Shrink-proof sheep

Shrinkage of woolen garments on 'wash-day' could soon be reduced dramatically following the discovery that wool shrinkage (felting) is a heritable trait that can be manipulated through selective sheep breeding.

Felting causes significant problems in the manufacture of knitted and woven wool products - particularly fine wool garments - and is a major factor in 50% of wool consumers rating woolen garments difficult to care for.

The finding that felting is a heritable trait - along with other wool characteristics such as dust content - means sheep can be bred to produce wool which is less prone to shrinkage.

"It is possible for wool growers to identify and select sheep which naturally produce low-shrinkage wool," says CSIRO Livestock Industries' Dr Tony Schlink.

By using pedigree information and removing the effects of fibre diameter, fibre curvature and yield, the wool's heritability for felting can be assessed.

"Altering the ability of wool to felt through conventional breeding may make a considerable contribution to wool processing," Dr Schlink says.

Studies conducted with CSIRO Textile and Fibre have shown that knitted fabric made from low-felting wool has reduced pilling and shrinkage. The studies demonstrate that differences between low and high-felting wools are preserved through the wool processing chain.

Low-felting wool also produced longer length and less entanglement during the scouring process, resulting in fewer breakages during spinning.

Dr Schlink says a biological approach to reducing the felting capacity of wool could also mean a reduction in the quantities of chemicals currently applied to wool to prevent shrinkage.

"Breeding offers the potential to eventually produce wool that does not need to be chemically treated to achieve desirable fabric characteristics," Dr Schlink says.

In a separate study conducted with University of Western Australia Honours student Melanie Ladyman, and supervised by Dr Schlink, the wool's ability to hold dust was also found to be a highly heritable trait.

"Some sheep are more susceptible to dust content in their wool than others," Dr Schlink says. "As with felting, wool growers in areas where dust is a problem can breed sheep with a stronger resistance to dust content."

Item provided courtesy of The CSIRO