Dwarfism is not because of linebreeding.  Linebreeding is the way to lock in both good and bad traits.  If it was used more in the past, the wrecks caused by dwarfism would not have happened.  Linebreeding would have shown the problems earlier before the genetics were so widespread.  Linebreeding isn't for everyone, but it will sure find the garbage before it is spread throughout the country.  EXT was a linebred bull, last I checked he was a decent bull.  Linebreeding may have locked in an attitude problem, but also locked in some very favorable genes.