title: Comparison of ultrasonic measurement of backfat depth on live pigs and carcases with a digital recording instrument.
abstract: A hand-held, digital recording ultrasonic backfat tester (Sonalyser) was used on 200 live pigs and their carcases to predict carcase P2 backfat depth measured with the Introscope optical probe. Readings were taken on live pigs at a position which approximated to the P2 site on the carcase. This site was tattooed. Sonalyser and Introscope readings were taken on the carcase at the P2 site and at the tattooed site. Regression equations of Introscope readings as a function of Sonalyser live pig and carcase measurements were developed. Calculation of partial F values showed the Sonalyser was more precise in measuring backfat on the live pig than the carcase. With R(2) = 0·77 and residual standard deviation (rsd) = 1·35 mm was judged to be acceptable for predicting carcase Introscope backfat from live pig measurement. Due to the lower precision, and other practical limitations to its use in abattoirs, the Sonalyser was not suitable for measuring backfat on the carcase. The limiting factors may have contributed to the lower R(2) (0·69) and higher rsd (1·55 mm) of the regression between Sonalyser and Introscope carcase fat depth.
authors: New South Wales Department of Agriculture, Agricultural Research and Veterinary Centre, Forest Road, Orange, NSW 2800, Australia.
authors: E B
authors: EB
authors: Greer
authors: T W
authors: TW
authors: Lowe
authors: L R
authors: LR
authors: Giles