Biosecurity practices of bovine tuberculosis affected French cattle farms between 2016 and 2023

In recent years, interest in biosecurity practices on livestock farms has expanded considerably, with improvements noted in pig and poultry farms but limited progress in cattle farms. In France, data regarding biosecurity practices in cattle farms remains scarce. Bovine tuberculosis (bTB) is one of the main animal health challenges. Each case leads to mandatory epidemiological investigation, led by state services. Biosecurity practices are also described. This creates a valuable data source to describe biosecurity practices in bTB-affected farms. This study aimed to describe biosecurity practices in French bTB-affected farms and identify factors associated with their biosecurity levels. Official investigation questionnaires from bTB-affected cattle farms between 2016 and 2023 located in two French administrative regions were collected, and 153 of them were analysed. Thanks to nine international experts in cattle biosecurity and/or bTB, risk scores were calculated regarding biosecurity practices related to animal introductions, contacts between herds, contacts with wildlife, visitors' management, equipment sharing, and effluent management. A global risk score was then calculated. Regression models were used to examine relationship between risk scores and predictors (e.g., herd size, production type, previous bTB outbreaks). Results revealed significant variability in biosecurity practices, with higher mean risk scores for animal introduction and wildlife-livestock contact. Production type, presence of a non-bovine unit, location and presence of wild boars around the farms significantly influenced biosecurity scores. Although the data provided by these questionnaires were incomplete, this first study suggests that biosecurity practices could be linked to farms typologies.