Scientific breeding methods and our vision for the future

Our vision for the future

We have a vision that is shared by many breeders of black alpaca around the world. That vision is one day to breed and maintain a herd of black huacaya that clip a fleece of a weight and quality equal to the best white alpacas. By learning from the research and experience in the merino, angora and alpaca industry in Australia and North America we can improve breeding decisions and explore the link between nutrition, physiology, genetics and fibre. Our own experience tells us that our goal is attainable if we apply all that we have learnt and use males that consistently produce uniform progeny that carry the traits we desire together with using newly developed scientific breeding strategies that are proven to improve the annual clip while keeping a uniform black colour.

SRS® – A Unique breeding System

Eight years ago Inca Alpaca adopted the SRS® breeding system to primarily improve fibre yield and quality. This innovative breeding system was developed by Dr. Jim Watts in the 1980s, and has been used successfully to improve fleece quantity and quality in Merino sheep and Angora goats by selecting for increased fibre density and fibre length (see If an animal grows more fibres (density) and if those fibres are longer, then it will produce more weight of fleece. The higher density also reduces the mean fibre diameter and the variation in fibre diameter of the fleece.

More recently, these selection techniques have been used successfully by alpaca breeders to improve fleece quantity and quality whilst moving rapidly towards eliminating “guard hair”.

Guard hairs are coarse and hollow centred primary fibres that form the outer coat on the fleeces of alpacas which lack fibre density. Guard hairs do not absorb fabric dyes and spoil the appearance of finished products.

There are two types of alpacas.

The Huacaya alpaca grows a fleece with crimp. The Suri alpaca grows a fleece which coils.

Both of these alpacas have measurably high levels of fibre density and fibre length with fine primary fibres. The fleeces consist of many long, thin and clearly defined staples which are soft and lustrous. The crimp of the Huacaya alpaca has high amplitude and low frequency. The Suri alpaca has gently coiling locks.

Using visual selection for these fleece traits together with measurements of primary fibre diameter, fibre density and fibre length, the following changes have occurred over the last four years in the herdsires selected for use in alpaca herds implementing the SRS® breeding system.

SRS3 The alpaca fleece (left) has many guard hairs protruding from the outer fleece surface. The alpaca fleece (right) appears to be mostly free of guard hair.


Primary fibre diameter (microns) Secondary fibre diameter (microns) Fibre density (per square mm2) Fibre length (mm per day) No. of alpacas
Selection pool available at outset:
38.1 26.6 43.3 0.31 72
Initial selection of herdsires:
33.0 23.4 47.6 0.36 42
After 4 years of selection:
29.1 20.7 49.5 0.36 37




The herdsires now being used have primary fibres and secondary fibres that are, on average, 9 microns and 5.9 microns finer respectively than were available at the commencement of the breeding programs. The fibre density has increased by 14% and fibre length by 16%.

The list of the 50 highest ranked alpacas for breeding values with equal emphasis on fleece weight and fibre fineness in the AGE (Across-herd Genetic Evaluation) program was published in Alpacas Australia, Issue 59, Summer 2009, pages 58-59. There are 747 sires in this analysis.

Illawarra Alpaca Stud, Cambewarra, New South Wales, has been applying the SRS® breeding system for 6 years. The stud has 4 sires in the top fifty with Illawarra Yucatan (IAR 62620) ranked first and Illawarra Yohimbine (IAR 62650) ranked second.

Illawarra Yucatan is a white Huacaya male, now 6 years old. His progeny produced , on average, 2.9 kgs of 18.7 micron wool (30 animals) on the second shearing and 3.1 kgs of 20.9 micron wool (12 animals) on their third shearing. When tested at 25 months of age, Yucatan had a density of 48.8 follicles per square millimetre of skin and a fibre length of 0.39 millimetres per day. Three of his male progeny were tested at 20 months of age and averaged 56.1 for density, 0.37 for fibre length, 29.5 microns for primary fibre diameter and 22.2 microns for secondary fibre diameter.

Illawarra Yohimbine is a solid white Huacaya male, also now 6 years old. He has an impressive frame and exceptional fleece length. When tested at 24 months of age, Yohimbine had a density of 46.0 follicles per square millimetre of skin and a fibre length of 0.44 millimetres per day.

Illawarra Alpaca Stud excelled in the same trait list for females with 13 of its hembra in the top list of 50.

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.

SRS4 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.

The fleece from an SRS® Merino ewe. Note that the fleece consists entirely of fibre bundles. Staples (locks) have disappeared. SRS5

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.

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.

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.

SRS6 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. SRS7
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.

SRS8 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.

SRS® Workshops:

The next SRS workshop will be held this summer. More information will be available soon.

SRS® welcomes new subscribers:

For an application form is available on the SRS® website.


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. 258-276

Stevens, 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-E12

Yang, S. (1993) The effect of the fibre length distribution on yarn evenness and tensile properties. Restricted Investigation Report, CSIRO Division of Wool Technology, Ryde