What is SRS?

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SRS® animals are fleece-coated animals bred using a new breeding system. The breeding system has been applied to Merino sheep flocks, Angora goat herds and Alpaca herds in Australia since 1988 and more recently in Argentina, Chile and New Zealand.
The breeding objective is to improve the quantity and quality of wool by maximising the density and length of the fibres grown. If the animal has many fibres on its body, and these fibres are long, it will produce a high fleece weight. High fibre density leads to low fibre diameter. High fleece weight and low fibre diameter are two important outcomes that make the fleeces of SRS® animals valuable.
The breeding system has specified breeding standards and wool standards which are quantifiable The SRS® animal has a thin and loose skin which makes it plain-bodied and non-wrinkly.

The Animal

The high levels of fibre density and length produced by SRS® animals is thought to be controlled by the genes regulating the number, distribution and signal strength of the follicle-forming pre-papilla cells in the foetal skin. The same biological processes are thought to be responsible for the animal's skin being thin

The SRS® fleece consists of very long fibre bundles which give the fleece surface a thatched appearance The fibre bundles have high crimp amplitude ('deep' crimp or 'character') of low frequency ('bold' crimp). The fleece is soft, lustrous and white. Each fibre bundle represents the fibres produced by a wool or hair follicle group in the animal's skin. Fibre bundles are visible in the fleece when follicles and fibres are closely packed and highly aligned

The Fleece and Skin Markers

The density and length of fibres on an animal are measurable. However, these measurements are slow and expensive to do, and are reserved for potential sires as well as dams to be used as embryo transfer donors. A subjective assessment, based on the visual and tactile recognition of the fleece and skin characteristics that accurately indicate the density and length status of individual animals, provides a low cost and practical alternative for classing large numbers of animals.