Optimising liver fluke management in cattle

Summary

Liver fluke infection remains a widespread challenge for cattle enterprises in the high-rainfall regions of south-eastern Australia. This project aimed to optimise producers’ management of liver fluke through investigating the prevalence of liver fluke, evaluating drench resistance, and determining the impact of drench timing on the growth of young cattle. Faecal egg counts, fluke egg count reduction trials and treatment comparison trials were conducted across beef properties in northeast Victoria and southeast New South Wales.

Liver fluke was commonly detected, although several farms with suitable environments showed no infection, highlighting the need for evidence-based monitoring rather than routine drenching. Resistance to triclabendazole was confirmed on all seven core producer farms; however, no measurable production loss from resistance was identified, likely due to low burdens, compromised but sufficient efficacy, or short monitoring periods. Pre-winter drench timing affected winter growth rates, with poorly timed treatments reducing growth of weaners by 8–15%. Economic analysis showed no direct cost from resistance but demonstrated substantial impacts from incorrect drench timing, influencing gross margins and production costs.

Extension activities improved producer knowledge, skills, and confidence, leading to practice change. The project underscores the importance of strategic drenching, routine monitoring, and further research into productivity impacts and improved diagnostic protocols.  

Objectives

By September 2025, in northeast Victoria and southeast New South Wales:  

1. Estimate the prevalence of liver fluke in beef cattle by conducting fluke egg counts on faeces collected from cattle on three to five core and 30 observer producer farms  

2. Determine the prevalence of liver fluke drench resistance to triclabendazole by fluke faecal egg counts on core producer properties and/or on observer producer properties where fluke has been identified through the prevalence survey  

3. Using focus groups with core and observer producers, record their current protocol for controlling liver fluke in cattle, including use of drench, monitoring and environmental control (eg. fencing off ‘flukey’ areas)  

4. Set up three different treatment/monitoring protocols for the control of liver fluke in cattle on three to five core farms with known liver fluke, and demonstrate the effects on:  

   • Weight gain in young stock - show any increase in growth rate in the 6-month period following treatment   

   • Fluke faecal egg counts (used to monitor infection), and  

   • Livestock Data Link for abattoir feedback (used to monitor infection).  

5. 100% of core producers and 50% of observer producers will have increased their knowledge and confidence in managing liver fluke  

6. Seventy-five percent of core producers and 50 percent of the observer producers will intend to adopt/or change their current management with revised treatment, monitoring and control protocols in their area  

7. Conduct a workshop with the core and observer producers to discuss the results of the prevalence survey and drench resistance results.   

8. Conduct an end of PDS field day to showcase the treatment, monitoring and control protocol demonstration results to 50 producers in north-east Victoria and south-east NSW.  

Key findings

The key findings from the demonstration sites included:

• Liver fluke was prevalent on beef farms in northeast Victoria and southeast New South Wales as expected, however on some properties, which had an ideal environment for liver fluke, infection could not be detected through faecal monitoring for fluke eggs. This highlighted the importance of monitoring for liver fluke, rather than just drenching cattle because liver fluke is assumed to be on the property. Properties with low fluke egg counts who traditionally drenched for fluke may not need to drench every year and could use monitoring to inform this decision.
• Drench resistance to a commonly used drench, triclabendazole, was found on all seven core producers properties involved in the PDS. However, no production impacts could be identified as a result of drench resistance on these properties. This may be a reflection of:
  • Low fluke burdens
  • Triclabendazole retaining sufficient efficacy to prevent production impacts despite the detected presence of resistance
  • The short time of monitoring being insufficient to show the effects of drench resistance
• There was potentially a 9 to 11 kg disadvantage over the winter/early spring period in weaners that did not receive a pre-winter drench, compared to weaners that did on farms with higher fluke egg counts.
• The timing of the pre-winter drench to strategically control liver fluke in cattle is important to ensure optimal growth rates in weaners over the winter/early spring period, with impacts on growth rates from 6.8 to 13 kg over this period.
• Challenges identified in this project included:
  • Not enough farms identified with fluke or high enough fluke egg counts included.
  • The limitations of using fluke egg counts to inform timing of pre-winter drenches when, given this only monitors adult fluke infection in cattle and not the presence of recently acquired immature fluke.

The key findings from the economic analysis include the following: 

• There was no economic impact observed due to drench resistance, despite all seven core producer properties having drench resistance present. Reason for this are outline above. The drench resistance trial did demonstrate that there was a reduced gross margin and increased cost of production associated with leaving animals undrenched over the winter/early spring period.
• The timing of the pre-winter drench had an impact on the gross margin ($10/DSE) and cost of production ($0.25/kg) due to differences in kilograms of beef produced per hectare (32 kg/ha), with the standard practice of one of the core producer properties determined to be drenching at the most optimal time, while one treating too early resulting in reduced growth rates over the six months following drenching.

The extension and communication activities that occurred throughout the duration of this PDS included:

• Workshops/seminars
• Written communication through Mackinnon Project newsletter
• Verbal communication through attendance to better beef groups
• Written communication in Agriculture Victoria’s email list, Newsflash – Beef and Sheep Networks
• Case studies and producer factsheets featuring results of demonstration sites of core group members for MLA Feedback magazine

The monitoring and evaluation outcomes as a result of the PDS:

• Despite limited post project survey responses and only two of four focus groups being held at the end of the project, there were benefits from the project observed through knowledge, skills and confidence, and practice change observed in both the core and observer producers.
• There was an increase in knowledge in 85% of core producers and 52% of the observer producers in the four key areas assessed.
• The skills of the core producers in relation to when they drench, what product they use and if they monitor for liver fluke in their cattle increased as a result of the outcomes of the PDS.
• The confidence of core producers increased from 5.8 to 7.6 out of 10 with 80% of producers indicating they felt more confident managing liver fluke, and the confidence of observer producers increased from 4.9 to 7.6 with 100% indicating that they felt more confident.

Benefits to industry

• Improved monitoring for fluke infections through fluke egg counts or copro-antigen ELISA is a tool that more producers in the red meat industry need to adopt to enable informed decisions around the timing of a drench and if a drench is needed or not, rather than routine drenching.
• Confirmation of resistance on producer’s farms, despite no demonstrated production impacts, is still important to enable producers to make informed decisions about which drench product to use, prolonging the effectiveness of an important drench to the red meat industry.
• Optimising the time of the pre-winter drench will improve the kilograms of beef produced per hectare.
• Liver fluke is having an impact on production if left untreated and could reduce overall profitability of red meat enterprises.

MLA action

MLA continues to deliver the Producer Demonstration Site (PDS) program, supporting livestock producers working in peer-to-peer groups to pursue new skills, knowledge and management practices applicable to their own commercial livestock production systems.

Future research

Based on the results of this project, there were three areas for future research. These were:

• What is the impact of drench resistance
• having on productivity?
• What impact is fluke having on productivity, especially on farms which have low fluke egg counts?
• Improved monitoring protocols to inform drenching decision.