Study On The Technology Of Pig Carcass Grading System

In this study, subcutaneous fat(P2) at the last rib and 6cm off the dorsal mid- line .and subcutaneous fat(RF) and m.longissimus depths(RM) between the last third/fourth rib and 6cm off the dorsal mid line were measured by Danish Fat-O-Meat'er (FOM) on a broad sample of 5821 commercial carcasses. From these carcass, 120 commercial carcasses were picked out randomly and the left side of the 120 carcasses were dissected into picnic, butt, loin .and ham. Then the four cuts were dissected into skin, fat, lean and bone tissue and every tissue was weighed and the lean yield of each commercial carcass was calculated. With the lean yield of each commercial carcass as dependent variable Y and different combination of P2 RF RM as independent variable Xj(i=l,2,3) respectively, regression equations were established for estimation of the lean yield in carcasses. Then the lean yields (LY) of 5861 commercial carcass was calculated by the regression equation and means and correlations of P2 RF RM and LY were calculated. We investigated the Purchasing Price System of Commercial Pig in some main commercial abattoirs in Sichuan province and gave some rationalization proposals by contrasting the Purchasing Price System in foreign developed countries, in animal husbandry.The result indicated that the regression equation(Y=58,6452-0.5410RF+0.1159RM) with RF and RM as independent variable was the best one in all equations. The R value for prediction of carcass lean yield was 0.9336 and the RSD value was 1.5479. The carcass quality in Sichuan province was not good: The percentage of lean averaged 44.7% and the average carcass weight was 49.24 kg; the percentage of lean was significantly correlated with P2(-0.9282) , RF (-0.9187) , carcass weight(-0.4063) and RM(0.1962).There were three Commercial Pig Purchasing models: according to the live weight, the carcass weight and the live weight or the carcass weight.There were no limits in pig carcass weight in some commercial abattoirs in Sichuan province when thecommercial pigs were purchased. The models of production in some commercial abattoirs didn't conform to the standard. For example, the pigs were not withdrawal before slaughter; the worker often moved the pigs with a metal stick .These would lower the pork quality.This study will give the theoretical basis and the rationalization proposals for predicting the lean yield and the price of pigs in Sichuan province and working out the laws and regulations concerned.