Prediction of lean meat proportion based on ultrasonic backfat thickness measurements of live pigs

In The Netherlands a system has been developed for classification of live p igs based on lean meat proportion. Ultrasonic backfat thickness measurement s were taken on 377 live pigs to assess the ability oft he developed system for estimation of the lean meat proportion. The measurements were made at the sites mid point (half the distance from the occipital bone to the base of the tail), mid point -2.5 cm and mid point +2.5 cm, 5 cm off the dorsal mid line. On the same day, these pigs were slaughtered and the lean meat proportions of the carcasses were estimated using the Hennessy Grading Probe (HGP). HGP measurements were taken between the third and fourth from last rib, 6 cm o ff the dorsal mid line on carcasses (3/4 LR). The day after slaughter, 88 l eft carcass sides were randomly chosen to be dissected according to a simpl ified European Union (EU) reference method. From the fat thicknesses measured, the one at the site mid point on live pi gs was the most accurate predictor for the EU lean meat proportion. The use of multiple site measurements, compared with a single site measurement, si gnificantly reduced the residual standard deviation for the estimation of l ean meat proportion. The site mid point on live pigs differed in longitudinal as well as in dors al-ventral direction from 3/4 LR on carcasses. The results of this study suggest that multiple backfat thickness measureme nts on live pigs can be used for prediction of lean meat proportion with su fficient precision for practical use. Therefore, the developed system can s erve as a classification system for live pigs.