Modified May 3, 2024

On March 25, 2024, the USDA, FDA and CDC announced the detection of highly pathogenic avian influenza (HPAI) H5N1 in dairy cattle. States with positive herds as of May 3, 2024, include TX, KS, ID, MI, NC, NM, SD, CO and OH. Clinical signs have been limited to adult lactating cattle, with the primary sign being a pronounced drop in milk production, a decrease in appetite and rumination, mild respiratory signs, low grade fever, and thickened "colostrum-like" milk. Some cattle have dark tarry stools while others have diarrhea. Milk and nasal swabs from affected cattle have both tested positive for H5N1 clade 2.3.4.4b, the clade currently circulating in wild birds in the US since 2022. Some of the affected farms have also reported high numbers of dead wild birds. The Animal Health Diagnostic Center (AHDC), as a National Animal Health Laboratory Network (NAHLN) laboratory, tests avian and mammalian samples for HPAI by PCR, and forwards all non-negative samples to the National Veterinary Services Laboratories (NVSL) in Ames, Iowa, for confirmation. All confirmed positives are reported to the state veterinarian’s office of origin. In New York, positive results in livestock and poultry require quarantine of the affected premises.

According to the Federal Order issued on April 24, 2024, lactating dairy cattle are required to have a negative HPAI PCR test within 7 days of interstate movement. Per USDA guidance: "For groups/lots of 30 or fewer animals moving interstate, all animals being moved must be tested. If more than 30 animals are moving interstate, then only 30 animals total must be tested." The premovement testing requirement does NOT apply to non-clinical lactating dairy cattle moving interstate direct to slaughter. Test results are available 1-3 days after samples arrive in the lab.

Veterinarians are encouraged to contact the AHDC Veterinary Support Services (607-253-3900 or email vetsupport@cornell.edu) to discuss testing protocol. Fees for testing bovine specimens for HPAI are paid by the USDA. When submitting samples, official premises ID must be included on the submission form. Contact the State Veterinarian's office to obtain a premises ID if the farm does not have one.

Samples to submit for interstate movement of lactating dairy cows:

• 10-12 ml of milk from all 4 quarters in one 15 ml screw top vial*, pictured. Do not pool from different cows 

Samples to submit for bulk tank testing:

• 10-12 ml of bulk tank milk representing cows from one single premises in one 15 ml screw top vial*, pictured

Samples to submit from non-lactating cattle:

• Nasal swab in one 15 ml screw top vial*, pictured, with 0.5 ml sterile saline added

AHDC submission protocol for bovine HPAI testing:

1. Completely fill out a general submission form, including the premises ID in the owner information box. The test code is BAIPCR.
2. Use an insulated shipping container. Ship overnight with cold packs. Place a copy of the submission form in an envelope adhered to the outside of the box. Use a separate submission form and package to request any other diagnostic tests. 
3. Write large "Fs" on all sides of the shipping box.
4. Email ahdcmammalfad@cornell.edu before 7am EST on the day the samples are due to arrive with the tracking number. Attach a copy of the completed submission form to the email. In the body of the email please write that you are sending samples for bovine HPAI testing.

*15 ml screw top vials are available at no cost through the AHDC supply center, ahdcshipping@cornell.edu or 607-253-3900.

The USDA has provided a FAQ page regarding HPAI in cattle here.