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23 July 2011 Moving-Average Trigger for Early Detection of Rapidly Increasing Mortality in Caged Table-Egg Layers
Sasidhar Malladi, J. Todd Weaver, Timothy L. Clouse, Kathe E. Bjork, Darrell W. Trampel
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Abstract

Rapidly increasing and unexplained mortality in commercial poultry flocks may signal the presence of a highly transmissible and reportable disease. Activation of an infectious-disease surveillance system occurs when a key production parameter, i.e., mortality, changes. Various triggers have been proposed to alert producers when mortality exceeds normal limits for a given production system to enable early detection of such diseases. In this article we demonstrate that a simple moving-average trigger is useful for detecting any disease syndrome in caged table-egg layer flocks that manifests itself as sudden, rapidly increasing mortality. We superimposed HPAI disease mortality output data derived from a disease transmission model and from a naturally occurring HPAI outbreak onto normal mortality data from 12 healthy commercial egg-layer flocks, and compared the performance of 7-day moving-average triggers to previously proposed triggers. The moving-average trigger is more efficient, resulting in fewer false-positive alerts and an earlier time to disease detection. It can be easily calculated by using a computer spreadsheet providing only 7 days of mortality data and can be practically and inexpensively implemented by large commercial poultry integrators. A moving-average trigger can be an active component of a production-based surveillance system.

American Association of Avian Pathologists
Sasidhar Malladi, J. Todd Weaver, Timothy L. Clouse, Kathe E. Bjork, and Darrell W. Trampel "Moving-Average Trigger for Early Detection of Rapidly Increasing Mortality in Caged Table-Egg Layers," Avian Diseases 55(4), 603-610, (23 July 2011). https://doi.org/10.1637/9636-122910-Reg.1
Received: 14 January 2011; Accepted: 1 July 2011; Published: 23 July 2011
JOURNAL ARTICLE
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