The First Lady's favorite commodity is moving again. Live cattle futures have plunged amid a supply glut. Prices fell 10%, to 67.35 cents per pound, before firming at 70.175 cents on Apr. 5. The big slide began on Mar. 17, when a tally of steers fattening at feedlots came in 10% higher than expected. Lot operators "could not move the meat as fast as their supply was coming at them," says Don Roose of U.S. Commodities, a hedging consultant. Weak retail demand for beef makes a rally unlikely soon, analysts say.