Preventing new lice infestations
Nearly all new infestations begin from contact with infested sheep. Major sources of lice are:
However, infestations can also result from sheep missed at muster and therefore left untreated in the previous year or from sheep not effectively treated after their previous shearing. Split shearings and treating ewes with lambs at foot or pregnant ewes due to lamb within 6 weeks of treatment are other causes of continuing infestations.
Sheep lice do not breed on animals other than sheep (with the possible exception of goats, in very rare instances). Birds do not carry sheep lice and they do not remain in wool rubbed onto fences, trees or other structures, so these are not sources of infestation.
A well-designed lice biosecurity plan that prevents contact with infested sheep is critical to keeping a property lice-free.
The LiceBoss Note: Sheep lice—biosecurity can prevent introduction, provides guidelines for developing an effective lice biosecurity program.
Figure 1. Broken fences allow sheep to stray and pick up new lice infestations from neighbouring sheep. Source: Sheep CRC