Mexican Agriculture Minister says Mexico will reinforce sterile fly dispersal in Sonora and Chihuahua to contain screwworm as phased border reopening to livestock trade starts

Screwworm-related suspensions of Mexican cattle imports have been a recurring feature of the cross-border livestock trade, and the pattern in past episodes is that closures and reopenings move in steps tied to verified containment rather than in one decision. Phased reopenings have historically been conditioned on sterile fly dispersal in the northern border states, since the sterile insect technique is the established eradication mechanism and its intensity is what US animal health authorities look at before restoring flows. The transmission channel for prices runs through feeder cattle supply into US feedlots: Mexico is a meaningful source of imported feeder cattle, so the pace at which crossings resume feeds directly into placement availability and, with a lag, into fed cattle and beef supply further out. The distinction worth drawing is between an announced phased reopening and actual inspected volumes crossing, since phytosanitary protocols and port capacity have on previous occasions made the restart slower than the headline suggests. The follow-ons that matter are any US-side confirmation of the schedule, inspection capacity at border crossings, and whether screwworm detections migrate south or north, since a fresh detection inside the dispersal zone has historically been the trigger for re-tightening.