The private sector was also concerned about ABR as a public health issue. But some veterinarians and agency level 1 and 2 representatives explained that reducing the burden of ABR resulted in increased profits for them. Indeed, according to them, farmers using less antibiotics will earn more money and be able to buy more supplies from their shop. Indeed, many agencies sold to farmers on credit. Additionally, mandatory prescriptions were sometimes perceived as an economic advantage for drug sellers. Indeed, farmers will have to rely on veterinarians to use the correct dosage of drugs, which will lead not only to accurate advice to limit the development of resistance but also an increase in their income. Using less antibiotics was also associated with reducing production costs for farmers and integrated companies.

#### Discussion

This study aimed to understand whether stakeholders in the veterinary drug value chain in Vietnam understood, accepted, and implemented regulations to reduce ABU, with a focus on the ban of antibiotics in feed (decree n°13/2020/ND-CP) and mandatory prescription (circular n°122020TT-BNNPTNT). To that end, we first obtained a comprehensive representation of the antibiotics andalternative feed additivesvalue chain, aswell asadescriptionoftheinteractions between the different stakeholder categories. We distinguished between stakeholders operating at the national level and the local level. We then identified the technical and social capital of each stakeholder in relation to the regulations designed to reduce ABU. We showed that the level of understanding, acceptance, and implementation of the newregulations varied according to the structural position and influence of the stakeholders within the chain. The level of influence, which dependsontheir level of legitimacy, resources, connections, and roles in the legislative process, seemed to be higher for drug companies, feed companies, alternative feed additives companies, and integrators than for farmers, level 1 and 2 agencies, and veterinarians. Finally, the first two steps allowed us to identify 10 factors that had a neutral, negative, or positive influence on the implementation of the new regulations. According to the respondents, the high proportion of small-scale farms represented one of the main barriers to their implementation, whereas large-scale production systems seemed to be the most adaptable to regulatory change and thus the least directly impacted. Indeed, small-scale production systems still predominate in Vietnam, but in recent years the numberoflarge farms has increased (Bâtie et al. 2022; GSOV 2016). At the local level, a lack of knowledge about ABU and ABR, the regulations themselves, and their objectives were reported to be important barriers. Finally, enablers to implement regulations were concerned about ABR as a health risk and food safety issue for all stakeholders. Advantages and bias of conducting an iterative stakeholder mapping and analysis In this study, we explored the structural position and technical and social capital of the stakeholders regarding the regulations related to ABR through a systemic (Peters 2014) and interdisciplinary approach to develop recommendations adapted to the Vietnamese context (Kakkar et al. 2018). We aimed to translate policy changes into changes of practice that would effectively reduce the use of antibiotics in chicken production (Baudoin, Hogeveen, and Wauters 2021). To accomplish this, we conducted an iterative stakeholder mapping and