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Five liver fluke myths debunked

Liver fluke can cost Australian producers $50-$80 million dollars per year in productivity losses alone.

When to treat it, how to treat it, and what exactly needs to be treated aren’t always crystal clear.

Matt Ball, Virbac’s livestock veterinarian, debunks five common myths around treating liver fluke.

1. If there are no signs or symptoms, you don’t have a liver fluke problem.

Before obvious signs of liver fluke occur, such as weight loss, scour or ‘bottle jaw,’ animals lose significant production. 

It is also not always clear which farms have liver fluke.

“Many producers that should be treating for liver fluke aren’t, while some are treating for liver fluke, even though they don’t need to be,” Matt says.

Liver flukes tend to be intermittent and irregular egg layers, which makes faecal tests somewhat unreliable.

The most effective tests on the market are blood tests like the ELISA (Enzyme Linked Immuno-Sorbent Assay), which detects the antibodies animals produce in response to infection. For dairy cows, samples can be taken from the milk vat.

2. There is no risk for liver fluke in dry or drought conditions.

“Because liver fluke larvae mature in water snails, it leads people to believe that they’re only present in wet or rainy conditions,” Matt says.

Liver fluke eggs hatch into larvae, which mature and multiply in the aquatic snail for five to eight weeks. Then tadpole-like larvae emerge from the snail and form cysts on vegetation. These cysts can last for months on the vegetation where water once existed – in a dry dam for example – putting grazing livestock at risk.

“When addressing liver fluke, it’s important to consider the timing of treatment and not necessarily rely on weather conditions to assess risk,” he says.

While treatment times depend on your specific region, a general rule of thumb is to treat liver fluke three times a year.

Late April to early May is the most important time as it is when liver fluke is most likely to be around two weeks old, which is its youngest treatable stage. Following this, treatment in August / September and then again in January / February helps eliminate any cysts livestock may have picked up throughout the year.

3. All application methods are created equal.

While pour-on applications are quick and easy, Matt says they’re not able to be absorbed as well as oral or injectable application,

“The treatment needs to be absorbed into the bloodstream and make its way to the liver, which happens much quicker when the medicine is administered directly into the animal’s system.”

He explains that the time you save upfront during application doesn’t always pay off when considering the increased speed of the injectable or oral treatment.  

4. The threat of resistance isn’t really that important.

Virbac has done some recent testing that has shown there is an emerging resistance in Australia to triclabendazole – an active used to treat liver fluke.

“Growing resistance to triclabendalzole in Australia will decreases the options to control the early stages of liver fluke” explains Matt.

To protect against the onset of triclabendazole resistance there is a need to use the most potent and current products, in addition to adopting alternative strategies. Matt recommends the best way to find an efficient method is to speak to your local Virbac adviser. You can find the nearest adviser in your area with this local representative finder.

5. Switching brands won’t reduce resistance.

It’s not the brand that matters so much as the active ingredient.

To delay resistance, Matt emphasises looking for combination products that will do a better job of wiping out flukes, like Nitromec and Flukazole C.  Nitromec does not contain triclabendzole so can be used in cattle as an alternative on farms with known resistance to triclabendazole or to delay the onset of triclabendazole resistance.

Flukazole C is a good choice in cattle and sheep to delay triclabendazole resistance because it is more potent than straight triclabendazole.

“Whether you’re looking to start a program or already implementing a program, you should seek expert advice to assess what the best approach is for your livestock and farm,” Matt says.

Trained Virbac veterinarians and representatives can help you identify the problem and devise an actionable strategy to control liver fluke on your property.

  Find your local representative