Import Alert: Import Restrictions on Canada due to Highly Pathogenic Avian Influenza 

Stakeholder Alert: Delays in Testing and Release of Quarantined Imported Fetal Bovine Serum  

Issuance date: June 17, 2025 

U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) currently requires safety testing of imported commercial fetal bovine serum (FBS) at the National Veterinary Services Laboratories (NVSL) by sheep bioassay prior to release of the FBS into the United States.   

Since February 2025, there have been delays in this safety testing due to a lack of suitable sheep for the bioassay. Samples are in the queue for testing in the order that they are received at NVSL. 

Efforts continue to procure sheep nationwide and testing continues for the imported FBS as quickly as possible as suitable sheep are available.  

APHIS expects these challenges will continue and is discussing with serum industry representatives the options for safety testing and mitigation treatments to replace the sheep bioassay.   

For questions, please contact NVSL at 515-337-7551 or by e-mail to NVSL.DVL.Heads@usda.gov.