Sub‐therapeutic Antibiotics and the Efficiency of U.S. Hog Farms
研究利用随机前沿模型和2009年美国农业资源管理调查数据，评估禁止促生长抗生素对养猪场产量和产量波动的影响，发现亚治疗抗生素使用对生产率和生产风险有小幅正面效应。
Abstract A substantial share of U.S. hog producers incorporate antimicrobial drugs into their livestock's feed or water at sub‐therapeutic levels to promote feed efficiency and weight gain. Recently, in response to concerns that the overuse of antibiotics in livestock could promote the development of antimicrobial drug‐resistant bacteria, the U.S. Food and Drug Administration adopted a strategy to phase out the use of antibiotics for production purposes. This study uses a stochastic frontier model and data from the 2009 USDA Agricultural Resource Management Survey of feeder‐to‐finish hog producers to estimate the potential effects on hog output and output variability resulting from a ban on antibiotics used for growth promotion. We use propensity score nearest neighbor matching to create a balanced sample of sub‐therapeutic antibiotic (STA) users and nonusers. We estimate the frontier model for the pooled sample and separately for users and non‐users—which allows for a flexible interaction between STA use and the production technology. Point estimates for the matched sample indicate that STA use has a small positive effect on productivity and production risk, increasing output by 1.0–1.3% and reducing the standard deviation of unexplained output by 1.4%. The results indicate that improvements in productivity resulted exclusively from technological improvement rather than from an increase in technical efficiency.