Practical Steps to Strengthen Lice Biosecurity with Flexolt

Every sheep you bring onto your property is a potential lice risk. Good biosecurity helps you to stop new infestations before they start.

Sheep lice cost Australian producers an estimated $107.6 million annually across the wool industry, with individual fleece penalties of $5- $22.45 per head^ in reduced value, from 0.2–0.9 kg lost clean fleece weight and yield reductions of 2.6–6%. It is estimated that between 20% to 40% of Australian sheep flocks are infested with lice and one of the most common ways lice enter a clean flock is through introducing sheep such as purchased rams, ewes, lambs.

MSD Animal Health Research found that 73% of Australian sheep producers buy in sheep, with rams being the most common class purchased (81% of buyers). Despite this high rate of introduction, only 31% of producers actually treat incoming sheep for lice. That means roughly 7 in 10 farms are bringing sheep onto their property without a lice treatment leaving the door wide open for infestation.

Making matters worse, industry feedback indicates that 70% of properties fail to eradicate lice in a single treatment attempt. The most common reasons? Not treating 100% of sheep correctly, split shearing, lambs at foot during treatment, and critically biosecurity failures, meaning new lice infestations can impact a flock for several years.

Five Practical Steps to Tighten Your Biosecurity

1. Assume every introduced sheep is lousy. New infestations can take 3–6 months before signs become evident so, regardless of vendor assurances or visual appearance, treat every purchased or agisted animal as suspect.

2. Quarantine and treat on arrival. The research shows that among producers who do quarantine, 8 out of 10 do not isolate sheep long enough (>30days). Quarantining for lice requires holding introduced sheep separately and treating them for lice and then quarantining them again after treatment (the quarantine length post treatment will depend on the product used) before they join your main flock. Treatment options include shearing and applying an off shears/short-wool product or using an oral treatment like Flexolt that does not require shearing and works regardless of wool length.

3. Inspect thoroughly — and repeatedly. Check at least 10 sheep with a minimum of 10 wool partings per side, focusing on animals showing wool derangement or rubbing. Remember that early infestations have low detection sensitivity, so quarantine and reinspect every 3–4 weeks for 4 to 6 months if nothing is found initially.

4. Maintain stock-proof fencing. Research shows 85% of producers have neighbours with sheep, yet only 37% of producers have a biosecurity and action plan in place for when stay sheep are found in their flock. A single lousy stray can reinfest an entire mob.

5. Never mix treated and untreated sheep. It is best practice never to mix treated and untreated sheep; however we know that boxing introduced sheep is sometimes necessary. If boxing is required, keep introduced stock separate until your lice treatment at introduction has had time to work. Mark treated animals clearly — with a need to quarantine after treatment for at least 4 weeks with Flexolt and 6 weeks for most off-shears products it can become hard to identify treated and untreated sheep it mixing occurs.

The Bottom Line

With lice capable of reducing fleece value by up to $22.45^, and a Flexolt treatment costing around $2–$3 per head without the need for shearing, prevention through strong biosecurity and good treatment and quarantine practices is overwhelmingly the better investment. The sheep you bring through your gate today could determine whether your clip holds its value next shearing.

Don’t let someone else’s lice problem become yours.

^18micron fleece with 0.9kg loss @2500c/kg clean.

For more information, visit flexolt.com.au or contact MSD Animal Health on 1800 226 511.