Sounds like your butcher is an idiot. Our biggest steer we took off last year weighed 1100 and dressed at 62%. He yielded 682 pounds of assorted cuts of meat. The rest dressed at 60% or better. Our 810 pound steer yeilded 495 pounds of assorted cuts of meat and dressed at 61%. Average is 50% give or take a few percent. Sounds to me like either you had a crappy steer, didnt feed him properly, or your butcher is an idiot. If the butcher told you to expect 40-42% hes an idiot and I wouldnt use him anymore. Sounds to me like you been had. I bet he gave some of your meat away. The slaughter house I use lets you watch them tag them as they go in. They give you a print out with your calves tag # when you go and pick up the meat. They have the dressing percentage, meat yield, yield grade, and whether they graded select, choice, or prime. They have all the meat vacuumed sealed and on a cart. They bring it out and the cart has the same tag # as the calf you brought in. Everyone I talked to that bought meat from me was extremely happy. In fact it upped my orders from 6 last year to 13 this year. I only sale wholes or halves. We use only continental bulls so that the carcass hangs heavier therefore yielding more meat. As it pertains to meat yield angus just dont cut it.
For those who think I might be bsing. Check this out. This isnt the sheet they gave me with the yield grade and whether it was choice or prime I couldnt find it but here are 2 of the 6 steers as proof. Granted I know that I blacked out the names on it. Granted I know that the lady at the slaughter house wrote in the the % and dressing weight.
This proves that either your butcher didnt know what they were talking about or you need to get better cattle with larger frames. I would say the butcher screwed up though.