Liver Fluke on Farms
As autumn approaches, both dairy and beef farmers can be fairly sure of the prospect of having Liver Fluke in their stock. Teagasc advisor Niall Treanor gives information about Liver Fluke and advice on treatment options.
The Liver Fluke parasite, Fasciola hepatica, is a parasite which affects cattle, sheep and goats. Adult fluke (Figure 1) in the bile ducts lay eggs which pass on to the pasture in the faeces. The eggs require mild conditions for the larvae to hatch and after some time, these enter the intermediate host, the mud snail, where they undergo further development. This snail is even more dependent on the presence of moisture and warmth. The immature flukes leave the snail and develop further until they reach the ineffective stage where they become attached to the herbage. It is only when ingested by the animal at this stage that they are capable of migrating through the body, reaching the liver and thus completing the cycle.
Figure 1: Adult Liver Fluke
Impact of weather
The reasonably dry weather conditions in many parts of the country this summer should reduce the risk of liver fluke-related disease this winter. This risk is moderate for the north, west, south-west and midlands. The east and parts of the south of the country can expect a lower disease risk. However, farmers in these lower risk areas should still remain vigilant for signs of disease.
Effectiveness of treatment products
There are a huge number of products effective at killing liver fluke. Farmers have been aware of the parasites for decades and most treat their cattle for fluke at housing. However, every year, a high percentage of livers in meat processing factories from housed cattle hhave live adult Liver Fluke. Why is this? There are a number of possible reasons, including:
- using a control product that only kills a proportion of the fluke in the animal
- underestimating the weight of the animal and not giving enough product
- incorrect treatment procedure
- using a product that the fluke are resistant to
How treatment products should be used
When purchasing a product to kill Liver Fluke, the most important question to ask is:
“When should I use this product so that it is most effective”?
Most of the available flukicides only control older immature liver flukes and/or adult fluke. This means that any fluke that have been picked up over the previous six to eight weeks or so will not be killed. A second treatment for fluke will then be necessary. Triclabendazole-based products will kill much younger fluke, but there are reports that resistance to them appears quite widespread in Ireland. To be sure that a fluke control programme has actually worked, it is a good idea to send off dung samples for testing eight weeks after you have given the last treatment. Only then will you know for certain whether or not it has been effective.
Now is the time to implement a dosing plan, in partnership with your Vet to effectively control fluke in your herd. Choose your product carefully, administer it correctly and check dung samples to know for certain if the job is done.