No third-party funding or support was received in connection with this study or the writing or publication of the manuscript. The authors declare that there were no conflicts of interest.
Johnson L, Li Y, Minnesota Swine Extension, University of Minnesota, Saint Paul, MN: Personal communication, 2021.
Direct-fired LB White Guardian, LB White Co, Onalaska, Wis.
Steam-Flo 20, Sioux Corporation, Beresford, SD.
Excel, Microsoft, Redmond, Wash.
SAS, version 9.4, SAS Institute Inc, Cary, NC.
RStudio environment, version 1.3.1093, RStudio Team, Boston, Mass.
R programming language, version 4.0.2, R Core Team, Vienna, Austria.
ggplot2 package, version 3.3.2, RStudio Team, Boston, Mass.
Ventilation shutdown with the addition of high temperature, a high concentration of carbon dioxide, or both
Ventilation shutdown with the addition of high temperature and humidity
USDA. Quarterly hogs and pigs report, March 2021. Available at: https://usda.library.cornell.edu/concern/publications/rj430453j?locale=en. Accessed Mar 6, 2021.
- 2. ↑
Kansas State University. Weekly hog slaughter. Available at: www.agmanager.info/livestock-meat/livestock-marketing-charts/weekly-hog-slaughter. Accessed Nov 6, 2020.
- 3. ↑
US Energy Information Administration. Weekly Midwest (PADD 2) oxygenate plant production of fuel ethanol (thousand barrels per day). Available at: www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=W_EPOOXE_YOP_R20_MBBLD&f=W. Accessed Jan 29, 2021.
- 5. ↑
Gonyou HW, Brumm MC, Bush E, et al. Application of broken-line analysis to assess floor space requirements of nursery and grower-finisher pigs expressed on an allometric basis. J Anim Sci 2006;84:229–235.
- 6. ↑
Petherick JC, Phillips CJC. Space allowances for confined livestock and their determination from allometric principles. Appl Anim Behav Sci 2009;117:1–12.
- 7. ↑
Leary S, Anthony R, Gwaltney-Brant S, et al. AVMA guidelines for the depopulation of animals: 2019 edition. Schaumburg, Ill: AVMA, 2019;43–45.
- 8. ↑
American Association of Swine Veterinarians. Recommendations for the depopulation of swine. Available at: www.aasv.org/Resources/welfare/depopulation_recommendations.pdf. Accessed Jun 15, 2020.
- 9. ↑
Bird N. Ventilation failure alarms: 2 case studies. Available at: www.dicam.co.uk/wp-content/uploads/filebase/research/Case_Study_2_ventilation_failure_incidents.pdf. Accessed Oct 4, 2021.
- 10. ↑
Robert MJ, Shaffer CS, Funk TL, et al. Carbon dioxide and temperature change due to ventilation failure, in Proceedings. Swine Housings II Conference, 2003;9–15.
- 12. ↑
Robertshaw D. Mechanisms for the control of respiratory evaporative heat loss in panting animals. J Appl Physiol (1985) 2006;101:664–668.
- 13. ↑
EFSA Panel on Animal Health and Welfare. Welfare of pigs during killing for purposes other than slaughter. EFSA J 2020;18:e06195.
World Organisation for Animal Health (OIE). Terrestrial animal health code. 28th ed. Paris: World Organisation for Animal Health, 2019.
Gavinelli A, Kennedy T, Simonin D. The application of humane slaughterhouse practices to large-scale culling. Rev Sci Tech 2014;33:291–301.
- 16. ↑
Berg C. The need for monitoring farm animal welfare during mass killing for disease eradication purposes. Anim Welf 2012;21:357–361.
- 17. ↑
Arruda AG, Beyene TJ, Kieffer J, et al. A systematic literature review on depopulation methods for swine. Animals (Basel) 2020;10:2161.
- 18. ↑
Leary S, Underwood W, Anthony R, et al. AVMA guidelines for the euthanasia of animals: 2020 edition. Schaumburg, Ill: AVMA, 2020.
- 19. ↑
Bargen LL, Whiting TL. Time to critical overcrowding of Manitoba swine barns in the event of restriction on animal movement. Can Vet J 2002;43:855–862.
Crispin SM, Roger PA, O'Hare H, et al. The 2001 foot and mouth disease epidemic in the United Kingdom: animal welfare perspectives. Rev Sci Tech 2002;21:877–883.
East IJ, Roche SE, Wicks RM, et al. Options for managing animal welfare on intensive pig farms confined by movement restrictions during an outbreak of foot and mouth disease. Prev Vet Med 2014;117:533–541.
Howden KJ, Brockhoff EJ, Caya FD, et al. An investigation into human pandemic influenza virus (H1N1) 2009 on an Alberta swine farm. Can Vet J 2009;50:1153–1161.
Laurence CJ. Animal welfare consequences in England and Wales of the 2001 epidemic of foot and mouth disease. Rev Sci Tech 2002;21:863–868.
Mangen MJ, Burrell AM, Mourits MCM. Epidemiological and economic modelling of classical swine fever: application to the 1997/1998 Dutch epidemic. Agric Syst 2004;81:37–54.
Weng HY, Yadav S, Olynk Widmar NJ, et al. Modelling the time at which over-crowding and feed interruption emerge on the swine premises under movement restrictions during a classical swine fever outbreak. Animal 2017;11:493–499.
- 26. ↑
Yadav S, Weng HY. Estimating the scale of adverse animal welfare consequences of movement restriction and mitigation strategies in a classical swine fever outbreak. BMC Vet Res 2017;13:83.
- 27. ↑
North American Meat Institute. Significant events and progress involving the meat and poultry industry during the COVID-19 pandemic. Available at: www.meatinstitute.org/ht/a/GetDocumentAction/i/179846. Accessed Dec 17, 2020.
Protocol used by the farm described in the present report for depopulation of pigs because of packing plant closures caused by the COVID-19 pandemic.
VSD+TH cycle CANNOT be initiated or ended without approval from barn veterinarian.
LogTag temperature and humidity recorders placed at each end of the barn.
Load pigs into the barn at approximately 1,500 head (finishing pigs) or 3,500 to 4,000 head (nursery pigs).
Barn owner: validates that the room is clear of all people.
Barn owner: all clear is communicated via 2-way radios to all staff and in-barn veterinarian.
Barn veterinarian: initiates cycle START via 2-way radio communication.
All doors are shut.
Barn exhaust fans are sealed with fan covers.
Barn veterinarian will be stationed in the control room.
Veterinarian will document all events throughout the cycle.
The veterinarian will begin a room timer for the barn.
Heaters turned on; no steam; beginning temperature recorded and recording of temperature throughout cycle.
At 54°C (130°F), time 0, the veterinarian turns heaters off. a. Can restart heaters to maintain a temperature range of 49°C to 65°C (120°F to 150°F), as needed.
At 54°C, time 0, veterinarian requests steam generation.
Veterinarian monitors and records:
Time to achieve 54°C in minutes from heat initiation.
The time when the room is silent (no pig movement, breathing, or vocalization).
Thirty minutes from time 0, the veterinarian evaluates barn for pig movement or vocalization in 5-minute intervals.
If movement or vocalization is noted, the cycle continues.
If no movement or vocalization is noted, the veterinarian will initiate END CYCLE (STOP) process.
End Cycle (STOP)
Veterinarian turns the heaters off, if operating, and communicates ALL STOP for steam generation.
Barn owner removes fan covers.
Veterinarian turns on fans from the control room.
All doors are opened.
The veterinarian visually evaluates the barn to ensure no animal movement while waiting for the barn's humidity to be ventilated.
Veterinarian, barn owner, and 1 additional person walk through the barn and evaluate each pig for any sign of consciousness.
If signs of consciousness (breathing, heartbeat, body movement, blinking, corneal reflex, or response to a painful stimulus) are seen, captive bolt euthanasia is applied immediately.
The veterinarian will declare the “all clear” after all pigs are verified as dead.
Carcass removal is permitted upon the veterinarian and all personnel exiting the building.
LogTag recorders are collected and identified to the barn on cycle record, records and LogTag devices are taken to the office, and the depopulation team will debrief at the end of each day.