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Pedigree Diversity

I engaged in an interesting exercise this spring. In beginning the search for the sire of our next litter, I did some extensive pedigree research on several potential boys. I have three dogs on my "short list", although we will have to wait for one of them as he is young, yet. A friend has a pedigree software program and has generously calculated the COI (Coefficient of Inbreeding) for several dogs for me. The COI basically indicates the chance (%) that certain traits...both desirable and not...will come down from various ancestors. Breeding first cousins gives a COI of 6.5 and, from what I've read, keeping the COI under 5 is what your goal should be. I don't know how many breeders use this information, which is easily calculated with the program and the very extensive breed database that the English Shepherd Club Registry provides, but my educated guess is that the more responsible folks would use as much information as possible when planning potential pairings. Unfortunately, this isn't always the case. At any rate, my goal is to be as responsible a breeder as possible and, towards this end, I do a LOT of research in preparation for a litter of puppies.

In addition to learning the COI of each potential match, I followed one of the points that Carol Beuchet, Phd (Institute of Canine Biology) made in her article, "Twenty Key Elements of a Successful Breeding Program", and calculated the number of shared vs. unique ancestors in each of these matches. In order to reach the best conclusion, the goal is to include as many generations as possible...ideally up to 10. I chose to go up to 8....which meant that I was looking at 254 names. That was enough for me to start with!

The premise is that calculating the shared/unique ancestors in a pedigree gives a better idea of the genetic diversity than simply finding the COI. And, with a small gene pool such as we have with English Shepherds, diversity is a goal.

It took me a LONG time to do the first match because, like balancing a checkbook, all the numbers had to work out correctly. The number of shared ancestors plus those unique to both Ginger and the sire had to equal the number of actual dogs in those first 7 generations. (I counted the litter as Gen 1) Well, I did this all by hand......paper & pencil, columns, hash marks, LOTS of erasing, rereading the pedigrees (thank goodness for ESCR!)....and reworked, reworked, reworked until all the numbers balanced. (I know....EXCEL would have made it easier but I'm old fashioned.)

It didn't help to find that, as I went further back in the generations, more and more dogs appeared multiple times on both sides, so it became more confusing by the time we got to Generation 8. (Let's many times does Johnson's Duke appear on Ginger's side as opposed to the sire's side???)

But...I came up with a system and, after that first exercise, the rest were much easier. I was actually enjoying myself by the time I was finished!

No definite pick yet for the father of next spring's litter but I have lots of information to help make a decision.

If you're interested......

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