Livestock farmers urged to test for autumn liver fluke

Despite a generally lower risk this autumn of liver fluke – one of the most economically significant diseases of cattle and sheep - the loss of one of the major treatments for the parasites means that more than ever, livestock farmers need to test before routinely treating their animals.

Dr Philip Skuce of the Moredun Research Institute

Experts at the Sustainable Control of Parasites in Sheep (SCOPS) and Control of Worms Sustainably (COWS) groups said that while the dry, cool spring followed by a low-rainfall summer with some hot spells was likely to see a reduced threat from liver fluke, producers still needed to make sure they didn’t either treat unnecessarily –and possibly increasing resistance to the remaining treatments - or get caught out.

Speaking on behalf of both groups, Dr Philip Skuce of the Moredun Research Institute said producers needed to test on their own farms to see if fluke was an issue – and where treatment was required, to consider the options carefully given the withdrawal of Trodax from the market.“We are already beginning to see the first signs of liver fluke infection acquired this year,” he said adding that tests on lamb and calf sentinel animals from the West of Scotland had already seen a significant proportion of both serum antibody and coproantigen tests come back positive – suggesting that some animals had encountered a fluke challenge as early as mid-July:

“This may seem odd in such a dry year, but many farms rely on field springs and streams to provide water for grazing stock, which can lead to permanent wet patches where the mud snails can persist.”

He said that such a conclusion was supported by the lack of fluke in a group which got its water from a water trough which deprived the snails which acted as intermediate hosts were deprived of the necessary damp habitat.Matt Colston, a vet with Elanco Animal Health, added:

“In a year like this, it is imperative we use the tests available to monitor the fluke situation on individual farms. We can’t just make assumptions based on general forecasts or previous history. Each farm needs to know if treatment is required, when to do it and what product to use.”And while the NADIS Liver Fluke Forecast, based on the latest Met Office rainfall and temperature data, also suggested a generally low risk this autumn, he said farmers should test rather than guess.

The withdrawal of Trodax from the market reduced treatments to only four actives authorised in the UK and available for sheep – and two of those only killed adult fluke and although five actives remained for cattle, three were adulticides.Rebecca Mearns, Sheep Veterinary Society President, said that to minimise the extra pressure on the only two actives that can kill immature fluke (triclabendazole and closantel), farmers needed to be more careful than ever when deciding if and when to treat and talk to their vets about the good diagnostic tests currently available.