Sheep producers urged to use new oral lice treatment carefully

Sheep Central July 10, 2023

Dr Graham Lean

SHEEP producers have been cautioned about relying solely on a new oral lice treatment being released on the market this month.

MSD Animal Health said from today, Australian sheep producers will be able to treat their flock for lice when it best suits them, with the world first oral lice treatment for sheep, Flexolt.

Flexolt is a part of the Coopers range of products from MSD Animal Health and will be arriving soon at rural retailers across Australia.

It’s cost is expected to be comparable to other exterior lice treatments available, depending on reseller margins, quantity and animal liveweght, at about $2 per treatment for a 60kg liveweight animal.

A single 20 litre drum of Flexolt can be used to treat more than 2200 sheep at 60 kg. The product is administered via a single oral dose and is easy to dispense with a backpack and oral applicator. With more doses in a single drum compared to other lice products, Flexolt makes transport, storage and disposal easier for producers, MSD Animal Health said.

Coopers Animal Health technical adviser Dr Jim Walsh said at the recent BestWool BestLamb Conference in Bendigo that Flexolt would be in resellers’ stores this month.

Flexolt contains a novel active ingredient that works systemically from the inside out. It can be used on any length of wool, allowing farmers to treat off-shears, short and long wool sheep and lambs. The product also allows producers to treat their flock for lice at any time, including pre-lambing, when lambs are at foot, or when new stock is brought onto the farm.

The company has said there is no known resistance to Flexolt’s active ingredient Fluralaner. However, Hamilton-based veterinary consultant, Agrivet Business Consulting principal Dr Graham Lean said although Flexolt will be a gamechanger in lice control, he urged producers not to rely on the product solely, to avoid developing resistance in lice populations.

“With any parasite resistance management what we want to do is keep changing chemical groups and don’t expose the parasite continual to one chemical.

“Resistance will inevitably develop if you use one chemical solely, because the genes for resistance are already out there in the lice population and we will select for them if we continually use that chemical solely for control or to eradicate lice,” he said.

“I think it is a gamechanging product that can really help us to eradicate lice, but it can also create a mess – the potential is there to stuff it up.

“Because it is very effective and will eradicate lice in any length of wool, six weeks of age and older, so any situation where lice are found you can get them and eradicate those lice, so you don’t need to wait for shearing or for a plunge dip,” Dr Lean said.

“The key thing here is that every sheep needs to be mustered and every sheep needs to be treated properly.

“So they must be drenched through a sheep handler and marked – and they’ve got a nice neat marking system for that,” Dr Lean said.

This would ensure no sheep are missed or any sheep spitting out the product is seen. Producers should do at least two musters and check again, perhaps with a drone, to ensure all sheep are accounted for, he said.

Dr Lean said lice treatment with Flexolt did not rely on shearing nor did it need to be done routinely as is the case with other products. Sheep purchased or coming in can be treated and quarantined.

MSD Animal Health technical lead and veterinarian, Dr Jane Morrison, said the breakthrough innovation will transform on-farm practices for Australian sheep and wool producers.

“Lice is a significant issue for the Australian sheep and wool industries which is estimated to cost the Australian sheep industry around $123 million per year through disease control and production losses,” said Dr Morrison.

“Flexolt gives producers greater flexibility, choice and control, allowing them to choose when it best suits them to treat their flock for lice.

“It also means farmers can consider management options like split shearing without compromise, which can boost their on-farm productivity.”

New South Wales sheep producer Ed Storey believes Flexolt is a game changer for wool producers, who can now finally consider a community approach to lice treatment.

“I run between 8000 and 9000 head of sheep on my property in Yass, and a lice outbreak can be devastating, not only for your own farm, but it presents a biosecurity risk for your neighbours,” he said.

“It means you can co-ordinate with your neighbours to treat for lice at any time, in any sheep, with any length of wool.

“Sheep farmers have never been able to do this before,” he said.


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