The Sustainable Control of Parasites in Sheep (SCOPS) and Control of Parasites Sustainability (COWS) are both urging sheep and cattle farmers to monitor for liver fluke this autumn. With the effects of liver fluke estimated to cost the cattle industry up to £40.4 million a year, and the cost to sheep farmers estimated at £3 - £5 per infected sheep, effective and sustainable control is essential.
With the heavy rainfall experienced these past weeks liver fluke is likely to be prominent this year. Last autumn and winter the levels of fluke were relatively low due to the dry weather, but as we have already seen much wetter conditions this year the indication is that there will be more fluke around this season. There have already been reports of disease in some areas and experts are warning the challenge will be patchy so the need for testing is greater than ever.
Despite the NADIS fluke forecast risk level being relatively low in our region it is important to take into consideration local conditions. If you have any boggy patches on your grazing they could be considered risk areas and so steps should be taken to keep animals off the wettest ground where possible.
Risk of autumn fluke is also dependent on eggs being present on the pasture, so areas that have been grazed by infected cattle or sheep earlier this year can be considered at risk.
If fluke infection is present, identification and exclusion of snail habitats from livestock offers some measure of control. Drainage eliminates the snail and offers an effective means of control, however the proliferation of environmental schemes to protect wetland areas has reduced the opportunity for this to be implemented. Therefore keeping stock off the wettest fields during the autumn and winter, when there is the highest risk of disease, will reduce the risks associated with fluke.
At this time of year a fluke infection cannot be detected with a faecal sample. With the fluke's lengthy life cycle we would not expect to see eggs until later in the season, once the fluke has matured through to adulthood and start laying them. It is still possible to test for immature fluke however. A blood test is available which looks for antibodies in the blood and can detect a challenge from 2-4 weeks post infection. A positive test will indicate the need to treat as the animals will only have been infected this summer/Autumn.
It is important to take action to avoid losses to fluke. It is recommended to test before treating to avoid unnecessary treatments, which will save you money and time and help us to protect the few available medicines which combat fluke.
It is important to always use an appropriate product for each situation when treating fluke - this decision should be based on fluke forecasts. Most flukicides available are effective at killing adult fluke, but few are effective in treating the immature stages.
A Triclabendazole based product is generally the drug of choice, however as reports of resistance to this product in the UK are rising, it is more important than ever to reduce our reliance on Triclabendazole alone. Alternatives should therefore be used wherever possible, particularly in late winter and spring, to reduce the development of resistance.
Information adapted from AHDB's 'Parasite Control Plan 2019' and SCOPS' 'Detection and treatment options for liver fluke