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Springtime liver fluke control planning vital

Liver fluke is a significant problem this time of year for young calves, especially in high rainfall production areas. But new research indicates good results can be had with treatments that eliminate two-week-old immature flukes.

Critical treatment periods are spring (August/September), mid-summer, and autumn (April/May). The spring treatment should prevent pasture contamination into the following year.

liver flukeAn adult fluke can be up to 3 cm long and can survive in cattle for up to two years.

What is liver fluke?

Liver fluke is caused by a parasite Fasciola hepatica. Fluke eggs are passed in the faeces of a mammalian host then hatch into larvae, which can only survive if they are then picked up by the lymnaeid snail. Development of the parasite continues in infected snails until the larvae are shed and attach themselves to firm surfaces, such as grass blades. Once inside livestock, they migrate through the gut wall, cross the peritoneum and penetrate the liver capsule and bile ducts.

An adult fluke can be up to 3 cm long and can survive in cattle for up to two years. Each adult liver fluke is capable of producing up to 50,000 eggs per day. Mild temperatures and above average rainfall provide optimum conditions for fluke development. Wet areas on dry farms are high risk.

Studies have shown that even as few as 30 to 40 flukes can reduce weight gains by up to nine per cent, with higher levels of infection reducing weight gains by as much as 29 per cent. The effect of fluke on milk production is also well documented, with a heavy infestation resulting in around 300 litres of lost milk production per cow per lactation.

Fertility is also impacted, with infections shown to reduce conception rates in heifers by up to 50 per cent and delay puberty by up to 49 days.

liver flukeAdult cattle may tolerate a fluke burden without it resulting in death; however fluke will severely affect productivity and can cost you millions of dollars in lost profit.

Diagnosing fluke and reducing resistance

Traditionally, microscopic detection of fluke eggs in animal faeces was the preferred method of diagnosis, but it is not considered reliable for cattle producers as liver flukes tend to be intermittent and irregular egg layers. The most effective test is the ELISA (Enzyme Linked Immuno-Sorbent Assay) which detects the antibodies cattle produce in response to infection. For dairy cows, samples can be taken from the milk vat. For beef cattle, blood samples are taken on average from a representative sample of 10 animals.

To assess treatment efficiency, the Faecal Antigen ELISA test is recommended. The test, only recently released in Australia, detects antigens or antibodies in the faeces of the host animal. These antigens build up as the animal’s body fights to fend off the parasite, meaning the presence of an antigen indicates infection at some point.

Producers should also know their property’s fluke vulnerability, be prepared with a fluke control program, and not underestimate the potential damage fluke can cause.

Regional vets will be able to give producers a good idea of the local fluke profile, but generally fluke-prone areas tend to be swampy and wet as the fluke snail are favourable marsh-like environments.  Liver fluke can also contaminate pastures through a host animal, which could be anything from sheep, cattle and horses to alpacas, wombats and kangaroos.

Dealing with liver fluke

New research suggests that treatments which eliminate very early immature flukes can dramatically improve finishing weights. There has been a demonstrated penalty in the order of 8 kg for animals not treated with products that can kill very immature fluke (from two weeks old). 

Virbac has developed the Flukekill program in conjunction with renowned fluke expert Dr Joe Boray. View full details of the program.

Flukazole C is one of only two products on the market to carry an APVMA approval that specifies the control of damaging two week old liver fluke and all older stages through to adult (the other is Virbac’s Nitromec Injection). Other ‘all stages’ flukicides target only flukes older than four weeks.

Flukazole C contains two active ingredients – the proven triclabendazole and oxfendazole. Bruce says there are two important benefits to this dual-action approach.

Triclabendazole and oxfendazole are synergistic – that means that in combination, they are more effective against fluke than triclabendazone alone. Additionally, oxfendazole is also effective against roundworm, so producers can deal with two pests at once.

Download a comprehensive brochure with more information on the impacts of liver fluke and Virbac’s FlukeKill program