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Treatment Decision Guide

LiceBoss Treatment Decision Guide

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Disclaimer:
Future events cannot reliably be predicted accurately. ParaBoss, UNE and Sheep CRC makes no statement, representations or warranties about the accuracy or completeness of, and you should not rely on any information relating to the LiceBoss Treatment Decision Guide ('Information'). ParaBoss, UNE and Sheep CRC disclaims all responsibility for the Information and all liability (including without limitation liability and negligence) for all expenses, costs, losses and damages you may incur as a result of the Information being inaccurate or incomplete in any way for any reason.
Is this a mob or stray(s) about to be or just brought onto the property, or stray(s) found in the flock?
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Do the sheep have lice?
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Are the introduced sheep, or the mob/s in which a stray/s were found, very few in number compared to your whole flock (e.g. some purchased rams or returned strays)?
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Can you effectively isolate (quarantine) the sheep until after next shearing?
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How much wool growth is on the sheep?
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Would the negative impact on your main flock be high if lice were introduced (e.g. costly for treatment, hurt your reputation)?
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Isolate the sheep as best as possible. Check for lice now and each 2 months until and at shearing: were any lice found?
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When did the introduced sheep come onto the property?
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LiceBoss Treatment Decision Guide

Recommendations

Date: %11 %Dec %2024

Your Selections

History of selection will appear here

Your Recommended Action

Consider a long wool treatment between now and shearing; apply an off-shears/short wool treatment to the mob or entire flock at next shearing.

NOTE: This recommendation may include a premature shearing option. While this is more rigorous from a biosecurity view, it can be expensive. You should weigh up the biosecurity benefits against the cost for your situation, which will include wool value loss from a premature shearing, and a further premature shearing if the sheep are then brought into line with the shearing of other mobs on the property.

Click here to see all treatment/management options

  1. If you are sure only certain mobs are affected, keep these sheep isolated as best as your facilities allow.
  2. If the mobs are not within a few months of being shorn, use the Long Wool Tool to decide whether to apply a long wool treatment to the affected mobs to lessen the ongoing fleece damage. The tool allows you to compare the cost of treatment against the cost of the wool damage from lice.
    Note: Long wool treatments will NOT eradicate the lice, and these sheep can still spread lice to other mobs if not properly isolated. An off-shears/short wool treatment will still be required at next shearing.
  3. If you can be certain that there have been no strays between the known affected mobs and the rest of your flock (and they have not been in adjacent paddocks), consider shearing the affected mobs as soon as possible. Weigh up the loss from premature shearing against the cost and inconvenience associated with the possible spread of lice to the rest of the flock.
  4. If straying has or may have occurred between the known affected mobs and your other mobs OR they have been in adjacent paddocks, then the other mobs should be assumed to be lousy. If the affected mobs have few sheep relative to the rest of your flock, consider earlier shearing and treatment. However, if most of your mobs could be affected, the best option will be to shear and apply an off-shears/short wool treatment to all sheep on the property at the same time, in which case, early shearing is unlikely to be warranted, although an interim long-wool treatment to limit fleece damage may be warranted (consult the Long Wool Tool).
  5. Apply a suitable off-shears/short wool treatment after shearing. Read the label to determine when that product must be applied in relation to shearing and how long after application the treated sheep must be kept isolated from other non-treated sheep.

There are many factors associated with successful treatment. Following are links to pages and tools that provide useful information for treatments:

Review these considerations if the sheep to be treated are late pregnant ewes or have lambs at foot and use the Ewe Lamb Treatment tool.

Use the Long Wool Tool to decide whether a long wool treatment is warranted.

Choose an appropriate chemical group for your treatment

Choose an application method

Learn about resistance and choose a product from your chosen chemical group/s

Learn about residues and check the likely residue levels if you target low residue markets

Apply the chemical safely

Keep lice out

Be aware that lice, or their signs, may not be detected for more than 6 months after shearing or a new infestation.

You can use the Short wool tool to assess the risk that the flock may have lice at shearing or indicate possible sources of infestation, so as to decide whether treatment at shearing is necessary.

You can also use the Treatment Factors Tool to check the likelihood that you eradicated lice at the last treatment.

Keeping lice out requires a biosecurity plan that includes:

Develop your own biosecurity plan by reading the following to find out what an effective plan includes:

Understand the economic effects of lice to better assess the cost/benefit of management and treatment options.

Check for lice now

See the full instructions: Monitoring sheep for lice and view images when you read the Biology of lice.

Be aware that lice or their signs may not be detected for more than 6 months after shearing, a new infestation, or an ineffective treatment.

  1. Check 10–201 sheep—choose those with the most severe signs of rubbing2 (if lice are present the likelihood of finding them increases by checking more sheep).
  2. Each sheep should be caught and held on its side in direct sunlight; you should use glasses if you need them to read the telephone book.
  3. On each sheep part the wool 5–101 times on each side with each parting 10 cm long; include the neck, shoulders and flank and look closely for lice.
  4. If a louse is found you can stop looking.

Once you have checked the sheep for lice, restart the tool

1 a) If the mob has suspect sheep (e.g. rubbed wool), search the mob thoroughly and choose the 10 most rubbed and check 10 partings per side.

b) If the mob does not appear to have suspect sheep (i.e. no sheep have rubbed wool), but you are concerned lice may be present in just one or a few of your mobs, isolate these mobs from others on the property and check monthly for rubbed sheep. If rubbing becomes evident then choose the 10 most rubbed and check 10 partings per side. If isolation is not possible, choose 20 sheep at random and check 5 partings per side, however, the chances of finding lice, if they are present, will be very low at this stage.

2While rubbing can indicate lice it can also result from other causes. See the following information.

Shear as soon as possible and apply a suitable off-shears/short wool treatment; or administer fluralaner to all sheep

NOTE: While this is the most rigorous option from a biosecurity view, it can be expensive. You should weigh up the biosecurity benefits against the cost for your situation, which will include:

  • Treatment cost (labour and chemicals), which ultimately may not be required if ongoing checking shows the sheep have no lice.
  • Wool value loss from a premature shearing, and a further premature shearing if the sheep are then brought into line with other mobs on the property.

If rams are to be shorn after purchase and before joining, this should be done at least 7 weeks prior to joining to avoid handling stress that may cause temporary infertility. Lice treatments themselves do not affect fertility.

(Click here to see all treatment/management options)

  1. Isolate these sheep until after shearing and a treatment. Do not mix with other sheep for the period indicated on the label. In particular, keep rams and small numbers of sheep secure, as they are more likely to try to join a larger mob.
  2. Apply a suitable off-shears/short wool treatment after shearing. Read the label to determine when that product must be applied in relation to shearing and how long after application the treated sheep must be kept isolated from other non-treated sheep.

There are many factors associated with successful treatment. Following are links to pages and tools that provide useful information for treatments:

Review these considerations if the sheep to be treated are late pregnant ewes or have lambs at foot and use the Ewe Lamb Treatment tool.

Choose an appropriate chemical group for your treatment

Choose an application method

Learn about resistance and choose a product from your chosen chemical group/s

Learn about residues and check the likely residue levels if you target low residue markets

Apply the chemical safely

Quarantine, then assess for treatment next shearing

This option relies on effective isolation of the introduced mob. If your facilities and management cannot prevent straying from or into this mob, restart (use link at bottom of page) the LiceBoss Treatment Decision Guide, and when questioned about quarantine, choose "No".

  1. Isolate the mob from the rest of your flock1 until next shearing or fluralaner treatment (and for a period after, if treatment is required).
  2. Check the introduced mob for lice now, and if no lice or signs of lice are found, continue to check at 2-monthly intervals through to shearing or fluralaner treatment.
  3. If lice or signs of lice become evident a few months or more before the planned shearing, consider whether a long wool topical treatment or fluralaner, or an early shearing and topical treatment is warranted. If a long wool topical treatment is used, lice will not be eradicated; the mob must also receive an off shears/short wool treatment when next shorn and continue to be isolated until that takes effect (the time required will depend on the product and application method chosen).
  4. If lice or signs of lice become evident within a few months of planned shearing or at shearing OR the sheep were introduced less than 6 months2 before they will be shorn, then apply an off-shears/short wool treatment at shearing or administer oral fluralaner to the introduced mob. The mob should only be integrated into the main flock after a further period of quarantine while the treatment takes effect (the time required will depend on the product and application method chosen; refer to the product label for the time required).
  5. If no lice and no signs of lice are present at shearing AND the sheep were introduced at least 6 months before shearing, do not treat. The mob can be integrated into the flock.
  6. Fluralaner can be administered orally to sheep with any length of wool. However for best results it is

1Generally, if fences prevent straying, the risk of transfer of lice to a mob in an adjacent paddock is low. However, if the two mobs camp next to each other along the fence or share a water trough on a fence-line, risk of lice transfer is much higher as sheep can make close contact through the fence.

2Be aware that in some cases, lice or their signs may not be detected for even more than 6 months after shearing, a new infestation, or an ineffective treatment.

There are many factors associated with successful treatment. Following are links to pages and tools that provide useful information for treatments:

Review these considerations if the sheep to be treated are late pregnant ewes or have lambs at foot and use the Ewe Lamb Treatment tool.

Use the Long Wool Tool to decide whether a long wool treatment is warranted.

Choose an appropriate chemical group for your treatment

Choose an application method

Learn about resistance and choose a product from your chosen chemical group/s

Learn about residues and check the likely residue levels if you target low residue markets

Apply the chemical safely

Apply a suitable off-shears/short wool treatment to these sheep before they have 6 weeks wool growth or administer fluralaner to all sheep (without shearing)

(Click here to see other treatment/management options)

  1. Apply a suitable off-shears/short wool treatment after shearing. Read the label to determine when that product must be applied in relation to shearing and how long after application the treated sheep must be kept isolated from other non-treated sheep.

There are many factors associated with successful treatment. Following are links to pages and tools that provide useful information for treatments:

Review these considerations if the sheep to be treated are late pregnant ewes or have lambs at foot and use the Ewe Lamb Treatment tool.

Choose an appropriate chemical group for your treatment

Choose an application method

Learn about resistance and choose a product from your chosen chemical group/s

Learn about residues and check the likely residue levels if you target low residue markets

Apply the chemical safely

Consider a long wool treatment between now and shearing; shear as soon as possible, and then apply an off-shears/short wool treatment to the introduced sheep and any other mobs where straying or contact may have occurred (this may be the entire flock).

NOTE: This option may include premature shearing and treatment. While this is a more rigorous option from a biosecurity view, it can be expensive. You should weigh up the biosecurity benefits against the cost for your situation, which will include wool value loss from a premature shearing, and a further premature shearing if the sheep are then brought into line with other mobs on the property.

(Click here to see all treatment/management options)

  1. Keep these sheep isolated as best as your facilities allow. If straying between the introduced and existing mobs occurs, the level of fleece damage in your main flock will be less than if the lousy sheep are mixed with the main flock.
  2. Use the Long Wool Tool to decide whether to apply a long wool treatment to the introduced mob to lessen the ongoing fleece damage. The tool allows you to compare the cost of treatment against the cost of the wool damage from lice. Note: Long wool treatments will NOT eradicate the lice, and these sheep can still spread lice to other mobs if not properly isolated. An off-shears/short wool treatment will still be required at next shearing.
  3. If you can be certain that there have been no strays between the introduced mob and your existing flock (and they have not been in adjacent paddocks), shear the introduced mob as soon as possible. Before doing so, weigh up the loss from premature shearing against the cost and inconvenience associated with the possible spread of lice to the rest of the flock.
  4. If straying has or may have occurred between the introduced mob and existing mobs OR they have been in adjacent paddocks, then the existing mobs should be assumed to be lousy. If the affected existing mobs have few sheep relative to the rest of your flock, consider earlier shearing and treatment along with the introduced mob. However, if most of your mobs could be affected, the best option will be to shear and apply an off-shears/short wool treatment to all sheep on the property at the same time, in which case, early shearing is not required.
  5. Apply a suitable off-shears/short wool treatment after shearing. Read the label to determine when that product must be applied in relation to shearing and how long after application the treated sheep must be kept isolated from other non-treated sheep.

There are many factors associated with successful treatment. Following are links to pages and tools that provide useful information for treatments:

Review these considerations if the sheep to be treated are late pregnant ewes or have lambs at foot and use the Ewe Lamb Treatment tool.

Use the Long Wool Tool to decide whether a long wool treatment is warranted.

Choose an appropriate chemical group for your treatment

Choose an application method

Learn about resistance and choose a product from your chosen chemical group/s

Learn about residues and check the likely residue levels if you target low residue markets

Apply the chemical safely

Shear at your normal time and apply a suitable off-shears/short wool treatment to the introduced mob.

(Click here to see other treatment/management options)

  1. Keep the sheep isolated.
  2. Apply a suitable off-shears/short wool treatment after shearing. Read the label to determine when that product must be applied in relation to shearing and how long after application the treated sheep must be kept isolated from other non-treated sheep.

Be aware that lice or their signs may not be detected until more than 6 months after shearing, a new infestation, or an ineffective treatment. If new sheep have been introduced or existing sheep are suspected of becoming infested within 6 months1 before shearing, an off-shears/short wool treatment is recommended.

1Be aware that in some cases, lice or their signs may not be detected for even more than 6 months after shearing, a new infestation, or an ineffective treatment.

There are many factors associated with successful treatment. Following are links to pages and tools that provide useful information for treatments:

Review these considerations if the sheep to be treated are late pregnant ewes or have lambs at foot and use the Ewe Lamb Treatment tool.

Choose an appropriate chemical group for your treatment

Choose an application method

Learn about resistance and choose a product from your chosen chemical group/s

Learn about residues and check the likely residue levels if you target low residue markets

Apply the chemical safely

No treatment is required. Integrate the introduced mob with the flock.

Lice or their signs may not be detected until more than 6 months after shearing, a new infestation, or an ineffective treatment.

When:

  • Introduced sheep have been on the property for 6 months or more before shearing, and/or
  • Existing sheep are not suspected to have become infested with lice within the 6 months before shearing, and
  • No lice or signs of lice are present,

then the chance of the sheep having lice is extremely low.

This recommendation should be read with the information provided below.


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