| An extensive study was conducted to standardize United States pork carcass composition assessment equipment. Grading equipment included a stainless steel ruler, Fat-O-Meater (FOM), Automatic FOM (AFOM), Carcass Value Technology System 1 (CVT1), CVT System 2 (CVT2), Hennessy Grading Probe (HGP), and the Ultrasound FOM (UFOM). Barrow and gilt carcasses were selected to meet the average backfat and carcass weight for selection cells based on three endpoints of hot carcass weight and three last rib fat depth endpoints (median, high, and low). Four pork primal yield endpoints were collected as bone-in, lean cuts (ham, loin, picnic shoulder, Boston butt) trimmed to 6.3, 3.2, and zero mm external fat depth, as well as zero trim boneless yield. Soft tissue was collected and sub-sampled for analysis of total ether extractable lipid. Fat-free mass was calculated to two endpoints: fat-free lean and lipid-free lean. Linear regression analysis was performed using fat and lean tissue obtained from each electronic grading instrument. Correlation coefficients were evaluated across instrument output and with carcass yield. Final prediction equations were determined using the STEPWISE procedure of SAS retaining independent variables at a level of P < 0.10. The highest correlations were observed between the FOM and HGP (r = 0.94; P < 0.0001), CVT1 and CVT2 (r = 0.93; P < 0.0001), and last rib fat thickness and AFOM last rib fat thickness (r = 0.915; P < 0.01). When the new equations were applied to predict compositional yield, no differences were observed across all instruments for yield prediction, suggesting that these equations can be used as an industry standard. |
