Abstract

Wool samples from 28 Merino wethers, 31 Corriedale ewes, 37 Perendale ewes and 30 Coopworth ewes were examined for propensity to develop yellow discolouration in relation to the mean fibre diameter and its variability. The propensity of wool to develop yellow discolourations was estimated by two techniques, namely, an incubation technique which measures the colour developed in the wool fibre during an incubation in the laboratory, and the predictive technique described by Aitken et al., 1994. Correlations between propensity to yellow (Y-Z) and mean fibre diameter were low in the Corriedale, Perendale and Coopworth samples, but high in the Merinos. Correlations between propensity to yellow and standard deviation of fibre diameter were also low in the Corriedales, Perendales and Coopworths, but moderate in the Merinos. The correlations between Y and Z and the fibre diameter statistics following similar trends to those for Y-Z. All correlations between propensity to yellow and coefficient of variation of fibre diameter were low. Thus while the propensity to discolour during growth is positively related to fibre diameter in fine wool, no such relationship exists in medium and coarser wool. This provides a further reason for Merino breeders to produce a fine fleece type.

CG, Prosser, G Nicholas, K Stelwagen, SJ Lacy-Hulbert, MW Woolford, and TB McFadden

Proceedings of the New Zealand Society of Animal Production, Volume 55, , 9-11, 1995