Liver Fluke

What causes liver fluke disease?

The disease is caused by the trematode parasite, Fasciola hepatica and the same species affects both sheep and cattle. 

The liver fluke cycle involves two different hosts - the cattle/sheep and the mud snail Galba truncatula which need to be present to continue the cycle. The snail host is mainly found in muddy, wet areas of ground with poor drainage.

The liver fluke life cycle is dependent on environmental and climatic conditions. Once present on a farm, they are very hard to eradicate. 

Liver fluke can also infect wildlife - most notably deer and rabbits - so the lifecycle of the parasite can be sustained even outside the grazing season. 

• Liver fluke infect both cattle and sheep so risk can increase when pastures are co-grazed 

• Increased temperatures in spring lead to likely infection of cattle in late summer 

The life cycle of liver fluke in cattle 

Signs 

Physical signs in cattle 

Cattle may display a number of physical signs to indicate the presence of liver fluke. These may include: 

• Ill-thrift -  When the cow has reduced weight gain and is not growing at a rate that should be expected given how they are feeding. 

• Anaemia - The animal may have less appetite or may be lethargic in its movements.

• Reduced milk yield - Dairy cattle may have lower milk yields than expected.

Diagnostic tests  

It is possible to test blood or milk for the presence of antibodies against the presence of liver fluke. It is also possible to test for the presence of adult fluke by analysing faecal samples. Consult with your local vet or animal health advisor to understand more about what options he/she may recommend. 

Treating liver fluke

Triclabendazole is the one active ingredient available that is effective against all stages of liver fluke. However, historical over-reliance on this flukicide has contributed to resistance development in F. hepatica which has been confirmed in the UK³.

Different active ingredients are effective against different stages of fluke therefore in choosing the treatment product, you should consider the time of the year. No flukicide offers a persistency of action, therefore in high risk areas, treatments will need to be rotated and repeated throughout the year.  

Autumn/Winter 

The highest risk for liver fluke infection in cattle is from late summer/early autumn on. The housing period can be a good time to treat for fluke as it marks the end point of exposure to new infection. Cattle can be treated from 7 weeks after housing to ensure that any fluke within the liver are susceptible at the time of treatment.  

Spring/Summer 

In risky conditions, a treatment 8-10 weeks post turnout may need to be considered. This will be effective against early infection from the pasture or from fluke that have survived within the cattle during the housing period.

Control

There are a range of management controls that can be implemented to control the spread of liver fluke on the farm. These include: 

• Quarantine & bought in-stock: Ensure that cattle purchased elsewhere are treated for liver fluke before being introduced to your farm and mixing with existing animals. 

• Flukicides: Treat all animals in Spring to kill adult fluke worm and therefore prevent eggs being laid. 

• Pick the right product: When treatment is necessary, chose the active based on the season and lifecycle stage of the fluke infecting your cattle.

• Dose properly: Ideally weigh individual animals or group together in similar weights to avoid under or over dosing.

• Fencing: Fence off any wet pastureland that you may have to ensure that cattle are not grazing on any habitat where the snail hosts may be present. Ensure sufficient drainage around water troughs and mend any leaks from taps and water sources.