Comparison of methods for measuring fibre diameter of Romney Wool

D.R. Scobie, N.C. Merrick, D.J. Saville

AgResearch, P.O. Box 60, Lincoln, 8152, New Zealand

Proceedings of the New Zealand Society of Animal Production 1994, 54: 155-158

Wool from lines of Romney sheep selected on the basis of staple strength was measured for mean fibre diameter using both the airflow apparatus and an Optical Fibre Diameter Analyser (OFDA). For wool from "low strength" and "control" selection lines, airflow measurements tended to be upwardly biased in relation to the OFDA measurements, while for wool from the "high strength" line the airflow measurements tended to be downwardly biased. Two sources of bias are known in the literature, medullation and standard deviation. In this work the latter seemed to be more important, which may be a consequence of the relatively low level of medullation present in these wools (8.6%). For research work the OFDA is put forward as the preferred instrument.

Keywords: NZSAPAB; wool; medullation; fibre diameter; standard deviation.

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