If I'm testing in shed do I need to scour (wash) the wool?

Technology for on-farm testing for diameter characteristics is now available. The FLEECESCAN system developed by CSIRO includes equipment, which cleans the sample prior to measurement.

For accurate measurements, this is necessary because wool grease and suint form a thin coating on the outside of wool fibres. This layer is removed during scouring, allowing a precise measurement of fibre diameter. Since the thickness of this coating may vary from fibre to fibre, and sheep to sheep, if it is not removed prior to fibre measurement, irregular and imprecise results will be obtained.

The OFDA 2000 technology developed by BSC Electronics does not clean every sample prior to measurement. Instead, the instrument is calibrated by cleaning some selected samples and adjusting all other measurements using the difference. This technique assumes the thickness of grease, suint and dirt on on the wool fibres of every sheep will be very similar, which is unlikely to be the case given that the washing yields of different sheep in every flock can vary up to 20-30%.

In short, not washing the fibres prior to measurement will reduce the measurement accuracy.