COMPARISON OF THE ‘MEASURE AS YOU GROW ’ TECHNIQUE FOR MEASURING FIBRE DIAMETER PROFILES BETWEEN TWO LABORATORIES AND TWO SAMPLE

Fibre diameter (FD) was measured on 2 mm snippets of wool from the base of staples and compared between 2 laboratories and 2 sample sites for 6 flocks. The base snippets were taken at regular intervals during the year, and the FD was plotted against staple length to produce a FD profile. There was a mean bias of 0.4 µm between laboratories in estimating the mean FD of the profile. The hip-bone sample site was 0.96 µm broader than the mid-side, although this differed significantly between flocks. The staple length estimates between both laboratories were strongly correlated (r2 = 0.99). There was no difference in the precision of estimating FD profile between the sample sites. The confidence limit of a mean FD estimate at a point along the staple profile was ± 0.54 µm within a sample site. The ‘measure as you grow ’ technique for estimating FD profile parameters appears precise enough to be used as a guide to growers. However, other alternatives need to be investigated which provide a more accurate and precise estimate of the FD profile