“Not a problem because we drench for it”: the management of liver fluke on sheep farms

Background: (liver fluke) imposes major productivity and welfare costs on ruminant systems and is increasing in temperate regions such as the UK. In the absence of vaccines, control on sheep farms remains heavily dependent on flukicides, particularly triclabendazole (TCBZ), despite widespread reports of reduced efficacy and resistance. Thus, understanding how farmers perceive and manage fasciolosis risk is critical to improving sustainable control. Methods: Between October 2023 and October 2024, semi-structured, in-depth interviews were conducted with farmers from 16 sheep farms across Wales, U.K. purposively recruited through farmer networks and social media. Interviews (mean length 52 min) were audio-recorded, transcribed, and analysed using an inductive thematic approach. Results: Despite heterogeneous farm types, farmers described fasciolosis as a "high stakes, low certainty" problem characterised by diagnostic ambiguity, limited confidence in test results, and difficulty distinguishing fluke impacts from other causes of ill-thrift. This uncertainty promoted risk-averse practises, with flukicide use functioning as "treatment as agency" and as habitual "insurance", often substituting for diagnostics due to cost, logistics, and turnaround time. Concerns about TCBZ resistance added further complexity but tended to influence behaviour after perceived treatment failure. A third theme, "making it fit", highlighted how control strategies were shaped by farm-specific geography, labour constraints, economics, and variable access to trusted veterinary support, limiting uptake of non-chemical measures and targeted treatment. Conclusion: Sheep farmers manage fasciolosis through pragmatic, risk-averse reliance on flukicides in the face of perceived diagnostic and advisory limitations. Interventions that improve practical access to reliable diagnostics, farm-specific risk profiling, and trusted, implementable guidance may reduce prophylactic treatment and support greater integration of non-chemical control, helping to mitigate flukicide resistance and improve sustainable fasciolosis management.