In 1986 the scientific recipe for breeding advanced Merino wools was put forward by CSIRO (Commonwealth Scientific Industrial Research Organisation) researchers Moore, Jackson and their colleagues. I then devised and implemented a practical breeding system based on this recipe.
The system means that when fleece-coated animals like Merino sheep, alpaca and Angora goats are bred specifically for high density and length of wool fibres, changes occur in the quality and fineness of the fibre.
Rare and unparalled quality
The mean fibre diameter of adult Merino ewe fleece is 16 microns, weighing 8kg after a year’s growth. The fibres are highly aligned and very even in diameter and length. The fibre surfaces are smooth.
This fleece type is very different to conventionally bred Merino wools. It consists of closely packed, thin ‘fibre bundles’ (rather than the traditional staples or locks). The crimp amplitude is high and frequency low relative to the fibre diameter. The crimp definition is near perfect and the fibres are elastic. It is exquisitely soft Merino wool, measuring as low as 3.9 kilopascals for resistance to compression. Alpaca wool and mohair bred in this way develop along similar lines.
Huacaya alpaca wool from an adult herdsire is amazingly soft, measuring 17.1 microns in fibre diameter. The fibre has high lustre and is free of guard hair. By selecting directly for low primary fibre diameter, guard hair (coarse primary fibres) is eradicated from alpacas. In addition, close examination on a black velvet board of fibres from each shorn alpaca fleece provides further guarantee that the fleece consists of fine and evenly sized fibres free of any residual coarse fibres or contaminating coloured fibres.
The fleeces of Angora goats and Suri alpaca are different to conventionally bred animals, yet almost identical to each other. In both cases, the fleeces consist of myriads of gently coiling, long and thin fibre bundles with super lustre.
The adult Angora goats are producing fleeces of 21 microns and finer after only six months fleece growth. Such a fine diameter is most unusual for adult mohair. The Suri fleece is grown over an 18 month period. Suri fibre is prized for its high lustre and cool silky handle. The fibres gently twist from the skin to the tip. The fleece itself is a thing of beauty.
SRS Merino breeders produce impressive volumes of this quality wool. At the ultrafine end, one SRS Merino breeder produces approximately 9,000 kg of 13 to 16 micron wool each year. Most of the SRS Merino breeders produce large volumes of wool in the range of 16.5 to 19.5 microns.
Ethical and sustainable wool production
The sheep breeding methods I have devised are used by around 1,200 Merino breeders across Australia, resulting in millions of sheep not needing to be mulesed. The sheep are plain bodied with soft and white wools, naturally resistant to flystrike.
Whilst the genetic solution to mulesing has been in place in SRS Merino flocks in Australia since 2001, this important message does not appear to have reached the ears of textile manufacturers and retailers.
Amongst the many advances made by SRS breeders is the breeding of naturally short tailed Merinos. Under the SRS breeding system, tail docking is an optional rather than standard practice for Merino breeders wanting to differentiate their flocks and wool on easy care and animal welfare grounds.
Merino stud breeder Don Mudford, of Parkdale SRS Poll Merino Stud in Dubbo, is the first Merino breeder in the modern era to successfully use genetic selection to breed naturally short tail Merino sheep that do not need tail docking.
Breeding for short tails and non-mulesing in a productive Merino sheep enterprise demonstrates how stud breeders and scientists thinking outside the box for genetic trait improvement can open up new welfare and management opportunities for the Merino sheep industry.
Among the many SRS Merino breeders in Australia an increasing number is focused on sustainable wool production using holistic grazing management. This grazing system improves soil structure and fertility, ensuring permanent plant cover of the land.
Many people now realise herbivores are important for trampling grassland material into the soil to provide biomass nutrient that would otherwise be converted into atmospheric carbon dioxide by bushfires. Sheep are a good choice, especially when bred to be environmentally fit and efficient grazing animals. Large mobs of Merino can graze in one of the many rotating cells (small paddocks).
Textile results
Itochu Wool Limited conducted worsted processing trials on SRS Merino wools from 1997-2002. In total 16 trials were carried out on commercially processed batches of Merino wools ranging from 17.3 to 20.7 microns in Italy, Japan, Thailand, India and Australia.
The trials showed that SRS Merino wools, which are characterised by high crimp amplitude and low crimp frequency, produce consistently long hauteur with low short fibre content in the top and low noil percentages. The yarns were soft and silky with very good elasticity. Yarn breakages were reduced by 20 to 30%. The fabrics were described as feeling more like cashmere with excellent drape, crease resistance, a natural ability to stretch and a deep rich appearance after dyeing, particularly with pastel colours.
Similar research findings have been reported independently by Australian textile researchers from 2002 to 2008. Knitted fabrics produced from low crimp frequency superfine Merino wool are thinner, more compressible (softer), lighter, more permeable, have greater spirality and less pilling compared with fabrics produced from high crimp frequency superfine wools. The physical properties of low crimp frequency superfine wool knits are closer to the properties of pure cashmere fabrics.
SRS alpaca breeders Julienne and Frank Gelber have recently developed a worsted fabric Surissimo from Suri alpaca fibre (see Twist January 2013). Surissimo involved a complete change in the breeding of the fleece structure of Suri alpaca to capture the beauty of the finer fibre in woven and knitted fabrics. Mills were, however, reluctant or unable to convert the raw fibre because of the slippery, almost hair-like nature of the fibre.
“We set about producing fine Suri fibre which would perform in yarn and cloth, without losing the fabulous lustre and silken handle that was inherent in the breed,” Julienne Gelber explains. “With the help of spinning and weaving specialists I had to identify which fibre characteristics were lacking and then search locally and overseas for animals that appeared to have unusual fleece that may impact on the quality of the Suris in our herd, forcing the fleece towards a more processing friendly style.
“The style of the ‘ideal’ fibre (the genetic improvement), the harvesting and care taken to deliver the uniform highest quality Suri for processing, is what sets Surissimo fibre apart,” Julienne concludes.