Endemic diseases are core drivers of medicine use in sheep. Resistance is driven by pathogen exposure to drugs within the animal and residues or metabolites in the environment. A reduction in the burden of endemic disease would reduce pressure on the existing medicines, decrease selection for resistance and reduce medicinal residues in food and the environment. Guidelines exist for the management of both parasitic disease and lameness, yet endemic disease continues to cause the industry significant challenges; negatively impacting sheep and farmer welfare.

This proposal aims to address key knowledge gaps concerning endemic diseases of sheep in Northern Ireland. Farm data will be used to co-develop, with farmers, realistic and practical, evidence based, on-farm solutions to mitigate against key endemic diseases of sheep as well as provide a case study for other UK sheep producing regions. One pillar of this work will be the application of diagnostic testing to underpin a "Test don't treat approach". In doing so this project addresses two of the strategic themes of the call: evidence-based on-farm management and the development of novel approaches to endemic disease control.

This initial one-year project aims to exploit sheep scab as an exemplar disease upon which a research framework for the control of endemic disease can be developed. Sheep scab, caused by infestation with the parasitic mite, Psoroptes ovis, is endemic in NI and represents a significant economic and welfare concern for the NI sheep industry, which consists of a national flock of ~ two million sheep at the 2019 census. There is a paucity of information on the distribution of sheep scab in NI. While some lessons could be extrapolated from previous work in Great Britain, given the highly fragmented land use by interconnected farms, driven in part by the traditional conacre system of land rental, specific data is required on the transmission and distribution of the disease in NI. This data will also serve as the basis for a model of other transmissible endemic diseases in the NI flock.

This project is centred around the farm and farmer. A series of knowledge transfer events will be held. These will include cross industry representation to allow farmers and prescribers, together, to understand the diseases and their control options. In addition, pre-intervention data will be obtained about farmer and prescriber knowledge and belief regarding endemic disease and its cost among the NI flock. Specific training will be given to local, private veterinary surgeons (vets) on current best practice for the diagnosis, prevention and where necessary, treatment of sheep scab. A system will be designed to allow farmers to self-report if they believe sheep scab is present in their flock. The project will pay for the vet's farm visit and for diagnostic testing. Standardised data will be collected and, where indicated, support given for the treatment of sheep scab. Data collected will be used to determine the distribution and transmission dynamics of scab in the NI flock, as well as assessing the behavioural economic constraints and barriers to control and the environmental impact (GHG emissions) of the disease.

Project findings will be shared with industry stakeholders. A process of co-development will be used to determine the future steps needed to control, and where applicable, eradicate disease from the national flock. This will include the optimisation of, diagnostic testing, treatment and prevention, as well as considering behavioural change for example in regard to stock movements and boundary management. Outputs from the project will be presented to government and industry policy makers in order to inform future endemic disease strategies with a focus on ensuring the legacy from this project can lead to longer term improved animal health and farmer welfare as well as contribute to the UK farming industry's stated carbon net zero aspiration.

Technical Abstract:
This proposal aims to develop foundational knowledge crucial to the development of control and eradication strategies for major endemic diseases of sheep within Northern Ireland (NI) using Sheep Scab as an exemplar disease. Data will be gathered from 100 flocks reporting the presence of Sheep Scab. Collected data will include; on farm management practices such as grazing strategies, infection risk factors such as inter and intra flock animal movements, current on-farm parasite treatment and prophylaxis strategies, and attitudes and behaviours relating to endemic sheep diseases including sheep scab. This data will be used for economic and environmental modelling of sheep scab. This modelling will focus on structural constraints and barriers to control and on the effects of sheep scab infestation on Greenhouse Gas Emissions at the farm and regional levels. Flocks enrolled in the project will be provided with an on-farm infection investigation. This will be conducted by veterinary surgeons trained and funded by the project. These investigations will include on-farm data collection and animal diagnostics for sheep scab using a blood test ELISA. Flocks with confirmed infestation will be provided with appropriate treatment materials by the project. Follow-up investigations will be offered where there is apparent treatment failure. This will assess whether there is evidence of treatment failure including if there is evidence of acaracide resistance. On the basis of this, further advice will be given to the farmer to support future prevention, treatment and control decision making. Summary findings from the project will be fed back to farmers and representative groups, the wider NI farming industry through the local farming press and social media as well as the UK industry through the Ruminant Health and Welfare Group. Key findings from this project will feed directly into the framing and development of future intervention plans for endemic diseases of sheep within NI.