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. 2022 Dec 29;13(1):140.
doi: 10.3390/ani13010140.

The Rise of Heatstroke as a Method of Depopulating Pigs and Poultry: Implications for the US Veterinary Profession

Gwendolen Reyes-Illg  1 , Jessica E Martin  2 , Indu Mani  3 , James Reynolds  4 , Barry Kipperman  5
Affiliations

The Rise of Heatstroke as a Method of Depopulating Pigs and Poultry: Implications for the US Veterinary Profession

Gwendolen Reyes-Illg et al. Animals (Basel). .

Abstract

Depopulation of food-producing animals is becoming increasingly common in response to both disease outbreaks and supply chain disruptions. In 2019, the American Veterinary Medical Association released depopulation guidelines classifying certain heatstroke-based killing methods as "permitted in constrained circumstances", when circumstances of the emergency constrain reasonable implementation of "preferred" methods. Since then, tens of millions of birds and pigs have been killed by such methods, termed ventilation shutdown (VSD) Plus Heat and VSD Plus High Temperature and Humidity. While no research using validated measures of animal welfare assessment has been performed on these methods, their pathophysiology suggests that animals are likely to experience pain, anxiety, nausea, and heat distress prior to loss of consciousness. Heatstroke-based methods may result in prolonged suffering and often do not achieve 100% mortality. Potential and available alternative depopulation methods are briefly reviewed. The veterinary profession's ethical obligation to protect animal welfare in the context of depopulations is discussed.

Keywords: animal welfare; animal-derived foods (ADF); euthanasia; farm animal; highly pathogenic avian influenza (HPAI); livestock; on-farm emergency killing; swine; ventilation shutdown (VSD); veterinary ethics.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Number, percent (%) of commercial poultry depopulations related to Highly Pathogenic Avian Influenza (HPAI) by depopulation methods: (a), 2014–2016; (b) 2022. VSD = ventilation shutdown alone, VSD + Heat = ventilation shutdown + heat, CO2 cart = carbon dioxide gassing in cart/container, WHG = whole house gassing with CO2, Physical Method = captive bolt, cervical dislocation, etc.
Figure 2
Figure 2
Number of commercial depopulations of poultry due to HPAI that involved the use of heatstroke-based methods.
Figure 3
Figure 3
Number and percentage (%) of birds killed in HPAI depopulations in from January through August 2022.
See this image and copyright information in PMC

References

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