Comparison of rankings for lean meat based on results from a CT scanner and a video image analysis system

•VIAScan® primal weights are significantly less than those from the CT scannner in heavier carcases.•The ranking of the lambs for lean weight between measurement methods across three years was 0.84.•The results are important for the use of VIAScan® data in the SIL genetic evaluation program.

Coopworth cross lambs born over three years were examined in this study. Differences between two machines; a computer tomography (CT) scanner and a VIAScan® system for the estimation of carcase lean weight in lamb carcases was examined. The CT scanner provided a significantly higher estimate of carcase lean. The rank correlation (0.84) between the CT scanner and the VIAScan® system for the prediction of carcase lean was significant, but there was a different ranking for carcase lean depending on which machine was used. This has important ramifications for the use of VIAScan® data in the New Zealand Sheep Improvement Ltd genetic programme.