Why with all the new tech. does the USDA still use fat to measure quality.  BEEF COULD BE SOLD THE SAME WAY THEY DO MILK. Letting each consumer pick the fat content they want. USDA meat research showed we could produce 3% fat beef that was just as tender as 10%(prime). With several traits that effect the tenderness of a given cut of meat, we use marbling (effecting tenderness by about 7%) because it can be seen with our naked eye and its tradition. Genetically we could be producing lean tender protein for the consumer(see Belgium blue& piedmonties cattle)