STUDY OF WOOL

Rotorua Morning Post, Volume 2, Issue 243, 3 June 1932, Page 6

STUDY OF WOOL

F. W.

Dry,

THE FLEECE OF THE SHEEP FIBRE BY FIBRE.

(By

D.Sc.)

(Massey College Bulletin.) PART II. Lambs come into the - world very far from naked, and wool fibre types may. ha placed into two big divisions, those beginning to grow before birth' and those that do not start until after birth. Fibres that begin their development before birth will be considered first. At birth coarse hairy fibres projecting above the rest of the coat are frequently in evidence. When abundant they produce something of the appearance of a halo, and so are called "halo" hairs. They are believed to ba the first fibres of all to begin to graw, some few weeks before birth. Most of these cease to grow at about two months, and soon afterwards fall out. These ara large birthcoat kemp, the term kemp being applied to fibres that are.shed after growing for only a limited time, and that not in consaquence of any abnormal conditions. The place of a shed halo hair is taken by another fibre grown from the same root. These suecessors, while sometimes a follicle often undesirable from the point of view of hairiness; sometimes a follicle continues to grow and «hed one kemp after another. Oecasionally a halo hair does not fall out, but continues growing indefinitely. The fibres. that are evidently the next to start their development after halo hairs are called sickle-fibres, from the shape of the more or less stout tip-end, the rest of the pra-natal part being finer. Many of these are small editions of halo hairs, with the part grown after birth hairy, but less coarsely so. Hairy sickle-fihres turn be shed or they may continue to grow indefinitely. When these fibres turn out to be kemps, that is, are shed, they are succeeded in the same root by persistent fibres that may or may not be hairy. When hairy sicklefibres persist they do of course play a part in the hairiness of the fleece. Hair Undesirable. On present knowledge it is certainly safest to regard the hairy fibres that have so far been described as undersirable, evan though they may fall out. If all fell out and all were followed by innocuous fibres the presence of kemp in the birthcoat would not be objectionable. This matter has received a good deal of attention and it does seem that the follicles of halo hairs and hairy sickle-fibres do, amongst tbem, always make some permanent contribution to the hairness of the fleece. It is also to be reported that some fibres with tips like the other birthcoat kemps have finished their gfowth at birth, thus being very short kemp, some of them extremely so. There is good reason to believe that hairy fibres that begin to grow in the very early weeks after birth are the suecessors of these small kemps. The abundance of halo hairs and hairy sickle-fibre varies greatly from lamb to lamb, and animals are not difficult to find that are entirely free from them. It will depend upon the strictness of the standards adopted how keen selsction can be, but lambs with many halo hairs do receive a very poor welcome from stud-breeders. Fibres of Lambs. The great mass of the fibres of the new-born lamb show no sign of hairiness, but have fine curly tips. This innocence may be deceptive. Save in very fine-woolled animals these fibres thicken markedly directly after birth, the part grown during the succeeding several weeks tending to be comparatively straight. These fibres may be free from medulla, or medullated n*. greatsr or less degree. Those with tips comparatively long at birth, which must be the early ones to begin their growth, tend on the whole to be the most hairy. These early tip-fibres make up the great bulk of the coat al birth, so that what they are largely determines the kind of fleece. Turing now to fibres that begin to grow after birth, there is little more to be added about medullation. The suecessors of birthcoat kemps have been dealt with already. A few fibres, lacking the regular fine erimping of the tip of curly-tip fibres, and beginning their development just around the time of birth, may he somewhat hairy. If such fibres are a little hairy, however, they are always topped in evil by abundant hairy curly-tip fibres. Usually these comparatively latostarting and fine fibres are not hairy at all. Early Growth. From about the time of birth up to the age of almost a year it does appear that the only new hairy fibres are those that succeed shed kemp. The other new fibres are fine and slow growing compared with coai'ser fibres, and it is especially in the early weeks of life that they establish themselves. In the winter some new hairy fibres that are believed to originate in new roots make their appearance. The extent of their contribution to hairiness is not yet known. We must ascertain also whether such fibres may come in if a fleece does not already possess hairy fibres. Fibres beginning their careers later in the animal's life have yet to receive serious study. The relationship between one fleece and the next will have to be explored from two points of view. We- must know how the same fibre, continuing its growth after shearing, resembles the part removed at that time. We must ako know when and to what extent, new fibres coming into the fleece may be hairy. These questions are being tackled, but it is too soon to make generalisations. Examples only will he given. A sheep with abundant medulla in the first two fleeces, but comparatively fine in its hairiness, has turned out coarsely hairy, in the third fleece, its nature then being more readily recognised at a glancr.

On the other hand, tests on animals now in their second year have shown that a lamb with a little medulla in the first fleece may have less or nonc in second fleece samples from the same regions of the body. This account will have shown that we are learning our way round the fleece and acquiring an intimate knowledge of the units of which it is composed. These various units are not yet familiar figures on the pages of agricultural journals, but their classifieation is essentially simple. It is with these types that we shall have tt. deal in building up a knowledge of the * eomposition and growth of the fleece] comparable with the stock-Jn-trade \ of fact about grasses and manures ■ If the tips are not broken, these types ■ can be recognised quite well by the naked eye if a wool specimen from a ;

lamb is examined fibre by fibre against a dark background. It is curit ous to refleet how much more is j known about invisihle molecules and j microscopical fungi. Common and [ readily visible as they are, they should I soon be recognised individually as the ffriends or foes of the woolgrower.