Interested producers can enroll in the HPAI Dairy Herd Status Program by contacting their APHIS Area Veterinarian in Charge or State animal health official. A herd monitoring plan for sample collection and testing is developed in concert with the producer, State, and APHIS officials. The date of first sample receipt at the NAHLN laboratory will be considered the participation start date. 

The producer may decide to cancel participation in the program at any time unless otherwise required by State regulations or a State herd plan. The cancellation should be in writing to an APHIS Veterinary Services representative or a State representative.

Once a producer enrolls, a written herd and/or premises monitoring plan will be developed between APHIS Veterinary Services in collaboration with the herd owner and State animal health officials. The plan will include biosecurity, movement, sampling, and testing parameters. The herd monitoring plan will become effective after it is reviewed by the National Incident Commander or their designee and signed by the APHIS Veterinary Services representative, the State representative, and the herd owner.

• Herds without a history of HPAI detection must have 3 consecutive weeks of negative test results from a NAHLN laboratory on bulk tank milk (BTM) samples collected on-farm.
• Herds with a history of HPAI detection have two options:
  • Option 1—BTM samples are collected and submitted to a NAHLN laboratory for 4 consecutive weeks¹ of negative test results.
  • Option 2—BTM samples are collected and submitted to a NAHLN laboratory for 3 consecutive weeks of negative test results. In the third week, samples composed of milk from all lactating cows in the sick and fresh pens are collected and submitted with negative results.
• Once the herd status is established, the producer continues to arrange for collection and submission of milk samples for weekly testing per their herd monitoring plan. Weekly samples will represent all animals in the milking strings and do not need to include samples from animals not contributing to the bulk tank milk.
• Provided all samples are negative, no additional premovement testing will be required for the animals in the herd while in a Monitored Unaffected status.
• State or Federal animal health officials may review required documentation and sample collection procedures at any time.
• The producer or producer's representative continues to monitor the herd for clinical signs consistent with HPAI in dairy cattle.

¹ Data shows that 4 consecutive weeks of negative BTM testing is sufficient to gain Monitored Unaffected status for herds with a history of HPAI detection. This is true even without testing milk from sick or newly freshened cows, which the Dairy Herd Status Program previously required for enrollment. Field data shows that BTM testing is very sensitive and positive results in BTM occur before widespread clinical illness in the herd. Therefore, it is unlikely that testing milk from sick or newly freshened cows significantly increases the chance of detecting an affected herd.

Below are the steps to clear your herd and regain Monitored Unaffected status after a positive test result:

• An epidemiological investigation is prioritized for any previously Provisional or Monitored Herd. This enables subsequent movement restrictions for low-risk animals to resume as soon as possible.
• Option 1: On-farm samples are collected and submitted to a NAHLN laboratory for 4 consecutive weeks¹ of negative test results.
• Option 2: On-farm samples are collected and submitted to a NAHLN laboratory for 2 consecutive weeks of negative test results. Concurrent with the second weekly test, the producer collects and submit samples composed of pooled milk from all lactating cows in the sick and fresh pens. This test must also be negative.
• The herd shall demonstrate an absence of all of the following for at least 2 or 4 weeks (depending on selected option above):
  • Clinical signs
  • Production changes (such as unusual drop in milk production) associated with HPAI in cattle
  • Rates of herd illness (in particular, mastitis and respiratory disease) above expected seasonal baseline levels

While a herd is in Monitored Affected status, the herd cannot move lactating animals as outlined in the guidance associated with the April 2024 Federal Order.

¹ Data shows that 4 consecutive weeks of negative BTM testing is sufficient to gain Monitored Unaffected status for herds with a history of HPAI detection. This is true even without testing milk from sick or newly freshened cows, which the Dairy Herd Status Program previously required for enrollment. Field data shows that BTM testing is very sensitive and positive results in BTM occur before widespread clinical illness in the herd. Therefore, it is unlikely that testing milk from sick or newly freshened cows significantly increases the chance of detecting an affected herd.