The Animals and their Fleeces'
We breed alpacas which have very fine primary fibres and high levels of fibre density and length.
Low primary fibre diameter
Very fine primary fibres ensure that the animals are free of guard hair. And because the wool follicles that produce very fine primary fibres require small numbers of pre-papilla cells to be involved in their construction during foetal development, more pre-papilla cells remain to be used in the formation of greater numbers of secondary wool follicles, thereby increasing the follicle and fibre density of the alpaca.
High fibre density
High fibre density brings to the Huacaya fleece an assembly of thin, not thick, staples with high crimp amplitude. The thin staples in the high density alpaca below are only about 3 mm wide and are approaching the 'fibre bundle' stage. In a low density alpaca, the staples can be very thick, as much as 40 mm wide.
This adult Huacaya alpaca female at 2 years of age tested 60 follicles per square millimetre for fibre density (c/w industry average of 35) and 0.40 millimetres per day for fibre length (c/w industry average of 0.30). The mean diameter of the primary fibres was 28 microns (c/w with industry average of 35 microns). The secondary fibres had a mean diameter of 22 microns.
The fibre bundle is the basic unit of fleece structure. It corresponds to the cluster of fibres produced from each follicle group in the animal's skin. Similarly, the follicle group is the basic unit of follicle arrangement in the skin.
For a Huacaya alpaca which has exceptionally high fibre density (and length), fibre bundles will be abundantly visible throughout the fleece and these fibre bundles will be closely packed together and very long.
It is the same phenomenon in Merino sheep, which like the Huacaya alpaca, produces wool fibres that crimp. The Merino fleece below consists entirely of fibre bundles, each about 1.5 millimetres wide (the same width as each follicle group in the skin). This fleece is from an adult Merino ewe which produced 8 kilograms of 16.0 micron wool for 12 months wool growth. Its fibre density is 120 follicles per square millimetre and its fibre length, 0.50 millimetres per day.
The fleece from an SRS® Merino ewe. Note that the fleece consists entirely of fibre bundles. Staples (locks) have disappeared.
High density also brings to the Suri alpaca fleece an assembly of many staples that are consistently thin from base to tip (see photo below). On close inspection, fibre bundles can be seen emerging from the skin, only to twist together into thin staples. The thin staples need to be fast growing and gently coiling to allow easy fibre separation.
An advanced Suri alpaca with visually high levels of fibre density and length. Now 14 months of age, these traits will be measured when the animal is 2 years of age.
In both Huacayas and Suris, high density produces fibres that are highly aligned, fine in diameter, evenly sized and evenly shaped with smooth surfaces (low cuticle scale height). These features give the fleece its exceptional softness and with the high fibre alignment, its exceptional lustre.
Electron micrograph of a wool fibre showing a cylindrically shaped and fine fibre with long and flat cuticular scales.
High fibre length
High fibre length throughout the alpaca's life is critically important to achieve genetically. It is a key SRS® breeding objective.
There is an urgent need to correct the current industry situation worldwide where it is commonplace for alpacas to lose fibre length with age. Tests at our laboratory on alpaca herdsires sampled globally testify to this fact.
| Age (years) |
Fibre length (millimetres per day) |
Crimping time (days) |
Number of Huacaya alpacas tested |
| 1 to 2 | 0.39 | 13.1 | 76 |
| 2 to 3 | 0.38 | 14.7 | 57 |
| 3 to 4 | 0.33 | 17.0 | 36 |
| 4 to 6 | 0.30 | 19.3 | 43 |
| Older | 0.28 | 27.8 | 35 |
The present situation is that fibre length decreases rapidly with age (also in Suris) and crimping time increases with age. This is typical of the condition known as 'dogginess'. It is accompanied by a decrease in crimp frequency with ageing.
To overcome this problem, it is probably necessary to select for reduced crimping time whilst maximising fibre length. This is likely to give rise to alpacas which are efficient feed converters with well-organised blood networks to the wool follicles (the latter feature accompanies selection for high follicle density).
Currently the minimum SRS® requirement for fibre length of an adult Huacaya alpaca between 2 to 4 years of age is 0.35 millimetres per day with many SRS® selected animals now exceeding 0.40 millimetres per day. The industry norm is closer to 0.30 millimetres per day.
Fibre length is greatest in fleeces which not only have long fleeces but also have high crimp amplitude and low crimp frequency.
If a semi circle is the maximum expression of a crimp wave, the fibres will be, on average, about 50% longer than the fleece. This high crimp amplitude is linked to high fibre elasticity and excellent drape in finished products. However, Huacayas, on average, have fibres that are only 11% longer than the fleece. The fibres are lazy and could be bred for much better elasticity and drape.
Diagram of a single wool fibre. The vertical arrows indicate crimp amplitude. The horizontal arrows indicate crimp frequency.
Processing performance and end product quality
Worsted processing trials conducted from 1997-2002, by Itochu Wool Limited (then, the largest buyer of Australian wool) showed that SRS® Merino wool processes exceptionally well during topmaking, spinning, and weaving. In all, 16 trials were carried out in Italy, Japan, Thailand, India, and Australia, covering Merino wools ranging from 17.3 to 20.7 microns. In each trial, SRS® wool was compared with traditionally bred wool of high quality.
The topmaking advantages of SRS® wool in these trials are summarised in Table 1.
Table 1 - Topmaking advantages of SRS® wool
| Italy | Japan | Thailand | Australia | |
| Number of trials | 4 | 6 | 4 | 2 |
| Fibre diameter (microns) | 17.3 - 17.9 | 18.7 - 20.7 | 18.7 | 18.2 - 18.7 |
| Extra Hauteur | 11% | 4% - 9% | 14% | 9% |
| Short fibre advantage | 12% - 25% | 21% - 35% | 25% | 58% |
| Noil advantage | 7% - 13% | 0% - 25% | 22% | 39% |
In these trials, SRS® wools produced consistently longer Hauteur, less short fibre, and less noil (waste). Longer Hauteur with less short fibre content allows for: considerably more length of yarn to be produced per kilogram of top; higher spinning speeds to be used; the yarn to be spun into lighter weight yarns than is normally attempted; and for a high level of yarn evenness to be maintained. Yarn breakages during spinning were reduced by 20% to 30%.
These results are in agreement with the findings of other textile researchers. For wools of the same fibre diameter, those with deep and bold crimp, as exemplified in SRS® wool, make tops 8mm to 16mm longer Hauteur, with approximately half the noil and card waste of wools of finer and less defined crimp. (Stevens and Crowe, 1994). Longer Hauteur tops spin more efficiently and produce yarns that are more even and break less often (Yang, 1993; Lamb and Yang, 1996).
SRS® yarn was assessed as being soft and silky, with very good natural strength and elasticity which again allow high processing speeds to be used during the weaving stage.
The SRS® fabrics were described as feeling more like cashmere than a traditional wool fabric with excellent draping qualities, a natural ability to stretch, less creasing, and a deep rich appearance after dyeing, particularly with pastel colours.
A Japanese knitwear manufacturer, reported (June 2008) that the garment quality of 10% cashmere and 90% 18.0 micron SRS® Merino wool is the same as 100% cashmere of 16.0 microns.
References
Lamb, P.R. and Yang, S. (1996)
Choosing the right top for spinning. In TOPTECH 96.
Papers presented at Geelong, Australia, 11-14 November 1996.
CSIRO Division of Wool Technology and International Wool Secretariat. Pp. 258-276Stevens, D. and Crowe, D.W. (1994)
Style and processing effects. In WOOLSPEC 94.
Specification of Australian wool and its implications for marketing and processing.
Papers presented at the seminar held by CSIRO Division of Wool Technology and International Wool Secretariat. Sydney, 23-24 November 1994. Pp. E1-E12Yang, S. (1993)
The effect of the fibre length distribution on yarn evenness and tensile properties.
Restricted Investigation Report, CSIRO Division of Wool Technology, Ryde
Latest News
13/06/13 - New England Alpaca Show
Four subscribers were represented at the New England Alpaca show consisting of fleeces and lead animals over the long weekend of the 8th & 9th of June. They were Glen Waverly Alpacas (Betty & Adrian Whitten), Sunline Alpacas (Jeff & Jill Willis), Towarri Alpacas (Stuart & Fiona Marshall) and Glenhope Alpacas (Bronwyn & David Mitchell). Everyone took home some ribbons from the event which attracted 44 fleeces and 136 animals. In the fleece section Glenhope entered 7 fleeces and received 3 Championships, 2 Reserve Championships and the Supreme Champion. Glen Waverly received a Reserve Championship. The judge commented on the weight of the fleeces and the quality of the presentation which is encouraging. In the animal classes Sunline received 2 Championships and a Reserve Champion and Glenhope received a Championship and 2 Reserve Champions.
24/04/13 - Castle Hill Alpaca Show
Castle Hill Show, near Sydney, Australia, on the 9 March was another great show for SRS(R) studs. Walkley Fields (Richard Brennan) and Gunnamatta Alpacas (Sue Maynard and John Hay) had a very succesful day collecting 7 out of 10 Champions, with Walkley Fields taking out Supreme Huacaya Alpaca and Sire's progeny.
Judge Joanne Ham commented on the "super softness" of the animals.
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