Skip to main content Accessibility help

Accuracy of prediction of percentage lean meat and authorization of carcass measurement instruments: adverse effects of incorrect sampling of carcasses in pig classification

  • B. Engel (a1), W.G. Buist (a1), P. Walstra (a1), E. Olsen (a2) and G. Daumas (a3)...


Classification of pig carcasses in the European Community is based on the lean meat percentage of the carcass. The lean meat percentage is predicted from instrumental carcass measurements, such as fat and muscle depth measurements, obtained in the slaughter-line. The prediction formula employed is derived from the data of a dissection experiment and has to meet requirements for authorization as put down in EC regulations. Requirements involve the sampling procedure and sample size for the dissected carcasses and the accuracy of prediction. Formulae are often derived by linear regression. In this paper we look at a particular type of sampling scheme. This involves selection of carcasses on the basis of carcass measurements not all of which are intended to be used as prediction variables. This sampling scheme frequently appears in requests for authorization of carcass measurement instruments and accompanying prediction formulae, despite the fact that it lacks formal statistical justification when used in conjunction with linear regression. The objective of this work was to assess the performance of the prediction formula that follows from this potentially faulty combination of sampling scheme and linear regression in relation to the requirements in the EC regulations. We show that this sampling scheme may produce poor predictions for lean meat percentage compared with proper sampling procedures with selection on prediction variables only or random sampling. We do so by computer simulation. Initially, simulated data were based on recent and historic data from The Netherlands. Prediction variables are fat and muscle depth measurements. The additional variable involved in sampling, but not included in the regression, was carcass weight. We also show that due to this faulty sampling scheme there is a serious risk that a new measurement instrument may not be authorized because performance criteria in the EC-regulations are not met.


Corresponding author

Address for correspondence: ID-DLO, PO Box 65, 8200 AB Lelystad, The Netherlands. E-mail:


Hide All
Anderson, T. W. 1958. An introduction to multivariate statistical analysis. John Wiley, New York.
Causeur, D. J. and Dhorne, T. J. 1998. Finite sample properties of a multivariate extension of double regression. Biometrics 54: 15911601.
Engel, B. 1991. Statistical analyses of the Dutch dissection data concerning harmonisation of methods for grading pig carcasses in the community. Unpublished research report available from the author.
Engel, B. and Walstra, P. 1991a Increasing precision or reducing expense in regression experiments by using information from a concomitant variable. Biometrics 47: 1320.
Engel, B. and Walstra, P. 1991b. A simple method to increase precision or reduce expense in regression experiments to predict the proportion of lean meat of carcasses. Animal Production 53: 353359.
European Community. 1985. EC regulation No. 2967/85, laying down detailed rules for the application of the Community scale for grading pig carcasses.
European Community. 1994. EC regulation No. 3127/94, amending regulation (EC) No 2967/85 laying down detailed rules for the application of the Community scale for grading pig carcasses.
GenStat Committee. 2000. The guide to GenStat. (ed. Payne, R.) VSN, International Ltd, Oxford.
Naes, T., Irgens, C. and Martens, H. 1986. Comparison of linear statistical methods for calibration of NIR instruments. Applied Statistics 35: 195206.
Press, W. H., Flannery, B. P., Teukolsky, S. A. and Vetterling, W. T. 1986. Numerical recipes. Cambridge University Press, Cambridge.
Walstra, P. 1986. Assessment of the regression formula for estimation of the lean meat percentage by HGP-measurements in The Netherlands. EC working paper, Brussels, VI/4849/86.
Walstra, P. and Merkus, G. S. M. 1995. Procedure for assessment of the lean meat percentage as a consequence of the new EC reference dissection method in pig carcass classification. Unpublished document ID-Lelystad, The Netherlands.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Animal Science
  • ISSN: 1357-7298
  • EISSN: 1748-748X
  • URL: /core/journals/animal-science
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed