Predictive value of slaughterhouse measurements of ultimate pork quality in seven halothane negative Yorkshire populations

Abstract

An experiment with 1969 pigs, belonging to Yorkshire sire lines, was set up in cooperation with seven Dutch breeding organizations. The pigs, which were claimed to be halothane negative, were slaughtered in weekly batches. Light reflectance was determined with the Hennessy Grading Probe (HGP) and Fibre Optic Probe (FOP), in addition to pH 1 and rigor mortis at 45 min post mortem (p.m.). Further meat quality determinations 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 light (HGP-PSE, FOP) and pH, measured at 45 min p.m., appeared to be indicative of the ultimate meat quality score. More accurate analyses, however, showed that the value of reflectance values is limited and less suitable in comparison to pH 1, especially with reference to the prediction of ultimate quality characteristics of water holding capacity. The correlations for pH 1 with drip loss were rather consistent, ranging from −0·34 to −0·52 per breeding population. In contrast, HGP-reflectance values ranged from −0·27 to 0·34, while those based on FOP 1 had a range from nearly zero (0·02) to 0·20. The proportion of variation ( R 2 × 100%) in drip loss, explained by a set of slaughterline measurements, ranged from 13 to about 28% per breeding population. The use of measurements carried out at 20 h p.m. improved the R 2 × 100% for drip loss to a range from 50 to 62%.