Ancestor Loss Coefficient & Relationship Coefficient

Everything you need to know about the breeding of kunekune Pigs.
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robnock
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Joined: Fri Aug 18, 2017 1:15 pm

Ancestor Loss Coefficient & Relationship Coefficient

Post by robnock » Fri Aug 18, 2017 1:18 pm

I was just looking at Coefficient of Inbreeding (COI) and Planned Breeding and wondering if someone could provide more details about all 3 indices but especially the Ancestor Loss Coefficient & Relationship Coefficient.

Are low percentages 'good' or 'bad'? What ranges are normal? All information appreciated.

Thanks,

Rob

simon
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Location: Yorkshire Dales
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Re: Ancestor Loss Coefficient & Relationship Coefficient

Post by simon » Fri Aug 18, 2017 2:24 pm

The Coefficient of Inbreeding (COI) is the main thing to look for. It tells you how closely related 2 pigs are, with a low number under 3% being good. This article is a good one to read. Few pigs have a COI of zero and theres nothing unusual with that in rare breed populations, so long as it doesn't get too high. Currently the BKKPS don't allow pedigree registrations with a COI above 10%.

The ancestor loss coefficient is a simpler measure. In 3 generations you have mum, dad, 2 grandfathers & 2 grandmothers. So 6 possible ancestors. If your 2 grandfathers were the same person then you would have 'ancestor loss' and have five out of a possible 6 ancestors. Or put another way 17% loss, or 83% of the possible ancestors. I would advise you to use this number to alert you that you might like to look at the family tree in more detail, but probably the higher COI will already have your interest by that point.

The Relationship coefficient is a measure of how closely related a pig is to the rest of the recent population. So here you might consider a low number to be 'good'. But unlike a high COI, which is a red flag to breeding, a high relationship coefficient just tells you that there are a lot of closely related pigs already in the population. So long as you are not mating with one of them, there isn't a problem. Its just that you are adding more of the same DNA to the gene pool. The pig with a lower relationship coefficient could be argued to be adding more 'uniqueness' to the gene pool.

A massive subject - hope that helps.

robnock
Posts: 6
Joined: Fri Aug 18, 2017 1:15 pm

Re: Ancestor Loss Coefficient & Relationship Coefficient

Post by robnock » Fri Aug 18, 2017 2:38 pm

Very helpful, and quick. Thanks,

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