Pesticide residues are a concern for the environment, people who handle sheep and wool and for the meat trade. There are even some ‘eco-wool’ markets now looking for low residue wool.
Structured reading
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Pesticide residues
An introduction to pesticide residues.
Meat and wool residues
Explanation of residues, their impact and their management.
Withholding periods for worm, lice and fly treatments for sheep
Descriptions of the various withholding periods.
Question and answer
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Each of the questions below links further down the page to the answers.
Questions:
- Why do lice treatments have a Sheep Rehandling Interval?
- Do lice pesticides tend to adhere to the wool fibre or bind with the wool grease?
- What do ESI and WHP refer to?
- What does the European Eco-label for Textiles do?
- Which pesticides cannot be used to control lice if the wool is to meet EU Eco-label requirements?
- What are the key ways to produce low residue wool?
Answers:
You can also click on the link in each answer below to go to LiceBoss pages with related information.
1. Why do lice treatments have a Sheep Rehandling Interval?
Sheep Rehandling Interval is the period between treatment and when the wool or treated sheep can be safely handled without the need for protective clothing. Some products can pose health risks to those handling the sheep for some time after treatment or to those handling the wool shorn from recently treated sheep. If a wool harvest interval is given on the label, this must be observed to prevent wool residue issues in shorn wool. Read More
2. Do lice pesticides tend to adhere to the wool fibre or bind with the wool grease?
Most chemicals used to treat external parasites bind to the wool grease rather than the fibre itself. These chemicals break down and decrease in concentration over time on the sheep.
When shorn wool is processed, scouring removes wool grease and any remaining pesticide residues at the same time, which can result in contaminated scour effluent and lanolin.
Wool Harvest Interval (WHI) is the period between treatment and when wool can be harvested to satisfy Australian environmental requirements. This period ensures that the remaining pesticide residues are at extremely low levels. Read More
3. What do ESI and WHP refer to?
Meat Withholding Period (WHP) is the time from chemical application to when an animal may be slaughtered for the domestic market. The WHP is mandatory for domestic slaughter and is always on the label, and with the ESI (below) they assist producers to manage chemical residues in product.
Export Slaughter Interval (ESI) is the time from chemical application to when an animal may be slaughtered for export. The ESI may not be on the label, but is required by any abattoir that may export meat. The ESI can be found in the Products list in LiceBoss Tools or on the APVMA website.
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4. What does the European Eco-label for Textiles do?
The European Eco-label for Textiles enables consumers to recognise garments that are made from raw wool (i.e. unscoured or ‘greasy’ wool) that meets residue specifications currently deemed acceptable in terms of environmental impact. Read More
5. Which pesticides cannot be used to control lice if the wool is to meet EU Eco-label requirements?
- SPs must not be used, even off-shears.
- The IGRs triflumuron and diflubenzuron must not be used, even off-shears.
- Dicyclanil (standard concentration of 50 mg/ml; e.g. CLiK®) must not be used, except when applied only to the breech at least 6 months before shearing. In this case it may not exceed the residue limit of 2 mg/kg in the fleece. The low dose dicyclanil product (CLiKZiN®) applies only one-quarter of the usual dose of dicyclanil and can be used on the body and breech up to 5 months before shearing.
- Apart from use as flystrike dressings, organophosphates must not be used within 7 months before shearing, but short wool treatments (applied within 6 weeks of shearing) will not usually exceed the required limits.
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6. What are the key ways to produce low residue wool?
- Reduce the need for flystrike chemicals by implementing an integrated control program for flystrike with increased reliance on non-chemical methods
- Implement a lice biosecurity program to prevent the introduction of lice on strays or purchased sheep and treat only when lice are found.
- If jetting for protection from flystrike close to shearing or when only a short period of protection is needed, use a chemical with a short residual period,
- Jet only the most susceptible mobs and only the most susceptible areas,
- If sheep are purchased without a declaration regarding any previous treatment then their wool should be kept separate at shearing.
- Wool from sheep that are struck and treated individually should be kept separate at shearing.
- If lice are found in long wool, consult the Long Wool Tool to determine if a long wool treatment is necessary and which chemicals to use.
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