The Science of SRS® Breeding

The SRS® breeding technology allows the density and length of fibres grown by the sheep, goat and alpaca to be increased rapidly. As a result, the animals produce high fleece weights of fine diameter wool.

In SRS® animals whose fibres crimp, such as the Merino sheep and the Huacaya alpaca, the high density and length of fibres will produce a fleece consisting of long ‘matchstick-like’ fibre bundles rather than staples. In SRS® animals whose fibres coil, such as the Angora goat and the Suri alpaca, the fleece consists of thin staples formed by fibre bundles being gathered together by the twisting action of the fibres.

Image 1. SRS® fleeces from: a Merino sheep (top left); a Huacaya alpaca (top right); and an Angora goat (bottom)

The fibres are highly aligned, uniform in diameter and length. The scales are long and do not protrude.

Image 2. SRS® wool fibres are highly aligned in the fleece (top left) with smooth surfaces (top right). Conventional wool fibres can be highly entangled (bottom left) with rough surfaces (bottom right).

The density, length and dimensions of the fibres are thought to be controlled by the genes regulating the number and distribution of pre-papilla cells in the foetal skin. If high numbers of pre-papilla cells are available to form wool (or hair) follicles, and these cells are arranged as small clusters, then the animal will produce a high density of fine diameter fibres.

Image 3. Prepapilla cells are shown here as a cluster of cells in contact with the epidermal cells (outer layer) of the foetal skin (left). The pre-papilla cells stimulate the epidermal cells to grow down into the skin to form a wool follicle. When the follicle is formed, the pre-papilla cell cluster becomes enclosed in the base of the follicle (right).

Long (fast growing) fibres appear to be the result of the pre-papilla cells producing specific mitogen(s) that stimulate rapid multiplication of follicle bulb cells to increase fibre output.