47The nutritional and economic potentials of livestock systems are compromised by the 48 emergence and spread of antimicrobial resistance. A major driver of resistance is the misuse and 49 abuse of antimicrobial drugs. The likelihood of misuse may be elevated in low-and middle-50 income countries where limited professional veterinary services and laissez faire access to drugs 51 are assumed to promote non-prudent practices (e.g., self-administration of drugs). The extent of 52 these practices, as well as the knowledge and attitudes motivating them, are largely unknown 53 within most agricultural communities in low-and middle-income countries. The main objective 54 of this study was to document dimensions of knowledge, attitudes and practices related to 55 antimicrobial use and antimicrobial resistance in livestock systems and identify the livelihood 56 factors associated with these dimensions. A mixed-methods ethnographic approach was used to 57 survey households keeping layers in Ghana (N=110) and Kenya (N=76), pastoralists keeping 58 cattle, sheep, and goats in Tanzania (N=195), and broiler farmers in Zambia (N=198), and 59 Zimbabwe (N=298). Across countries, we find that it is individuals who live or work at the farm 60 who draw upon their knowledge and experiences to make decisions regarding antimicrobial use 61 and related practices. Input from animal health professionals is rare and antimicrobials are 62 sourced at local, privately owned agrovet drug shops. We also find that knowledge, attitudes, and 63 particularly practices significantly varied across countries, with poultry farmers holding more 64 knowledge, desirable attitudes, and prudent practices compared to pastoralists households. 65 Multivariate models showed that variation is related to several factors, including education, 66 disease dynamics on the farm, and sources of animal health information. Study results emphasize 67 that interventions to limit antimicrobial resistance must be founded upon a bottom-up 68 understanding of antimicrobial use at the farm-level given limited input from animal health 4 69 professionals and under-resourced regulatory capacities within most low-and middle-income 70 countries. Establishing this bottom-up understanding across cultures and production systems will 71 inform the development and implementation of the behavioral change interventions to combat 72 AMR globally. 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 5 95 96 97 Antimicrobial drugs are essential to maintain animal health within livestock production 98 systems but their misuse and/or abuse increases selection for the emergence, transmission, and 99 persistence of antimicrobial resistance (AMR) [1-3]. AMR results in therapeutic failures and 100 increases lengths and/or cycles of treatment, thereby producing downstream impacts on animal 101 welfare, food security, and public health. AMR in animals may impact prevalence in people as 102 resistant microorganisms (e.g., bacteria, viruses, parasites) can be transmitted across the human...