The accuracy of measuring backfat and loin muscle thicknesses on pork carcasses by the Hennessy HGP2, Destron PG-100, CGM and ultrasound CVT grading probes

Research was undertaken to evaluate the accuracy of different grading probes measuring backfat (F) and loin muscle thicknesses (M). Thus, 270 pig carcasses were selected according to a 2 × 3 × 3 factorial arrangement. Gender (barrows and gilts), fat thickness at the Canadian grading site ( 19.75 mm), and hot carcass weight (75.5 to 81.8, 81.9 to 86.2 and 86.3 to 92.7 kg) were the main factors. The Hennessy (HGP2), Destron (PG-100) and CGM optic probes and the CVT ultrasound probe with two transducers [PCA-5049, 172 mm (CVT-1) and PCB-5011, 125 mm (CVT-2)] were evaluated. Grading measures were compared to the equivalent measures taken in a digitized image. The F and M precision was evaluated in terms of random bias (ED). Hennessy F and CVT-1 M had the lower ED. For F measurements, CGM, Destron, CVT-2 and CVT-1 ED was respectively, 1.65, 1.72, 1.78 and 2.14 times greater than Hennessy ED. For M measurements, ED of CVT-2, CGM, DPG and Hennessy was 1.02, 1.84, 2.03 and 2.20 times greater than CVT-1 ED. Measures of the intercostal muscles were not reliable in any of the probes able to take that measure. Key words: Pork, carcass grading, grading probes, HGP2, PG-100, CGM, CVT