What's New ? - 2022

What's New ? - 2022

Ventilation shutdown for mass depopulation

11 February, 2022

Ventilation shutdown (VSD) with either or both heat and carbon dioxide (VSD+) will be permissible in the event of necessary depopulation following exposure to HPAI. The USDA-APHIS will allow VSD+ under specific circumstances for confined poultry including aviary and cage-housed hens. USDA will grant application of VSD for mass depopulation provided:
-Alternative methods are unavailable within an acceptable period.
-Recognition that multiplication of virus will represent a danger to farms within a three mile zone
-Approval by state officials, incident management and the National Incident Coordinator
In considering the application for VSD+, a farm-by-farm evaluation will be conducted taking into account available resources and the epidemiologic implications of any delay in depopulation given a 24 to 48-hour goal for a specific farm or complex.
The 2019 AVMA Guidelines for the Depopulation of Animals provides for either VSD alone or with supplementary heat and or carbon dioxide providing all other options are evaluated and considered infeasible.  Ventilation shutdown alone is regarded as a last resort measure. For floor-housed flocks, carbon dioxide or water-based foam will be deployed providing equipment is available and trained personnel conduct the procedure under supervision of state and federal authorities. The efficacy of either VSD or VSD+ is dependent on the specific size of the flock, construction of the house, and availability of personnel to achieve depopulation within 48-hours following a diagnosis.