Pig carcass grading methods authorised in France in 1997

The development of French grading methods is based on the use of a general dissection trial and a specific calibration trial. The calibration procedure developed by the authors now allows the methods to be tested whatever the predictors used. In 1997, 2 grading methods, predicting carcass lean meat content (TVM), were authorised in France. One uses the CGM device from the French company, SYDEL and the other uses the Ultra-Meater device from the German company,CSB. The calibration trials showed that there was a significant sex effect, therefore equations were developed for females and castrated males.For CGM, 3 predictors are used, a lumbar fat thickness (G34VL), a rib fat thickness (G34DC) and a rib muscle thickness (M34DC) :• females: root MSE = 1.92 and Y = 61.68 - 0.142 G34VL - 0.449 G34DC + 0.154 M34DC• castrates: root MSE = 2.06 and Y = 58.15 - 0.198 G34VL - 0.570 G34DC + 0.255 M34DCFor Ultra-Meater, 2 predictors are used, a rib fat thickness (G23DC) and a rib muscle thickness (M23DC) :• females: root MSE = 2.13 and Y = 60.87 - 0.797 G23DC + 0.209 M23DC• castrates: root MSE = 2.17 and Y = 58.44 - 0.953 G23DC + 0.304 M23DCThe CGM method, which uses measurements made at 2 sites, gives better accuracy in terms of Mean Square Error (MSE), but suffers from a slightly higher proportion of outliers.