A mixed method approach to analysing patterns and drivers of antibiotic use and resistance in beef farms in Argentina

Abstract

Introduction: Antimicrobial resistance is a challenge to be faced by all livestocksectors; within beef farming, antibiotic use patterns vary by country andmanagement practices. Argentina is a country with high beef production &consumption but limited information surrounding antibiotic use. The aims ofthis project was to understand how antibiotics are being used across the beefindustry in Argentina and exploring drivers of usage.Methods: Quantitative and qualitative data was collected by: A survey of breedingand feedlot farms including antibiotic use (from purchase data); a detailedanalysis of two feedlot farms’ therapeutic antibiotic use records; a survey ofvets’ views on certain antibiotic practices; and a focus group of farmers andvets focusing on wider influences affecting decision making. Antibiotic use datawas calculated using mg/population corrected unit (PCU) (ESVAC) and thematicanalysis was used to identify drivers of antibiotic use among participants.Results: 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 recordsshowed that the largest reason for treatment was group treatments (72.92% oftreatments) followed by treatment for respiratory disease (12.75% of treatments).Macrolides accounted for 76.37% of treatments. Nearly half of farms used routineprophylactic treatment for arriving animals (n = 7/18). The use of quarantine and ‘sickpens’ were seen as important by surveyed vets with antibiotic prophylaxis and in-feedantibiotics seen as contributors to antibiotic resistance. The focus group highlightedthe influence of the economic and political landscape on husbandry practices andthe responsibility the farming sector had towards antibiotic stewardship.Discussion: Overall, Argentine beef feedlots resemble North American beef feedlotsin terms of antibiotic practices but with considerably lower usage, with in-feedmonensin representing a large proportion of total ABU. The adaptation periodpresents a challenge to animal health; antibiotics are administered a prophylaxis,metaphylactic and individual treatments depending on farm management practices.Further research into internationally comparable measures of ABU and detailedcost-benefit analysis of practical, on-farm interventions are needed to aid improvedantimicrobial stewardship in livestock systems globally.