May 16, 2025

 

US stops imports of live cattle from Mexico over concerns of New World screwworm

 

 

The spread of New World screwworm (NWS) has prompted the United States to suspend imports of live cattle, horses and bison through ports of entry along the border with Mexico.

 

NWS was recently detected in remote farms with minimal cattle movement as far north as Oaxaca and Veracruz, about 700 miles away from the US border, according to APHIS.

 

The first case of NWS in Mexico was reported to the US in November 2024. When NWS fly larvae burrow into the flesh of a living animal, they cause serious and often deadly damage to the animal. NWS can infest livestock, pets, wildlife, occasionally birds, and in rare cases, people.

 

The import suspension ban includes animals originating from or moving through Mexico and will be in effect on a month-by-month basis, until "a significant window of containment is achieved," according to the US Department of Agriculture (USDA). The department added that it will continue constant collaboration with Mexico, including a review of latest data and metrics in two weeks.

 

Any livestock currently in holding for entry into the US will be processed normally, which includes an inspection exam from a USDA Animal and Plant Health Inspection Service (APHIS) Veterinary Medical Officer and treatment to ensure they are not carrying NWS.

 

The US imports approximately 1.2 million cattle from Mexico each year, amounting to around 4% of the total cattle slaughter in the country, according to Michigan Farm Bureau Lead Economist Loren Koeman.

 

"This number has been increasing in recent years due to droughts in key US cattle producing regions," Koeman said. "The cattle imported from Mexico tend to be younger and lighter cattle destined for US farms to finish out to market weights, so this will have impact to US farms along the border who rely on Mexico to supply cattle for finishing."

 

Agriculture Secretary Brooke Rollins announced the suspension on May 11 — just 10 days after Mexico agreed to stop impeding USDA efforts to fight NWS as detailed in Rollins' letter to her Mexican counterpart on April 29.

 

Rollins emphasised that Mexico has since been working in good faith, but said it's her duty "to take all steps within my control to protect the livestock industry in the United States from this devastating pest."

 

"The protection of our animals and safety of our nation's food supply is a national security issue of the utmost importance," Rollins wrote in a statement.

 

"Once we see increased surveillance and eradication efforts, and the positive results of those actions, we remain committed to opening the border for livestock trade. This is not about politics or punishment of Mexico, rather it is about food and animal safety."

 

The USDA noted that the US previously and successfully led the eradication of NWS in the US and Mexico — but said it cost billions of dollars and took decades.

 

According to APHIS, effective eradication requires a three-pronged approach of:

 

    - Robust active field surveillance with education and outreach to ensure prevention, treatment, and early detection;

 

    - Controlled animal movement to limit spread;

 

    - Sustained sterile insect dispersal.

- Michigan Farm News