From fires to tornadoes to foreign animal disease outbreaks, no two emergencies are identical on the farm. That’s why depopulation plans must take a number of specific circumstances into account.
The American Veterinary Medical Association (AVMA) recently released revisions to its Guidelines for the Depopulation of Animals. After years of research and work, foam depopulation is now recognized as a tier 1 method.
“The addition of foam-based depopulation methods to our toolbox provides a critical advantage in speed, cost and logistics,” says Andrew Bowman, DVM, with The Ohio State University. “This is a gamechanger for swine producers.”
Tier 1 methods are given highest priority and should be used preferentially when developing emergency response plans and when circumstances allow reasonable implementation during emergencies, according to AVMA’s guidance.
“For producers, this update expands the set of AVMA-recognized depopulation methods that can be considered as part of emergency preparedness and response planning,” says Stephanie Wetter, director of animal welfare at the National Pork Board. “The Tier 1 designation means that water-based foam and nitrogen-filled foam are now recognized alongside other Tier 1 methods commonly used on farms for euthanasia and depopulation.”
Importantly, Wetter says a Tier 1 designation does not require producers to use these methods. Instead, it provides additional flexibility and confidence that foam-based approaches meet the highest professional standards for humane use when properly applied.
“Method selection remains site- and situation-specific and should be made in consultation with a veterinarian, based on factors such as facilities, pig size, labor availability and the nature of the emergency,” Wetter says.
What’s Best for the Animals and Caretakers?
In 2019, the AVMA’s first guidance for depopulation came out after the AVMA Panel on Euthanasia recognized the importance of evaluating methods and agents that might need to be applied when animals are killed under conditions in which meeting the panel’s definition of euthanasia may not be possible.
The guidelines cover a broad range of animal species and help veterinarians assess risks and methods for the rapid killing of animals during emergency situations. They provide recommendations for procedures, training personnel and anticipating equipment needs.
In general, the 2026 revisions include:
• Introduction of a new tier system for classifying depopulation methods
• Development of 11 criteria to guide assessment of depopulation methods
• Expansion of species-specific chapters and inclusion of additional species
• Reorganization of species chapters to include images for improved clarity
• Inclusion of special considerations within each chapter
• Updates to the veterinary ethics section
Tier 1 Methods for Swine
The tiers distinguish methods according to their demonstrated welfare outcomes, feasibility and suitability during emergency response operations. The Tier 1 methods for swine include:
• Commercial or private humane slaughter processing
• Inhaled methods (carbon dioxide, carbon monoxide, nitrogen)
• Non-inhaled methods (injectable agents)
• Physical methods (gunshot, nonpenetrating captive bolt, penetrating captive bolt, electrocution, manual blunt force trauma)
• Foam-based methods (water-based, N2-filled foam)
Paul Ayers, animal care manager with The Maschhoffs, believes producers need as many depopulation options as possible.
“There are trade-offs with all methods, and it’s important to have several methods available that will meet producers’ site-specific needs,” Ayers says. “Every depopulation scenario will be different, and we must provide producers with several options to help meet their needs.”
AVMA urges veterinarians to also consider factors such as human safety, psychological impacts on personnel, availability of trained responders, infectious disease concerns, conservation and population objectives, regulatory requirements, equipment availability, disposal options and potential secondary toxicity.
A Step Forward for the Pork Industry
“The AVMA’s decision to classify water-based foam and nitrogen-filled foam as Tier 1 depopulation methods reflects the strength of the available science and validates years of research, field experience and veterinary review,” Wetter says. “For the U.S. pork industry, this provides clarity and consistency around humane depopulation options for pigs that prioritize animal welfare, worker safety and operational feasibility during emergency situations.”
By diversifying the depopulation methods available, Bowman says the U.S. swine industry will be more resilient in the face of emerging disease threats. He offers three major reasons why foam-based depopulation is a valuable tool for producers.
1. Leverages existing infrastructure
“One of the greatest benefits of water-based foam depopulation is that it utilizes equipment already housed in the USDA National Veterinary Stockpile and owned by poultry production companies,” Bowman says. “While water-based foam has long been a standard for poultry, recent studies have shown it is highly effective for swine.”
2. Cost effective
“In an emergency, financial barriers can slow down response times,” Bowman says. “Water-based foam is an affordable alternative to other depopulation methods. The necessary specialized equipment (high-pressure water pumps and expansion nozzles) is often already available in local communities through fire departments or can be purchased for under $1,000. Additionally, unlike gas-based agents, foam concentrate can be stockpiled, ensuring farmers are prepared before a crisis hits.”
3. Allows for rapid scalability
“Efficiency is the best way to lessen the economic impact of a disease outbreak,” he adds. “Foam-based methods are group applied, meaning it is specifically designed for rapid, large-scale depopulation. It can be adapted to handle everything from nursery pigs to adult swine quickly. By providing a ‘stamping-out’ method that is both fast and thorough, we can effectively create firewalls around a disease outbreak, saving the livelihoods of neighboring producers and stabilizing the industry.”
Years of Research
“Historically, depopulation methods that AVMA has reviewed and endorsed have allowed producers to qualify for indemnity,” Anna Forseth, DVM, director of animal health with the National Pork Producers Council (NPPC), explained at the Ohio Pork Congress. “Prior to this version, foam depopulation was not included.”
The U.S. pork industry has been funding research for years to explore more depopulation methods.
“I’d like to acknowledge the Ohio Pork Council and industry stakeholders in Ohio, because a significant amount of work was completed by them in this area of foam depopulation,” Forseth says. “Dr. Andrew Bowman and his team at the Ohio State University have provided the industry with important data on these depopulation methods. AVMA wouldn’t have been able to add them to the list without important research that has been funded by the National Pork Board and the National Animal Disease Preparedness and Response Program.”
See the AVMA Guidelines for the Depopulation of Animals: 2026 Edition here.
Read more:
It’s Time to Talk About Depopulation in the U.S. Swine Industry
Sad Doesn’t Mean Wrong: The Impact of Animal Depopulation on Employees
