The liver fluke parasite, Fasciola Hepatica, is a parasite which impacts cattle, sheep and goats, writes Niall Treanor, B&T drystock advisor, Teagasc, Galway/Clare.
Adult fluke 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. Coming into the autumn both dairy and beef farmers can be sure of the certainty of having liver fluke in their stock coming to this time of the year.
Due to the dry weather conditions experienced in many parts of the country this summer, there is a moderate risk of liver fluke-related disease this winter for the north, west, south-west and midlands, with a lower disease risk expected for the east and parts of the south. However, farmers in these lower-risk areas should still remain vigilant for signs of disease.
There are a huge number of products effective at killing them, farmers are aware of the parasites for decades and most treat their cattle at housing for them. However, every year we still see a high percentage of livers in meat processing factories from housed cattle that have live adult liver fluke in them.
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; and, using a product that the fluke are resistant to.
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 flukicide that are for sale 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.