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Wool Quality and Market Access

COLOUR IN WOOL - INVESTIGATION OF THE USE OF TOPICAL APPLICATIONS OF ZINC COMPOUNDS

Project leader: Dr Terry Reid
Research organisation: Wool Research Organisation of New Zealand (Inc.)
Project number. 01WR16
Phone number. 03 3252 421
Location: Lincoln
Fax number: 03 3252 717
Email: reid@wronz.org.nz
Funder: Meat & Wool Innovation

Project outline: Zinc compounds are well known to be important in optimising skin health in animals, and this project examines the potential use of zinc compounds at dipping to reduce yellowing in wool. Because increasing yellowness restricts the colours which wool can be dyed, it reduces the value of wool as a raw material for processing. This project explores the potential for zinc sulphate, applied as a dip, to reduce the yellowness of wool at shearing. If it has this effect, then this could be developed into a simple treatment system to improve the colour of New Zealand's wool clip. The trial is being carried out on five farms, from Raglan in the north to Balclutha in the south. These farmers are applying zinc in a dip at convenient times after weaning, and again before shearing. The trial design calls for three groups of sheep:

" Control (no treatment)
" Dipped once with zinc sulphate
" Dipped twice with zinc sulphate.

The colour of the wool from each treatment group is to be determined on core samples collected at shearing. By the end of March 2002 both treatments have been carried out on all five farms. Sheep have been shorn on two farms and the core samples are being analysed for colour and zinc content.

WOOL BULK-ENHANCING PRODUCTION

Project leader: Dr Roland Sumner
Research organisation: AgResearch
Project number: 01AR60
Phone number: 07 838 5272
Location: Ruakura
Fax number: 07 838 5117
Email: roland.sumner@agresearch.co.nz
Funders: Meat & Wool Innovation

Project outline: Wool bulk is a measure of the ability of a fibre mass to fill space. As such it improves insulation of knitting yarns and both the wearability and appearance-retention of carpet yarns. Bulk is therefore desired by many users of New Zealand crossbred wool to improve the quality of their end products.

As a result of research on aspects of the biology of wool bulk it is now possible for wool growers to produce high-bulk wool to specification. However, because of its cost the measurement technique is not suited to routine use for individual sheep. Work is progressing to develop a lower cost method of predicting bulk that will assist in the identification of superior sheep for breeding purposes.

This project will also develop a model incorporating operational details associated with a strategy to supply repeatable, objectively specified contracted orders at regular intervals during the year. The model will provide guidelines against which to increase the profitability of growing this specialty wool type, and thereby the size of the contracted grower base, to meet ongoing processor requirements.

Refer to Wool Grower Summer 2000 (issue #8, p. 12): 'High five!' - Five of the top research projects to make you money; Autumn 1999 (issue #2, p. 15): 'Look out for bulk carriers' - Industry support sought for new wool category.

WOOL COLOUR - IN-VITRO INVESTIGATIONS

Project leader: Dr Roland Sumner
Research organisation: AgResearch
Project number: 01AR59
Phone number: 07 838 5272
Location: Ruakura
Fax number: 07 838 5117
Email: roland.sumner@agresearch.co.nz
Funders: Meat & Wool Innovation

Project outline: Wool yellowing is a cumulative biological process associated with warm, moist atmospheric conditions. The process begins while the fleece is growing on the sheep's back and continues throughout storage and processing. Wool yellowing ultimately limits the range of shades that a batch of wool can be dyed. Buyers are willing to pay more for wool with 'good colour' as it has greater flexibility in processing. Research has shown the rate of yellowing on the sheep's back is related to that of yellowing during processing. It is thus in wool growers' commercial interests that the wool they offer for sale is as white as possible.

Research indicates that bacteria, which thrive in warm moist conditions such as the skin of sheep, may be implicated in fleece yellowing. Zinc sulphate is a readily available substance with known bacteriocidal properties. There is anecdotal evidence that spraying sheep with a weak solution of ZnSO4, when treating sheep against flystrike during the summer, slows wool yellowing.

This project will objectively evaluate, under in-vitro conditions, the effectiveness of ZnSO4 , as a topical application, on the rate of yellowing in samples of Merino and Romney wool collected from throughout New Zealand.

Refer to Wool Grower Autumn 2002 (issue #13, p. 23): 'Selecting for whiter wool' - The yellow wool challenge.

WOOL CRIMP

Project leader: Dr Clive Marsh
Research organisation: Wool Research Organisation of New Zealand (Inc.)
Project number. 95WR02
Phone number. 03 3252 421
Location: Lincoln
Fax number: 03 3252 717
Email: marsh@wronz.org.nz
Funder: Meat & Wool Innovation

Project outline: Our research aims to determine what dictates the shape of a single wool fibre. The shape of fibres, often referred to as their level of crimp, has significant effect on the performance of the end product and on the most effective configuration of manufacturing equipment. This is therefore an important property, which is likely to gain commercial significance for raw wool trading.

It has been believed for some time that the shape of fibres is strongly affected by the pattern of cell types within the fibre cortex (the central core). Fibres with high crimp typically have a bilateral pattern with two distinct cell types in each half of the cortex. As the fibre emerges from the follicle it dries out, and the loss of water causes some lateral shrinkage, which in turn places stress on the cells in the cortex. The two types of cell respond differently to these stresses, and crimping results in a similar manner to the bending of a bi-metallic strip under heating.

This project has contributed a mathematical model to describe this effect. Although there is currently no way to change the cellular makeup of the fibre cortex, this fundamental understanding will be needed to capitalise on any future ability to modify cellular patterns. A further important contribution is a measurement rig, which enables the shape of a fibre to be fully measured and described. This is a useful research tool, but has the potential to be developed into a commercial fibre-measurement device capable of giving superior curvature measurements for predicting processing and end-product performance.

Refer to Wool Grower Winter 2000 (issue #6, p. 21): 'Bulking up' - AgResearch and WRONZ scientists are hoping to unlock the secret of crimp formation in wool.

 

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