Ours straightbed Angus heifers,born late March and early April, weighed 780# when they went to grass. We know because we weighed them. Wintered on grass hay and mineral. Sometimes we added a little soybean supplement called Forage Pro. They bred up well and stayed in the herd a long time. We didn't want big cattle--1200#-1300 at the outside when mature. There is a lot of variables talking developing replacement heifers. Breed, age, mature size, etc.
There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.