Comparison of ultrasound and carcass measures as predictors of ham composition

Abstract

<p>The objective of this study was to compare ultrasound and carcass measures as predictors of ham composition. Data from six hundred twenty-four pigs representing 6 commercial genetic types in the Quality Lean Growth Modeling Project conducted by the National Pork Producers Council were used to develop live animal ultrasound and carcass measurement prediction equations for ham composition. The project included three replications, and four diet programs within each replication. Pigs were weighed and a cross-sectional 10th rib scan was taken bi- or tri-weekly until pigs reached one of three designated market points (114, 132, 150kg). Six body scans were taken on the market weight pigs on their right side within five days prior to slaughter. The images were captured with the ALOKA 500V (Corometrics Medical Systems, Wallingford, CT) real-time ultrasonic machine fitted with a 12.5 cm, 3.5 Mhz linear array transducer. There were three longitudinal scans at the 5th, 10th and last rib. The transducer was aligned horizontal to the spine, 5 cm off the dorsal mid-line. A 10th rib cross-sectional scan was taken perpendicular to the spine between the 9th and 10th rib. A ham scan was obtained with the probe being placed on the transverse plane on the outside of the ham approximately half the distance from the tail to the hock. Upon completion of the test, pigs were transported to Quality Processors packing plant in Austin, MN. Fat-O-Meter[Superscript TM] and carcass measurements for loin eye area, and fat measurements were also taken. The hams from the right side of the carcass were removed and sent to Texas A&M University, College Station, Texas for complete physical dissection. R2 ranged from .63 to .81 for the fixed effects models that predict the subcutaneous fat weight, outside ham muscle weight, total lean weight and total fat weight of the ham. The results from this study indicate that prediction equations with live ultrasound measurements are similar to the Fat-O-Meter[Superscript TM] and to actual carcass measurements in predicting components of ham composition.</p>