A single backfat measurement taken by optical probe as a predictor of lean body content of the pig carcass

Abstract

Carcass data obtained from 528 pigs which comprised gilts, barrows, and entires reared to slaughter at 40, 80, and 100 kg liveweight at 1 location and to 100 kg liveweight at another centre, were analysed to determine the value of a single backfat measurement as a predictor of the lean body content of the carcass. This measurement was taken on the slaughterline with an optical probe 4 cm lateral to the centre of the vertebral column immediately posterior to the last rib. At slaughter weights of 40 and 80 kg, sex of the carcass did not influence either the slope or elevation of regression lines relating the backfat measurement and percentage lean body content. At the heavier slaughter weight, corresponding regression equations established for entires differed in slope and elevation from those for gilts and barrows and there were no differences between these 2 latter types. Separate regression equations established for the 40, 80, and 100 kg slaughter weight groups ignoring sex and location, had residual standard deviations of 2.25,2.70, and 2.31 in percentage lean body content respectively. Overall a change of 1.0 mm in backfat depth represented a change of between 1.25 and 2.00 in percentage lean body content.

Keywords:

• Backfat
• optical probe
• lean body
• pigs
• carcass evaluation