printStock Article - August 2024
Sheep lice cost producers both in treatment costs and lost production. Strong biosecurity practices can help you avoid introducing lice to your flock. Keeping newly purchased sheep separate until you have a chance to shear and treat them will minimise your risk. A helpful resource for developing your properties biosecurity plan can be found at www.onebiosecurity.pir.sa.gov.au.
Treating your sheep for lice is most effective after they have been shorn. Backline treatments are used more commonly because they are relatively quick and easy to use. It is important to remember that most backline treatments must be applied within 24hrs of shearing for them to be effective. These products often have a label recommendation for long wool treatments, but they do not guarantee eradication of lice if applied as a long wool treatment. A new lice treatment in the form of a drench is on the market which may help producers with wool shedding breeds treat for lice as the product can be administered on sheep with any length of wool. Previously sheep have always had to be treated off shears in order to eradicate lice, with traditional application methods being difficult to ensure 100% coverage in wool shedding breeds. www.liceboss.com.au has a good product and application selector tool, which can help you decide on the best chemical control measure for your circumstance.
The percentage of lice detections in wool shedding sheep breeds in S.A. is slowly increasing. In the last financial year 53% of all SA saleyard lice detections were in wool shedding breeds, despite those breeds not making up that proportion of sheep sold through saleyards. Producers should be aware that while wool shedding breeds are popular due to being low maintenance, they can become infested with lice and although there is no devaluation of fleece due to infestation, there are production losses associated with reduced grazing time and irritation.
In South Australia a spike in lice detections through the saleyard is usually observed in the winter months. Sheep are generally carrying nearly a full fleece, increasing chances for potential exposure to lice and the ability for populations to build up. It is an offence to have lice infested sheep at a public market, this includes putting your sheep into a saleyard (even if they are in transit) or field day or show. It is also an offence to allow your sheep to stray off your property onto roads or neighbouring properties. If you would like a second opinion on identifying lice or want to report stray lousy sheep please contact your local Animal Health Officer whose details can be found on the PIRSA website https://pir.sa.gov.au/biosecurity/animal_health/contact_us.