Phenotypic associations with fibre curvature standard deviation in cashmere

Abstract

Cashmere fibre curvature (crimp) impacts on the softness and quality of cashmere textiles, the efficiency of cashmere processing and cashmere production. This study investigated the relationship between cashmere fibre curvature standard deviation (FCSD) and other fleece attributes, and how this relationship differs with animal and farm attributes, for 10 commercial cashmere flocks in Australia. Data was analysed using general linear model analysis. Nineteen parameters were recorded for 1168 goats. Following log transformation, the best model for FCSD included farm, goat age, mean fibre diameter, fibre curvature, fibre diameter standard deviation, cashmere yield, cashmere staple length and live weight and the interactions between these terms. The percentage variance accounted for was 82%. Mean fibre diameter and fibre curvature accounted for 55% of the variation in FCSD and farm accounted for 41% of the variation. Cumulatively mean fibre diameter, fibre curvature and farm accounted for 75% of the variation existing in FCSD. For the other terms, age added 2% and the remaining measurements a further 5% to variation accounted for by the best model. Environmental (farm-effects) on FCSD are large and may explain the difficulties cashmere growers experience when they evaluate cashmere goats. Increasing the fibre curvature of cashmere was associated with an increase in cashmere FCSD, but for some combinations of farm and MFD the increase in FCSD was ≈35°/mm while with other combinations the increase was ≈5°/mm as fibre curvature increased. At a given fibre curvature the response of FCSD to mean fibre diameter differed substantially between farms, from strong negative to strong positive. Increasing cashmere yield from 20 to 55% was associated with decline in FCSD. Increasing fibre diameter SD from 3 to 5 μm increased FCSD by 6°/mm, increasing staple length and live weight were associated with small declines in FCSD. There was strong evidence of an age effect that differed with farms, but there were few clear cut trends in FCSD with increasing age. The results suggest that farm based influences are affecting the point at which fibre keratinisation is completed and thus influencing the variation in FCSD. We conclude that, because the differences between farms in the relationship been fibre curvature standard deviation, mean fibre diameter and fibre curvature are great, it is unlikely that crimp rate and crimp definition will be good indicators of cashmere fineness across farms.