04/05/2026
Autumn shearing - a time to get on top of lice
Winter is a time when lice numbers can get to their highest, mainly because, unlike us, they do not like the sun! But shearing the ewes in the autumn is a good opportunity to reduce those numbers, along with all the other gains we get with shearing at this time of the year.
However, shearing will not get rid of all the lice, as they are very good at hiding in warm, moist areas, such as the groin. BUT this is a good opportunity to treat the sheep to knock down those lice numbers even further and kill those hiding.
Off-shear lice pour-ons are a perfect product to use at this point – but you need to follow the label instructions to get the optimum results, which includes timing of application and where you apply the product:
• ExPO Extinosad Pour-On is spread over the body by passive diffusion and physical contact (e.g. rubbing with other sheep). To facilitate product movement, treated sheep should be penned closely and held in the yards immediately after application. It can be applied to sheep with up to 3 months of wool growth, but for optimum results, off-shears is recommended.
• Zapp Encore - For fine wool breeds, it should only be applied off-shears (machine shorn). For coarse wool, Zapp Encore can either be used as an off-shears application or at a higher volume application for up to 6 months of wool growth.
• Magnum - For control of lice on strong-wool type breeds, it can be used up to three months off-shears and Merino type breeds off-shears only (machine shorn). For optimum results, treatment is recommended off-shears (within 24 hours after shearing).
• Vanquish - Optimum results can only be achieved off-shears (within 24 hours of shearing). When used in longer wool, efficacy may be reduced in sheep, especially in fine-wool breeds.
• Flexolt – oral lice treatment, can be used anytime, any wool length, any weather – so good to use on animals not being shorn but need to be treated (i.e. you should be treating ALL animals at the same time for the most effective lice control).
So, although these products can be used some time after shearing (depending on breed and wool length), you get the most effective results i.e. kill the most lice, doing it off-shears (i.e. within 24 hours).
However, lice control isn’t JUST about the product/chemical you are using; there are other things to consider:
• Ensuring a complete muster so that no animals remain untreated – so are all being treated if not being shorn?
• Attention to stock security following treatment (neighbours’ animals?).
• Quarantine treatment of new stock arrivals.
• Thorough and accurate dipping/treatment management - correct application!
• DO NOT mix treated sheep with untreated sheep.
• It is good agricultural practice not to treat animals when they are wet or if rain is likely. However, moderate rainfall following treatment does not adversely affect the effectiveness of the product. Prolonged heavy rain following treatment may reduce efficacy.
If you want to review your lice management control plan before shearing, give one of our sales reps or vets a call to go over your options.
