YOLK IN WOOL

Waikato Times, Volume 112, Issue 18803, 26 November 1932, Page 10

YOLK IN WOOL

RECENT RESEARCH. EXPERIMETB IN SELECTION. THE BETTER-SHAPED FIBRES. •• Notwithstanding the great amount of research work that has been carr e out from time to time on the structure and growth of the wool fibre there seems to be a great deal of uncertainty about the causes of certain faults reappearing where least expected," said Mr A. Hunter, of Haweia, In the course of an address at Massey College. . "The report of the work carried out on the Romney woo sent to Torridon has given a good idea oi the type they found to be the most suitable; this in itself is very valuable becausfl it confirms the opinions held by til? leading breeders in New Zea- “ Wool showing the medulla seems to be one of the greatest difficulties we have to contend with, and it is not confined by any means to the Romnej breed but owing to the great preponderance of the Romneys in New Zealand there is, of course, more medullated wood than any oilier. "The benzol test is an easy one for finding out the proportion of medul lated fibres in a fleece, and if breeders will follow it up it should help them considerably. Another method, though not so thorough, is to hold the bunch of fibres up to the light; the flat ones can be detected in this way. The Good Fibre. ‘‘The question the breeder wants solved Is whether this defect can be overcome by selection, or whether the fault is caused by some deficiency in the feed of the animal, thereby not giving the right nourishment to the wool. My experience leads me to believe that selection will succeed, provided the breeder is prepared to confine his operations to a medium count of wool of the right quality. To follow this method to its logical conclusion, however, would possibly result In a lighter fleece and probably a less robust animal. There are two substances which no doubt affect the growth of the wool —sulphur in the form of cystine, which affects the growth of wool, and potash, which I believe has an effect on the supply ot yolk. , “Medullated fibres are usually of a dull white colour, and have a flat appearance, and to the eye are devoid of yolk Rood fibres, on the other hand, arc bright and usually show a fair amount of yolk in a liquid form. "To try out the effect of using strong-wool rams with a certain amount of mcdullation I bred from two sheep, one of which had a dull, lustrous wool showing very little yolk, and the other a strong, bright wool with a good yolk, but a proportion of medullated fibres. The former was a sad failure, but the latter has proved a success. They found at Torridon that a fairly yolky fleece gave the best results, but on the other hand, a fleece showing a heavy, thick yolk was not a desirable one. “The angle of the curl in the wool is a good indication of whether the fibre is elastic or not. I have never found that a fibre with a short, rightangled curl had much elasticity; on the other hand, a gradual curl running up the staple or fibre is usually elastic. Distinguishing Difference. “At Torridon they have investigated the shape of the fibre and seem to favour one not quite so round, but very nearly so. Now the question is how the breeder is to distinguish the difference. My theory is that the better-shaped fibres pack together in the lock neater and cleaner than the flat ones. This also indicates that the fibres are uniform in size, and, given a level tipped fleece, is apparently what the manufacturer requires. "It lias been given out from Torridon that wool is damaged if in scouring there is less than 1 per cent, of grease left in Ihe wool, and that it should have about 2 per cent, left in the fibre to keep it pliable. From the above research work it is evident that the question of yolk In the fleece is a very 7 important factor to be considered in the breeder’s operations. "One could compare yolk to the sap of a tree; when the tree is dormant In the winter the sap comes down; so with the yolk In wool—when the sheep Is not thriving the flow of yolk is retarded, but when it Is doing well the yolk flows out to the tip of the locks ”