Technology & Standards Committee Evian Meeting
Total Page:16
File Type:pdf, Size:1020Kb
TECHNOLOGY & STANDARDS COMMITTEE EVIAN MEETING Commercial Technology Forum May 2004 Chairman: A.G.DE BOOS (Australia) Report No: CTF 02 The 2003 Australian Wool Innovation on-farm fibre measurement instrument evaluation trial - Part 2: Performance in objective classing and ranking for animal selection By Peter Baxter, Jim Marler SGS Wool Testing Services PO Box 15062, Wellington, New Zealand Australian Wool Testing Authority Ltd PO Box 190, Guildford, NSW 2161, Australia SUMMARY This report summarises the results of the 2nd phase of a substantial trial carried out by Australian Wool Innovation Ltd. (AWI) in which the performance of the two common on-farm fibre diameter measurement technologies (OFDA2000 using midside samples and Sirolan Fleecescan using sampling of the whole skirted fleece) were compared with traditional midside sampling followed by laboratory fleece measurement, and with the outcomes of IWTO Certification of lots prepared using these technologies. In this phase, only Mean Fibre Diameter measurements were considered. The specific processes evaluated in this phase were the measurement-assisted classing of single mob wool clips, and the ranking of individual sheep. The evaluation was carried out on one superfine and one fine-wool property in Victoria, and a medium-wool property in South Australia. The work illustrated that these two specific on-farm sampling and measurement technologies (i.e. OFDA2000 measurement on midside samples and Fleecescan measurements on the skirted fleece) produced very similar outcomes with slightly lesser precision than laboratory fleece testing carried out on midside samples in accordance with AS/NZS 4492. There was a strong relationship between the two on- farm technologies and their ability to measure Mean Fibre Diameter compared with certificate testing, and when used for fleece classing, they both produced lines of wool of different diameters in the expected order (i.e. the line that was expected to be finest was the finest, etc). Biases were observed between the expected classed line diameters and the certified test results (from –1.1 µm to +0.9 µm), and these varied from property to property. The phenomenon sometimes called "Micron creep" was similarly observed for both technologies and would also be expected to exist if laboratory measurements were to be used for fleece classing. From both the fleece classing and sheep selection results it can be concluded that the precisions of the two on-farm technologies for mean fibre diameter are near equal. Finally, it was concluded that the larger the range in diameter within a flock, and the more precise the measurements, the more likely it is that classed lot measurements and animal selections using different instruments or systems will be consistent. INTRODUCTION BACKGROUND Since the late 1990s, both OFDA2000 (measurement based on imaging technology) and Sirolan Fleecescan™/Sirolan Laserscan™ (measurement based on laser technology) instruments have been regularly used in Australia to measure Mean Fibre Diameter (MFD), but also other wool fibre traits, on samples taken from fleeces on-farm; in a race pre-shearing and in shearing sheds at shearing time. The 2003 Australian Wool Innovation on-farm fibre measurement instrument \…:- Page 1 of 39 Commercial Technology Forum Report: 02 In September 2001, Australian Wool Innovation Ltd. (AWI) initiated a series of research projects to gain a greater understanding of the issues involved with the development and application of the On-Farm Fibre Measurement (OFFM) technologies and systems. Nine research projects were initiated with respect to OFFM covering: market research, a world-wide search for new technologies, an assessment of potential enhancements to existing technologies, scoping of a Quality Assurance (QA) program, scoping of a wool grower extension program, a benefit cost analysis, an assessment of the potential for electronic identification, an assessment of existing and future decision support systems and a comparison of existing technologies. The market research commissioned by AWI (TQA 2002), which was completed in June 2002, indicated an increasing need by wool producers for an independent and objective assessment of the commercial application of the two current OFFM technologies. At that time, there had been little independent published information on the performance of the two instruments with respect to their use by woolgrowers for clip preparation, sheep breeding and/or flock management. There was also a scarcity of published data that used recognised and industry accepted statistical methods to determine the precision limits of each instrument and/or to compare their outcomes and their application methods. By June 2002, AWI had established a draft protocol for an extensive trial that would address the above issues. AWI also established an OFFM Expert Advisory Group (EAG) to provide assistance and guidance with the trial design, the implementation of the trial, and the analysis and interpretation of the trial results. Details of membership of the EAG, project management and consultancies are given in the Acknowledgements. OBJECTIVES OF THE OFFM INSTRUMENT EVALUATION PROJECT The key objectives of the instrument evaluation project (trial) were to quantify: 1. The precision/repeatability and accuracy of both instruments, with respect to an entire fleece; for the measured characteristics, principally, MFD; but including: Standard Deviation of Fibre Diameter (SDD), Coefficient of Variation of Fibre Diameter (CVD), Mean Fibre Curvature (MFC) and Comfort Factor (CF). 2. The ability of both instruments to class a single mob wool clip into lines of distinctive MFD categories (minimum category of one micrometre (µm)); and 3. The ability of both instruments to rank individual sheep on the basis of MFD. The above objectives relate to the instruments being a part of an OFFM system operated in an on-farm environment. Note, for the purposes of this document an OFFM system, which comprises the measurement instrument, any associated apparatus and application procedures, will be referred to as an “instrument”. The trial was specifically directed towards providing knowledge that could be used by wool producers (or their sheep and wool customers) to make informed decisions with respect to the use of these OFFM instruments for clip preparation, sheep breeding and/or flock management. The trial provided an opportunity to benchmark one instrument against the other; and against the commercially accepted method of fleece measurement using on-farm midside sampling and off-farm laboratory measurement; and against IWTO Certified results for on-farm prepared sale lots. Objective 1 of this project (phase 1) is described in the companion Part 1 paper (Marler & Baxter, 2004). Objectives 2 and 3 (phase 2) are described herein. SCOPE OF TRIAL DESIGN The trial was limited to providing information to wool producers specifically in relation to the classing and the ranking of the measures defined above. The trial did not assess: • The other wool fibre measurements that may be provided by either instrument; • The performance of either instrument in an in-store environment; or • The two instruments in relation to issues such as ease of use, robustness, Occupational Health and Safety, after sales support, quality assurance, pricing, etc. The 2003 Australian Wool Innovation on-farm fibre measurement instrument \…:- Page 2 of 39 Commercial Technology Forum Report: 02 OBJECTIVES 2 AND 3 The objectives of Phase 2 of the project, reported herein, were to compare the performance of two OFFM instruments (OFDA2000 in conjunction with midside sampling and Fleecescan applied to skirted fleeces): • in terms of classing of individual fleeces for the preparation of lines of wool (wool classing), and • for the ranking the individual fleeces for the purposes of sheep selection. Comparisons were also made with midside sample measurements conducted at a commercial fleece testing laboratory using both OFDA100 (LabOFDA) and Sirolan-Laserscan (LabLSN) instruments. Phase 2 involved three properties, with approximately 800 sheep randomly chosen from a single mob from each property. At each property, an OFDA2000 instrument was used in a race prior to shearing and a Fleecescan instrument was operated in the shed in conjunction with shearing. Two properties were located in Victoria (one superfine and one fine-wool) and one in South Australia (medium wool). TRIAL PROTOCOL AND PROCEDURES COMMON PROTOCOLS The following summarises trial protocols that are common to both Phase 1 and Phase 2. The on-farm instruments evaluated in this trial were the OFDA2000 and the Sirolan Fleecescan™/Sirolan Laserscan™ (hereafter called the Fleecescan); which are both used to measure wool fibre characteristics on-farm. The on-farm sampling and measurement environments were at a race in the shed prior to shearing and in the shearing shed in conjunction with shearing, respectively. Note, OFDA2000 instruments are often operated outside the shearing shed; however, for reasons of controlling the trial methodologies, the OFDA2000 testing was conducted inside the shearing shed. The measurements from the on-farm instruments were also compared with measurements derived from laboratory testing using the OFDA100 and the Sirolan Laserscan™ (hereafter called the Lab OFDA and Lab LSN) instruments. Other aspects of the trial methodology were: • Each sheep was uniquely identified; with each fleece sampled, tested and shorn linked to the unique sheep identification. •