No way to know how many will follow it. But I know a few who TRY! It's certainly hard to keep a calf all the way to yearling age if it obviously not on par with the rest.
When weaning time comes it's hard not to move them for cash flow alone.
I kept all my bulls in a contemporary group last year and had an "on farm" bull test instead of sending them to the Auburn bull test.
I hope it helped in the long run. I KNOW it was more expensive.
Contemporary groups are key to accurate EPD's, for sure.
I don't think this is practical for most producers. Waiting too weaning time to castrate the calves is more work (compared to cutting the steers at 100 days; but waiting for yearling wts and ultrasounds to be finished on the group will be a mess with effectively marketing those staggy steers. I also think that would encourage more seedstock guys too sell bulls they KNOW are mediocre too unsuspecting commercial guys.