Sustainable Control of Parasites in Sheep (SCOPS) nematodirus forecasting tool will prove an invaluable method of checking the risk to lambs this spring.
To find out more and sign up to alerts, visit: https://www.scops.org.uk/news/5856/invaluable-parasite-forecasting-tool-relaunched/
Farmers wanting to learn more about Liver fluke met with experts this week in Yorkshire and Cumbria. Full details will be published in due course.
You can view the details here: https://www.scops.org.uk/workspace/pdfs/anthelmintics-scops-lssc-web-version-2020.pdf
Cumbria and Yorkshire farmers have joined forces to fight the challenge of living with and managing liver fluke in hill sheep flocks.
The Farmer Scientist Network has secured European Innovation Partnership (EIP-AGRI) funding and set up Hill Sheep North working with farmers and industry experts to study flock health issues and formulate strategies. The project is being facilitated by The Farmer Network.
Liver fluke is a major parasite problem in the north of England and control is difficult, particularly where flocks are only gathered for treatments several times a year, and the conditions on moors and upland fields can be ideal habitats for the mud snail host.
The days of just drenching animals to control fluke are gone. The build-up of resistance to triclabendazole is considered to be widespread, and while the total picture is unknown, pockets of resistance have been found all over the west of the UK. Wetter, warmer conditions, particularly in the west, mean that the cysts are available to be eaten nearly all the year round.
So testing for presence of fluke, grazing management and careful use of the right flukicide product to treat the right life-stage of the fluke at the right time are all key to living with fluke.
In the liver fluke project, farmers, vets and experts are sharing their knowledge and information to help form a solution, working together to improve and evaluate disease control programmes for hill flocks.
To gain greater understanding of the parasite, farmers are participating in regular testing and working closely with their vets. They have discussed their current flock treatments and are recording and linking their data with a phone app.
A questionnaire for 25 hill farms with flocks in Cumbria averaging 1,055 sheep and Dales farms averaging 592 head of principally Swaledale, Swaledale crosses, Herdwicks and Mules, highlighted fluke as the most frequently reported problem in 2018 with 16 of the farms reporting cases and mortality.
Dr Bryony Jones, Research Associate with the Royal Veterinary College and joint academic lead of the project, said among the farms that reported cases of fluke, the estimated mortality rate in the affected groups was up to 18.9%, and averaged 4.7. The proportion of the group affected was estimated to be between 1.3 to 100%, an average of 25.0%. These estimates were similar in Cumbria and Dales farms.
“Most fluke cases were diagnosed by the farmer, but some were vet-diagnosed by post mortem and/or lab tests, and some were based on abattoir feedback.
“The reported clinical signs of fluke disease included acute cases with sudden death, and chronic cases of wasting.”
Recent workshops have been held on farm in Cumbria (Goosewell, Keswick) and Yorkshire (Cogden Hall, Grinton, Richmond).
Sheep flock health specialist Fiona Lovatt explained to the Richmond meeting how it is important to use the most appropriate medicine for the time of year and life stage of the fluke.
She advised identifying which fields and which groups of livestock are most risky. Graze any finishing lambs in fields where there are no snails so that you won’t have to treat them with flukicide.
She said: “The products that only treat adults – e.g.albendazole, (short withdrawal period for meat), will not treat any immature fluke which are damaging the liver of these lambs, so it is pointless using this flukicide in the autumn.
“If they are picking up cysts and carrying immature fluke, they need to be treated with closantel, nitroxynil or triclabendazole and of course they won’t be able to be slaughtered until after the withdrawal period. Hence ideally weaned lambs need to be somewhere where they are not picking up the cysts so they don’t need treatment.
“It is also very important to protect any snails on your farm from being infected by fluke from other farms, particularly those at high risk of being resistant to triclabendazole.
“This can be done by keeping any bought in sheep in a dry field, which doesn’t have any snails. Dose the new sheep twice with a closantel or nitroxinil product, six or seven weeks apart, to make sure that any fluke that is resistant to triclabendazole is killed before the new sheep go into an area where they could infect any snails living on your land.”
The best way to avoid over-treating, under-treating or treating with the wrong product is to check what is present in flock, especially testing at the right interval after treatment to see if the product has worked.
A range of tests are available. Monthly faecal egg counting provides a guide to when numbers of adult fluke are increasing in the sheep. This can be done on the farm, following instructions provided in the Moredun Foundation handout, or through the farm’s vet practice.
At the Keswick meeting, alongside Dr Phillip Skuce, of Moredun Research Institute was joined by national liver fluke researcher Dr Rhys Jones, of Aberystwyth University, who studied one farm for fluke alongside livestock management for five years, explained the activity of mud snails and fluke.
“Mud snails are most active from April to October, some overwinter and then die in the spring and some die in dry conditions over the summer. But we mainly see the symptoms of fluke in livestock mainly in the autumn/ early winter.
“Moisture in summer is the most important factor for the snail – they can survive in moist conditions for months, but can survive in dry conditions for only one month.
“Thick grass, or moss without any bare mud is not good habitat for snails. Light poaching by livestock disturbs the surface and allows bare mud to be colonised by algae – which the snails graze.”
He explained that the underlying geology affected how dry, wet or acid the conditions are for snails. They did not colonise soil that is sandy, peaty, or less than pH 5.1 – or deep water, but slow-moving streams.
In dry years livestock tend to graze the wetter areas that they wouldn’t go into in wet years – sometimes these are more risky areas.
“We had a problem in the autumn of 2017 after a particularly wet summer with a lot of the ewes returning to service and not thriving,” said Carol. “The protein levels in the blood were indicative of fluke. I am a member of local group Ladies in Livestock and our vet Sarah Harker had shown us how to do a liver test post mortem and I found it to be infested with adult fluke.
“Since we have joined the project we have tried to avoid using triclabendazole and used flukicides more often. We have a much better understanding of the liver fluke cycle and we can make decisions on whether to dose the sheep. We are using the special app where we can record treatment details.”
Carol and her father are also making some adjustments to grazing management including running sheep in smaller groups to help avoid poaching. The farm’s meadow ground can be boggy and this is grazed by lambs before they are sold in September – the gimmers are sold for breeding and weathers store.
The weathers are also sold sooner in advance of the ewes being flushed on the meadow ground.
“As well as learning more about fluke and its treatment, the project has allowed us to share and discuss our problems with other sheep producers,” said Carol.
NADIS publishes a monthly Parasite Forecast for farmers and vets based on detailed Met office data and the forecast. The Parasite Forecast outlines the parasitic challenge facing cattle and sheep in the different regions of the UK.
The Parasite Forecast is used to promote SCOPS and COWS recommendations in a seasonal context and underlines the importance of parasite control being part of a veterinary health plan. To see the latest forecast, please visit: https://nadis.org.uk/parasite-forecast/
Farmers can sign up to SCOPS – Sustainable Control of Parasites for disease and parasite forecast, please visit: https://www.scops.org.uk/forecasts/
Following the meeting that took place with Yorkshire Farmers in January, participants discussed feedback from their abattoirs, those that were able to get feedback had been ok so far. Farmers received the AHDB Beef and Lamb information booklets that give guidance on likely causes of damage to liver and other organs.
Three farmers in the group had done their own post-mortem on sheep that had died, to look for evidence of fluke in the liver and bile-ducts.
The Yorkshire farmers were very keen to learn more about this and arranged a workshop with Davinia Hinde, Bainbridge Vets, Leyburn, was arranged to show them how to do it, enabling them to monitor the presence of fluke if sheep died over lambing time.
The video and photos below are available as resources taken from the post mortem evening.
****It is important to wear gloves and overalls when preforming this on farm, and always wash your hands thoroughly afterwards****
Image 1, Davinia opened up the dead ewe which was from a local farm, the group were shown where to make the incision and how to cut out the liver, the incision was made just below the rib cage on the right-hand side of the ewe – if you make a smaller incision it is easy to tie the wool up together so the rest of the insides don’t all come out which makes it is easier for the knacker man to collect.
She brought out part of the liver to inspect for signs of liver fluke; the liver had begun to decompose from this ewe, however no signs of fluke were found, the bile ducts were clear and the liver looked fine.
Image 2, For the second ewe that was opened up (which was also from another local farm) was also free from fluke and had no signs of scaring from previous infestations. The bile ducts were clear as well, notice the red dark pink healthy look of this liver.
Image 4, There was some calcification (circled in red) in the liver of this ewe which is a sign of a diet in balance, but again no fluke or signs of previous liver fluke damage. Red arrows pointing to the bile ducts, where adult fluke live.
Eight farmers in Yorkshire and six in Cumbria met to discuss their experience with sheep health last year, their progress with the treatments App and findings from tests for the presence of liver fluke in their flocks.
No-one had seen any signs of liver fluke in lambs last summer and over the autumn. The dry year had reduced numbers.
Farmers had been offered a free test for presence of fluke eggs in faecal samples in June and/ or August before doing routine fluke treatments in the autumn. Most samples had not had enough fluke eggs present in the August samples to warrant doing a second test to measure the efficacy of triclabendazole.
The end of January/ early February 2019 is a good time to check again for the presence of fluke, before routine treatments at scanning (especially if not treated for fluke since early December). The project can offer free tests for the presence of an antibody to fluke – which may be sooner and more reliable then looking for fluke eggs in the sample. By doing another sample from the same sheep 2 weeks after treatment, the test can be used to get an indication if treatment by triclabendazole has been effective (not fully accurate).
Those who could get feedback from their abattoirs had been ok so far. Three farmers had done their own post-mortem on sheep that had died, to look for evidence of fluke in the liver and bile-ducts. The Yorkshire farmers were very keen to learn more about this and arranged a workshop with one of the farm vets to show them how to do it.
A proven way to reduce the incidence of liver fluke is to target dosing with different products at different times of year, to target the most likely life stages, and avoid over-use of triclabendazole when it is most likely to be only adult fluke in the sheep. Targeted treatments for adult fluke currently (usually late winter and spring) are likely to reduce the shedding of eggs onto pasture. One farmer had done this regularly (4 treatments a year) for a few years and noticed reduced incidence of fluke, and now only needed 3 treatments per year.
Farmers can reduce infection rates by grazing more susceptible animals in less risky areas. Treating according to the conditions may mean that treatment patterns need to change every year. Copies of the life-cycle of the liver fluke and its stages along with the latest version of the AHDB Beef and Lamb parasite Control Guide were distributed.
The use of the treatment App was discussed, and some farmers had recently updated the information on it. One farmer mentioned that it would be valuable to know which flock (moor sheep or mules) had had which treatments. This is to be added to the App.
Use of the National Animal Disease Information Service parasite alerts was discussed and 3 farmers in the group look at it regularly, especially for Nematodirus in spring. They find it is worth registering for email updates: http://www.nadis.org.uk/
It’s a busy time of year for our participating farmers. In September and October breeding and store sheep are sold and bought at sheep sales all over the north every week. This year, because of low rainfall and Brexit uncertainty, sale prices have been low and feed costs are high.
In August and September, farmers sent faecal samples from their flocks in to Liverpool University for the standardised composite faecal egg count reduction tests (FECRT). This test detects the level of efficacy of the flukicide Triclabendazole (TBZ). The dry season reduced the incidence of liver fluke and there were low numbers or no fluke eggs in the samples. This made it impossible to determine the efficacy of the flukicide most of the flocks, but the reduced level of fluke has improved sheep health. This may change as the year progresses, but the FECRT will not be able to be repeated until February or August 2019.
Farmer Meetings took place in August at Braithwaite and September in Leyburn to go through the phone application, data collation, how to interpret the dashboard and review flock health plans. It was a chance to talk to the project members about the next steps for the year.
