Controlling the right stages of liver fluke, at the right time, with the right product

Sustainable liver fluke control

Sustainable liver fluke control

The need for sustainable liver fluke control

Liver fluke - a growing threat

Liver fluke is known to cause severe clinical diseases and death.

Now spreading to new regions liver fluke can increasingly be found throughout Ireland, largely due to the impact of climate change.
All these factors favour liver fluke:

  • Warmer temperatures throughout the year.
  • Increased rainfall in autumn and winter.
  • Dry eastern areas becoming wetter.
  • Flooding moving snails infected by the parasite into new areas.
  • The grass growing season increasing by 4 weeks over the past 40 years.
  • Increased movement of liver fluke infected animals around the country.
  • Resistance to some commonly used flukicides.

A seasonal challenge

Due to this lengthening of seasons, and the impact of warm, wet weather on the liver fluke lifecycle, the liver fluke challenge can now be higher for a longer period with the risk of high fluke burdens in both sheep and cattle extending throughout the year if not treated effectively.

A complex lifecycle - allows vast multiplication

Inside the sheep:

  • In 10-12 weeks the liver fluke develop through 3 stages – early immature, immature and adult.
  • All stages damage the liver and can cause clinical disease and production losses.
  • An adult liver fluke, on reaching the bile duct, can lay up to 50,000 eggs every day.

On the pasture:

  • Liver fluke eggs, passed in faeces, start to develop when temperatures reach 10°C, with most of the eggs deposited over the winter hatching in May and June.
  • The larvae (Miracidium) once hatched seek out mud snails in which to continue their development. Those that are successful then take between 5 weeks and a few months to multiply in number by several hundred times before final stage larvae Cercaria are released from the snail.
  • Cercaria form infective cysts (Metacercariae) on grass which are consumed by animals such as sheep and cattle.

'Warm & wet' escalates the liver fluke burden by:

Liver fluke - threatening profitability

The rise of resistance

Resistance to certain active ingredients has been identified on a number of farms. Once liver fluke have become resistant to an active ingredient, and can survive exposure to a treatment that would normally kill them, there is no evidence to suggest they will return to susceptibility.

As individuals, and as an industry, we can’t afford to allow this to happen. To achieve effective control now – and to preserve the efficacy of the existing active ingredients for the future – we need to adopt a new approach to liver fluke management.
This can be achieved by concentrating on 4 key elements.

4 elements of sustainable liver fluke control

  • Pasture protection – to prevent liver fluke eggs reaching the pasture when snails are active.
  • Pasture management – to reduce snail habitats and therefore reduce snail numbers.
  • Grazing management – to avoid grazing high risk pastures with susceptible animals at high risk times of year.
  • Strategic treatments for at risk animals – using the right product at the right time in the right animals.

A new sustainable approach

The 4 elements of sustainable liver fluke control

1. Pasture protection

Treating for liver fluke in the late spring/summer to remove remaining adult liver fluke thereby reducing the number of liver fluke eggs reaching the pasture at a time when snails are active. This reduces the number of infected snails that maintain the liver fluke lifecycle into the autumn.

2. Pasture management

Managing pasture to minimise snail habitats and reduce snail numbers which in turn reduces the number of infective stages released onto pasture.
Measures to consider include:

  • Fix leaky troughs.
  • Avoid poaching ground.
  • Maintain effective drainage.

3. Grazing management

The infective stages of liver fluke will only be found where snails have been present. Grazing management therefore can reduce livestock’s exposure to snail habitats and infective cysts and so reduce/limit the number of infective cysts (Metacercaria) ingested by grazing animals.

  • Wet, boggy areas are typically high risk.
  • Avoid grazing high risk areas at high risk times of the year (late autumn and winter depending on weather patterns).
  • Use of temporary/electric fencing is useful to prevent access to high risk areas.

4. Strategic treatments for at risk animals

Treating animals with flukicides is an essential part of maintaining good animal welfare and performance. As the liver fluke season is now more variable and covers a larger part of the year, the traditional set time of treating in the autumn/winter is unlikely to give full control. Therefore, a more strategic, targeted approach should be implemented.

  • For each treatment, select the product that will kill the stages of liver fluke that are likely to be present at that time.
  • Use different active ingredients as appropriate at the right time throughout the liver fluke season to reduce the risk of resistance developing to any one active.

4 elements of sustainable liver fluke control

Breaking the life cycle, to achieve a new approach to sustainable liver fluke control.
Breaking the fluke cycle
  1. Pasture protection from liver fluke egg contamination
  2. Pasture management to reduce the snail population
  3. Grazing management to reduce the level of challenge
  4. Strategic treatment of ‘at risk’ animals – the right product at the right time

Strategic treatment

Controlling the right stages of liver fluke, at the right time, with the right product.

Seasonal, strategic liver fluke treatments can help reduce the risk of resistance developing and the levels of infective cysts (Metacercaria) on pastures. The suggested treatment timings are for guidance only. Levels of risk in your area, or on your farm, can be determined by consulting with a local animal health adviser or veterinary surgeon and checking current liver fluke forecast data.

Sheep Flukicide Efficacy

As not all active ingredients kill all stages of liver fluke, knowing which active ingredient kills which stages is important to ensure you choose the correct product for the stages of fluke likely to be present.

To avoid overuse of any single active and to reduce the risk of resistance development, targeting the right stages of liver fluke at the right time of year with the right product is essential.

Quarantine treatment

Always follow the SCOPS guidelines on quaratine treatment (see

  • Give bought-in stock a quarantine flukicide dose.
  • Whilst treatment with Triclabendazole will remove a very high proportion of susceptible liver fluke of all stages it will not remove Triclabendazole resistant liver fluke.
  • If sheep are infected with early immature liver fluke, treatment wilth Closantel will have to be repeated after the immatures are old enough to be killed by these products. Consider the use of two doses of Closantel given 6 weeks apart.
  • Treatment with more than one product with activity against immature liver fluke (Closantel or Triclabendazole) will reduce the risk of introducing liver fluke with resistance to any one product. However, it is not recommended that two products are used at the same time, (seek advice from an animal health adviser or veterinary surgeon).
  • Keep treated animals away from snail habitats (wet, boggy areas) for 3 weeks as treated sheep can still shed eggs for up to 3 weeks.

Coproantigen testing and Feacal Egg Count (FEC) monitoring can be used to determine the need for further treatments.

Elanco Liver Flukicide Use Guidance

Elanco recommend that liver flukicides are selected to control those stages of liver fluke which are likely to be present in higher numbers at treatment time.

This allows for easy rotation between active ingredients to reduce the risk of resistance developing and encourage effective and sustainable control.

Autumn/Early Winter

Fasinex logo
  • Contains Triclabendazole, the only active ingredient to kill all 3 stages of liver fluke down to 2 days old in sheep.
  • Minimises liver damage and blood loss, for faster recovery and better growth.
  • Kills adult, immature and early immature liver fluke.

Late Winter/Early Spring

  • Contains Closantel.
  • Active against immature and adult liver fluke.
  • For the control of chronic and sub-acute fascioliasis in sheep and lambs.
  • Kills Triclabendazole resistant liver fluke1.
  • Also controls Oestrus ovis (Sheep Nasal Bot Fly) and inhibited, immature and adult stages of Haemonchus contortus (Barber Pole worm) including benzimidazole resistant strains.
  • A combination flukicide and wormer to be used when it’s necessary to treat liver fluke and GI worms at the same time.
  • Contains Closantel.
  • Active against immature and adult liver fluke.
  • For the control of chronic and sub-acute fascioliasis.
  • Kills Triclabendazole resistant liver fluke1.
  • Plus Mebendazole a 1-BZ class wormer.
  • Controls gastrointestinal roundworms, lungworms, tapeworms and nasal bot.

Late Spring/Summer

  • Kills adult liver fluke responsible for chronic liver fluke disease.
  • Benzimidazole group 1 white drench.
  • Treats and controls major parasitic worms in sheep.
    • Broad spectrum roundworm (stomach and gut worm) control
    • Spring/early summer Nematodirus control
    • Tapeworms (Moniezia) and lungworms