Drenching for liver fluke

Most producers understand there are treatments available to control internal parasites such as liver fluke.

A question worth considering, is when to strategically use those treatments.

Liver fluke is an internal parasite that can live in the liver and bile ducts of cattle, sheep, goats and alpacas.

Humans can also be infected if they consume contaminated vegetables like watercress. Some native animals, rabbits and hares are important reservoir hosts.

The parasite has a complex life cycle that requires the involvement of a snail called Austropeplea tomentosa. This small (<10mm) freshwater snail can be identified by the clockwise spiral of its shell and its triangular dogear-shaped tentacles.

The snail is usually found in shallow water or on plants at the edge of swamps, springs, drains and irrigated pastures, is dormant below 10 degrees, and cannot survive frosty conditions, so consideration should be given for treating your livestock for liver fluke following the first frosts.

Liver fluke control strategies vary by region, industry and even from property to property.

Flukicides, the chemicals used to treat livestock for liver fluke, should be used strategically at specific times of the year to minimise pasture contamination and most effectively kill the liver fluke.

There are six different flukicides available for use in livestock in Australia, and they are effective against different life stages of the parasite and have different withholding periods.

In recent years fluke resistance to the most widely used flukicide, Triclabendazole, has been identified in parts of Victoria and NSW.

Dairy farmers in the Macalister Irrigation District have adopted the use of new coproantigen ELISA tests to determine when to treat with flukicides and monitor potential on farm resistance.

Producers should talk to their veterinarian for specific recommendations for their property.

This will enable them to put in place an effective and economical fluke control plan.

It is important to remember that withholding periods are likely to apply following treatment with a flukicide.

For further information please contact your local veterinarian, Agriculture Victoria veterinary or animal health officer.