Economic Impacts of African Swine Fever on Regional Pig Production in the Philippines: A Robust Regression Analysis

African swine fever (ASF) has caused substantial disruptions in the Philippine pork sector, with economic impacts varying across regions due to differences in production scale, biosecurity capacity, and market integration. This study quantified the regional economic effects of ASF outbreaks in CALABARZON, Eastern Visayas, and SOCCSKSARGEN using Huber robust regression with heteroskedasticity-consistent standard errors to account for outliers and structural breaks typical of disease shock periods. Quarterly data on pig production (explained variable) and barangay-level ASF cases (central explanatory variable) were analyzed, while yellow corn farmgate prices and fourth-quarter seasonal demand were included as control variables to account for feed-cost and seasonal market effects. Results indicate that pork production in CALABARZON was significantly and negatively affected by ASF incidence, with each additional barangay case associated with a decline of approximately 142 metric tons of liveweight output. In contrast, ASF cases in Eastern Visayas and SOCCSKSARGEN showed no statistically significant effects, highlighting heterogeneous regional vulnerability. Elevated yellow corn prices significantly reduced pork production in CALABARZON and Eastern Visayas, while fourth-quarter seasonal demand positively influenced output across regions. This study provides the first empirical assessment of the regional economic impacts of ASF in the Philippines, emphasizing the need for differentiated, region-specific policy responses. Targeted biosecurity investments, strengthened surveillance systems, and market stabilization measures are recommended to mitigate production losses. These findings contribute to broader international discussions on managing transboundary animal diseases in developing-country livestock systems and enhancing food system resilience.