Classing Merino fleeces into uniform lines with predicted adult
fibre diameters.
R.N. Andrews, J.T.L. Land, K.G. Dodds and T. Wuliji
AgResearch, Invermay Agricultural Research Centre, Private Bag
50034, Mosgiel.
Proceedings of the New Zealand Society of Animal Production. 1997,
57: 73-76
The effectiveness of 3 wool classing methods, to separate
fleeces into uniform lines of different mean fibre diameter (MFD) and to
maximise net financial returns were compared. The methods were
predictive (i.e. uses hogget MFD), objective (i.e. adult MFD) and
subjective (i.e. visual). A flock of mixed-age Merino ewes, (n = 2,640;
adult MFD = 19.9 ± SD 1.3 um) were randomly drafted into predictive,
objective and subjective groups for midside sampling and measurement of
adult MFD pre-shearing. Predicted MFD was calculated from the
correlation of hogget with adult MFD.
MFD of grab-samples of lines were, predictive 20.0 um, objective 20.1
um, and subjective 19.9 um. The % CV of fibre diameter of grab-samples
of objective lines was 0.4 and 0.9 less than predictive and subjective
respectively. For a range of prices, premiums for the fine edge of the
clip were generally insufficient to cover objective measurement costs.
Keywords: NZSAPAB;
Merino; fleece classing; fibre diameter; prediction.
Last Updated 12-09-1998
