Mating a half brother to a half sister.

[NickC]

If I was after advice on breeding I would seek out the counsel of someone who had been breeding for a very long time and whose dogs' record, in terms of working ability and health, spoke for itself - not a computer program or theoretical expert.

i think it will confuse, because the kc have made it public like this, and people will just assume the COI is very important, and probably the most important thing.

I completely agree. The COI gives a single measure of a complex picture and is very misleading. A high COI can be the result of a very close mating recently in the pedigree, or a number of common ancestors way back. You need to look at the whole pedigree, the complete picture, understand every dog in it and what they bring to the party - good or bad.

[southern cockers]

i doubt i will use it much, if only for a nosey at COI, but two dogs, one giving pups of a COI of 12, and the other 20. i doubt it would make a difference to my plans of which one i had favoured in the first place.

Scot-ish,
As Nick has correctly demonstrated the C.O.I. can be tremendously influenced by the immediate preceding parentage and in an instance whereby the prospective pups carry an index of 20 it would take very selective future breeding not to exceed the threshold of 25%.
In this regard as an exercise let me show how a sire giving an index of 6.1% mated to a bitch of 15% , both well within the limits , the resultant litter would carry an index of 23%.
Guess to ensure that any future litter did not exceed the 25% registration embargo, if indeed such be the case and confirmed verification awaited, one would have to use a show strain sire ! !

[scot-ish]

i doubt i will use it much, if only for a nosey at COI, but two dogs, one giving pups of a COI of 12, and the other 20. i doubt it would make a difference to my plans of which one i had favoured in the first place.

Scot-ish,
As Nick has correctly demonstrated the C.O.I. can be tremendously influenced by the immediate preceding parentage and in an instance whereby the prospective pups carry an index of 20 it would take very selective future breeding not to exceed the threshold of 25%.
In this regard as an exercise let me show how a sire giving an index of 6.1% mated to a bitch of 15% , both well within the limits , the resultant litter would carry an index of 23%.
Guess to ensure that any future litter did not exceed the 25% registration embargo, if indeed such be the case and confirmed verification awaited, one would have to use a show strain sire ! !

surely with just the two dogs % you cant be sure of that, again its dependant on the actual dogs, or do i have a misunderstanding of it?

for example.

if tha bitch is 15% over 11 complete generations, and the dog is 6.1% over only 5 complete generation, then the pups will only be allowed a complete 6 gen COI calculation, as per the KC way. thus if the bitch is 15% but the repetiveness/inbreeding, is out in genereations 7,8,9,10 these wont be counted in the new pedigreee COI calculation?? so the new COI as per would come in lower? or is this not correct?

[arwesa]

i think it will confuse, because the kc have made it public like this, and people will just assume the COI is very important, and probably the most important thing.

its only as important as any metric, its just another consideration. I feel like Im being expected to be defending something as a panacea when Ive never said that, its information opened up to the masses.. the more is opened up the better for all. If you can get emperical evidence of a historical dogs abilities ( assuming you know someone who actually really saw a lot of a given dog in the past) and not just hearsay, if you can find someone who knows the outcomes of other similar matings and where all those dogs went then youre going to understand and all the health issues of those dogs then great.

what I find personally annoying is the nay sayers who think considering health issues and risks of issues resulting from inbreeding is 'wrong' and their way is 'right'. Knocking some new information for the sake of it. Its about a balance.....Surely we all have the same objective 'healthy and great working dogs'...

Nick

no one is saying choose x over y JUST because of a lower COI.......the COI bears no relevance to all the attributes a dog shows in its performance as a working dog, its purely an issue of genetic health... one of lots of other factors to consider. I just see it as another string to the bow when it comes to looking to create healthy, great working dogs... surely thats not a negative thing?

[arwesa]

i doubt i will use it much, if only for a nosey at COI, but two dogs, one giving pups of a COI of 12, and the other 20. i doubt it would make a difference to my plans of which one i had favoured in the first place.

Scot-ish,
As Nick has correctly demonstrated the C.O.I. can be tremendously influenced by the immediate preceding parentage and in an instance whereby the prospective pups carry an index of 20 it would take very selective future breeding not to exceed the threshold of 25%.
In this regard as an exercise let me show how a sire giving an index of 6.1% mated to a bitch of 15% , both well within the limits , the resultant litter would carry an index of 23%.
Guess to ensure that any future litter did not exceed the 25% registration embargo, if indeed such be the case and confirmed verification awaited, one would have to use a show strain sire ! !

surely with just the two dogs % you cant be sure of that, again its dependant on the actual dogs, or do i have a misunderstanding of it?

for example.

if tha bitch is 15% over 11 complete generations, and the dog is 6.1% over only 5 complete generation, then the pups will only be allowed a complete 6 gen COI calculation, as per the KC way. thus if the bitch is 15% but the repetiveness/inbreeding, is out in genereations 7,8,9,10 these wont be counted in the new pedigreee COI calculation?? so the new COI as per would come in lower? or is this not correct?

Im loosing the will to live

no any COI is calculated with the maximum dogs known in the pedigree history. where a dog is unknown a 0 is inserted. think of a COI a bit like someone looking at a warehouse and saying is x% full. the more information they are provided about what is on the shelves the more accurate they can then calculate how full it is. ... does that help?

[kelco]

So with no health risk after both dogs tested and they were straight powerhouse spaniels would you mate 1/2 brother to 1/2 sister?

[scot-ish]

i think it will confuse, because the kc have made it public like this, and people will just assume the COI is very important, and probably the most important thing.

its only as important as any metric, its just another consideration. I feel like Im being expected to be defending something as a panacea when Ive never said that, its information opened up to the masses.. the more is opened up the better for all. If you can get emperical evidence of a historical dogs abilities ( assuming you know someone who actually really saw a lot of a given dog in the past) and not just hearsay, if you can find someone who knows the outcomes of other similar matings and where all those dogs went then youre going to understand and all the health issues of those dogs then great.

maybe if you didnt write "next" at the end of one of your post( which you've now edited out, to say "any more" then you wouldnt feel like you were denfending something.

[Gignesthai]

we were strongly advised to breed from our half brother/sister but this was from a breeder who used the same sire regularly and doesnt feel there is a need for health tests.

We decided we didnt want to get into breeding despite having lovely dogs etc, but the COI would have been lower than 25% so pups could have been registered.

I wonder what any health tests would show from our two!

[NickC]

The whole point of line-breeding is to double up on dogs in order to accentuate an attribute(s) and increase the chances of breeding true to type. This is at direct odds with aiming for a low COI.
Now if the COI is used to keep in check how closely you are line-breeding and when to outcross, it can be a useful thing. The danger, as has been said before, is that the general public equate low COI = good, high COI = bad. Not that that's too much of a problem though, they'll carry on breeding their son of a son of FTCH Billy Bob to daughter of daughter of FTCH Soppy Sue and the rest of us can carry on trying to breed decent working dogs.

[arwesa]

So with no health risk after both dogs tested and they were straight powerhouse spaniels would you mate 1/2 brother to 1/2 sister?

Yes in theory if it were two great dogs with great ability and healthy....their COI % wouldnt be excessive (my current bitch would be higher)......however my personal preference is to also try to see what progeny of a sire have resulted (health and performance wise ) so youd be taking a sire thats from a sires early litter and mating to a dam from that sires later litters...