Abstract

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.

RN, Andrews, JTJ Land, KG Dodds, and T Wuliji

Proceedings of the New Zealand Society of Animal Production, Volume 57, , 73-76, 1997