Following on from the discussion about Essex pigs, I am mystified how any pig can be considered to be "pedigree" at all, as I understand it, ie from one dam and one sire bloodline, and thus unrelated to another pig of the same breed with a different dam and sire, and thus a potential spouse when they grow up. For instance if you had 64 completely unrelated bloodlines to start with, and bred completely pure each time, you would run out of fresh bloodlines by generation 6. By this time, if your original pig had been the only one with genes A, its sixth generation offspring would only have 1/64 of genes A, and all the rest would be from 63 other sets of genes.
Of course in real life there are not this many original bloodlines, and gene A would creep in all over the place, a great grandmother here, an uncle of your third cousin there, and so on, but even so, there wouldn't be an awful lot of gene A left in the sixth generation gilt, still classified by its bloodline name A, (plus a breeder name and unique number). Even with "line breeding" as explained in the Andy Case book, where breeders deliberately use one particular bloodline regularly to accentuate good traits, but not so frequently as to cause in-breeding, the resulting pigs would surely still be an awful mish-mash of virtually every single bloodline that had ever existed for that breed. I would have thought the only definite thing you could say about a pig was that all its ancestors, back to 1884 when the records started according to the BPA, were definitely Tamworths of one kind or another, and that it wasn't mixed up with a Saddleback or anything else along the way. And that it has consistently had an A dam since the beginning, but that the proportion of A in her at the present time is very small indeed, due to every single piglet ever being born having a father which always divides the gene pool by half.
Also, how did different bloodlines start? Were they what was around in 1884, in geographically isolated pockets, and if so, how could anyone know for sure what their breeding histories had been before that? People and pigs must have travelled around since the beginning of time. Have any new bloodlines been created since 1884, and if so how?
The point I am trying to make is that it is standard practice to register, show, advertise, buy and sell individual pedigree pigs on the basis of their immediate dam and sire bloodlines, possibly adding that they come from an incredibly rare bloodline, but in reality this could be very misleading in terms of the actual gene mix, and these pigs are, actually, just purebred Tamworths (or whatever) at the end of the day.
Or have I got if all wrong? Perhaps serious breeders really do go back through the records for generations and generations to work out the exact proportions of each bloodline in their current pigs, and before deciding who to mate with whom next time around. Would be most interested to know - Tamsaddle
Topic: Pedigree pigs (Read 6613 times)
