Real-Time Ultrasonic Evaluation Of Swine

Abstract

This study shows no difference in the backfat data collected on live and dead animals. In adjusted data, barrows had more backfat according to sonic and actual carcass measurement. There was a significantly (P<0.05) lower value in gilts in the first and last rib positions and in barrows in all positions but the tenth rib for sonic data as compared with carcass measurement. A high and significant (P<0.01) correlation existed between sonic and carcass measurements of fat thickness across sex. Within each sex, correlation was highest on the tenth rib followed by the last rib in gilts and the last lumbar in barrows. There were no significant differences in longissimus area measurement taken ultrasonically or in the carcass although correlations between them were high, being higher in gilts. 3MHz scanning produced greater accuracy in gilts than barrows for fat thickness and longissimus area determination, 5MHz, however, gave data that were closer correlated with carcass data. Except for the first rib position, there were no differences between scans taken on the hot carcass and actual carcass measures taken on the chilled right and left sides 48h later. The result suggests that hogs can be scanned a forthnight before slaughter and the data can be used in computing hog carcass yield at the point of sale. It also suggests the possibility of complete grading for hot carcasses and may further encourage hot processing if adopted. In cold processing situation, it may remove the necessity to enter the cooler for carcass measures.