I did use the analogy of the shepherd, but am pretty sure I clearly described it as an inbred breed, but I'm not sure that mixed breed dogs have any specie benefit or expand the original gene pool, rather, I'm pretty sure that any dog that issues from a crossbred mating does not establish a new, pure gene pool, but actually only produces another new mutt gene pool.....I will agree with your position that cattle have been bred for disease resistance, ability to withstand severe weather conditions, increased meat production, along with selectively breeding in various other salability qualities, but the breeding of cattle has been thoroughly and is continually studied, unlike the cross-breeding of parrot species.....
Since you sculpt horses, you might find something I read a couple of years ago interesting, it's about the relationship between human chromosome 20 and horse chromosome 22, with a little bit of mouse chromosome 2 thrown in, and though I don't remember any Texas cattle baron having been mentioned anywhere, the primary researcher was from College Station.....
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http://www.genomenewsnetwork.org/articles/05_03/horse.shtml]
I've also heard that Don Brightsmith, the primary researcher of the Tambopata Macaw Project is now teaching at A & M, so maybe the two researchers will get together & we'll have beefier macaw leg-quarters in the poultry section of your nearest H-E-B supermarket in the next few years.....
It's not so much that I have an aversion to cross breeding endangered species, I have a problem with people interested in creating "designer" birds, macaws or other parrot species, chasing the almighty dollar, but then you may have noticed that I prefaced my earlier post with
"and while I am not a zealot on this subject, but I do think it is wrong to cross-breed different parrot species so that we can command a higher sales price for the offspring....." I have the same problem with breeders of "designer" dogs too, but I don't think we'll have to worry about finding any designer dogs being fattened up in any Kansas feed lots.....