Do Dairy Farming Systems Differ in Antimicrobial Use?

SIMPLE SUMMARY: The overuse and misuse of antimicrobials in dairy farming may lead to the development of antimicrobial resistance and thus to the reduction of the antimicrobial treatment efficacy against animal or human bacterial diseases. This study aims to investigate antimicrobial use differences in four farm groups: mountain farms with specialized high-yield dairy breeds or with dual-purpose breeds raised for milk production, and lowland farms with specialized high-yield dairy breeds or with dual-purpose breeds raised for milk production. From the results, we found a significant difference between mountain farms with dual-purpose breeds and lowland farms with specialized breeds for the overall antimicrobial use and for the use of those antimicrobial classes that are most important in human medicine. Mountain farms have a generally lower milk production and smaller herd size than lowland farms, provide cows with access to pasture, and limit concentrates in the diet. These management practices and the use of local/dual-purpose breeds could reduce the risk of production diseases and the consequent need for antimicrobial use. ABSTRACT: The quantitative assessment of antimicrobial use (AMU) in food-producing animals contributes to the provision of essential information for developing relevant and effective policies to reduce use and to control antimicrobial resistance. Information on AMU is available mainly for intensive dairy farming systems and specialized high-yielding breeds. The aim of this study is to investigate AMU in different dairy farming systems by comparing the treatment incidence in mountain farms with specialized high-yield dairy breeds or with dual-purpose breeds raised for milk production to the treatment incidence in lowland farms with specialized high-yield dairy breeds or with dual-purpose breeds raised for milk production. Significant differences were found only between the overall treatment incidence, as well as the treatment incidence of highest-priority critically important antimicrobials for human medicine, in lowland farms with high-yielding breeds and mountain farms with dual-purpose breeds. Mountain farms have a generally lower milk production and smaller herd size than lowland farms, provide cows with access to pasture, and limit concentrates in the diet. These management practices and the use of local/dual-purpose breeds could reduce the risk of production diseases and the consequent need for AMU.