Tailoring Biosecurity Advice in Dairy Cattle Farms: Decision Analysis to Estimate the Most Cost-Effective Option

The implementation of biosecurity measures on dairy farms is influenced by multiple factors, including farmers' experience, perception of disease risk, social influences, and epidemiological and economic factors. The aim of this study was to identify the biosecurity option providing the highest economic return for dairy farms. To achieve this, a biosecurity cost calculator was developed using a database of prices associated with the different components required to implement each biosecurity measure. The probability of pathogen introduction was estimated through a quantitative risk assessment model, while the economic consequences of a disease outbreak were evaluated using the stochastic dynamic model SimHerd. The outputs from these tools were combined through decision tree analysis, integrating scenario costs with the estimated probability of occurrence. For each scenario, the expected monetary value (EMV) was calculated, and the alternative with the highest EMV was considered the most profitable option. Bovine viral diarrhea (BVD) was used as a case study because of its well-documented effects on dairy production. The framework was applied to three dairy farms located in northeastern Spain, where biosecurity and production information were collected. The annual biosecurity cost per cow was estimated at €27.49, €44.50, and €71.94 for farms A, B, and C, respectively. The annual probability of BVD introduction under current conditions was 2.66%, 15.70%, and 0.36% for the same farms. Simulation of a BVD outbreak indicated an average reduction in gross margin (GM) of ~6% during the first 5 years after introduction. Across the evaluated scenarios, the provision of dedicated boots for cattle transport drivers was identified as the most economically advantageous measure. The proposed framework enabled the comparison of biosecurity interventions by jointly considering implementation costs and risk reduction. By demonstrating the economic and epidemiological value of biosecurity, this approach may support decision-making and encourage wider adoption of preventive measures on dairy farms.