This study evaluated 167 Angus sire heifers which were managed as either potential replacement breeding stock or feedlot performance heifers. Each heifer was scanned three times over the experiment period. This study would indicate that evaluation for percent intramuscular fat (PFAT) would be more feasible under typical replacement heifer development management schemes than evaluation for subcutaneous fat or REA. The difference in the level of energy fed had a much smaller response on the rate of change for PFAT than on either subcutaneous fat or REA.