Abstract

The change in yellowness (D Y-Z) of wool samples maintained in an environment intended to stimulate yellow discolouration was determined in two experiments. In the first experiment, DY-Z was determined following one of six treatments - no extraction (control), solvent wax extraction (-W), aqueous suint extraction (-S), extraction of wax and suint (-WS), removal then reapplication of wax and suint (+WS), or detergent washing (D). Removal and reapplication of wax and suint, or removal of wax alone resulted in similar yellowing to the control (D Y-Z mean±SD); (control 1.6±1.2; +WS 1.5±2.8, p = 0.92; -W 2.1±1.3, p = 0.37). Detergent scouring, and removal of suint, or both wax and suint, reduced wool yellowing (D 0.6±2.2, p = 0.24; -S 0.5±1.6, p = 0.09; -WS 0.3±1.3, p = 0.04). In the second experiment, greasy wool from two chimaeric sheep producing both Lincoln and Merino wool types yellowed to a similar extent (Y-Z post challenge; mean±SD) (Lincoln 7.3±1.5; Merino 6.5±1.1; p = 0.45), suggesting that the fleece environment influences the propensity for yellow discolouration when distinct wool types are grown together. The data presented here support the hypothesis that a water soluble component of the fleece is involved in wool yellowing.

L, Winder, A Rea, D Scobie, and A Bray

Proceedings of the New Zealand Society of Animal Production, Volume 58, , 274-276, 1998