Birth weight is NOT the only thing in the formula for CE. I cannot explain the process because too many factors enter into it. Cow SIZE does enter into the evaluation. We are asked to turn in weights, height and disposition scores in addition to the normal info. Calculations evolve when better ways are developed. Environment (location) enters into the equation. They do NOT take the average of the breed for the year to give you EPD's. They are calculated on an individual basis. Yes, if the bull has NO data (homegrown sire out of homegrown dam and sire, etc), then the EPD's are very, very low in accuracies and breed average "may" enter the picture, I am unsure of that. If you take a sire with no genetic history (homegrown out of homegrown with little to none progeny) then they have nothing to work with. Maybe DNA data would help.