@conference {41049,
	title = {Unravelling the causes of wool yellowing: Part I Involvement of a water soluble component},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {274-276},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	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{\textpm}SD); (control 1.6{\textpm}1.2; +WS 1.5{\textpm}2.8, p = 0.92; -W 2.1{\textpm}1.3, p = 0.37). Detergent scouring, and removal of suint, or both wax and suint, reduced wool yellowing (D 0.6{\textpm}2.2, p = 0.24; -S 0.5{\textpm}1.6, p = 0.09; -WS 0.3{\textpm}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{\textpm}SD) (Lincoln 7.3{\textpm}1.5; Merino 6.5{\textpm}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. },
	issn = {1176-5283},
	author = {Winder L and Rea A and Scobie D and Bray A}
}
@conference {41050,
	title = {Unravelling the causes of wool yellowing: Part II Involvement of bacteria},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {277-280},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Wool was collected from five sheep with a propensity for wool yellowing. Sub-samples, from which the wool tip had been removed, were cut into 2cm lengths and incubated at 40{\textdegree}C for 6 days to provide an environment conducive to wool yellowing (YCT).Five treatments were applied to sub-samples of each fleece prior to YCT. Four sub-samples were gamma irradiated in an attempt to kill all bacteria present on the fleece (-B), the remaining subsample was not irradiated. Two -B sub-samples were re-inoculated with bacteria collected from the original fleece samples (+B). Each of the +B and -B samples was then either incubated at 0\% humidity (-H) or 100\% humidity (+H) for the YCT. Wool yellowness (Y-Z) was measured before and after YCT using standard methods. No relationship was apparent between the number of bacterial colonies in the original fleece (plated onto nutrient agar), and the pre-YCT Y-Z (R2=0.20; P=0.06), Y-Z after the YCT (R2=0.19; P=0.06), or the change in wool Y-Z during the YCT (R2=0.07; P=0.27). Gamma irradiation eliminated bacteria from the wool samples but increased their Y-Z pre-YCT (mean {\textpm} S.D,  non-irradiated 2.46{\textpm}0.55; irradiated 4.35{\textpm}0.43; P<0.001). Discolouration of wool (Y-Z) was increased by humidity during YCT  (-H  1.06{\textpm}0.45, +H 4.96{\textpm}1.46; P<0.001). At 100\% humidity, reinoculation with bacteria increased wool Y-Z during YCT (+B  6.13{\textpm}0.87; -B 3.78{\textpm}0.75; P<0.01). This effect of reinoculation was lost at 0\% humidity. The interaction between humidity and reinoculation was significant (P<0.05). This study supports the hypothesis that bacteria are involved in the yellow discolouration of wool in the presence of high humidity.},
	issn = {1176-5283},
	author = {Winder L and Baronian K and Webber J and Muller B}
}
