Mexican ranchers prepare to resume livestock sales to U.S. under tight controls over screwworm risk

Mexican ranchers are poised to resume selling livestock to the United States after nearly a year of import restrictions due to concerns over the New World screwworm, a parasitic fly that poses a serious threat to animals. Starting August 24, live cattle will begin crossing the U.S.-Mexico border at the Douglas, Arizona, port of entry, which connects to Agua Prieta in Sonora state. This marks the first step toward restoring trade, though strict measures will remain in place to prevent the spread of the parasite, which has already been found in parts of Texas and New Mexico. The import ban, imposed in May 2025, disrupted cattle and beef markets on both sides of the border. In the U.S., it worsened a growing livestock shortage, while in Mexico, it hit ranchers hard, many of whom had relied heavily on exports, generating $1.2 billion annually before the closure. The situation has left many ranchers struggling financially, especially in regions like Sonora, where drought conditions have compounded the economic strain. The New World screwworm, named for its larvae's ability to burrow into open wounds, affects all warm-blooded animals, including domestic livestock, pets, and even humans. The outbreak in Mexico began in November 2024 and has since spread to 30 of the country’s 32 states. As of the latest count, there are 1,969 active cases, down from nearly double that number a year earlier. While officials acknowledge progress in containment efforts, they emphasize that complete eradication will take time. Ranchers in Sonora, such as Martín Alfonso Ibarra, are cautiously optimistic about the resumption of exports. However, they face new challenges introduced by U.S. regulations designed to mitigate the risk of spreading the parasite. Under the initial phase of the reopened trade, only 700 cattle per day will be permitted to cross the border, increasing gradually to 1,300 daily as confidence grows. These limits are part of a broader set of requirements, including mandatory radio-frequency identification tags placed in each animal’s ear and inspections using electronic readers and trained detection dogs. Veterinarian Arturo Ruiz, who oversees animal health in Sonora, confirmed these procedures will be conducted by U.S. Department of Agriculture officials prior to allowing cattle to enter Arizona. Although Mexico agreed to comply with the U.S. protocols, some ranchers feel the restrictions are overly burdensome and may hinder the recovery of the industry. Critics argue that the political considerations behind the initial ban and the current limitations may not reflect the technical realities of managing the outbreak. Juan Carlos Ochoa, president of the Regional Livestock Union of Sonora, expressed frustration with the lack of coordination between the two nations during the crisis. He called for a more pragmatic approach to facilitate trade while ensuring biosecurity. Despite these concerns, the resumption of livestock exports offers hope for both countries. For the U.S., increased availability of cattle could help ease supply constraints and potentially lower beef prices, which have reached historic highs. Meanwhile, Mexican ranchers see an opportunity to rebuild their export markets, although they must navigate the complexities of new regulatory hurdles. As the first shipments move forward, the success of the reopening will depend on how effectively the new measures can balance trade interests with the need to control the screwworm. Both nations continue to monitor the situation closely, aware that the path to full restoration of normal trade relations remains uncertain.