We used one rack of Hairy Bear last year. We got 7 calves. All came easily from mature cows. I would guess 75 pounds or so average. I would not reccomend his use on heifers because we didnt breed any heifers to him. The style is good on the calves, and he sires a lot of hair. The calves that we got from average quality cows, were a little finer boned. From our use only, I would say that he does not add bone. Growth seems to be average to very good. All in all, we were well satisfied. I hope this helps a little.