Onderstepoort Journal of Tl eterinary Science and A nfrnal lnditstry, Volwne 12, iVumber 1, Janum·y, 1939.
Printed in the Union of South Africa by the Government Printer, Pretoria.
Methods for Determining Length in the Merino F leece.
Hy V. BOSMAN and M. L. BCYrHA, ·wool Research Section, Onderstepoort.
TnE importance of length as a characteristic of the merino fleece has often been stressed. It has been shown (Bosman 1937) that, in a stud ram producing 40,000 fibres per square inch of skin, every half an inch increase in staple length adds · 9 pounds of ,,·ool to the scoured fleece, when it is a fine \Yoolled fleece, nnrl 1 ·4 pounds when it is a coar,.;e~' woolled fleece.
The wool farmer considers length and uniformity of length :is a basis for classification '"hen his wool dip is being prepared for the market (Cowley 1928; National ·wool Growers' Association.
1934; vVilson, 1935, et alia), and several authors have referred to Uie importance of length in the manufacturing processes of wool (Barker 19~.H; Stanhury, 1935; Speakman and Sun, 1936, et alia).
Since length is an important attribute both from the wool ]iroducer's and wool manufacturer's points of view, it is necessary that suitable methods for its r1etermination be available. In practice, and in merino experimental \York, the methods should be as quick and simple as possible so that they can he applied to large numbers of fleeces and should he applicable for use on the live sheep as well as on the shorn fleece. Those that have been evolved and are used on the merino, are here outlined.
STAPI~E LENGTH, STRAIGHT F1mrn LENGTH, Cnnrr ILurn.
The staple length does not give a true measure of the actual length of wool, this depending on the type of crimping, (Duerclen anu Bosman, 1931) whether it is shallow or deep. In the latter case the straight length may bear a ratio of l · 8 to 1 with the staple length and in the former case the ratio may be only l ·2 to 1. In practice it is therefore possible that two wools of the same staple length say 8 centimetres, may differ in straight fibre length to the
" Among South African Woolmen the term coarse is synonymous with strong and signifies a thick fibred wool.
261
DETElL'.llIXL'iG LEXGTII lX THE )lElUXO FLEECE.
extent of the difference beh1·een 14 · 4 cm. and 9 · G cm. or u 50 per cen L difference. Even greuter difference,; than these huYe been recorded hy Hoherts (19:18), who a:;serts thut a 4 inch straight fibre length tan be reduf"ecl to a l~ inches staple length or a crimp ratio of :2 · 4 to 1.
In practice, both the 'rnol farmer and the wool buyer take into aecouut staple length, rather than straight fibre length, the latter heing a refiuement that is uot w readily determined. In e:>.perimcntal ,,·ork where length is studied from such aspeets as breeding, nutrition, enYironu1ent, wool growth and spinning, it is often necessary that determinations on straight fibre length be made, or alternately, 011 ;;taple length in ('onjunetiou with the crimp l·atio.
V.1.RL\.JHLT1T IX THE )!ElUXO FLEECE.
The rnerino, unlikt> other breeds of sheep, has a di,;tinctin:
c,wering ot fine \niol growing at a constant rate from month to month and from year to year (Duerden and .Mare, 1931; Bosman, 1937) at approximately S cm. staple length or 12 cm. strnight leug-th per annum. 'l'he rate of growth Yaries on the same animal (Duerden aud Palmer, 1923) and also among indiYidual fibrns constituting a staple (Duerden and Hosman, ]!)'.H) so that the length of any one fleece must be expres,;e<l in terms of the mean Yalue uf several measurements. This clt>pencls on the extraction of a representatiYe sample of the fleece which is controlled by the rnriabilit~· of the fleece.
. 2 3 5
10 .. 0. · ...
o .... t .. · ·
O· · · ..0. . 16 17
· .. 11 12 13 14 15 · . . . Q .. 18
o ....
0 · ... O· ... ·O· .... ·0· ... 0 .. ·O16
20 21 22 23 24 25····O····O····O· ···O·· ...
- o·.
··0·FIGURE 1.
Diagram showing the points from which measurements were. taken from Sheep A an<l 13. The results are analysed in Table 1.
262
V. llOS)L-lcS A1'\"D ~l. L. DOTH.\.
J~Xl'EHL\IEXTAJ,.
Slllnplin.r; on the Lire Shap.
In sheep e:xpenments dealing 1Yith breeding, nutrition, wool
~rmdh, cin<l also 1Yhere bree<1ing records for farmers are concrnne<l, the length of the flet>ce must often be r1<'termined on the liYe animal l•eiore shearing. vYith this object in Yie\\·, st-mlie,-; on the nwtho<ls (lf sampling on tlw liYe sheep 1\·ere mu1ednken. Two animals, chosen as t.vpical r<·presentatiYes of. the type of meriuo sheep that rue usually frnhjecter1 to rnea,;urernent, ·\\"ere studied. A larg·e m1m lJPr of me:i<:urement,; 1rns taken from earh animal. GG on the OIJ(~ anc1 64 ou the oi.her, half of the measurements bei°ng made on ihe left hall(l side, aud halJ on the right han<l side of each sheep.
The poinfa from which rnea~uremeuts \Yere takt'n are those ,;hown in figure 1. The 1rnol is a twehe months growth.
The metho1l of rnr:isuring ,,·as that of placing a suitable ruler, g1·arhrntecl in cPntimetrec; anf1 tenths of centimeh·Ps, along the staples and mea~tniug thei1· ]p11g·ths from base to tip.
The measnrenwni,;, taken from 1.hP hYo fleeces. \Yere usef1 for e~hihlishing whPt11er thP selection, taken frow the leH ha!l(l sidP of 1.he :fleect>, 1\·:1s :-:irnilar to thnt taken from the rig·ht }1and side of the fleece. A surnmm·~· of the re:rnlt,.; is g-in•n in T:ihle 1.
'TABLE 1.
Staple len.!)th mens1u·ements of tu·o me1·i110 shNp t11f<t'11 011 tl1e left a11rl 1'i.r;ld hanrli .1£rles of NlC'h animal.
::\umber Mean
I
Stand~rd
I StandardSheep and T.vpe of of staple
of Re1narks.
region. sheep. regions length clenat10n. error
measured. (cm.). inean.
- - --- -
.c\.- Hight-hand Showinf! 33 G·7 ·782 _'... . 136 Kot
sirle n1editnn significantl.v
bo<h· different.
dev~lop- lnent*
Left-hand :33 6·7 ·6:W J_ · 108
side
Bntirc 66 6·7 ·700 ± ·086
fleece
- - - --- - - -- ---- -
B.- Hight-hand Sho,\'ing 32 7·9 ·844 J_ · 149 Not
side exces· significantly
siYe different.
bodv clev~lop- ment
Left-hand 32 7·8 . !J36 .L · 165
side
Entire 64 7.9 ·844 ± · 106
fleece
* Among South African and Australian Sheepmon the term "development " has reference to skin folds on the body of the sheep.
263
'1'.111u; 2. (11). A111ilysls of Stopl<' J,e1111tl1 Jlew11r<'111ei1/s of ,\fiepp i\. /,eft /!11111/ Sirle. (Oil 1/1:e a11/111ol.) H·cgio11. 27 .................. . 28 ........................ . 2!) ...................... . 30 ........... . 31 ..................... .
l.
-I
2. 3.I
G·G 7·0 6·G-6-·6 I G·ri 4·6 G·7
M l
7·1 I 7 ·I 6· 6I
7·0 7·0I
7·4 ' 6· 7 ,, 7. l 6·6 1(i·5 6·6 4·6 7·3 7.3 0·6 7·1 6·G
4. G·ri 6·5 4·6 7·0 G·7 O·G
I
I5. 6·G 7. I. 6·6 7·0 G·!J
G. 7·0 6· (j 7·1 7·6 6·7 ;;.!)
l
I I I II
7. IHI 7·1
-
6·G - 7·1 - G·G8. D. G·5 - - 7·1 -
-
I- -- 7 .;) - -I - - I
- 7 .;) 7 .;1 -- 6·4 I
- - -- - -- 7·0 - - G·7 - - ii·!) G·G 6·G G·O
10. - - 7·:J 6·8 7·1 7 .:i 7·1 6·4
. I - I -
6·6 . 7·2 ----7·2M ~~ -
.. -..~~- .
-.. -.-.~~-:-~1-- 6 - · 7 -1-- 6 ·
8 --- ~~ _l --~3 - -GS_l __ G s - G.° !J _l __ ~7 -1l __ G.° !J -l-- 1 0 -
Number of rcg101rn.... .. ... .I
33 17 10 fi (i 6 6 6 6 6 Stanclal'd ol'ror... ± ·09.~() :l: ·1517 ± ·24[7 ± ·:1516 ± ·O!J:11 ± ·2330 ± ·lOflii :L ·22121 ± ·120:l ± ·1414 Stancla.rcl deviation............ ± · 5509 :l: · 6:2i;:i :I: · 7642 ± · 8612 :I: · 2280 ± · :'5707 ± · 268:~ + · •)4Hl ± · 2946 ± ·346432 ................... . 33 ....................... .
G·G 7·0 7·0 6·5 6·6 0·6 6·5 7·1 4·G 6·7 6·2 7· ::1 6·8 7·1 7·3 7·1 6·4 6·6 5·8 7·0 7·6 7·0 7·0 7.4 6·7 6·7 6·!.J 7·1 5·!) 6·6 G· 6 7·2 6·7 CoefTkicnt of rnriability... .. ... 8·2% !J·~~ -11~6% 1:3·7% 3·4';<, 8·4% ~!)% __ -~l~-1 ~3% __ 4·0%
r-:: >-.; tc ~ ~ ..., ?': H '7. Q r ~ '...: Q ...; H H '...: "' Pi t'1 ~ .... ~ " H '7. "' '°1 :-< h ll t'1
'l'AHLE 2 (71) . . ·l.11al.1Jsl.1 of Staple Le11,11tl1 Jlcas11re111e11fo
0/
Sheep /J. Left H1111d ,",/de. (On lire anlnuil.) Beg ion.I
1. 2.I
3. 4. 5. 6. 7. 8. 9. 10. 1 .................. 6·8 6·8 6·8 2 ...•... 6·\) - 3 ................... 8·;) 8·i5 ---8·:') 4 ................. 8·2 -8·2 8·2 --
-8·2 5 ....•.................. 7·5 7. i\ -7. [j-
6 ....................... 7·8 ---7·8 7 ............... 7·6 7·6 7·6 7·6 -- 8 ...................... 7·8 --7·8 7·8 --7·8 9 ........................ 6·7 G·7 6·7 6·7 10 ..................... - 11 ........ D·O 12 ....................... 6·7 6·7 6·7 ---
6·7 -G· 7 13 ............... 8·6 ----8·() -8·6 14 .............. 8·\) 8·9 -------8·9 l;) .........•... 8·3 8·3 ---8·3 8·3 8·3 ~ 16 .................... 8·2 8·2 ---8·2 -8·2 w 17 .................. 6·6 ---6·6 6·6 u• -- 18 ...................... 7·8 7·8 7·8 -7·8 -7·8 19 ........••........ 6·7 20 ........................... 9·0 !)·(I 21 ............... 6·7 --6·7 22 ...................... 8·1 8· J -8· l ----8·1 2:1 .............•... 9·3 ---9 <l 24 .......... 8·4 8·4 --- 25 .................... 8·5 ----8·t) 26 .............. 9·6 9·6 -\)·6 ---
-9·6 -<1 27 .............. 6·6 -6·6 -----
':;:I 28 ................... : .. 8·7 8·7 8·7 ---8·7 ---0 29 ............... 7·8 ----7·8 -7·8 --[fl !,,-' 30 ........... 7·4 7·4 7·4 7·4 --7·4 7·4 7·4 -f"o. > 31 ....................... 7·5 ---7·5 --7·i5 --~ 32 ........ 6·6 6·() ---6·6 ---
> 33 ...................... 8·2 -8·2 ------?'. b
--- l\Tean. . . . . . . . . . . . . . . . . . . . . . . . . I 7 · 8 7 · !) 7 · () 7 · 0 7·8 7·9 7. f) 7·4 8·2 7·9
" "
N "m 00, of ,.gfom. . . . . . . . . . . 3'I
16 IO 6 6 6 6 6 6 6 "'"''"'.' e<ro• . 0 • .. • .. .. .. I ± · 1~71. ± ·2307 1
cl · '296 ± ·'°"'
± ·::!68;) ± ·2692 ± ·:3250 :I: ·2661 ± -i304l ± ·3661 t< Stan~~tcl de'.tat1on.: "... . . . . . . . _l · 888() ± · fl2~7 ± · 72611 I ± · 9791 :::'::: . 7871 ± . 6505 ± . 7961 ± ·6494 :I-. 7448 ± ·8969 ;;j Coefhc1cnt of va1·1ab1lity ... I 11·4% 11·7';0 9 · 6';0 12 · 4'io L1·3% 8·3% 10·1% 8·8% 9·1% 11·4% 0 """' ----------·-----__ I --------, ----·----· ~ >DETEIOJlXII\G LESGTH [~ THE illEIUI\O J:'LEECE.
In sheep ~\, ;3:1 measurements ou the right hnrnl ,;j(lt• of thP fleel'e gin· a mean 6 · 7 cut. \Yitlt n Standard enm· of ± · .l:Hi. Those b ken 011 the left haucl sicl.e giYe a mean of (j ·I ± · lOS, showing 110 sign i fi c·a1tt differem·e behn~en the JJH'allci of the hn; ,;ides. When
the (j() 111easnrerne11b, taken from the eutire flee!·e, are compared
11·i th those takeu 011 the left and right hand c>icles respediYe h-, no signifieant !hftereuce exists lid1Yee11 the hotter h1·0 nnd !hose from the entire fleeC'e, imliC'uti11g: tlwt :):i rneasm·ement8, t.aken on Pither the rig·ht hand or left hancl "i,1es of the fleece, form a iepre- sen.Liti 1·e seledion of the fleece. ,\ similar result wns obtained from sheep
n,
IYhich 11·a,; a lll()f(! deYelope<l type th:111 A :rn<l repre;;en!P<l nu ex!Yenw case of rlPYelnpment.Althoug·h :B (or:):!) i11e;1sure-rncnts taken on ;rn~· 011e ,;ide of the
fj eece form a represen ta ti Ye .,;el el' hon of the fl ee!·e, i ( i,; con tellllecl that ihis 11nrnhe1· is too large· to lw applic:1ble in pn1dice. vVhere the dwra('teri,;tic of leugth is (letenuiuecl iu experillll"Lds anll lJl'eediug \l·ork, iunJh-ing large JLullllJPrn of ;rnimab, the minimum Ht1Htl1er of rneasuremenb t·lrnt (·a11 be usPd to gi.,·e a mea11, that is re1n·esentatiYe of the fll'e('e, 11·ns !letermined.
A fnrthe1· anahsi:; of tlw iesnlts v± the leugth measurerne11ts of sheep .\ all(l B "is giYell in 'L'ahles 2 (a) aucl 2 (/1) "·here the seleetion of 3:) (or 32) mea><urerneuh are compared "·ith selections of l i (or lGJ, HJ, and of (i. 111 ad<lition, seYen differiup: seledio11s each !·on:;i:;tiug of G mensu1·erneuts, an• shown 11 ith their means <llHl
other st.ati:;ticnl coHstauts.
'l.'he means obtai11ed from ~)J, 17, lU anrl G mea:;uremeut,; [gi1·en iu '!'able 2 (a)
J
show 110 sig11ificaut differenu•,,; :1mong these. It i6 therefore coucluded that a selection of 6 mcasun·1nents giYes a suffieientlv reliable mean for ihe :fieece. .\ sin1ibr i·e:;ult is obtaiuecl from she~p B, shown iu Table 2 (Ii). It is suggeste<l that, for co11Yenie1H·P, tl1e six rneasu1eme11b be taken oIL a line joi11ing the 11ef'k nnil h1·itch regions of the she1)p. Further tests on the reliahilit.,· of six mea~urernen!-s were also lll:ulP on the measurements giYen h.\: Dnerdeu and 1';dmer (19:32) "·here 12 fleeces are measured for staple length rli,.;tributiou. The results are smnrnnrised in 'l'able =~.The meaus of shple length.-;, oiitainecl from the t\Yelve fleeceB.
an: gi,·eu with their stan(lard errors, in addition to the meaus ohtnine<l from six places, ead1 a random selection taken on a line behl'een the ueck and brii"<.:h reg·ious d the fleeee.
n
is sh0\\'11 ihat the mean,; of six meatnirernents <lo not <lifter ~igni:fi(':111tly from the 11H·am of the whole fleece.The method of ta king :;ix nwasurernents on the li ,.e animal, ou a line between the neck ancl britch regious of the sheep, \1·orks well in practice since it can be u;;ed on lnrge 11umbt'1·s of flheep giYing reasonable reliahilit:;·. The mean of si.x rneasuremeuts <loPs
110L ho"·eyer appear 1.o be indi<·atiYe of the degree of Yarinbilifr in length of the fleece. ll lrns been found that in stud merinos, anrl e;o;pe('i ally so among th f' wrinkly 1 ype, that the Y:niabil i ty among su1ples, eYeu adjacent staples, can giYe a Yaric1bility equal in wagnitude to that found on regions representi11g ihe extremes of the fleece. Furthermore, in this respect there appears to be a
266
V. li0S1JAX .~X]) )[. L. JIOTlH.
g1 eat variability among fleeces, so t:ha t it is extremely difficult to obtain a method applicable for ge11eral use that giYf'S the mean as well as the variability, unless mauy more than six. measurerneuts are considered for the fleece. It is contended that the ln tter becomes too cumbersome for practical application on large nu m hers of animals and practically eaeh type of merino sheep would haYe to be considered on its own. In general, as 8tated by Duerc1f'n and Palmer (1932), the extremes iu staple of the merino are the neck and britch regions and the largest portion of the fleece, {'.onforming to the 3Yerage, is found on the sh01ilcler and side regions.
j n stud sheep, that are mostly brerl to haYe large ne<'k foltls, the variation between these, the wool grown on the folds and that comprising· the rest of the fleece, is often Yery great, so th'.1t each t.\·pe of sheep would ha>e to be stutlied separately.
'f.rnLE 3.
An analysis of the staple length meas1nements g1Tei1 by Duerden and Palmer (1932).
Figure.
1. ............ . 2 ....... . :3 .......•......•.........
4 .............. . 5 .............. . 6 ...................... . 7 ......... . 8 ... . 9 ............. . 10 .............. . 11 ......•...••...
12 .................. .
AVERAGE .. . . .• • . . .•.
Number of regions measured.
:Mean of fleece.
Standard error of mean.
- - - - -- --
142 3 . 53 ± . 122
261 4·12 ± ·088
294 5·18 ± ·128
265 3·60 ± ·093
236 3. 05 ± · 109
225 5·00 ± ·ll5
199 3·29 ± ·143
203 3 . 95 ± . 096
161 4·08 ± · 123
211 2·60 ± ·085
l __ l~----L~ _ _I ; :~~- '
4·01
Mean of six regions.
3·60 4· 17 5·58 3·57 3· 15 4·9!) 3·40 4·08 4·32 2·63 3·35 6·73
4· 10
- 1 = = =· -- - - - -- -- --
Sam.pli11_q tl1e Sliou1 Flel'<'e.
Usually, rneri110 sheep are shorn so that !he tleel'es e:rn he spread
"'ll the skirting t<ihle \Yithout losing· ihe irlentity of the reg-io11s of the fleece. rn<ler these UJ'Hlitlons i he method of t:tJ\ing '-amp)e:;
horn six regio11s, :q>plieahle hl ihe liYe anirnal, can :dso he 11:;ed.
It freqneutly happens, ho,YPYer, that 11·heu fleece;; are shorn and sent OYPl' lung· tli.~tnnce,;, the irlentity of ilw regions heeorne~
un eertain. 111 South Africa, where a sys tern of fl ee<'e a nal_\·si s for sbeep breeders has been instituted, fleeces sueh as the~f' are frequently encountered and it, ha,; been nel'eRs:uy tlw t· method,; foT sampling sneh fleet"es be conRi<lered.
267
DETER'.1111\ING J.EXGTII JI\ THE :IJE IUI\O l:'J .l•:ECE.
The fleeces of the two stud sheep A and B were shorn so that the identity of the regions of the fleeces \\·as lost.
Each fleece was evenly spread out on the floor in the form of a rectangle and demarcated into ten equal regions by means of ... demarcating frame (sho\\·u in figure :2). Ten regions \\·ere decided (•n since it waR shown that a selection of six measurements, one from each of six demarcated regions, did not give a sufficiently reliable mean for the fleece. Tests \Yere made to establish whether the taking of one measurement from each of the ten regions, demarcated by the frame gave a sufficiently reliable mean for the fleel'.e. Six measurements taken from each region were compared with three and one respectively, giYing selections of 60, 30 and 10 rneasuremen ts respectively from the whole fleece. The results ohtaiue<l from fleeces A and l3 are summarised in Table 4. It is sho"·n that there is nu significant difference between the means of selections of 60, :~o
and 10 samples of the fleece. Several random selections of 10 measurements (taken one from each square) showed no significant
<lifferences among them and this number, therefore. g-iYes a reliable mean for the fleece.
I
Sheep.
I
A
B
TxBLE 4.
Staple Length Ji e1M1aemen t.1 of two Ji e1·i110 FleerPs A and ll, after shearing.
I
' Number of
I
)foanstaple Standard
Type of sheep. I measure-men ts length deviation.
I taken. I (cm.).
I
Medium developed ..... 60 6· l ± ·54
30 6· I ..L ·54
10 6·2 ..L ·54
Standard error of
n1ean.
± ·07
± · 10
..L ·17 - --- - - --
.Extremely developed .. 60 7·2 ± ·69 ± ·09
:lO 7·1 ± ·81 ± ·15
10 7·2 ± ·48 ' ·l.'i
- - - - -
Sa 111117 in g tl1 e !Jruken-uz1 Fleece.
lH many sheep experiments, \Yhere \\·ool-production 1,; ,.;tudie1l, and also where fieece,; nre analysed for sheep breeders, such as is at present being clone iu South A:hiC'a, factors such as clean yield, fibre fineness etc. are detenniuecl in the ordinan· course of the \York and these require definite methods of sampling-.· To obtaiu representatiYe samples, a method of mixing- the fleel'e thornughl,,- by a fleece hreak\:'r is oHen elllplo.\·e1l. 1 t huF hc•en shO\nt that sueh broken up fleeces (·a11 also be (·011Yeniently usrd for the determination of st;, ple leugtli mea:-iurem en r:-;.
Fleeces A and l3 "·ere broken up, spread on thr floor and demarcated by the franw so that 30, 10 and 6 points \1·rre measured.
268
\'. BOSMA:-: Al\D :M. L. llOTIIA.
150
II
50 100 150
FlGlTRE 2.
Frame use<l for demarcating shorn fleeces. Tho sicles of th<: frame are 300 and 200 centimetre~, :respectively, and contain groo\'('S for holding the rigid transverse rods, \rhich demarcate the fleece into 10 equa.J portions.
269
DE'l'ERi\IIKING LEKG n-r lK THE i\IEl{l:"O l:'T.EECE.
11he mean,; obt:1iHed from these selections are shown rn Table 5.
TABJ~E 5.
Staple Length Jfeasureme11 ts on two 111 el"i110 Fl Pee es A n11d II a/ ter they harl been thorovghly brokni 1117 and ?ni.rPd.
I
Number ofI
J\'[ean StandardI
staple Starnfaed Shecp.
1
Type of sheep. measure- of
men ts Length deviation. error
taken. (cm.). 1ncan.
I
A
I
llfodium developed ... 30 6·4 ± ·42 + ·0810 6·3 + ·45 ± · 14
6 6·3 ± ·47 ± ·19
H Excessively developed .. 30 6·8 ·67 ::r: ' ·U
10 6·9 ::r: ·66 -~l
6 6·6 ' ·86 ± ·35
The measurements of :)O, 10 anrl 6 points on the broken up fieece are sho"· JI in 'l'a ble 5.
There are no significant differeuceb iudi<'ating that a ~elt>ction of 6 rneastuement~.
gives a suffi('.ien tJy reliu hle mean.
beh1·een the means.
of the broken up fit>ece
vVhen the rneans, obtained from 1he fleece on the li1·e animal are comparecl with the means, obtained from the shorn fleeee, there is a difference due to the shearing, sinc;e a c-ertain amount of wool i~ always left 011 the animal. In genen1l, from a half to one ceuiimetre haR hee11 observed to 1·enrnin 011 the skin of the sheep.
Snnipli11!} frl'1· S.trai!Jhf Fibre _T,r11gtl1 and Crimp Ratio.
'Where the determination of siraight fibre lf'ngth aJJd c-rirnp ratio is net><led, the nurnher of Hdual cleif'rmiuatiuns of straight filire length mut;t necessarily be reclncP(l to fl minirnum, smce thc>y are laborious and not· practif'able 011 a lnrge S!'ale, c!nc·h estimatioll n quiring thP strnight length mensurements of at least 00 fibre;;.
11he mos-t ,; u i ta lile mPi ho cl for cl et errn in in g the straight leug-t h, is i.hat of strnightf'uing Pach fibre hy meuns of fi11ely poiutPd fun·ep,;
ag·airt.-;t a grnduate<l ,;cale ancl rearliug oft t.he length of the fibre. 'l'he crimp i·:1ho i,; :111 PxprPssio11 of the ratio uf the st-raight fihre length oYvr Hw ,;L1ple leugth (Duenle11 ancl Hosman. 19:11).
lu the measu1·pn1Put of sbplt> length for tlw purpose of :J1taininµ·
the c-rimp ratio, it has bec>n fnunrl tlrnt more reliable results nre obtained by clipping- nft, at right angle~ to !he leuf!'th of the s!aple, sm:1ll pol'!ions nt both Pncls of the staple ancl then rne~1sm·in.!.t the !rimmed stupl1! rather than the irntrirnmed st-aplc>. ThP straight filirf' length~ woulcl al~o llP nht:1ined frorn l'ht> trirnnic>rl stnple.
270
V. DOS~L\X AXD )(. J .. HOTJU.
}[ea,;urements of t;rirnp rntio. taken on cl fp"· poiuts on sheep
..;\. :..lnfl ]J, nre :-;ho-\YU in 1\tLle G. 1'hc point~ :-;elected ~u:e taken on
a li1te hehYeen the ne('k mid hritch regions of the sheep, this pmtion of the fleece rornpnsrng the hulk of the fleece.
TABLE 6.
Regions. 11. 13. 1±. 1.5. 16. 17.
- - - - - - - ·- - -
Sheep A ............... . 1·5 l ·5 J-.5 l ·5 1·6 l ·6
Sheep 13 ............... . l ·5 4 l ·4 1-i.i 1·6 l · .5
It is suggested that, si.n('e the work attached to the tleterrninatior1 o [ n irn p rn tio is too large to be rt ppliecl for µ;eneral use, at lea st one determination of the crimp ratio 1Yould µ:iYe a good iudicatim1 of the nimp ratio of the fleece. Obserrntions ha1·e shown that there is a smaller yai·iability iu the same :fleece than there is among :flee('es awl the cletenniuation of a ,;:1rnple bken frorn the ~houlcler
i·egion of the fleece is suggested, this giYing a good indication of the ('l'imp ratio of thP flee<'e.
::\Iethod,; for determ iuin g leugth iu the merino :fleece are outliuf'd.
The significa11ce of the staple leugtb, the draight fibre length and the Y:nia hi lit:-· of the merino fleece i,; cliscn~sed.
There is iw sign ific-aut difference heh1·eeu the ,;taple length of the left hnnc1 ~icle of the merino fleece ancl ihat of tht> right hand side of the fleece.
For sampling thP me1·i110 fleece on the liYe animc1 l, a selection of six mec1.~nrernents gives a sufhcit>utly reliahle mean for the staple len g-t h of the fleece.
\Vhen the shorn fleece is spread on a table so that the itlentity of the regions is presen·ed, six measuremeuts gi.Ye u reliable select.ion for the mean staple length of the fleece.
\Vhen the identity of the regions of the shorn fleece i" los1. mul the fleere mixed, the fleece is tlemarcated into 10 equal regions by a frame, and 10 measurements, one from each region taken for obtaining nn aYerage of the fleece.
A cone ct ion fo dor, due to shearing, is necessary when the length of the fleece on the hve animal is compared "·ith that of the shorn :fleece and in geueral, a half to one centimetre of staple le11gth has been observed to remain on the live sheep.
It is suggesforl that, since the complete determination of crimp ratio is too cumbersome for application in general vractice, one
det<~rmination at the shoulrler region \vould give a good indication of the crimp ratio of the :fleece.
271
DETETLVUNING LE~GTII l~ THE ;\IEllLNO FLEECE.
The authon; are indebted to the South .African ·wool Council for assistance in carr_ving out the 'York. 'l1hi.::; forms a prehmi11ar,v part of a project on " -Yietho<ls for Analysing- the Merino Fleece " which work is financed h.Y the \Vool Council cut of \Vcol l.f'Y.\. }'111Jd~.
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272
