Improving sustainable parasite control in British dairy cattle

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The development of tools to inform and promote sustainable parasite control is a priority from a One Health perspective. This study aims to improve the understanding of parasitic diseases in British dairy cattle and of animal health, production and food safety within the scope of controlling parasitic infections. This project will then develop and assess tools to promote sustainable parasite control, reducing reliance on antiparasitics and their associated concerns such as drug resistance, public health and the environment. Through collaboration with UK National Milk Records (NMR), information will be gathered of their existing clients (~40% of British dairy farms) relating to production records, grazing practices and parasite control strategies through the use of existing milk recording data and a brief questionnaire. This allows identification of farms that graze lactating dairy cattle for subsequent seroprevalence analysis and herd level factors of parasitic infection. Seroprevalence estimates will be obtained UK-wide via bulk tank milk (BTM) sample testing. Parasite-specific antibody ELISA's will be used to determine herd-level exposure to Ostertagia ostertagi, Fasciola hepatica and Dictyocaulus viviparus which are estimated to cost the UK dairy industry in excess of £147 million annually (Charlier et al., 2020). Longitudinal sampling will be utilised during the 2024-2025 grazing season to provide UK spatio-temporal distribution for each parasite, with further targeted testing to assess and validate disease risk forecasting models developed below. Concurrent analysis of seroprevalence allows opportunity to determine relative abundance and timing of infection risk periods. Climate warming is estimated to have already impacted the geographic distribution and seasonal abundance of some parasite species, which could result in an unexpected difference in seasonal risk of parasitic infection (Veneer, 2020). The use of disease-risk forecasting models can form part of a sustainable parasite control plan. Seroprevalence data collected will subsequently by used to assess, develop and validate existing meteorological-based mechanistic disease risk forecasting models for each parasite with the aim of identifying whether these models may be used to determine risk periods for targeted diagnostic testing and therapeutics use. This hypothesis will then be tested on candidate farms in the 2026 grazing season.To quantify the impact of helminthiasis on animal productivity, the relationships between seroprevalence and NMR health data will be explored to identify and further refine targeted testing and treatments to the individual level. In collaboration with Newcastle University, these relationships will then be further explored with on-farm pharmaceutical usage and milk residue testing to provide an understanding of the risk to food safety, food chain contamination and environmental implications of antiparasitic use. It will be assessed whether the proposed developments, interventions and tools postulated by this study may improve the sensitivity of residue testing strategies by allowing more focused testing during high risk periods. It is hypothesised that this study will improve the understanding of parasitic disease in British dairy cattle and quantify the impacts of this on both public, environmental and animal health. Moreover, it is hypothesised that this study will develop disease risk forecasting models to identify periods of risk and contribute to sustainable parasite control. References:Charlier et al. (2020). doi:https://doi.org/10.1016/j.prevetmed.2020.105103.Vineer, H. (2020). doi:https://doi.org/10.1016/j.cvfa.2019.11.002.