It bothers me to read this post, as always the breeding age is determined by weight...a heifer can be bred at 750lbs and sometimes less depending on the full grown weight. One of the nicest animals I bought was a 750lb bred angus, and I should add kept her heifer and she has grown into a nice cow.
I don't know if Dun and other persons on this page are raising show animals or what thier goals are. But a 900 lb heifer due to calf will gain a few lbs and be a 1200lbs animal...the goal that dun and many have here. One day they question frame size the other not...but the truth is ..well i think u get it.
Have nice day