How a Cheshire farmer eradicated liver fluke from his flock

By taking a holistic approach to flock health and working closely with his vet and animal health adviser, farm manager David Cross has eradicated liver fluke problems in his sheep flock.

Mr Cross first noticed problems with the disease when he started buying in Romney ewes to establish the now 680-ewe flock at High Ash Farm, Tarporley, in Cheshire.

“The first time I saw fluke was in a dead ewe. A post-mortem showed she had acute fluke. I think I hadn’t been observant enough and had left it too long between dosing,” admits Mr Cross, who sought the advice of vet Gethin Edwards from Willows Farm Animal Veterinary Practice.

“Investigations revealed that he had quarantined the ewes after being purchased from other flocks but they weren’t treated for fluke, which was exacerbating the problem”, says Mr Edwards.

He has been working closely with Mr Cross and SQP Mark Pass from Beeston Animal Health, Tarporley, to ensure effective quarantine regimes for bought-in ewes and timely treatment protocols.

Upon closer investigation they found a large number of mud snails in wet patches of ground and nesting close to ponds on the farm.

To prevent sheep picking up fluke at the source steps have been taken to reduce sheep getting into wet areas.

See also: Advice from Scops on treating sheep for liver fluke

“I have worked pretty hard to try and drain areas that are relatively close to ditches and ponds,” explains Mr Cross.

Where ponds couldn’t be drained, higher-risk areas of land have been fenced off and put into an environmental scheme.

Overflow pipes have also been fitted into the farm’s ponds to prevent water from breaching the banks and snails from spilling over on to grazing pastures.

“By minimising the risk of ewes coming into contact with the mud snail in wet areas, you are reducing the risk of liver fluke completing its life cycle,” says Mr Edwards.

Management of wet areas has been fundamental in getting liver fluke under control, as the farm is heavily reliant on low-cost grazing all year round.

David Cross

Grazing management

“We use all grass wintering in the winter and in the summer sheep are mob grazed in four-day rotations,” adds Mr Cross.

The aim for all grass wintering is to start the winter with an average cover of 2,500kg/DM rotationally grazing down 1,000kg/DM, on one- to two-day rotations.

Ewes are set stocked two to three weeks before lambing, according to grass cover and number of lambs.

Singles are stocked up to eight an acre, twins are four an acre, and triplets three an acre.

During the summer, the aim is for the sheep to go on to 2,300kg/DM and graze down to 1,500kg/DM on a three- to four-day mob grazing rotations.

Monitoring treatment efficacy

Mr Cross also conducts regular faecal egg counts (FECs) and autopsies on any thin-looking ewes.

With the advice of Mr Pass he alternates products to prevent resistance building up against certain classes of fluke drench.

“Careful monitoring of fluke treatment is essential to identify early resistance problems.

“By rotating flukicides we are reducing the risk of resistance developing,” explains Mr Pass.

During the summer grazing season around eight FECs are taken every two weeks.

Monitoring temperature is also key to effective treatment.  

“The temperature has to be above 10C for mud snails to survive.

“So if they don’t have a cold spell over winter they will lie dormant,” says Mr Edwards.

“If it has been 10C or above and relatively wet for three months between May and October then we would have to use Triclabendazole in the autumn to kill all stages of fluke, from two-day-old early immature forms to adult fluke.

“If warm weather persists then a further immature fluke treatments would be required in winter.

“But if we have a colder winter and the risk is smaller, then we might look at using something different like Closantel, which only treats late immature and adult fluke.

“A further treatment to kill adult fluke in spring with Closantel, or Nitroxynil, reduces pasture contamination and minimises the risk of the mud snail picking up the early fluke stages,” adds Mr Pass.

“It is about treating with as much information as we can possibly get.

“The sheep are run as a separate entity to other farm enterprises and have got to carry themselves, so wasting money on drugs isn’t an option” says Mr Cross.

Last year the flock was dosed twice – reduced from three the year before.

They dosed once in February, with Closantel to combat immature fluke down to six weeks, and again in October, with Triclabendazole to kill early immature fluke.

But there is no “one size fits all” and every farm should have their own fluke plan devised based on their specific farm risk, advises Mr Pass.

Mr Edwards says the biggest problem is many farmers want to treat with a combination worm and fluke product to save time. But he warns against this.

“Ideally, if you have a fluke problem you want to treat all the sheep, but for worms you need to leave 10% untreated to prevent resistance problems developing.”

Benefits

As a result of this comprehensive approach to fluke management, they have seen significant improvements in flock health and productivity.

“I haven’t seen any evidence of liver fluke at all this year. I have found snails but I haven’t seen any evidence in sheep. Worm counts and autopsies have all come back negative.”

Scanning percentage has also improved by 11% – up from 158% last year to 169% this year.

The long-term goal is to move away from routinely treating for fluke by continuing to monitor for fluke and quarantine in coming stock.