Infectious Disease, Productivity, and Scale in Open and Closed Animal Production Systems
分析动物贸易中传染病的外部性如何影响养殖户选择开放或封闭生产系统，发现纳什均衡可能导致过度交易，且限制贸易或采用封闭系统可提高效率。
Trade in feeder animals creates externalities when animal diseases can spread beyond the purchasing farm. If growers choose between open and closed production systems, then Nash equilibrium likely involves excessive trading. While first‐best equilibrium involves market‐wide adoption of either an open‐trade or closed‐farm system, equilibrium may entail heterogeneous systems. If so, then the feeder trade should be restricted. Supply response to an increase in marginal costs may be positive. Within a farm, infectious disease risk can create decreasing returns to scale when the technology is otherwise increasing returns. Contractual procurement and damage control technologies will likely increase scale in finishing.