Treat lice and fly separately

IT MAY BE HARD TO HEAR, BUT farmers have to learn to live with some lice, as they won’t get the last one.

That’s the advice of Jason Gray, who has worked in veterinary practice and represented animal health companies in the Upper South Island since 2000. Being based in the heart of fine and medium wool country in Marlborough, he’s well placed to offer advice on lice.

“This is not a cop-out, just a result of changing systems and return on investment, and never being able to get every last louse on the farm or at the neighbours.

“But keep knocking them down, so you don’t see rubbing or wool damage.”

His advice is four-fold. Make a separate plan for lice and fly, work with neighbours to synchronise dipping sheep on neighbouring farms, understand the chemical families and correct application, and feed stock well.

The gold standard lice plan should have two lice treatments a year, to eradicate post shearing then follow with a knockdown in autumn.

“Starting from off-shears, either jet or pour-on off-shears, or immerse in a plunge later in the year.”

If using pour-on, the best time is within 24 hours off shears, he said. This will ensure the pour-on will translocate through the fresh lanolin expressed by the sheep. As the grease gets colder, it slows down the spread.

“Then do another lice treatment in autumn, perhaps this one in sync with an autumn fly treatment.”

Gray encourages farmers to work in with neighbours so sheep can be treated for lice at similar times, to avoid cross-contamination. Feeding sheep is a great preventative as low condition score is linked to lower immunity.

“Lower condition score and lice go together like bangers and mash.”

He is a fan of the Spinosad (Extinosad) chemical range for an emergency quick knock-down pre-shearing, as it has no residual.

“It’s a good product to use when you get caught out.”

“My rule of thumb is the longer and finer the wool, the harder to kill the lice.”