We don't give any extra feed, all what calves get is mothers milk. One bull calf we've gains ~3.3lbs per day, others ~3- 3.26lbs, heifers ~2.7-3.25lbs.
I'm sure it depents on genetics. The bull, those calves are sired by, was fast growing: was sold at age of 22 months, weigh 1510lbs, got ~2.2lbs triticale per day for 4 months since weaning and then was let into the herd to work, where he has been working for 7 months.
We've used many bulls and by some calves were fast growing, by anothers weren't out of the same dams.