Why are Lice Such a PEST?

Biting and sucking lice significantly irritate cattle, sheep and goats, triggering them to bite, scratch and rub. Infested stock will rub against fences, buildings, yards, trees and other fixtures, reducing fleece value and hide quality.

The coats of lousy cattle look rough and scruffy, and areas of skin may be rubbed raw. This is not consistent with on-farm quality assurance programs, such as “Cattlecare”, and can impact sale value through appearance and decreased hide value.

So how do lice impact sheep, goats and cattle?

Lice are species-specific and will not live and breed on other species; sheep lice will not set up a population on goats. They are spread entirely by direct contact between animals.

Cattle lice populations reach a peak during winter when the dense winter coat and cool weather provide the ideal breeding environment. The declining plane of nutrition often experienced on winter pasture can lead to a decrease in body condition, and this can also be associated with a rapid build-up of lice numbers. Similarly, drought conditions also lead to a decreased body condition and can cause an increase in the effects of a lice burden.

All breeds of sheep, including shedding breeds, can carry sheep lice. An infestation causes a significant impact in wool producing breeds, reducing both fleece weight and value. Sheep lice control can be complex and requires both management strategies and chemical use.

Our tips

When selecting a lice-control product from the numerous types of insecticide (Organophosphates, Synthetic Pyrethroids, IGRs, Macrocyclic Lactones, etc.) on the market, it is important to consider the product’s suitability for your situation, withholding periods and also the impact the chemical may have on other parasites, such as worms.

When treating for lice, it is important to treat all animals of that species on a property at the same time, adhering to the manufacturer’s instructions for application. To prevent re-infestation, ensure stock proof fencing, quarantine/treat all introduced stock and don’t mix treated and untreated animals.

For more information and treatment tools, watch our recent webinar on effective management of lice in sheep, cattle and goats.