Comparison of national ZP equations for lean meat percentage assessment in SEUROP pig classification

The objectives of the present work were (1) to compare pig carcass classification using different ZP ("Zwei-Punkt-Messverfahren") equations approved in the EU, applied on the same dataset, and to discuss the origin of differences between member states; (2) to evaluate the effect of a possible common ZP equation from the combined dataset and analyse how do the different subsets perform; and (3) to discuss the consequences of different national equations within the EU in view of the harmonization of pig carcass classification. A dataset of 951 carcasses from Belgium, France, Germany, Slovenia and Spain was used, 12 approved ZP equations in Europe were applied and the results were compared. Observed differences can be due not only to differences in genetics and sexes, but also to differences in the ZP measurement and dissection trials performed to obtain national equations. Important differences between some equations (up to almost 5 lean meat percentage) indicate a low harmonization among them and a need for improvements.