Prediction of ewe mutton carcass composition from carcass weight, GR and C measurements, and the Hennessy grading probe

A.H. Kirton, C.L. Feist and D.M. Duganzich

Ruakura Animal Research Station, Ministry of Agriculture and Fisheries, Hamilton

Proceedings of the New Zealand Society of Animal Production. 1986, 46: 59-62

The composition of the dressed carcasses of 54 mixed-breed ewes was predicted from their hot carcass weight (HCW), measurements C and GR, and carcass wall thickness taken on the left (GPL) and right (GPR) sides 13 cm from the mid-line between the 11th and 12th ribs with an electronic Hennessy grading probe. The right side of each carcass was dissected into fat, muscle and bone. Mean HCW was 25.4 kg, GR was 16.9 mm, C was 6.6 mm, GPL was 22.1 mm, GPR was 22.7 mm, dissectible fat was 32.4%, muscle was 52.4% and bone was 14.1%.

Of the variation in carcass fat %, GPR accounted for 74% and GR for 78%. When combined with HCW, GPR accounted for 77% and Gr for 80%. This last value was not further increased by adding more variables. GPR accounted for 67% of the variation in carcass muscle % and GR for 68% of this variation. When combined with HCW these values increased to 71% and 73% respectively and were not further increased by adding more variables. GPR and GR were also the best predictors of percentage bone.

Keywords: NZSAPAB; Mutton carcasses; grading; Hennessy grading probe; carcass weight; GR

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Last Updated 18-03-1997