This narrow to non-existent Choice/Select spread will hopefully be a blip on the screen.  Since it takes a long time to see genetic improvement in a cow herd, I can't imagine abandoning a well planned breeding goal of improving marbling because of a 3 or 6 month market disruption.  Now I don't think a person would get too far on this forum even suggesting that single-trait selection for any trait would be  wise.  But with today's genetic offering and information, it is very possible to place some steady upward pressure on carcass traits without upsetting the apple cart.  My two cents.

HP