Checking sheep for lice

Early detection and treatment of lice can reduce the infestation and limit damage to the wool.

Check all mobs of sheep twice a year. The best times to check are:

• at crutching
• before shearing
• any time sheep are seen with rubbed or pulled wool.

Always check sheep:

• prior to purchase
• when mobs are moved from other properties
• before mobs are combined
• that have strayed, on or off your property or into other mobs.

How to check for lice

Lice are most commonly found near the skin. However, lice can move up into the staple when the fleece is shaded.

Select sheep that are rubbing, biting or have pulled wool as this is a sign of lice. Follow these steps to effectively check for lice:

• inspect sheep in a well-lit area (lice move away from sunlight)
• part a 10 cm length of wool and look closely for lice
• check 10 parts of wool down the side of each sheep
• check areas where the sheep has pulled wool
• check as many sheep as possible.

The presence of a single louse means the mob is infested and treatment must be considered. Finding a louse in each 10 cm parting of wool indicates 3,000 to 4,000 lice per sheep. A heavily infested sheep can have more than 10,000 lice.

When to treat for lice

The ideal time to treat sheep for lice is after shearing. For information on lice treatment chemicals go to the Liceboss website or consult your local rural retailer.

Other options include treating long wool, shearing early, or keeping the infested mob isolated until next shearing. Long wool treatments will not eradicate lice. The decision to treat before shearing depends on the level of infestation and the value of wool loss.

More information

For more information go to the Liceboss website or talk to your local PIRSA Animal Health adviser.