Animal-health controls affect the same supply chain that delivers beef.
The United States has reopened one Arizona port to limited cattle imports from Mexico under new safeguards designed to prevent New World screwworm.
Screwworm is a destructive livestock pest. Restrictions on live-cattle movement can protect animal health, but they also affect the cattle supply moving into American feedlots.
This is one reason beef prices are not explained by one thing alone. Weather, herd size, animal-health controls, processing capacity, and trade policy all move through the same supply chain.
