I can see why the judge liked the heifer, but she is just too big and too late maturing. She is still a very well proportioned very well conditioned heifer. I agree the grey calf is a dandy.
By the length of the cannon bone. For the practised eye its not difficult to distinguish either whether the animal's growth plates on the long bones had closed yet and whether the carcass has started to mature as opposed to more long bone growth. This heifer is still growing.