Desirable muscle type and pattern have changed over the years. Extremely thick, bunchy - muscled pigs were once selected. While these hogs produced lean and heavy muscled carcasses, their productivity (litter size, farrowing ease, sound- ness, mating ability, pork quality, lack of stress, and maturity pattern) was not so desirable. Modern producers now select breeding stock that is longer and flatter muscled with a bigger skeleton. However, muscle is still our saleable product and thickness of muscle is important. Ideally, we want the greatest amount of total muscle mass(length, depth, and thickness) possible without interfering with overall productivity.