When reports of African swine fever outbreaks in China hit the news in 2018, the U.S. pork industry went right to work to boost preparedness and prevention efforts. Industry strides and advancements in these areas were shouted across the news headlines; meanwhile, work taking place on the critically important aspects of depopulation and mortality management were less talked about.
If the worst-case scenario happens and animals need to be depopulated in an effort to contain and eradicate the disease, how would the pork industry respond?
“No one is excited about the process or idea of depopulating, whether it’s one or multiple animals. I would say it’s quite the contrary,” says Jeremy Seiger, agriculture department manager at Envirotech Engineering. “However, it is an unfortunate likelihood that a catastrophic event of this nature will eventually occur.”
That’s why the U.S. pork industry can’t afford to not be prepared.
The National Pork Board has teamed up with university researchers to explore new methods of depopulation and mortality management to increase the number of tools available to U.S. pork producers should the worst-case scenario happen.
After a five-year process, the National Pork Board began working with state pork associations and state agriculture departments to practice implementation of depopulation and mortality management activities in a real-world environment to better increase stakeholder understanding.
“We know that our producers need to be able to help themselves,” says Stephanie Wetter, director of animal welfare, sustainability at the National Pork Board. “They are the experts in their own production company. They need to have a plan, understand what equipment and resources they have available, know what land is available and what’s associated with their mortality management options, and understand their state and federal resources.”
The reality is emergencies don’t always happen in a vacuum, she points out. A foreign animal disease (FAD) in pigs could strike during a disease outbreak affecting another species, which could hinder response plans.
“We know no two states have the same resources,” she says. “In addition, the restraints, restrictions and laws may not be the same either. That’s why we must expect the unexpected, and always have a plan B in place.”
What’s the Difference Between Euthanasia and Depopulation?
It is critical to understand the difference between euthanasia and depopulation, Wetter says.
“The American Veterinary Medical Association defines euthanasia as the ending of life of an individual animal in a way that minimizes or eliminates pain and distress,” she explains. “But comparatively, depopulation is the rapid and efficient destruction of a complete population of animals in response to urgent circumstances, with as much consideration for the welfare of animals as is practical.”
It’s not just about one animal as depopulation considers an entire farm full of animals (or area), Wetter points out. Urgent circumstances could include regulatory diseases, non-regulatory highly pathogenic diseases, emerging swine production diseases, zoonotic diseases, intoxications and adulterations, radiologic exposures, natural disasters and market disruptions — similar to what happened during the early stages of the pandemic.
AVMA further categorizes approved methods of depopulation as preferred and permitted in constrained circumstances. Many of the preferred methods look similar to euthanasia. But if you’ve gone through your preferred methods list, and none of those are available for any reason, then the “permitted in constrained circumstances” list offers alternatives.
The Knowledge Gap
China’s ASF outbreak and the COVID-19 pandemic highlighted a gap in knowledge around large-scale efforts for FAD preparedness, Wetter adds. Although many tools were available, additional actions were needed to drive the development of preparedness plans.
In 2020, the National Pork Board Euthanasia and Depopulation Task Force funded a literature review of available swine depopulation research, followed by two rounds of research funding with a new focus on on-farm validation and process creation for producers.
“Despite the research from over three decades, we did not have a safe and reliable way to induce rapid unconsciousness and mortality in larger populations,” Wetter says. “The development of rapid depopulation methods available to a large group of pigs was going to be necessary with suitable low-cost emergency preparedness procedures, while still considering personnel safety and animal welfare standards.”
In 2021, the National Pork Board pursued a multimethod project comparing different methods utilizing carbon dioxide gas, nitrogen gas, compressed air foam, water-based foam and various combinations.
But Will it Work on the Farm?
To apply research findings on-farm, the National Pork Board has hosted on-farm FAD exercises.
“Every time we do this, we learn new things and have new questions come up. Then we can build those into new research projects, seeking to find answers to the gaps we find,” Wetter says.
During a recent on-farm exercise at Michigan State University, more than 70 people were invited to a private demonstration of four depopulation methods and a mortality management demonstration. The methods included CO2 depopulation, N2-filled foam depopulation, and water-based foam depopulation.
The exercise took place over two days. The first day provided a deep dive into the different methods of depopulation, followed by a tour of the equipment used with each method. Participants were allowed to ask questions and visit with the technicians. On day two, participants observed the process of depopulation with each method and were asked to assess them accordingly.
“I was impressed at how far along we have gotten as compared to when we first started talking about mass depopulation,” says veterinarian Randy Jones with Four Star Veterinary Service. “Now there is a clearer path to get it done. It’s still a massive undertaking, but we are heading down a good road to being prepared.”
Paul Ayers, animal care manager with The Maschhoffs, was glad to see how the level of preparedness and technical understanding of depopulation methods has improved over the past three years.
“I have more confidence that there are viable options available for producers if/when they are needed,” Ayers says.
Do We Need More Options?
Some people believe more methods are needed should a FAD outbreak occur in the U.S. Others think the methods the U.S. currently has are sufficient.
“I believe the currently available methods are good, and we do not need more depopulation methods, but we need to continue to fine-tune our current methods,” says Attila Farkas, DVM, with Carthage Veterinary Service.
But Ayers maintains producers need as many 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.”
Jones says it’s important to always be thinking about this question: Is there a better way?
“People are very entrepreneurial and can think of new ways of doing things. Those ideas just have to be vetted and researched to make sure they are an approved method,” Jones says. “We can’t ignore that part. They have guidelines and procedures about how to do depopulation properly. It requires a lot of training and consideration of human safety.”
Unknowns and Work to Be Done
It’s one thing to see a successful demonstration. It’s another to be faced with a major outbreak requiring large-scale depopulation.
“In the event of a FAD outbreak, my biggest concern would be our ability to conduct depopulation at large scale,” Ayers admits. “Several depopulation methods are effective but become much more complex when scaled to multiple sites. Resources such as CO2 or carbon material for composting potentially could become constrained.”
Sourcing the tools and supplies needed to execute the depopulation process effectively and safely is Farkas’ concern, too.
For Jones, mortality management remains a big question mark. Although he was glad to see discussion and trials taking place, he is worried about the logistics of where carbon sources will come from.
“Some tweaking needs to be done on the mortality management and how that will get done, but I know there are a lot of people working on it,” Jones says.
What Producers Need to Know
The swine industry has multiple depopulation methods that minimize distress and anxiety in animals, Farkas says. To him, that’s the most important thing producers need to know.
“The research National Pork Board has supported has significantly advanced our operational readiness with depopulation methods,” Ayers says. “This research not only ensures we understand the best methods but provides the opportunity to gain hands-on experience in controlled and lower risk settings. The projects have also provided the opportunity to engage and educate other stakeholders such as AVMA and state/national government agencies.”
Knowing people are planning and collecting scientific information to support the pork industry through difficult animal mortality management decisions is a comfort to Seiger.
“The equipment demonstrated at this event are some of the most logical options when the pork industry is faced with difficult decisions resulting from a catastrophic event or disease-infected herd,” Seiger says. “Educate yourself and your team of the available options so you can effectively plan, plan, plan.”
Producers need to understand the appropriate equipment needed to manage the entire process. He also advises producers to plan for and locate appropriate locations for potential mortality management areas.
“Whether it be a result of a FAD, other types of illness or other natural events resulting in loss of life such as fire, snowstorms, flooding or other weather-related events, producers need to know what options and resources are readily available (or who to contact) for planning a catastrophic event,” he says. “It is reassuring knowing there are dedicated people working to ensure technology and efficient methods are available to humanely depopulate animals and manage carcasses in an environmentally proper and approved location.”
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