Lice

Biting lice and sucking lice are the two main types of lice that affect livestock. Cattle and goats can be infested with either biting or sucking lice but sheep are mainly infested with biting lice. Lice are usually host-specific, which means that different species of lice are found on cattle, sheep and goats.

The MLA-funded LiceBoss website is based on best practice parasite management strategies. LiceBoss provides the information and tools to help implement each of the three control elements as required. The tools are interactive and simple to use, allowing you to input your own information and select options relevant to your situation.

Biting lice

Biting lice feed mainly on skin scurf, superficial skin cells and bacteria.

The most common biting louse in Australia are:

• the body louse (Bovicola ovis) in sheep, which mainly infests wool sheep
• the red louse (Bovicola bovis) in cattle
• the common goat louse (Bovicola caprae) in goats and Angora goat louse (Bovicola limbatus) which is restricted mainly to Angora and crossbred fibre goats.

Sucking lice

Sucking lice feed by penetrating the skin with their mouth parts and sucking blood from capillaries and blood serum that exudes from the damaged skin surface.

The most common sucking louse in Australia are:

• the face louse (Linognathus ovillus) occurring mainly on the face and the foot louse (Liongnathus pedalis) mainly found on the legs in sheep
• the longnosed cattle louse (Linognathus vituli) in cattle
• the common goat sucking louse (Linognathus stenopsis) in goats.

Conditions where lice infestations are likely to occur

• Sucking lice:
  • more likely in winter
  • animals in poor condition such as lambs with low growth rates and stock under stress from poor nutrition or disease
• Biting lice:
  • introduction of infested sheep into the flock
  • well-fed sheep, at any time of the year
  • takes time for the population to build up to the point where clinical signs become apparent.

Identification and diagnosis

Clinical signs that would lead a producer to suspect lice include the following:

• irritation that leads to biting, scratching or rubbing
• stock are irritated and restless
• sheep or goats with rubbed or pulled wool/hair should be checked
• cattle coats will start to look scruffy and their skin may be rubbed raw.
• All sheep should be checked for lice twice a year. This can be done at convenient times such as shearing, crutching, drenching etc.

Prevention

An integrated approach to lice control should consider the following:

• Preventing lice-infested livestock from joining the flock or herd is the biggest single strategy
• Ensure fences are intact and able to prevent entry by stray livestock
• Keep introduced sheep in a quarantine pen or paddock until they have been thoroughly inspected for signs of lice such as disturbed fleeces (rubbing, biting, scratching), or lice in wool partings over the shoulders and rib cage
• Light infestations in cattle, meat sheep and goats with short hair fibre are unlikely to affect growth rates and chemical treatment may not be warranted.

Chemicals (dips, back-liners, ear-tags etc.) should be used judiciously (only when necessary) as part of an overall parasite control program. Follow all label directions or restrictions, including directions for dose rates, safety precautions, personal protective equipment, withholding periods (WHPs), export slaughter intervals (ESI), re-handling intervals and disposal of empty containers and unused product. Record the appropriate information and include on the LPA NVD/Waybill if the livestock are sold.