The effect of increasing carcass weight of finishing boars and gilts on joint composition and meat quality

Two hundred and eighty-eight crossbred (3/4 Landrace x 1/4 Large White) pigs, comprising equal numbers of boars and gilts, were housed in single sex groups from 50 kg liveweight to slaughter at liveweights of 92, 105, 118 and 131 kg (carcass weights of 70, 80, 90 and 100 kg). Sample joints from the left longissimus dorsi muscle were obtained at slaughter for dissection and meat quality assessment. As carcass weight increased there were significant (p < 0.001) increases in eye muscle area and subcutaneous fat content. Lean content decreased (p < 0.001) with increasing carcass weight while intermuscular fat content was not affected. There was a significant interaction between carcass weight and gender with % drip loss in pork from gilts at 100 kg having a higher drip loss than boars and gills at all other weights. There were small but significant (p < 0.01) reductions in ultimate pH with increasing carcass weight. Cooking loss was also reduced (p < 0.001) at the heavier weights. There was no effect of carcass weight on shear force or on intramuscular fat. Dry matter (DM) and crude protein (CP) contents of m. L. dorsi increased (p < 0.001) at heavier weights while sarcomere length decreased (p = 0.001). Compared with boars, gilts had greater eye muscle area (p < 0.05), more subcutaneous fat (p < 0.001). Meat from gilts in comparison with boars had higher % DM and % CP contents (p < 0.001), higher intramuscular fat content and shear force (p < 0.05). It is concluded that meat quality may be improved when carcass weight is increased from 70 to 100 kg. (C) 1999 Elsevier Science Ltd. All rights reserved.