Stay vigilant for liver fluke this winter

• Cases rise after wet autumn

• Keep on top of testing regime

• Take action where necessary

More cases of liver fluke are being reported following the wet autumn – with farmers reminded to keep a close eye on livestock.

The number of positive liver fluke cases is beginning to rise, in line with forecasts that livestock farmers in some areas could face a high challenge after a rainy and mild back end to 2024.

As cases increase, farmers should keep up with testing to avoid being caught out, say the industry groups for the Sustainable Control of Parasites in Sheep (SCOPS) and Control of Worms Sustainably (COWS).

More widespread

John Graham-Brown, of the National Animal Disease Information Service (NADIS) says unpredictable weather patterns mean it is likely that suitable snail habitats, and therefore liver fluke, will be more widespread.

This means a more prolonged window for infection than in previous dry summers, says Dr Graham-Brown. Farmers must stay on their guard and keep testing where appropriate, he explains.

Independent sheep consultant Lesley Stubbings says it is vital to establish whether fluke is present so treatment can be given at the right time. That also means using the right animal health product.

Correct timing

“We are particularly concerned about those farmers who have treated sheep already.”

Flukicides do not have any residual effect, which means a dose given too early offers no protection if sheep have been put back on infected pastures.

The coproantigen test can detect the presence of liver fluke a little earlier than faecal egg detection, says parasitologist Philip Skuce, of the Moredun Research Institute.

This is particularly useful when the risk is considered high, says Dr Skuce. But faecal egg count testing methods are likely to be most appropriate at this time of year after livestock have been housed for winter, he adds.

Biobest veterinary adviser Rebecca Mearns warns against the over-use of flukicides: “We are concerned about reports that sheep farmers are repeatedly treating sheep with closantel against Haemonchus contortus –the barber’s pole worm.

“Dosing at intervals of less than six weeks risks adverse effects in sheep, including blindness. If farmers then use the same drug to treat liver fluke, the risks of overdosing are higher.

This risk is made worse because some producers have assumed they have resistance to triclabendazole, ruling out the use of this potentially useful flukicide on their farm. Talk to your vet to confirm the position rather than jumping to conclusions..

Extra exposure

While less commonly affected by acute disease than sheep, the tendency to leave cattle out for longer if the weather is milder could mean longer exposure to fluke infection on pasture.

“Testing is essential to gauge the degree of exposure, with a number of testing options available at or over the winter housing period,” says livestock Lis King, of the Agriculture and Horticulture Development Board.

Clear communication key over feed additives

Better communication could encourage people to be more accepting of environmental innovation in agriculture, say scientists.

It comes after milk processor Arla announced it was trialling the feed additive Bovaer in a bid to reduce methane emissions in dairy cows. People responded by posting social media clips showing milk being poured down the sink.

The British Society of Animal Science said there was an urgent need to address the climate crisis. Feed additives such as Bovaer were a promising step forward in reducing methane emissions from ruminant livestock, it added.

Risk assessments

“The product has undergone rigorous risk assessments in multiple jurisdictions, evaluating its safety for animals, humans handling the product, consumers and the environment,” said BSAS.

For scientific innovations to succeed, societal trust was essential, it added. “Clear communication about safety and efficacy, supported by peer reviewed science, can bridge the gap between scientific innovation and societal acceptance.”

Feed additives offered significant potential to enhance sustainability in livestock production, said BSAS. “Building consumer trust through transparency and engagement will be key to realising the benefits of such innovations.”

Arla said the furore – reported on national media – had no effect on milk sales. The Bovaer trial is being conducted among 30 dairy farmers.