Don’t FLUKE IT this Autumn.

Cattle – Liver Fluke – Season

 

In brief, Liver Fluke (Fasciola hepatica) infections in cattle, results in a loss of livestock production and condemnation of livers in abattoirs.

Liver fluke infects both the final host (Cattle or Sheep) and the intermediate host lymnaeid Fresh Water snails. While numerous fluke eggs are deposited in faeces of infected grazing livestock, the fresh water snail must be present for the liver fluke to complete its life cycle and proceed along its infectious pathway into grazing livestock. Liver fluke can have a relatively long lifecycle, 12-18 weeks over spring / summer and 25 weeks from autumn / winter through to spring.

The presence of liver fluke is dependent on moist / wet environment and the snail. These conditions are favourable for the intermediate host to be present. They are more commonly found in marshy, boggy country, and less in dams or large creeks. Snails multiply rapidly in spring and summer, leading to heavy contamination of pasture in late summer to autumn, allowing cattle to pick up fresh larvae in autumn through to early winter.

Adult liver fluke (Trematodes) are visible to the naked eye in the liver and bile ducts of infected livestock. They are flat and leafed shaped of a brown / grey colour and are found to be approximately 20-25mm in length.

Fun fact, liver fluke are hermaphrodites (they have both male and female sex organs in the one body).

Symptoms:
Typical symptoms of cattle and in particular young calves ingesting large amounts of fluke larvae (metacercariae) in the autumn can suffer acute fluke disease as seen in cattle and sheep, (jaundice, bottle jaw, loss of condition, death). The usual condition seen is chronic fascioliasis (slow growth rates, loss of body condition of cows after calving cows, lost milk production especially after calving). Heavy infections are often associated with wet summers / autumns. Disease signs may only be seen in winter, after the accumulation of larvae in autumn.

Check:
Local district knowledge from livestock advisers including but not limited to, local Veterinarians, Livestock agents, Resellers and alike. While, bulk milk vat test (for dairy farmers), blood test and faecal egg counts can guide you, the Fresh Water snails need to be present and identified.

Prevention & Treatment:
A combination of the following three strategies, can reduce the risk and severity of liver fluke infection to your livestock, they include;

1. Drenching of livestock to remove the fluke: April and August.

A drench with the active Triclabendazole is the drug of choice, such as Fasinex, Flukazole oral or Abatch Pour-On as it kills both adult and all immature and juvenile stages of fluke.

A range of Injectable drenches are available some with a combination of Nitroxynil or a Macrocyclic Lactone (ML) + Clorsulon – is effective against adult fluke and immature stage as well as a range of gastrointestinal parasites and sucking lice species.

Young stock should be treated with Triclabendazole based drenches in autumn and again in winter period. Adult beef cattle should be treated once with Triclabendazole in late autumn, or twice (May & August) in severe areas. Introduced stock from drier areas should be treated more frequently as they are more susceptible.

In all cases, check withholding periods of your class of cattle to be treated.

2. Removal of the snail by fencing off the snail habitat like swamp and boggy areas will assist.

Fencing off or draining swamps can be very effective. Chemical control to kill snails has been attempted but may be an environmental hazard and snails multiply rapidly the next season.

3. Control by grazing management systems incorporating rotational grazing of areas with different classes of livestock.

Compiled by
Andrew Schmetzer
Senior Farm Consultant
B.App.Sci.Ag. Post.Grad.Ruminant Nutrition.
Ph: 0408 366 599.
Meridian Agriculture
96 Harbours Road, Yendon, VIC 3352 | P: 03 5341 6100