REDFIELD, Iowa (DTN) -- Feeder cattle futures rallied Monday on news that the United States is halting imports of Mexican cattle following the detection of New World screwworm (NWS) in Mexico.

On Nov. 22, the Chief Veterinary Officer of Mexico notified the United States Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) of a cow with NWS in the southern Mexico state of Chiapas, according to an APHIS news release on Nov. 24.

"Given the northward movement of NWS, APHIS has in recent months stepped up its efforts in Central America to partner with impacted countries to push this pest out of newly affected areas," Rosemary Sifford, chief veterinary officer of the U.S., said in a statement. "With this latest find in Mexico, we will further intensify this work to protect American agriculture and reestablish the barrier in Central America."

Given the severity of the threat from NWS, APHIS has restricted the importation of animal commodities, including live cattle, from or transiting Mexico effective immediately. USDA eradicated NWS from the U.S. in 1966 using the sterile insect technique, a pest-control method that uses mass-produced, sterilized insects to reduce or eliminate insect populations.

MARKETS ARE HIGHER, RALLY UNCERTAIN

DTN Livestock Analyst ShayLe Stewart said markets opened sharply higher on Monday with news of all cattle imports from Mexico being restricted as of Nov. 22. "U.S. feedlots have been relying on Mexican feeder cattle to fill their lots since the U.S. cow herd is at a historical low," she added.

Mexican feeder cattle imports are near 1.2 million head so far in 2024, up 13% from 2023. Canadian numbers, however, are 12% lower, totaling just over 137,000 head, compared to a year ago.

"We just don't have enough feeder cattle in the U.S., and with restrictions on Mexican cattle, it's hard to tell where prices will go and how long this will last," Stewart said.

NWS DETAILS, SYMPTOMS

NWS are fly larvae that infest living tissue of warm-blooded animals, causing infection. According to APHIS, these maggots will burrow into a wound, feeding as they go and doing extensive damage by tearing the host's tissue with sharp mouth hooks. The wound becomes larger and deeper. NWS can cause serious, even deadly, damage to the animal.

The adult screwworm flies are about the size of a common housefly with orange eyes, a metallic blue or green body, and three dark stripes along their backs.

Affected mammals and birds show signs of irritated behavior, head shaking, smell of decay, evidence of fly strike, and presence of fly larvae in wounds.

APHIS said the best prevention of NWS in the U.S. is to avoid infestation. The agency recommended people be alert to symptoms in pets and livestock, ensure that pets traveling internationally are inspected for screwworm, and to check their vehicles for screwworm flies if they are in an NWS-infested area.

There is a constant threat of NWS due to it being detected so close to the U.S. APHIS is releasing sterile flies through aerial and ground release at strategic locations throughout Central America and is working to eradicate NWS from the affected areas to reestablish the biological barrier in Panama.

Click here to access the full stakeholder announcement from APHIS: https://www.aphis.usda.gov/….

For more information about screwworm, visit https://www.aphis.usda.gov/….

Jennifer Carrico can be reached at jennifer.carrico@dtn.com

Follow her on social platform X @JennCattleGal

(c) Copyright 2024 DTN, LLC. All rights reserved.