["Journal of Agricultural Economics, EarlyView. ", "\nABSTRACT\nThis paper quantifies the economy‐wide consequences of two independent global stress‐tests in livestock production. The first assesses the effects of phasing out antimicrobial growth promoters (AGPs), and the second evaluates the long‐term impacts of antimicrobial resistance (AMR) progression. We use a sequential, one‐way modelling framework combining a global partial equilibrium (PE) model and a global computable general equilibrium (CGE) model to trace how scenario‐defined shocks in livestock production propagate through world agricultural markets and the wider economy. The highest‐impact AGPs phase‐out scenario results in cumulative global livestock production losses, valued at constant 2021–2023 prices, of roughly USD 53 billion over 2025–2040, with annual deviations that peak in the mid‐2020s and then decline as output converges along scenario‐defined recovery paths. In contrast, the highest‐impact AMR scenario produces persistent and compounding reductions by construction, with cumulative production losses of about USD 318 billion by 2040, while cumulative economy‐wide welfare losses in this high‐impact case reach approximately USD 1.25 trillion, concentrated mainly in upper–middle‐income countries. Results are scenario dependent by construction and represent indicative orders of magnitude rather than forecasts. The baseline implicitly reflects prevailing levels of AGPs and AMR embedded in historical production trends. The study provides a framework for quantifying the production effects of antimicrobial use (AMU) and their economy‐wide spillovers, highlighting the asymmetric timing of the economic costs of action and inaction under the imposed scenario structure.\n"]