Cherrill Bedford ^1* Maria L. Galotta ² Guadalupe de Yaniz ² Georgios Oikonomou ¹ Matías Nardello ² Peers Davies ^1* Sergio Sanchez Bruni ²

• ¹ University of Liverpool, Liverpool, United Kingdom
• ² Centro de Investigación Veterinaria Tandil, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Tandil, Buenos Aires, Argentina

Antimicrobial resistance is a challenge to be faced by all sectors; within beef farming, antibiotic use patterns vary by country and management practices. Argentina is a country with high beef consumption but limited information surrounding antibiotic use. The aims of our project were to understand how antibiotics are being used across the beef industry in Argentina and exploring drivers of usage. We collected data via four methods: A survey of farms including antibiotic use (from purchase data); a detailed survey of two farms’ therapeutic antibiotic use; a survey of vets' views on certain antibiotic practices; a focus group of farmers and vets focusing on wider influences affecting decision making. Antibiotic use data was calculated using mg/population corrected unit (PCU) using the European Surveillance of Veterinary Antimicrobial Consumption method (ESVAC). The median use across 17 farms that supplied purchase data was 76.52 mg/kg PCU (ESVAC) (IQR = 36.81 mg/kg PCU [ESVAC]). The detailed farm records showed that the largest reason for treatment was group treatments (72.92% of treatments) followed by treatment for respiratory disease (12.75% of treatments). Macrolides accounted for 76.37% of treatments. Nearly half of farms used routine prophylactic treatment for arriving animals (n = 7/18). The use of quarantine and sick pens were seen as important by surveyed vets with antibiotic prophylaxis and in-feed antibiotics seen as contributors to antibiotic resistance. The focus group highlighted the effect of the economic and political landscape on the way they farmed and recognised the responsibility the farming sector had towards antibiotic stewardship. Overall, Argentine beef farms resemble North American beef farms in terms of antibiotic practices but with considerably lower usage. Monensin is widely used in Argentine beef farms and represents a large proportion of total ABU. The adaptation period presents a challenge to animal health; antibiotics are used in a range of measures from prophylaxis to individual treatment depending on farm management practices. Further research into internationally comparable measures of ABU and detailed cost breakdowns of practical on farm interventions are needed to aid improved antimicrobial stewardship in countries such as Argentina.