Supplementary file - Ferreira et al. Biosecurity practices in dairy farms from the south of Brazil - 2023

Biosecurity is the set of practices in a production system to prevent and/or control the entry, spread, and exit of harmful biological agents. The general aim of this study was to survey biosecurity practices and associate them according to the size of the production systems. To this end, a biosecurity assessment form was applied to 69 farms in the Campos Gerais region of Paraná. The questionnaire was divided into two sections: general and specific on the Bovine Viral Diarrhea Virus (BVDV) and Bovine Herpesvirus type 1 (BoHV-1). The general section covers topics on traffic control, quarantine and animal isolation, hygiene practices, carcass disposal, and monitoring/control of diseases. The specific section is made up of questions about reproductive and respiratory factors, the use of antimicrobials, and the vaccination schedule. The 69 farms were classified as small (≤ 61), medium (62 to 201), and large (≥ 202 lactating cows), according to the number of lactating cows. Multiple correspondence analysis (MCA) was carried out between biosecurity measures and farm size. The main risk factors and variability observed were related to traffic control of people, animals, and vehicles/equipment; animal quarantine/isolation, and hygiene practices. The MCA showed that small farms were commonly associated with a lack of biosecurity measures, such as those related to traffic control, animal quarantine, and hygiene. On medium-sized properties, contact between bovine animals of different ages and difficulty in isolating any category animal in quarantine system were some of the main risk factors. On the other hand, on large properties, isolating sick animals was easy, but the purchase of cattle was frequent and represented an important risk factor. These results contribute to a clearer understanding of the relationship between biosecurity and farm size, providing valuable insights for the development of accurate biosecurity plans that take this characteristic into account.