Brims, M. A., A. D. Peterson and S. G. Gherardi (1999). Introducing the OFDA2000 - For rapid measurement of diameter profile on greasy wool staples. IWTO, Raw wool group report RWG04, Florence, Italy.
Provides a general introduction to the concept of the OFDA2000 instrument and some preliminary results on performance.
Anon. (2000). Fibre formation, fibre properties and processing performance. the Wool Press. 7: 4-5.
Describes the work of the Wool CRC and refers to research being done on diameter-length profiles using OFDA2000.
Mata, G., D. G. Masters and J. Ive (2000). Components of staple strength in young superfine merino sheep from Southeastern New South Wales. 9th Congress of Asian-Australasian Ass. of Animal Production, Sydney, Australia.
Concludes that the OFDA2000 prediction of position of break is well correlated to the measured position of break (r = 0.73, n = 60, P < 0.01)
McLaughlin, I. (2000). Innovative wool testing - OFDA, Australian Wool Taskforce 2000.
Description of the OFDA technology and the application of OFDA2000 to in-shed testing.
Oldham, C. M. and A. D. Peterson (2000). The influence of date of shearing on the processing performance to top of mini-commercial consignments of merino fleece wools grown in either southwestern or eastern Australia - 1. Systematic deviations from team predicted values. 10th International Wool Textile Research Conference, Poster session, Aachen, Germany.
An experiment is described in which sale lot display samples were used to build weighted processing batches (mini-commercial topmaking consignments each ~ 30kg greasy) that mimicked standard commercial 20 tonne containers of Merino fleece wool. Each batch was built to produce tops of 21.5 micron diameter and TEAM predicted hauteur of 68 mm. The wool classer's specification was used to assign each sale lot and consignment to a month of shearing within the 1997/98 wool selling year. On average 3 mini-commercial topmaking consignments were built for each calendar month out of wools either grown in southwestern Western Australia (sold in Fremantle) or eastern Australia (sold in Sydney). Greasy staples were collected from each sale lot used and the fibre diameter profiles were measured on the OFDA 2000. The mini-commercial consignments were sent to CSIRO, Division of Wool Technology, Geelong and processed at random to top through a single combing line using recommended CSIRO settings for 21.5 micron wool. The results showed a dramatic difference in hauteur between wool shorn in spring (71 mm) and autumn (83 mm), but more importantly showed that there is a systematic increase in the deviation from the TEAM predicted hauteur between spring and autumn in wools grown in southwestern Western Australia. In contrast, the actual minus TEAM predicted values of hauteur for the wools sourced out of New South Wales were consistently around 7 mm with little systematic seasonal variation in hauteur. However, for the coefficient of variation of hauteur there was a similar pattern of deviation from the TEAM predicted values for both selling centres; from minimum values (around -1%) in the consignments shorn in spring to maximum values (around -10%) for those shorn in autumn. Similarly, the deviation in romaine from the TEAM predicted values were not large (< 1%) but increased from spring to autumn shorn wools and then decreased again from autumn back to spring in the wools from both selling centres.
Oldham, C. M., P. R. Lamb, G. R. S. Naylor, et al. (2000). Manipulation of the strength or fibre diameter profile of staples and processing performance. 9th Congress of the Asian-Australasian Ass. of Animal Production, Sydney, Australia.
Reviews the effects of staple strength on hauteur, and summarises work being carried out on using diameter-length profiles to predict processing performance.
Oldham, C. M. (2000). The hauteur, CV of hauteur and short fibre content of mini-commercial consignments of tops is strongly dependent on the mean fibre diameter profile of staples of component sale lots. 10th International Wool Textile Research Conference, Poster session RW-P4, Aachen, Germany.
Describes the relationship between diameter-length profile measurements made on staples from component lots of combing consignments, and the resultant H, CvH, and short fibre properties of the resulting tops. The author concludes that the effect of fibre diameter profile on these top properties has important commercial consequences.
Peterson, A. D., S. G. Gherardi and M. R. Ellis (2000). "Managing the diameter profile leads to increased staple strength of young Merino sheep in South Western Australia." Asian-Aust. J. Anim. Sci 23.
The effectiveness of 3 management strategies to increase staple strength was investigated. Length-diameter profile changes were measured using an OFDA2000. Staple strength was significantly increased by restricting feed intake on green feed after the break of season compared with sheep grazed at low stocking rate. Restricting feed intake at break of season also resulted in finer wool.
Peterson, A. D. and C. M. Oldham (2000). The influence of date of shearing on the processing performance of mini-commercial consignments of merino fleece wools grown in either southwestern or eastern Australia - 2. improved prediction from the FD profiles of staples from component sale lots. 10th International Wool Textile Research Conference, Aachen, Germany.
An experiment is described in which sale lot display samples were used to build processing batches that mimicked standard commercial 20 tonne containers of Merino fleece wool. The wool classer's specification was used to assign each sale lot and consignment to a month of shearing within the 1997/98 wool selling year from wool either grown in South-Westem Australia (Fremantle) or New South Wales (Sydney). Greasy staples were collected from each sale lot and the fibre diameter (FD) profiles were measured on the OFDA 2000. The mini-commercial-consignments were sent to CSIRO, Division of Wool Technology, Geelong and processed through to top using recommended CSIRO settings for 21.5 micron wool. Utilising data from the FD profile, a fibre breakage model was developed which predicted the fibre length distribution of the top. The model was able to differentiate differences in hauteur between the consignments that otherwise were under-predicted using the TEAM equation (r2 = 0.38). The model could predict over 73% of the variance in hauteur from 56 consignments. Furthermore, the model was able to predict short fibre content (% fibres < 25µm) of the resultant tops. The new model offers scope for better prediction of wool shorn at different times of the year and offers greater efficiency to topmakers as well as providing a fairer payment to growers who produce longer hauteur wool that otherwise would not be rewarded due to the anomalies of the TEAM equation.
Peterson, A. D. (2000). A new prediction technique for estimating hauteur from the fibre diameter profile. 10th International Wool Textile Research Conference, Poster session RW-P3, Aachen, Germany.
Describes a prediction process based on fibre diameter profile measurements using OFDA2000. The model was able to differentiate differences in hauteur between consignments that otherwise were poorly predicted using the TEAM equation. Over 80% of the variance in the actual hauteur for 56 consignments was explained by the model compared with less than 40% using TEAM.
Schlink, A. C., D. J. Brown and M. Longrée (2000). Role of fibre length variation in staple strength of merino wool. 10th International Wool Textile Research Conference, Poster RW-P1, Aachen, Germany.
Reports experiments with 16 two-year old merino wethers run together at Armidale, NSW. Concludes that 93% of the total variation was accounted for by the coefficient of variation of fibre length for fibres longer than the staple length, the square root of the sum of the across and along fibre squared SD values, and the minimum fibre diameter along the fibre.
Baxter, B. P. (2001). "Precision of measurement of diameter, and diameter-length profile, of greasy wool staples on-farm, using the OFDA2000 instrument." Wool Technology and Sheep Breeding 49(1): 42-52.
The OFDA2000 is an instrument specifically developed to measure wool properties on farm without involved sample preparation. It allows an operator with minimal training to measure a greasy wool staple from an individual animal for mean fibre diameter, diameter distribution, and diameter profile along the staple length, all in 30 seconds or less. Issues related to sample selection and the measurement of greasy wool are examined, and precision data is given for two scenarios of use. This indicates that the single staple measurement regime is of similar precision to traditional midside sampling and testing in a typical fleece testing laboratory. Prediction of the mean fibre diameter of farm lots prepared using measurements on individual fleeces can be of adequate precision to allow financial benefits to accrue from such a selection process. Estimates are given for confidence limits for 10 key parameters from fibre diameter profile measurements.
Baxter, B. P. (2001). "On-farm classing of animals & fleeces with the OFDA2000." Wool Technology and Sheep Breeding 49(2): 133-155.
This paper describes the OFDA2000 instrument. Results of experiments to determine the accuracy and precision of the instrument are compared to documented data for conventional measurement techniques. These confirm that the measurement system is capable of providing diameter-related data as accurate and precise as that obtainable from a typical fleece-testing laboratory. Additionally, the instrument provides staple length and length-diameter profile data that appear of adequate accuracy and precision for input into processing prediction models that are currently under development.
Douglas, S. A. S. (2001). 'On-farm testing' revolution. Wool Record: 41.
Briefly reviews the development of newer technology for both laboratory and on-farm diameter measurement.
Greeff, J. (2001). Is selection of hogget ewe replacements on measurement profitable? 14th AAABG Conference, Queenstown, New Zealand.
The availability of new measurement technology such as the OFDA2000 and Fleecescan to measure fibre diameter of individual fleeces in the shearing shed, makes it possible to identify the most profitable animals for replacement purposes. As the phenotypic relationship between fleece weight and fibre diameter is negative, it is important to determine whether selecting replacement animals on fibre diameter alone or on an economic index is profitable.
Lyons, K. (2001). Feeding the young ones. Wool Grower: 12.
Reviews the use of OFDA2000 diameter-length profiles in managing feed levels, especially with respect to growth between weaning and puberty under New Zealand conditions.
Peterson, A. D. (2001). Report on Fleecescan and OFDA2000 trial - Mingenew Property. Perth, W. Australia, WA Dept. Agric.
Details the results of a trial between Fleecescan and OFDA2000 on-farm testing technologies, carried out over 3 days at the Mingenew property (which is run under the guidence of the Australian Merino Society). 600 ewes were measured, and 300 were ranked by each instrument. The results showed that the OFDA2000 was slightly more precise, although the accuracy of ranking of animals was similar for both systems. The OFDA2000 results on the midside samples gave good agreement with the conventional fleece testing method on midside samples. There was no difference in the abilities of either system to predict the MFD of the whole unskirted fleece. The Fleecescan suffered from a bias during part of the trial which was undetected during the measurements. The overall average from the OFDA2000 classed lots was in agreement with the overall average of the AWTA coretests.
Peterson, A. D. and S. G. Gherardi (2001). "The ability of the OFDA2000 to measure fleeces and sale lots on-farm." Wool Technology and Sheep Breeding 49(2).
The OFDA2000 is an instrument primarily designed to measure the fibre diameter and it's distribution on single greasy staples outside the confines of a laboratory. This paper investigated the precision and accuracy of the OFDA2000 to measure mean fibre diameter and other staple properties that may be used to select individual fleeces, or measure sale lots. The OFDA2000 was close to the precision of commercial mid-side fleece testing when one greasy staple was measured from the mid-side (95% confidence limits = ± 1.2 mm). The OFDA2000 also showed good agreement with the OFDA100 for a range of fleeces (r2 = 0.70; range from 17 to 24 mm). The OFDA2000 offers a low cost method of selecting finer animals and preparing lines of wool based on a number of fibre characteristics. As a result, the OFDA2000 is a serious tool that can be used to improve the income of woolgrowers.
Presented at the 10th International Wool Textile Research Conference, in Aachen, Germany, November 2000:
PRECISION OF MEASUREMENT OF DIAMETER, AND DIAMETER-LENGTH PROFILE, OF GREASY WOOL STAPLES ON-FARM USING THE OFDA2000 INSTRUMENT
THE INFLUENCE OF DATE OF SHEARING ON THE PROCESSING PERFORMANCE TO TOP OF MINI-COMMERCIAL CONSIGNMENTS OF MERINO FLEECE WOOLS GROWN IN EITHER SOUTHWESTERN OR EASTERN AUSTRALIA – 2. IMPROVED PREDICTION FROM THE FD PROFILES OF STAPLES FROM COMPONENT SALE LOTS
Preliminary precision results:
Precision and Accuracy of the OFDA 2000 , 18 Jan 01