Sheep and cattle farmers urged to start testing for liver fluke this autumn
Sheep and cattle farmers have been urged to monitor for liver fluke this autumn amid concern 2019 could be a year of higher risk for the parasite.
The provisional National Animal Disease Information Service (NADIS) fluke forecast for autumn 2019 indicates high risk in Scotland, North West England and North Wales, and moderate risk in Northern Ireland.
Speaking on behalf of SCOPS (Sustainable Control of Parasites in Sheep), Lesley Stubbings said: “Last autumn and winter the levels of fluke were relatively low, but many areas have been wetter this year and early indications are that there will be more liver fluke around this season.
Reports to date show there is already some disease in high-risk areas and, with experts warning the challenge will be patchy, the need to use testing is greater than ever.
The provisional NADIS fluke forecast for autumn 2019 indicates high risk in Scotland, North West England and North Wales, and moderate risk in Northern Ireland.
John Graham Brown of NADIS said: “While the predicted risk may be low in some areas, local conditions are very important. Farms in these regions that have consistently wet, boggy grazing, must assess their risk carefully in the coming months.
“Autumn fluke risk is also dependent on eggs being present on the pasture, so areas that were grazed by infected cattle or sheep earlier in the season should be considered a risk.”
Speaking on behalf of Control of Cattle Parasites Sustainably (COWS), Diana Williams of Liverpool University said: “Farmers now have some very useful testing tools available to them, including a blood test.
“At this early stage in the season, blood testing this year’s lambs gives us the earliest indication of a challenge, because it only takes about four weeks after infection for antibodies to be present.
If they test positive, we know liver fluke are present and treatment is indicated, because they can only have been infected this summer or autumn.
“Taking action will avoid losses due to fluke in high-risk situations, but remember that testing can also avoid unnecessary treatments If animals are not infected with liver fluke.
“This saves money and time and helps us protect the few medicines we have available to combat this parasite.”
What are vets advising?
Philip Skuce, who works for Moredun in Argyll warned farmers to be careful about relying solely on faecal tests.
“From the initial work we’ve done in the West of Scotland this year, we’ve seen animals that are positive on the blood test,” he said.
“However, they have been negative for faecal indicators (coproantigen and faecal egg count) because the flukes are still immature. This highlights the need to be careful if you are relying solely on faecal tests.
“It might just be a case ‘not yet’, so be prepared to re-test to avoid getting caught out.
“It’s very important to understand what each test tells us about the liver fluke challenge in any given year and to make appropriate decisions in terms of whether to treat or not, when to treat and what product to use.”
Rebecca Mearns of Edinburgh-based Biobest Laboratories said: “We have only had a few positive coproantigen ELISA tests so far this season, but this may be because it is quite early in the season and the flukes in the animals are still too immature,” she said.
“It is really important to consider re-testing in four to six weeks if this is the case. In contrast, the blood test has shown some high positives in parts of Wales from as early as the end of July.
In dairy cattle we’ve also seen some high antibody levels in bulk milk samples in some herds and, with housing for cattle now starting, it is important to seek advice on appropriate treatment.
“Where results have been negative, it is important these flocks consider repeating the screening and monitor abattoir feedback to determine the need to treat.”
“It’s much earlier than I would expect,” he said. “This could suggest the challenge will be earlier and heavier than last year, so vigilance is required. In addition to serology, post mortem examinations of any sudden deaths are the most sensitive indicators of acute liver fluke at this stage in the season.”