Quick Drying Fleece The Aim

Press, Volume CIV, Issue 30769, 5 June 1965, Page 10

Quick Drying Fleece The Aim

The fleece that dries as quickly as possible is best able to resist the effects of weathering and climate, according to Professor A. E. Henderson, professor of wool science at Lincoln College. He gave this answer at the annual conference of the South Island Wool Association recently when he was asked to describe the fleece that would best serve this purpose.

Professor Henderson indicated that the sort of wool staple that afforded near ideal ventilation in the fleece was that where the fibres all bent

in the same wavelength and packed closely together. The wool that was exposed on the outside of the fleece was affected by the short light rays in the sunlight—these were the ultra violet rays. These were responsible for breaking down the internal structure of the fibre, which always involved the removal of sulphur. This sulphur was a bonding agent and was necessary for stability and once removed the fibre became more soluble and a certain amount of it was washed out of the fleece. A gummy feel about a fleece was evidence of a substance that was degraded by sunlight. The more often the fibre became wet and then dried again the more degradation there was. The fibres became brittle and broke off.

There had been estimates of how much wool was lost from a fleece by this process. It was known that if sheep were covered through the whole year they normally grew $ to 11b more wool, and Professor Henderson added, he would not be surprised if this was riot the amount that was normally lost from every sheep in the country in the course of a year.

This could be an important factor in double shearing. The extra wool that might be obtained from double shearing, if indeed it was, might be in part, at least due to the saving of this loss. Discussing the reasons why weathering was important, Dr. Henderson said that apart from the actual wool loss, there was a change in the reactivity of the wool with dyestuffs, a changed performance when it came to felting or matting, and there were indirect results in staining and discolouration which all resulted in limiting the use of this wool. Dr. A. P. Mulcock, a senior lecturer in microbiology at the college, likened the fleece to sewage or the soil as a habitat of micro-organisms. In the normal fleece he said that as many as 100 m live microorganisms were found per gram of wool (about one twenty-eighth of an ounce) and there were probably 10 times as many that had lived but were dead. The majority did no harm to the wool.

Of prime Importance was the fact that these organisms could not multiply without water—although they might go into a state of suspended animation to burst into growth they needed to have plenty of moisture. “It is the length of time that is taken by the fleece to dry out that is important,” said Dr. Mulcock. ‘‘Ventilation and drying out is important.”

Speaking of the colour producing micro-organisms, Dr. Mulcock indicated that some, such as the one that produced a blue discolouration, formed granules on the outside of the fibre, but another producing a green discolouration was bonded to the fibre.

Stating that only a few sheep were affected by the mauve and purple and blue and green discolourations, Dr. Mulcock said that while it was known that moisture reten-

tion played a part, they wondered whether some animals might be predisposed to this sort of attack. If this was definitely known then these sheep could be eliminated from a flock.

The micro-organism that attacked the fibre occurred in the soil and it attacked the keratin molecule which was the building block of the wool fibre.

Dr. Mulcock said that they had been able to isolate the bacteria responsible for the pigments involved in the incidence of mauve or purple wool, which was to be found throughout the country. This discolouration ranged from dark purple to a pretty pink. He appealed to men in the wool trade, who came across discoloured wool, to send it to him at the college. He said that quite a lot of discoloured wool was needed to produce only a small quantity of the dyestuff.