Improving the control of liver fluke infection in cattle in the UK

Lead Research Organisation: SRUC
Department Name: Research

Abstract

Liver fluke is a common parasite that affects sheep and cattle in the UK. It is found throughout the world and in some countries it affects humans too, causing serious and sometimes fatal disease.
Fluke infected cattle lose weight, become anaemic, lethargic and stop being productive. This has a serious effect on the welfare of the animal and serious economic consequences for the farmer. It is thought that fluke costs UK agriculture at least £300million pounds a year through direct losses, but real costs are probably much higher.
Fluke has become much more common over the past 10 years, due in part to our changing weather patterns, wet summers and mild winters favour the development of the parasite and its vector - a mud snail, found commonly throughout Britain. In a recent study we found 75% of dairy herds had evidence of fluke infection. Future climate change is predicted to have a significant impact on prevalence of infection, changing the epidemiology and increasing incidence of disease. Increased cattle movements and changes to both farm management and environmental schemes are exacerbating the problem. A limited range of drugs is available to control fasciolosis. Only one drug - triclabendazole (TCBZ), is effective against early and late juvenile and adult stages of the parasite and is used extensively for prophylaxis and treatment of disease. There is growing evidence of resistance to TCBZ in fluke populations, moreover the European Medicines Agency has recently revised its advice on drugs used to treat fluke such that they are now contra-indicated in dairy animals.
Targeted use of drugs, at specific times of year will slow the development of drug resistance and reduce the overall quantity of drug used, but a better understanding of the epidemiology and transmission of disease is vital if we are to develop control programmes that rely on improved on farm management practises rather than depending solely on drugs. This ultimately will be a sustainable and cost-effective way to control both clinical and sub-clinical disease in cattle and is the express desire of the livestock industry.
Specifically requested by the farming industry, the purpose of this project is to produce new, sustainable, bespoke control programmes for beef and dairy farms, to reduce losses associated with fluke infection.
In order to achieve this we must first develop diagnostic tests to identify infected herds. We already have good tools that we can use on milk samples to detect infected dairy herds but we need similar tests that are appropriate for beef herds. In addition we are aware of a newly emerging parasite problem, the rumen fluke. It is not clear if this parasite causes disease but it has the potential to interfere with the diagnostic tests we are developing for fluke. Therefore we will also develop a molecular test for rumen fluke.
Secondly we will develop a system to categorise snail habitats that can be used to analyse satellite maps on a regional geographic scale to obviate the need to visit every farm to investigate snail habitat. We will also investigate how cow behaviour affects how the parasite gets to a snail host and from the snail host back to the cow.
These are risk factors for fluke infection on a farm. Other risk factors, particularly husbandry practices, physical and environmental factors will be obtained from a study of 250 farms and these data fed into statistical and mathematical models to determine theoretically which of these factors are the most important in determining whether a farm has fluke or not. Concurrently we will assess the cost-benefit of changing these practices. Finally we will conduct a trial to evaluate if changing farm practice is effective in reducing levels of infection. We are working in partnership with the Agricultural Levy boards of the UK to implement improved control of fluke infection to benefit animal health, welfare and profitability of livestock farming in the UK.

Technical Summary

Requested by the farming industry, the purpose of this project is to produce new, sustainable, bespoke control programmes for beef and dairy farms, to reduce losses associated with F. hepatica. This is a focussed, integrated project combining cutting-edge mathematical and economic models, informed by data collected from the field culminating in farm level intervention programmes to fully evaluate the theoretical outputs from the models. The project is divided into five interlinked workpackages:
WP1: Development and validation of herd level diagnostic tests, to identify farms with fluke infection and to discriminate between Fasciola and paramphistome infection
WP2: Field level classification of snail habitats and identification of factors that influence contacts between cows, snails and the parasite.
WP3: Identification of on farm risk factors for F. hepatica infection in dairy and beef enterprises and development of statistical and mathematical models to predict the likely benefits of implementing changes to farm practice on fluke prevalence
WP4: An economic analysis to define costs of fluke infection at herd and national level
WP5: Evaluation of on-farm intervention programme on reducing prevalence of fluke infection on dairy and beef farms.
The disease is of such importance and relevance to the industry that all five UK agricultural levy boards are making significant contributions to this project. To ensure the outputs of the research are fed back to the industry the final component of the project is an implementation and impact programme in collaboration with the levy boards.

Planned Impact

This project, aimed at "Improving the control of liver fluke infection in cattle in the UK", will benefit the commercial private sector, policy makers and the wider public.
Commercial impact
Liver fluke has been identified as a threat to animal welfare, productivity and profitability by the agricultural industry; this proposal is submitted with full support from the 5 UK Levy Boards. Fasciolosis is a significant constraint on beef and milk production in the UK. The parasite affects feed conversion, growth rates and milk yield and has a negative impact on farmers' incomes, abattoir profitability (in 2010 this was estimated to cost the industry about £3.2million in England, Wales and Scotland) and availability of meat and dairy products for export and home consumption. Cereal costs are increasing world wide - this is severely affecting the cost and profitability of producing beef and dairy and appears to be driving a move to grass reared beef. Grass-fed cattle are at an increased risk of exposure to liver fluke. In addition, warmer and wetter winters, environmental protection schemes, resistance of liver fluke to drugs, and the potential withdrawal of treatment products from the market may add to the risk of infection and limit the options for disease control. The outputs from this project will directly benefit beef and dairy farmers, enabling them to improve fluke control on their farms, reducing reliance on blanket drug treatment and improving productivity and biological efficiency. Abattoirs will have a secure supply of animals with reduced waste, dairy processing companies will benefit from improved milk yield and the retail sector will benefit from improved local production. Overall this will benefit the wider UK economy.
Policy impact
The UK has international (Kyoto Protocol) and domestic (Climate Change Act 2008) targets to reduce greenhouse gas (GHG) emissions. Enteric fermentation in ruminants makes a significant contribution to agricultural GHG emissions (http://www.decc.gov.uk/en/content/cms/statistics/climate_stats/gg_emissions/gg_emissions.aspx). Disease management has been specifically identified as a tool to improve agricultural productivity whilst reducing GHG emissions (Foresight. The Future of Food and Farming, 2011). This project will produce validated protocols, epidemiological and economic models and robust guidelines for detection and management of liver fluke on cattle farms, which will contribute to the dual policy aim of providing food security whilst limiting agriculture's carbon footprint. Another policy goal of the UK and devolved governments is to protect the country's Ecosystem Services. For example, it is part of Defra's business plan to establish nature improvement areas (http://www.number10.gov.uk/wp-content/uploads/2012/05/DEFRA-2012-Business-Plan.pdf). However, environmental protection schemes may result in unintended side effects as shown by the increase in liver fluke risk in association with the Agri-environment schemes that encourage wetter grassland conditions for breeding and migrating birds and invertebrates, including liver fluke host snails. Improved understanding of on-farm risk factors for liver fluke, including snail ecology, will help policy makers to balance demands from competing ecosystem services, such as food production and conservation of biodiversity. Involvement of the Levy Boards will ensure direct dissemination of the outputs to both commercial beneficiaries and policy makers.
Wider public
The reliable availability of affordable and healthy food is in the interest of the wider public. Beef and dairy product supplies, their quality, environmental impact and price depend on an international balance of trade which will be affected by the prevalence of fasciolosis. Our economic models will include an assessment of impacts on national markets and hence indicate consumer benefits from a more secure supply of food, produced to higher environmental and welfare standards

Publications

10 25 50
 
Description Project outcomes @March 2017 for:

WP4 - A herd level economic model has been parameterised for dairy, grower, suckler and finisher enterprises. This will be used in the next stage when inputs regarding potential control measures are provided from WP3 (Univ Liverpool). The winners and losers at a national level, when fluke prevalence changes in the national dairy herd have been identified (national economic welfare model). Development of a national economic model for two beef management systems is under way.

Project Outcomes @ March 2019
From the national level economic welfare models (two beef finishing systems and the dairy herd) - Interventions to control the herd-level national prevalence of liver fluke could favour consumers of milk and beef as well as farmers of infested herds in the UK.
There is an overall loss for the UK associated with liver fluke in the national dairy and beef herd systems. Farmers of dairy and beef herds infested with liver fluke and milk and beef consumers lose out financially as a result of the parasite, while farmers of uninfested herds benefit financially. Hence, interventions to control the herd-level prevalence of liver fluke could favour consumers of both milk and beef as well as farmers of infested herds in the UK, while reducing the financial benefits that farmers of uninfested herds currently experience.

From the herd-level intervention models - there is substantial variation between different industry sectors in the potential gain/loss to be made in a herd by the application of the same intervention. Different interventions will be better for different systems and in all systems it is essential to know your herd status, in order to optimise the gain.
Exploitation Route The findings will inform policy makers on the relative economic importance of fluke as an endemic disease. For the industry, combined with outputs from other work-packages in this award it will lead to improved advice on cost-effective control measures and improved strategies.
Given sufficient funding to do so, there is potential for the herd-level intervention models to be adapted into a herd-level cost calculator that could be used in individual circumstances to demonstrate the farmers the effect on their herd. This could be combined with outputs from other work-packages to provide tailor-made farm-specific advice i.e. into a consultancy service.
Sectors Agriculture, Food and Drink,Environment

 
Description Members of the consortium have participated or organised 16 workshops and presentations to farmers groups, industry, vets through CPD and the public (2014). This has raised awareness of the impact of fluke infection in cattle, in terms of disease and welfare of individual animals but also the economic impact of sub-clinical infection. We have also had impact on the use of the drug, triclabendazole. We recently tweeted and published a news flash through the COWS website advising on the treatment of cattle this autumn after a dry year for much of the country (http://www.cattleparasites.org.uk/news/pr03.html (2014) Throughout 2015, continued dissemination to farmers groups, industry, vets and the public, through CPD, workshops, briefings and presentations have maintained awareness levels, as above, despite an initially low level of fluke occurrence. There is some evidence that as a result there is increased use of diagnostic testing. Such dissemination continued throughout 2016 and 2017. There is further evidence that as a result there is increased use of diagnostic testing. In 2017 conditions have raised the level of fluke occurrence and increasing numbers of cases of resistance to the commonly used treatment are being identified. This increases the need for alternative feasible, practical control measures and messages. In 2018,workshops and presentations to farmers groups, industry, vets and other scientists have maintained awareness of fluke, despite the atypical year weather-wise. In the intervention work-package, we worked with a number of farmers to establish the feasibility of some of the intervention options. Outputs from this study and the economic modelling have been translated into industry facing outputs e.g. the revision of COWS material. This should lead to impacts within the industry despite the award coming to an end. However it is difficult to specifically measure what contribution to the overall impact can be attributed to this workpackage/award.
Sector Agriculture, Food and Drink
Impact Types Economic

 
Title Herd level economic models for fluke control with interventions 
Description The initial herd-level economic models are being adapted to incorporate a number of identified potential intervention strategies into the partial-budget. 
Type Of Material Computer model/algorithm 
Year Produced 2018 
Provided To Others? No  
Impact Not yet 
 
Title Herd-level structural models for economics of liver fluke 
Description Herd-level stochastic models for the different sectors of the British cattle industry - growing animal, beef suckler herd and dairy enterprises - were developed. These can each be modified to simulate the major management systems used. Variables were parameterised with estimates derived from: literature, publically available data, industry and expert opinion, and implemented using @Risk. Linked to partial-budget models, they have been run for fluke vs. no fluke. 
Type Of Material Computer model/algorithm 
Provided To Others? No  
Impact Outputs from these models will be aggregated to estimate national/regional net benefits of improved control of fluke of use for policy decision support. This will enable the devlopment of the next objective - the national economic welfare models for the dairy and beef industries. In later stages of the work, the suite of models will also provide a means to rank (by cost-benefit) potential control measures based on improved management practices. 
 
Title National economic welfare model for dairy cattle for fluke 
Description National economic welfare model for dairy cattle for fluke 
Type Of Material Computer model/algorithm 
Provided To Others? No  
Impact Baseline outputs for next stage of award 
 
Title National economic welfare model for two beef industry systems 
Description A national-level economic welfare model (Barratt et al., 2018) was adapted and then used to simulate the market-level impacts of liver fluke per year. The national-level economic model estimated changes in the price and quantity of milk and beef produced, and the associated net economic welfare, i.e. financial gains or losses, for farmers of infected herds, farmers of uninfected herds and for consumers. The objective was to estimate the net economic welfare due to liver fluke for selected UK production systems, for three stakeholder groups, for a number of scenarios based on different herd-level prevalence estimates. The beef production systems selected were 18 month finishing beef breed cattle that were spring/summer born and 24 month finishing beef breed cattle that were autumn/winter born. The three stakeholder groups were:farmers with uninfected herds, farmers with infected herds, and consumers. The model outputs were compared with those of the NEWM for dairy cattle, which was developed previously. The conclusions were: On aggregate, the UK loses out financially as a result of liver fluke with the absolute economic effects in the dairy sector being relatively higher than those for the beef finishing sector. Farmers of dairy and beef finishing herds infected with liver fluke and milk/beef consumers lose out financially as a result of liver fluke, while farmers of uninfected beef and dairy herds benefit. The winners (i.e. farmers of uninfected herds) gain more as herd-level prevalence increases and gain less as herd-level prevalence decreases. The losers (i.e. farmers of infected herds and milk/beef consumers) lose more as herd-level prevalence increases and lose less as herd-level prevalence decreases. 
Type Of Material Computer model/algorithm 
Year Produced 2019 
Provided To Others? No  
Impact Final project report to levy boards/industry partners - impact not yet fully realised 
 
Description Co-infection of liver fluke and E.coli O157 in cattle 
Organisation Moredun Research Institute
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution SRUC provides the study sampling design, epidemiological input and interpretation, questionnaire data, and faeces samples from study FS101055; plus input, and critical review of the publications (2) that were outputs of this collaboration.
Collaborator Contribution Moredun provided the original idea and the copra-antigen testing; UOL statistical modelling for the sample size calculations and the data analysis
Impact Output - G.L. Hickey, P.J. Diggle, T.N. McNeilly, S.C. Tongue, M.E. Chase-Topping, D.J.L. Williams. The feasibility of testing whether Fasciola hepatica is associated with increased risk of verocytotoxin producing Escherichia coli O157 from an existing study protocol. Preventive Veterinary Medicine (2015) 119 (3-4) 97-104 http://dx.doi.org/10.1016/j.prevetmed.2015.02.022 Output - A. K. Howell, S C. Tongue, C. Currie, J. Evans, D.J.L. Williams, T.N. McNeilly,Co-infection with Fasciola hepatica may increase the risk of Escherichia colii O157 shedding in British cattle destined for the food chain. Preventive Veterinary Medicine (2018) 150 70-76 https://doi.org/10.1016/j/prevetmed.2017.12.007 Posters at ISVEE 14 (2015) and WAAVP 2015 on output 1
Start Year 2015
 
Description Co-infection of liver fluke and E.coli O157 in cattle 
Organisation University of Liverpool
Country United Kingdom 
Sector Academic/University 
PI Contribution SRUC provides the study sampling design, epidemiological input and interpretation, questionnaire data, and faeces samples from study FS101055; plus input, and critical review of the publications (2) that were outputs of this collaboration.
Collaborator Contribution Moredun provided the original idea and the copra-antigen testing; UOL statistical modelling for the sample size calculations and the data analysis
Impact Output - G.L. Hickey, P.J. Diggle, T.N. McNeilly, S.C. Tongue, M.E. Chase-Topping, D.J.L. Williams. The feasibility of testing whether Fasciola hepatica is associated with increased risk of verocytotoxin producing Escherichia coli O157 from an existing study protocol. Preventive Veterinary Medicine (2015) 119 (3-4) 97-104 http://dx.doi.org/10.1016/j.prevetmed.2015.02.022 Output - A. K. Howell, S C. Tongue, C. Currie, J. Evans, D.J.L. Williams, T.N. McNeilly,Co-infection with Fasciola hepatica may increase the risk of Escherichia colii O157 shedding in British cattle destined for the food chain. Preventive Veterinary Medicine (2018) 150 70-76 https://doi.org/10.1016/j/prevetmed.2017.12.007 Posters at ISVEE 14 (2015) and WAAVP 2015 on output 1
Start Year 2015
 
Description BCVA 2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Poster and questionnaire to explore whether the economic models would be worthwhile adapting into a herd cost calculator; explore veterinary practitioners views

Published in proceedings
Year(s) Of Engagement Activity 2016
 
Description BCVA Congress 2014 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Poster presentation at the three day congress that highlighted the work that would be done within this award and supported a presentation given by other members of the consortium. Was visited by approximately 50 attendees,who engaged in discussion with the presenting author,and its visible to others. Abstract was published in Cattle Practice 22 (2) 281, so reaching a wider audience of veterinary mebers of this association of Britisho work with cattle
Year(s) Of Engagement Activity 2014
 
Description Cattle Industry Interface 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Industry/Business
Results and Impact Informing users of our research outputs about those outputs and soliciting information, whilst ground truthing our assumptions and generating 'buy-in' for outputs
In 2017 this was combined with a sheep interface day
In 2019 this was also combined with a sheep interface day - sparked discussion about liver fluke control and what the messages to the farming community could be from these economic models

Farmers are more willing to participate in our project and can feed information into the project.
Year(s) Of Engagement Activity 2013,2014,2017,2019
 
Description Cross SRUC beef, sheep and dairy KE group - March 2019 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Outcomes and outputs of results - discussion with farm business consultants and other SRUC researchers - awareness raising/dissemination and feedback from 'the ground'
Year(s) Of Engagement Activity 2019
 
Description ISESSAH 2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Abstract accepted and poster presented at 1st meeting of International Society for Economics and Social Sciences of Animal Health on the value of both the interdisciplinary working that has been necessary to develop the economic models and the economic models themselves, developed in this research award; how they can be used to inform decision making and thus achieve impact and what input might be needed from the social science field to do so.
Year(s) Of Engagement Activity 2017
URL http://www.isessah.com/
 
Description ISVEE 15 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Oral presentation and abstract in conference proceedings, in Economic section of International Society for Veterinary Epidemiology and Economics, in Thailand, well attended and a number of questions and discussion about applicability of the model and the difficulties in translating outputs into appropriate messages for the farming community.
Year(s) Of Engagement Activity 2018
 
Description ISVEE 2015 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Oral presentation 'Liver fluke - fasciola hepatica: comparative losses in key sectors of the British cattle industry' to delegates during the economics section fo the international epidemiology and economics, with associated abstract published in the proceedings. There were immediate questions and a considerable number of further discussions with other delegates afterwards, who were working in similar or associated fields. There was also arequest to use some of the materials that had been developed, as teaching materials for veterinary undergraduate students

Conference proceedings published include abstract
Year(s) Of Engagement Activity 2015
 
Description Industry Open Day 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Industry/Business
Results and Impact 2014 - small study tour of English farmers; 2014 SRUC Be-efficient Beef Open Day - presentations
Year(s) Of Engagement Activity 2014
 
Description Industry Partners meeting Jan 2019 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact End of project meeting with project team and industry partners (levy board representatives)
Year(s) Of Engagement Activity 2019
 
Description Levy Board representatives 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Briefings have been prepared for and presentations given on an annual basis to the levy board representatives who are the 'industry' part of this BBSRC-IPA. These events always raise interesting questions and provide constructive input and avenues for the research direction.
Year(s) Of Engagement Activity 2014,2015,2016,2017,2019
 
Description Northern Irish Translating research into practice day 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Project team presented at AFBI stakeholders day in autumn 2016. Near Belfast, mixed audience veterinary practitioners, farmers, other industry members, diagnostic laboratories, researchers and policy makers. Lively discussion.
'How much is liver fluke costing you? was WP4 contribution
Year(s) Of Engagement Activity 2016
 
Description Report to data providers 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Industry/Business
Results and Impact Reports on the analysis were returned to and discussed with the data providers. They then used relevant information in their own dissemination channels to acheive a wider reach within the farming community. They also asked additional questions, provided constructive feedback and a new proposal for a funding call was developed (decision on award not yet made) that involved a couple fo members of the consortium .
Year(s) Of Engagement Activity 2015
 
Description SAC consulting with farmers 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Supporters
Results and Impact Discussion about research at the SRUC

Increased willingness to participate and provide information for the project
Year(s) Of Engagement Activity 2013,2014
 
Description SVEPM 2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Abstract accepted and poster presented at Society of Veterinary Epidemiology and Preventive Medicine annual meeting on the value of both the interdisciplinary working that has been necessary to develop the economic models and the economic models themselves, developed in this research award; how they can be used to inform decision making and the necessity of epidemiological research to be integrated with other disciplines in order tp achieve impact.
Year(s) Of Engagement Activity 2017
URL http://www.svepm.org.uk/posters
 
Description Veterinary Advisors group 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Practicing livestock vets provide input into research and are informed of outputs of research

Two way information flow, informs veterinary practice
Year(s) Of Engagement Activity 2013,2014,2015,2016,2017
 
Description World Buiatrics Congress 2016, Dublin 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Comparative losses due to liver fluke (Fasciola hepatica) in key sectors of the British cattle industry - oral presentation in Economics section of the conference; questions and discussion afterwards

Conference proceedings published
Presentation available on the web (pay to view)
Year(s) Of Engagement Activity 2016