SANTA TERESA, N.M. — Mexican cattle returned to the Santa Teresa livestock crossing Thursday, Sept. 24, after more than a year of interruptions linked to New World screwworm. The first group entered the United States shortly before 11 a.m. and cleared the process without problems, drawing applause from ranchers and officials gathered at the facility. The reopening restores a major channel for the cattle industry. Santa Teresa handled about 500,000 head annually before the shutdown and processed 43% of cattle entering the United States from Mexico. Trade through the crossing generated about $1.2 billion in 2024, but fell to roughly $140 million in 2025, according to figures provided by facility director Daniel Manzanares. For now, cattle entering through the facility must come from Chihuahua. Their route to the border includes new safeguards developed by the U.S. Department of Agriculture, which reopened Santa Teresa as part of a phased plan to limit the risk of screwworm entering U.S. livestock. In Mexico, accredited veterinarians at export gathering centers check animals for health requirements, including tuberculosis and tick protocols. Cattle receive an FDA-approved screwworm treatment three to five days before they can enter the United States. Animals with open wounds, lameness, anemia or other potential health concerns are barred from proceeding, said USDA Under Secretary for Marketing and Regulatory Programs Dudley Hoskins. At the border, USDA Animal and Plant Health Inspection Service staff and detector dogs conduct additional screening. The agency previously tested the protocols at the crossing in Douglas, Arizona. Hoskins said officials had assessed the system daily for 30 days and found it was working, while emphasizing that safety—not the number of cattle processed—would guide the pace of reopening. Santa Teresa has also spent more than $60,000 on a scanner that reads cattle’s electronic identification tags and records the information in a database. The data is linked to an electronic veterinary inspection certificate, allowing officials to track animals after they leave the crossing. “That traceability could become critical if authorities later discover a screwworm infestation or another animal health concern,” Manzanares said. He described rapid tracking as essential to containing a potential problem. About 75% of the cattle crossing at Santa Teresa go to feed yards in the Texas Panhandle, Manzanares said; others head to Oklahoma and elsewhere. The trade also supports U.S. producers who sell breeding bulls and heifers to Mexican ranchers. Some calves bred from that stock later travel north for U.S. feeding operations. The interruption hurt businesses on both sides of the border. Manzanares previously estimated that his U.S. operation lost about $3 million. Smaller Mexican ranchers, especially those with 100 cattle or fewer, also lost access to a key market, he said. The reopening comes as officials continue responding to screwworm detections in New Mexico, including a recently confirmed infestation in a horse in Grant County. Hoskins said authorities increased surveillance and trapping in the area and released sterile flies. The technique is intended to suppress the parasite’s population because female screwworm flies mate only once; mating with a sterile male prevents viable offspring. Hoskins said the USDA receives 100 million sterile flies weekly from a facility in Panama, while another facility that began operating this summer is increasing production. The agency is also accelerating construction of an additional sterile-fly facility. New World screwworm larvae feed on the living tissue of warm-blooded animals. Hoskins said the parasite is not a disease and does not pose a food-safety concern. Federal officials have not set a daily target for cattle crossings at Santa Teresa, saying volumes will depend on how the safeguards perform.