PREDICTIVE VALUE OF SLAUGHTERHOUSE MEASUREMENTS OF ULTIMATE PORK QUALITY IN 7 HALOTHANE NEGATIVE YORKSHIRE POPULATIONS

An experiment with 1969 pigs, belonging to Yorkshire sire lines, was s et up in cooperation with seven Dutch breeding organizations. The pigs , which were claimed to be halothane negative, were slaughtered in wee kly batches. Light reflectance was determined with the Hennessy Gradin g Probe (HGP) and Fibre Optic Probe (FOP), in addition to pH(1) and ri gor mortis at 45 min post mortem (p.m.). Further meat quality determin ations were performed either in the slaughterhouse at 20 h p.m., or in the laboratory at 24 h p.m.. At first sight, both the scatter of ligh t (HGP-PSE, FOP) and pH, measured at 45 min p.m., appeared to be indic ative of the ultimate meat quality score. More accurate analyses, howe ver, showed that the value of reflectance values is limited and less s uitable in comparison to pH(1), especially with reference to the predi ction of ultimate quality characteristics of water holding capacity. T he correlations for pH(1) with drip loss were rather consistent, rangi ng from -0.34 to -0.52 per breeding population. In contrast, HGP-refle ctance values ranged from -0.27 to 0.34, while those based on FOP1 had a range from nearly zero (0.02) to 0.20. The proportion of variation (R(2) X 100%) in drip loss, explained by a set of slaughterline measur ements, ranged from 13 to about 28% per breeding population. The use o f measurements carried out al 20 h p.m. improved the R(2) X 100% for d rip loss to a range from 50 to 62%.