Nothing makes most people’s skin crawl quite as much as lice.

Sheep suffer most from lice during winter. Photo Crispin Caldicott.

It is important to remember though lice are host specific – sheep lice are sheep lice, human lice are human lice. In New Zealand, there are three species of sheep lice – two are sucking lice which generally don’t prove to be a problem, but should not be ignored all the same.

The third is a biting louse which can reduce fleece quality and quantity as well as causing cockle – a defect in sheep pelts.

Lice spend their entire life cycle of around 22 days on the sheep. The adult feeds by biting at the skin surface which irritates the host, which then bites and pulls at their fleece or rubs against anything they can find. 

Like human head lice, the adult lice spread from sheep to sheep by close contact.

Female lice may lay 10 to 30 eggs in their lifetime. Lice populations build up in autumn to a peak in winter, then decline spring and summer.

Shearing removes large amounts of lice from infested sheep. When dipping for lice, try to treat all sheep at the same time.

New sheep should be treated as soon as they arrive on the property. Methods used to control lice have developed considerably over the years.

For large flocks, shower dips are an effective way of treating for lice. For smaller flocks, a pour-on method should do the trick nicely.