The prediction of pork carcass composition using the Hennessy Grading Probe and the Aloka SSD-210DXII Echo Camera
Carcasses, with an average weight of 80.8 kg, from 130 Lacombe and 96 Yorkshire pigs were probed for fat and muscle depth at the carcass grade site using the Hennessy Grading Probe (HGP). Similar data were collected by the Aloka SSD-210DXII Echo Camera (AEC) at the carcass grade site and at the Canadian Swine Improvement Program loin and mid-back sites. Muscle-width and muscle-area measurements were also made with the AEC. The R2 (residual standard deviation: RSD), using the HGP, for prediction of carcass lean yield at the grade site using fat and muscle depth was 0.58 (16.4). When fat and muscle depth were measured by the AEC, the R2 (RSD) at the mid-back, loin and grade sites to predict carcass lean yield was 0.41 (19.7), 0.47 (18.5), and 0.53 (17.5), respectively. When the AEC muscle-depth measurements were replaced with muscle-area measurements, the R2 increased (RSD decreased) at the mid-back, loin and grade sites to predict carcass lean yield (0.60 (16.0), 0.64 (15.2), and 0.59 (16.4), respectively). Real-time ultrasound (AEC) provides precision for the prediction of carcass lean content similar to that of the electronic grade probe (HGP). However, combining fat- and muscle-depth measurements made by the HGP with muscle-area measurements made by the AEC at the loin increased the R2 from 58 to 66% for the prediction of carcass lean yield. The suitability of the use of real-time ultrasound as an alternative to electronic grading probes, at this time, appears to be limited. Key words: Swine, real-time ultrasound, carcass grading