Dr. Michael Payne, UCD School of Vet Med and Director CDQAP and Dr. Nicki Humphrey, Cattle and Swine Specialist, Animal Health Branch, CDFA
On August 24, USDA reopened the Douglas, Arizona port to cattle imports, which was followed by the September 24 reopening of the Santa Teresa port in New Mexico. Historically, the Santa Teresa port is the busiest livestock inspection port on the border, handling roughly 43% of all Mexican cattle imports. While there are no cattle inspection facilities along the Mexican-California border, reopenings at several additional ports in other states are being planned.
Investigation into the dissemination of New World Screwworm (NWS) suggest that fast, long-distance spread most frequently results from transportation of infested livestock. With these recent port reopenings, California producers remain understandably concerned about California and U.S. biosecurity.
So how is USDA preventing Screwworms from entering the U.S. on imported cattle?
Inspection & Treatment Requirements for Mexican Imports: Protocols for permitting, inspection and treatment were recently released by USDA and its equivalent Mexican agency, SENASICA. Protocols may differ if animals are being imported as general cattle imports or if they are intended for immediate slaughter. Here are some of the highlights:
• Inspection of individual, Mexican born and raised cattle will be conducted at separate USDA and Mexican inspection facilities. Inspection will be performed by specially trained and certified government veterinarians for evidence of NWS infestation or castration, dehorning or other wounds.
• Animals with visible wounds are not eligible for export. Samples from suspect infestation cases, once confirmed, the Mexican Herd of Origin losses export eligibility.
• Each bovine entering the U.S. will be treated with a systemic product approved by USDA for treatment and prevention of NWS. This currently includes IM or SQ doramectin formulations, which will treat or prevent NWS infestation for 21 days and carry a 35-day slaughter withdrawal period. Label use is not permitted in female dairy cattle 20 months of age or older.
• Each bovine entering the U.S. for immediate slaughter will be dipped for ticks within 7 to 14 days treated with a topical insecticide product approved by USDA for cattle being imported from NWS-affected countries. This requirement was already in place to prevent movement of Cattle Fever Ticks into the U.S.
Likely Impact on U.S. Beef Prices:
While the USDA is easing import restrictions on Mexican cattle, it is unlikely that U.S. beef prices will fall quickly. The Santa Teresa cattle inspection port is the busiest in the country, but only about 1,000 cattle a day are expected to cross down from an average of about 3,000 per day. In addition, it takes about five to eight months to raise imported Mexican cattle to slaughter weight. Finally, recovery from the mid-western drought and a 75-year low of the U.S. beef herd inventory will take time.
How Can Producers Best Protect Their Herds from Screwworm?:
The decreasing number of new U.S. cases suggests that USDA’s rapid response which includes release of sterile flies appears to be working. If all imported Mexican cattle are inspected and treated prior to entering, the risk of the pest entering at border ports should be low.
The fact that we continue to detect new, albeit infrequent, U.S. cases in animals without a history of travel suggests that NWS is present, but perhaps in low numbers, perhaps brought across the border across by wildlife. Particularly when importing cattle from areas known to have had NWS cases, it is essential that producers comply with animal movement requirements. CDQAP and CDFA have collaborated on guidance for producers to protect their herds from NWS. Also check out our list of best information resources.