A comparison of the OFDA2000 with conventional mid-side testing of mohair

Author: M.B. Ferguson and G. Kearney
Year: 2004
Issue: 5
Volume: 34
Page: 4 - 6

The portable fibre-testing instrument OFDA2000 has applications in the mohair industry for both fibre classing and animal selection. A comparison was completed between single-staple mid-side testing using an OFDA2000 and conventional laboratory mid-side testing using an OFDA100. Mid-side mohair samples (n=504) were collected from two consecutive shearings of a mixed sex group of Angora kids at 6 and 12 months of age. The samples were at the fine end (average 20.9 mm) of the mean fibre diameter range of mohair. There was a bias between the estimates of mean fibre diameter at both shearings. The other traits studied also had biases between measurement methods. The regression analyses results of mean fibre diameter from the two test methods accounted for 91% and 88% of the variance for first and second shearings, respectively. Regression analyses between test methods for standard deviation, coefficient of variation of fibre diameter and fibre curvature accounted for less variance than the regressions of mean fibre diameter results. The results indicate OFDA2000 is suitable for estimation of mean fibre diameter of greasy kid mohair staples and is therefore useful for both mohair classing and Angora selection.

Keywords: bias, correlation, Fibre diameter, portable fibre-testing
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