With the National Animal Disease Information Service (NADIS) forecasting high risk of liver fluke in Scotland, northern England and North Wales, and cases now being seen south of these regions, parasite experts with the Control of Worms Sustainably (COWS) group, are urging farmers in these areas to consider treating cattle two weeks after housing.
“Treating infected cattle shortly after housing with a product containing triclabendazole, will kill immature and mature fluke provided no resistance is present. This will also ensure animals do not re-infect the pastures with liver fluke eggs next spring,” says Professor Diana Williams of the University of Liverpool. “
However, before reaching for the flukicide, it would be good to check whether treatments are justified. For example, is there a history of fluke on the farm, have animals been grazing muddy areas where intermediate host mud snails live, or have cattle been purchased from fluky areas? If the answer to these is ‘no’, treatment is unlikely to be necessary, saving time and money and helping to protect the few medicines available to combat this parasite.”
Testing individual animals using new blood and dung tests can confirm if cattle have picked up liver fluke during the grazing season.
There are three active ingredients that will kill immature liver fluke – triclabendazole, closantel and nitroxynil, which can all be applied in the autumn and winter. When using triclabendazole, it is a good idea to test to see if a treatment has worked by using a Faecal Egg Count Reduction Test (FECRT) afterwards, as there is evidence of parasite resistance to this drug.
Only two products are licensed for use in milking cows; albendazole and oxyclozanide – with withdrawal periods of 60-72 hours and 108 hours respectively.
“The COWS group strongly advises farmers to discuss product choice with their vet or SQP as part of their Herd Health Plan,” says Professor Williams. “But essentially, strategic treatment of ‘at risk’ animals in winter will help protect pastures in the spring. (See Figure 1 – The Four Point Plan attached).
“Unfortunately, there is no blueprint for liver fluke control – it very much depends on the farm, the animals and the weather in any one year. When treating cattle, producers should follow the COWS group’s 5 ‘Rs’ – the right product, given to the right animal, at the right time, at the right dose rate and in the right way.”
COWS Technical Manual
The COWS group is updating the chapters of its Technical Manual, which aims to provide sound advice to industry, including one on controlling liver and rumen fluke in cattle. This will be published on www.cattleparasites.org.uk this winter.