lowering the COI. When I get them it will be interesting to see how they turn out as they will be an outcross but I like to think an informed outcross rather than haphazard breeding using slightly dodgy or perhaps not fully understood science. I am pretty sure the best breeder I know personally as a friend would not have a clue what a COI was but he bred some pretty good dogs and I would have one of his pups tomorrow if he was still breeding.
As Dawnrazor says the COI may have come about after the issues highlighted on TV. But these were, as far as I am aware, for show dogs who only have to be able to be of a very consistent breed type and walk around a ring and so much of the things we will be looking for in working dogs may be masked as they will never be tested.

[kennel maiden]

I think we are all saying pretty much the same thing: COI is certainly not the be all and end all (but something to be aware of) and careful line breeding (and periodic outcrossing) can improve the consistency of your stock.

[Nickheref]

I would like to think so but as it costs nothing to check a COI and health testing costs money I worry that a low score may, in time, be used as a quasi guarantee of good health whereas it is nothing of the sort. It is at best an indication of the risk of inherited diseases but takes no account of the health status of the parents.
In the same way that if an insurance company hears that the average driver is involved in a crash on average once every 10,000 miles and they price their policies on the amount of miles driven a year without asking the more important questions like when did you last have a crash, they will come up with the wrong answer. If you have driven 25000 miles a year for the last 10 years without a crash you are a better bet than someone who has only driven 3000 a year but had a couple of crashes. As governments all over the world demonstrate on a regular basis, statistics can be used to prove many things.

[Judy]

I agree, the classic case being the Lab x Poodle, just as susceptible to HD as the parent breeds but people think they are safe not testing because its two different breeds.

http://www.instituteofcaninebiology.org ... sires.html