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Online learning: Checking for lice

Checking sheep regularly and thoroughly for lice is an essential tool for maintaining a lice-free flock.

Structured reading

For those who like to see all the information and simply read through it in order. Each heading is a link to a page of information—the dot point provides a summary of the page.
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Monitoring sheep for lice
A description of how to properly go about checking a mob and individual sheep for lice.

Causes of rubbing in sheep
Description of conditions aside from lice that will cause sheep to rub their fleeces.

Itch mite in sheep
Description of itch mite, its diagnosis and control.

Rubbing Tool
An interactive tool that allows users to determine the cause (or causes) of rubbing in their sheep. 

Question and answer

For those who prefer a problem based approach to learning, answer the following questions.
Each of the questions below links further down the page to the answers.

Questions:

  1. How often should existing sheep on a property be checked for lice?
  2. When buying rams, what is recommended to avoid introduction of lice?
  3. What should you do when straying sheep have been returned by the neighbour?
  4. Which sheep in the mob are the best candidates to check for lice?
  5. Aside from lice, what else causes sheep to rub?
  6. How do you go about checking each sheep for lice?

Answers:

You can also click on each question below to go to WormBoss pages with related information.
 

1. How often should existing sheep on a property be checked for lice?

All mobs should be checked for lice at least twice each year. Useful opportunities for monitoring are when sheep are yarded for drenching, crutching, marking and shearing or other management procedures. Any sheep seen with rubbed fleece or pulled wool should be checked as a matter of urgency. It is also a good idea to ask your shearers and shed hands to look out for lice at shearing. Make sure to check every mob on your property, including the killers and rams.
 

2. When buying rams, what is recommended to avoid introduction of lice?

All newly purchased sheep, agisted sheep or sheep returning from other properties should be inspected before release onto the property. New rams can pose a significant risk, but are generally introduced only in small numbers; therefore, an automatic policy of shearing and off–shears treating rams for lice on arrival (use a product that will kill lice before the rams are joined) is recommended.

 

3. What should you do when straying sheep have been returned by the neighbour?

Any stray sheep found in the mob or returned from neighbours should be closely examined. Follow the management options in Question 1. Some owners prefer not to risk the chance of lice and to dispose of stray sheep rather than return them to the mob.

Lice are difficult to find soon after shearing. Even if sheep have not been treated, it is unlikely that lice will be easily found less than three months off-shears. If sheep have been treated, but lice not eradicated, it may be more than six months before lice can easily be found.
 

4. Which sheep in the mob are the best candidates to check for lice?

Look for sheep showing signs of rubbing or biting at their fleece.

Rubbing is a very powerful indicator of infestation and sheep will begin to rub with quite low lice numbers. If sheep are not rubbing, even if lice are present, they will be in such low numbers that it will be almost impossible to find them by random inspections. Therefore, time is most efficiently used by carefully going through the mob trying to identify any sheep with rubbed or pulled wool.
 

5. Aside from lice, what else causes sheep to rub?

Other causes of rubbing include grass seeds, fleece rot, lumpy wool, flystrike and itch mite. Sheep with tender wool or frequently walking through bush or long grass and some breeds that shed their fleece may also appear to be rubbing. Read the LiceBoss Note: Causes of rubbing in sheep or use the Rubbing Tool in Liceboss to help to diagnose other causes of rubbed fleece.
 

6. How do you go about checking each sheep for lice?

  • Lay the sheep on its side in a well-lit position, part the wool and look for lice.
  • If you need glasses to read the telephone book, make sure you use your glasses when looking for lice. A magnifying glass can help.
  • Check at least 20 wool partings on any rubbed sheep; partings should be at least 10 cm long. The more sheep you inspect, the more chance you have of finding lice if they are present.
  • Once you have found one live louse you can stop; there will be many more lice that you can’t find. All sheep should be treated after the next shearing. 

 


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