Beware The Black Fibre
27 March 2002
Wool Exporters Council
Farmers should take care when selecting replacement ewes for their flocks not to increase the incidence of black fibre in their wool clips, say wool exporters and WoolPro.
Wool Exporters’ Council executive manager, Nick Nicolson, says that in the past couple of seasons, exporters have noticed a little more black fibre in lambs’ wool.
“This is more obvious when lambs are shorn before slaughter,” he says.
“Many of these lambs are sired by terminal sires, which are not necessarily selected for freedom from black spots.
“The lack of black fibre in New Zealand wool is one of its main attractions for buyers, and they are prepared to pay a premium for that assurance.
“The recent increase in the use of terminal sire meat breeds within crossbred flocks raises the possibility of contamination if farmers are not careful when selecting sires and rigorously culling ewe lamb replacements.”
Mr Nicolson says shearing contractors should also ensure their teams follow good practices in the shed to make sure black fibre doesn’t get into the clip.
John Crosbie, from the Australian office of Wool Interiors, endorses this view. He says some overseas carpet mills are concerned that wool quality might drop if it becomes a less important part of farmers’ income.
Several Australian carpet mills have recently told him that it has the potential to have an impact of the supply of good quality wool.
“This is especially so with more New Zealand wool being used in the colour-critical residential market,” he says.
The Wool Classer Registration Scheme’s registrar, Struan Hulme of WoolPro, says farmers should clean the shearing shed and yards thoroughly before shearing and draft sheep into separate breeds.
“Shearing teams should shear the pure white breeds first, before moving onto other breeds that might be contaminated,” he says.
“All the wool from one breed should be pressed, and bins and containers emptied and removed from the working area before shearing the next breed.”
WoolPro sheep production specialist, Alan Marshall, says sheep crossbreeding is here to stay.
“It’s a common sight today to see white-faced terminal sires used to breed composite dual-purpose flock replacements,” he says.
“However, the terminal sire breeds have been bred with the emphasis on meat production, knowing that all their progeny would be slaughtered.
“I’m not suggesting that these white faced breeds – whether they are terminal sires or more-recently introduced high prolificacy breeds – have any more black spots than any other breed. But their population base is generally small and that restricts culling on the full range of characteristics.”
Alan Marshall says crossbreeding generates hybrid vigour due to a greater mixing of different genes.
“This mix of genes creates more variation in the type of animals produced and increases the likelihood that the odd animal will be thrown up with a greater number of black spots.
“On the positive side, however, hybrid vigour generally causes higher fertility, which means extra ewe lambs for selection. The advantage is farmers can have a more rigorous culling programme for various wool characteristics, including black spots.”