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Unravel Liver Fluke By Preventing Mud Snail Contamination

02 September 2015

ANALYSIS – Ground could be gained in the battle against the hugely complex liver fluke parasite by focusing on a specific link in its life cycle, leading experts are suggesting.

A team of scientists and veterinarians at the Farming Against Liver Fluke (FALF) action group say the growing liver fluke problem can be addressed by preventing contamination of the mud snail with fluke eggs.

According to sheep veterinarian, Fiona Lovatt, this can be done through management of pasture and grazing and killing adult fluke at the start of the grazing season.

“Pasture management is very important,” she told FALF action group. “To the extent that my recommendations are the same for organic flocks.”

In response to a recent industry survey highlighting major farmer misconceptions about liver fluke, the products to treat it and its life cycle, she said that practical pasture-level measures were something for advisers to concentrate on.

She said: “Farmers appear to be better at recognising practical measures than understanding some of the theory.

“We need to look at ways that messages can be linked to a practical activity or time of year on farm.”

She narrowed it down to four key action points to address liver fluke – reducing mud snail contamination, reducing mud snail friendly wet areas, avoiding grazing sheep on high risk pasture at high risk times of year and strategic treatments.

Intermediate Host

Mud snail’s host a critical period in the liver fluke’s life, according to Dr Phillip Skuce, senior scientist at the Moredun Institute.

He said: “It is important for farmers to have a working knowledge of the liver fluke cycle, as well as the treatment and diagnostic options.”

The fluke organism undergoes a period of “rapid amplification” inside the snail, producing Cercaria, the stage of the fluke found on grass.

IMAGE NAME/DESCRIPTION
The Liver Fluke Cycle, picture courtesy of Hybu Cig Cymru (HCC, Wales).

Four Points to Address Fluke

Pasture Protection

  • Treat to kill adult liver fluke in late spring/summer
  • This reduces the number of fluke eggs reaching the pasture at a time when snails are active
  • Fewer infected snails means smaller liver fluke population being maintained into the autumn

Pasture Management

Reducing snail habitats to lower snail populations and therefore the chance of liver fluke eggs finding an intermediate host through the summer months.

  • Fix leaky troughs
  • Topping rushes
  • Improving drainage and poached areas

Grazing Management

  • Fence off wet areas which could harbour snails
  • Avoid wet fields altogether
  • Time grazing rotations to avoid high risk fields at high risk times of year – late autumn to early spring

Strategic Treatments

Speak with vet and Suitably Qualified Persons to target liver fluke with the right drug at the time in the right animals.

Many farms typically treated for liver fluke in autumn/winter time but this is “no longer adequate”.

Autumn/Early Winter

All stages of fluke present – Triclabendazole, Closantel

Late winter/spring

Treatments should target immature and adult fluke as infective larvae on pastures are declining – Closantel, Albendazole

Late Spring and Summer

Killing adult fluke now reduces the numbers of eggs reaching the pasture when snail are active, putting a chink in the fluke life-cycle – Albendazole.

Photograph courtesy of the Agri-food and Biosciences Institute (AFBI)

Michael Priestley

Michael Priestley
News Team - Editor

Mainly production and market stories on ruminants sector. Works closely with sustainability consultants at FAI Farms.



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