Guth obviously doesn't buy bad doers or rubbish, which is a miracle buying out of market, as you can't be sure on the pneumonia/bvd/johnes history, especially if you haven't reared them yourself.Just when we were buying calves off dealers we ended up with a portion of rubbish.
If your buying your own you will be able to use your own judgement and avoid the duffers.
We rear conti x now only because i have a good sorce of calves from one farm.