Wool faults cost country millions

Waimarino Bulletin, Volume 1, Issue 12, 23 August 1983, Page 12

Wool faults cost country millions

Wool that is tender, or breaks under tension, costs farmers an estimated $50-$ 100 millioh a year in lost earnings. /

According to Whatawhata Research Station wool scientist, Dr Murray Bigham, tender wool is the major fault in New

Zealand's wool clip, affecting about half total production. But he says the fault can be improved through selection. Mid-winter problem "Wool fibres break at the point where the fibre diameter is at its minimum, and this is usually in mid-

winter when feed supplies are short." "However, there are factors such as breed and strain of sheep, the age of the ewe and how many lambs she has reared, which add to the influence of feeding and cause tenderness." "Tender fleeces are generally lighter than sound fleeces and they are also more cotted and more yellow," Dr Bigham said. He says there are three things a farmer can do to cut down on wool tenderness. 1. Pick a shearing time to suit the fibre' s growth pattern. However this means shearing in mid-winter and is not always practical and entails big risks. 2. Feed better during winter. This is not always economic and tightening up sheep in a controlled rotational grazing system may even encourage tenderness. 3. Breeding — studies by Dr Bigham using data from different strains of sheep at Rotomahana Research Station have shown that tenderness has a fairly high heritability. "This means that there is a very high chance of improving the fault by selection — picking replacement ewes and rams that are free from the fault," Dr Bigham said. Yellow Turning to another fault in New Zealand's wool, Dr Bigham said our crossbred wools are considered among the best in the world for carpet manufacture but

they can be downgraded because of yellow discolouration. He said the problem occurs when the fleece is wet a lot of the time and doesn't have a chance to dry out. Chemical action combines with the grease and sweat from the sheep 's skin causing the discolouration. "Unfortunately there is little the farmer can do to avoid this problem," Dr Bigham said. "One possibility is to shear before the spring rise in colour. However this means shearing after lambing which can affect the ewe's milking ability if the weather is cold and feed is short." Recent studies at the Whatawhata wool laboratory on wool samples from the different strains of Romney sheep at the Rotomahana Research Station have shown the fault to be only weakly inherited so there is little chance of rapid improvement through selection. Despite this he recon^^ . mends that farmers ta^P care to avoid rams with highly stained wool at selection time and to cull any ewes that show very high yellow colour ation.