It is so much easier to leave the bull(s) in with the cows. I leave them in until weaning. The only concern is that bulls may breed some of this years heifer calves but a shot of lute after weaning takes care of that. Bulls are calmer in with the cows even though they are all bred.  It is easier for me to manage one group rather than two.

People say they pull the bulls because they don't want a spread out calving season. But if the cows aren't bred after 2 cycles/45 days either the cows or bull should be sold anyway. jmho.

Jim