Carcass Fat-free Lean Gain of Chinese Growing-finishing Pigs Reared on Commercial Farms

Five regions and 258 pigs were selected for this study: North (Beijing), Central (Wuhan), South (Guangzhou), Southwest (Chongqing), Northeast (Harbin). Five typical genetics of growing-finishing pig were selected: Landrace${\times}$Large White${\times}$Beijing Black, Duroc${\times}$Landrace${\times}$Large White, Duroc${\times}$Large White${\times}$Landrace, Landrace${\times}$Rongchang, Landrace${\times}$Harbin White, respectively at each sites. The basal diet was a corn-soybean meal containing sufficient nutrients to meet requirements. Carcass fat-free lean gain was determined by dissecting and analyzing chemical composition of the carcass. Cubic function fitted lean moistures to live weights better than other functions. Exponential function fitted lean lipids to live weights equally to allometric function. Carcass fat-free lean gain of Duroc${\times}$Large White${\times}$Landrace, Landrace${\times}$Large White${\times}$Beijing Black, Duroc${\times}$Landrace${\times}$Large White, Landrace${\times}$Harbin White, Landrace${\times}$Rongchang from 20 to 100 kg of average body weight was 259 g/d, 261 g/d, 311 g/d, 220 g/d, 200 g/d, respectively. All are lower than intermediate fat-free lean gain in NRC (1998).