described by Castleberry and Nolen (Castleberry and Nolen 2018). We used the qualitative software package NVivo to facilitate the managementandorganization of our data (V.12,2, QSR International, USA). Thematic analysis is an inductive approach to identifying and analyzing patterns within the transcripts. Codes are descriptive labels attached to similar words or sentences in raw data. They are then reassembled into themes, allowing us to get a bigger picture of the data regarding the research question. Themes were defined a priori based onthe guide of the interviews. Themes were refined and new ones emerged through a process involving both forward and backward methods.The first author conducted the coding, and the team validated the codebook. Thethematicanalysis allowed ustofirst confirm andimprovethemapoftheantibiotics and alternative feed additives value chain, identify the structural position of the stakeholders, and define their role within this chain. Secondly, each stakeholder who was interviewed was analyzed based on three themes related to their technical and social capital in relation to regulation: legitimacy (institutional position, involvement in the law design, formal or informal flow of antibiotics), resources (knowledge and technical capacities to implement the regulations), and connections (number and quality of relationship) to other stakeholders in the chain (Figure 1) (Zimmermann and Maennling 2007; Poupaud et al. 2021) . We were able to categorize each actor according to their capital level by assigning a score ranging from absent (-) to strong(+++). Eachcategory of stakeholderswas assigned the averagescore of participants within that category.Third, weidentified the factors influencing the implementationof the new regulations using the chain map, stakeholder classification, and semi-structured interview coding (barriers, and levers to implement the new regulations). Data were triangulated (Olivier de Sardan 2008) through multiple sources of information (different respondents, flow chart), observation when possible, and team discussion.

#### Results

- 1) Structural position of the stakeholders within the veterinary drug value chain

The veterinary drug value chain, as mapped during the FGD, was revised three times during semi-structured interviews. Figure 1 shows the result of the mapping. From our interviews, there wasnodifferenceinchainstructurebetweenrespondentsfromNorthandSouthVietnam. Finished productsareimportedormadeinVietnamusing importedcomponents.Theyarethen distributed either directly to farmers or through agencies. An agency was defined by the participants as a shop selling drugs, agricultural equipment, or animal feed and owned by a veterinarian. Agencies 1 and 2 differ in size, source of supply (level-1 agencies are directly connected to drug companies, veterinarians and farmers and sometimes provide level-2 agencies, whereas level-2 agencies target mostly small-scale farmers). Both types of agencies mustberunby aveterinary technician that ownsaveterinary college or anintermediate degree representing twotothreeyearsofstudy or byaveterinarianwithauniversity degree.They often receive the help of their spouse or other personnel that does not necessarily have the