Fiber Processing

The topmaking performance of fleeces from sheep that were ranked high or low on index selection using objective measurement was compared with that of sheep from the same flock that were ranked high or low on visual assessment. A flock of 451 15-month-old fine-wool Merino sheep were classed by 2 experienced fine-wool sheep classers into 3 grades: best, average and culls. Forty-four sheep were assessed as ‘best’ and 77 sheep were graded as ‘culls’ by both classers. These sheep were defined as the ‘best visual’ and ‘worst visual’ sheep, respectively. Measurements of clean fleece weight, mean fibre diameter, coefficient of variation of fibre diameter and body weight were used in a selection index to rank all sheep in the flock. The selection index was designed to rapidly reduce mean fibre diameter and slowly increase clean fleece weight, whilst maintaining staple strength and body weight. The 44 sheep with the highest index value were defined as ‘best index’ sheep and the group of 77 sheep with the lowest index or obvious physical faults were defined as the ‘worst index’ sheep. Twenty-five fleeces were randomly selected from each of the ‘best’ and ‘worst visual’, ‘best’ and ‘worst index’ sheep for individual processing through to top. The fleeces from the ‘best index’ sheep produced greater quantities of tops that were significantly finer, longer, of lower curvature and produced less noil than all other groups. In contrast to the large difference in quality between tops from the ‘best’ and ‘worst index’ sheep, there was little difference in quality between tops from the ‘best’ and ‘worst visual’ sheep. This indicates that the traditional wool producer views of wool quality are unrelated to processing performance. It was concluded that Merino sheep selected by index selection using direct measurement of fleece weight, mean fibre diameter and coefficient of variation of diameter as selection criteria produced greater quantities of wool of superior processing performance to that from sheep selected using visual assessment. more »

A benchtop scouring procedure was used to evaluate the ability of conventional detergent scouring systems to adequately clean fleece samples from a selection of Western Australian Merino wools. Sixteen fleeces were selected from the Western Australian Department of Agriculture resource flocks, covering a wide range in yield (49.2 to 77.5%), wax (7.3 to 26.9%), suint (4.9 to 11.6%), and dust (1.4 to 16.3%) contents. Using a simple detergent-based system, 50% of the fleeces were classified as effectively scoured, based on residual wax content. When scouring liquor was not refreshed between subsamples drawn from the same fleece, wool wax, staple length and dust content in the greasy fleece accounted for 93% of the variation in the rate of residual wax increase observed in sequential 10 g samples of wool. Residual ash content also increased but the greasy fleece parameters measured were not statistically significant predictors of residual ash changes. The rate of scoured wool colour change, when sequential samples of greasy wool from the same fleece were scoured without liquor change, could be predicted from greasy fleece yields. The scouring efficiency of the more difficult to scour wools was improved by the addition of sodium carbonate to the main scouring bowls. more »

Australia has great potential for a viable alpaca fibre industry. The Australian Alpaca Association (AAA) was founded in 1989 to provide co-ordination for a growing national herd of high quality alpacas in Australia and to enable a viable and sustainable animal and fibre industry. The Alpaca Co-operative P/L (Alpaca Co-op) was established in 1995 to market products derived from alpaca fibres. Both organisations promote alpaca fibres and products in Australia as well as overseas. Australia has sound pastures and modern technologies for breeding the best stocks and currently has the largest alpaca herd outside South America. There is also an increasing interest in luxury fibres among fashion houses. The alpaca fibre industry in Australia is still very young and relatively small compared to the wool industry, and there has been strong desire to process alpaca fibres in Australia on the established wool processing systems. Knowledge on luxury fibre processing is often kept secret by international processors who have the know-how. Local industry needs to understand the properties of Australian grown alpaca fibres and their processing performance, so that the industry can market the fibre effectively and export high quality alpaca fibre products. more »