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The complicated story of fluke - Part 1


Work in Animal Health Ireland has shown that fluke could be costing €70 per finished steer in lost performance if not treated correctly. Martina Harrington, Teagasc Beef Specialist in the first of a two part series this week discusses liver fluke. Here she explains the stages of fluke in the animal

While animals will develop immunity to lungworms and gut worms, they do not develop immunity to fluke, so this always need to be considered when housing all classes of cattle including suckler cows.

Once housed, animals cannot pick up any more fluke or worms so this provides us with an opportunity to “clean out” the animal. This will allow the animal to perform to its optimum while also ensuring the animal is not a source of infection onto pasture next year and thus reduces the infection pressure in the next grazing season. 

To get your housing treatment right, you need to understand the different stages of fluke while it is in the animal.

The stages of fluke in your animal

  • Once eaten the larvae are freed from a protective cyst and bore through the intestinal wall and move into the liver. This can take 2 weeks.
  • In the liver the immature fluke burrow through the liver, severing blood vessels and destroying liver cells for 8-10 weeks. The level of damage is dependent on the number of fluke in the liver.
  • The immature fluke then move into the bile duct where they mature and start to produce eggs which are passed out in the faeces. In the bile duct they feed on the blood of the animal. In heavy infections they can cause anaemia.

These different stages are hugely significant when we decide what products we are going to use.

Active ingredients

There are 7 different active ingredients that control liver fluke, see the table below.

An active ingredient is the ingredient in the product that kills the parasite.

The same active ingredient can be in several different products e.g. Endofluke and Fasinezl both contain the active ingredient triclabendazole.

It is the triclabendazole that kills the fluke so they are essentially the same product.

The different active ingredients kill fluke at different “ages”. From a farmer point of view it is the age at which each product kills the fluke that is important and this is dependent on the length of time the parasite is in the animal as explained above.

  • early immature fluke (1 to 5 weeks)
  • immature fluke (6 to 9 weeks)
  • adult fluke (>10 to 12 weeks)

Table 1: List of Active Ingredients that kill fluke

Note some of the products in the Table are combination wormers/flukicides, for this article we are concentrating on fluke

The Beef Edge podcast

Listen in to The Beef Edge podcast on When do I need to treat for Liver Fluke? 

Check out Part 2 of this article series tomorrow on Teagasc Daily which covers the Treatment of Fluke and How do you know if your dosing programme is working?

You may also be interested in this link Current News (agriculture.gov.ie) to the DAFM website which contains a fluke update on forecasting.