I can say that for the bull candidates and steers that by weaning 90% of the selection is done. Bad disposition or other traits may still get a bull turned into beef.
The heifers first cut comes at weaning with handling ease playing a large part follow by performance and visual appraisal and pedigree. The heifers are cut again at breeding time for handling ease, visual appraisal, and performance and any opens after breeding season are sold.