Relationships of fleece and fibre traits with unscourable yellow discolouration in a survey of strong wool sheep flocks

A.R. Bray and M.C. Smith

AgResearch, PO Box 60, Lincoln, New Zealand

E-Mail:braya@agresearch.cri.nz

Proceedings of the New Zealand Society of Animal Production. 1999, 59: 46-48

Wool samples were collected over two years from sixty two lines of sheep in flocks spread around New Zealand, to provide wool from a variety of strong wool genotypes and farming environments. Within-line relationships of unscourable discolouration with objectively measured and subjectively assessed fleece and fibre traits were determined by correlation and regression analyses.

The trait most highly correlated with the CIE measurement of yellow discolouration (Y-Z) within lines was Z (R² = 0.58). CIE X and Y values were more weakly correlated (R² = 0.19 and 0.18, respectively), as was the maximum visibly assessed yellow discolouration score along greasy staples (R² = 0.22). An index of four traits (maximum yellow score, fibre diameter, mid staple yellow score, and staple definition) accounted for 33% of the variation. Variation in other fleece and fibre traits within flocks was not associated with Y-Z. The reasons why the scoured wool of some sheep in a flock show more discolouration than that of others were not found among the 38 traits examined in this project.

Keywords: NZSAPAB; Wool; unscourable yellow discolouration; fleece; fibre.

Last Updated 06-08-1999