it might be interesting at this point to look at breeds that seem to have different immune responses and how that relates to different things.
like say a sire who has no milk and why and why even through several generations, that effect has not been diluted very much.
at this point, the idea of breeds is simply a group of animals that had minimal infusion, usually because of a valley, distance or some other geographic limitation. that is really all a breed is, along with a certain color pattern and here, its a couple to 5 genes, some really small amount that gives the illusion of a breed, ie polling and black hide. there really is no such thing as a breed, only isolated populations and a bottleneck of some sort.
breeds are simply a way to have, well, you know......