Tough Decisions: Animal Mortality Disposal During a Disease Outbreak

( Jennifer Shike, Farm Journal's PORK )

African swine fever (ASF) is taking over the news headlines now, but it’s not the only foreign animal disease posing a threat to animal health, the national economy and the environment. Still, it is causing pig farmers to take another look at their animal mortality plan if a disease outbreak would hit their farm.

“All outbreaks start with one mistake and then if it is not managed well, it spreads quickly and then you have a national crisis,” says Neslihan Akdeniz, University of Illinois assistant clinical professor. “Being ready for a disease outbreak is important, it’s important to be precautious. We don’t need to panic, but we do need to be prepared.”

Akdeniz and graduate student Tiago Costa have been studying disease outbreaks that have taken place since the 1960s and recently reported their findings in the scientific journal, Waste Management. A key discovery was that if producers don’t respond quickly when an infectious disease hits, the disease spreads widely and gets out of hand fast.

They summarized some lessons learned during the major animal disease outbreaks including the 2010 foot-and-mouth disease, 2016 highly pathogenic avian influenza, and recent African swine fever outbreaks.

Disposal Methods
Intense livestock production, increased travel and changing climate have led to the increased risk of catastrophic animal losses if an infectious disease would hit, Akdeniz says. In the event of an outbreak, it is essential to properly manage the infected animals to prevent the spread of diseases. 

“With ASF or any outbreak, we need to make a scientific decision when the time comes,” Akdeniz says. “We can’t bury or compost them all, so we have to take a look at all of the options.”

The most common disposal methods used during a disease outbreak include burial, composting, landfilling, and incineration. However, biosecurity, transportation logistics, public perception and environmental concerns limit the use of some of these methods. 

During a disease outbreak, the large number of mortalities often exceeds the capacity of local rendering plants and landfills, Akdeniz says. Rendering facilities often do not accept diseased animal mortalities. Transporting mortalities to disposal and incineration facilities outside the production operation introduces biosecurity risks. Portable incinerators can’t be used in a disease outbreak, she says. Not only are they expensive and have the potential to aerosolize infectious particles, but they are also hard to get approved by EPA. 

Burying mortalities is limited by the size and availability of suitable sites and it has the risk of pathogen survival and contamination of groundwater and soil.

“One of the challenges with burial is that there is no heat treatment, which is important to kill the ASF virus,” Akdeniz says. “When we bury animals, they stay there for many years. In an outbreak, we want to get them out as soon as possible.”

What’s the Most Biosecure Option? 
Composting, on the other hand, has been recognized as a biosecure disposal method. Research shows that it eliminates bacterial pathogens such as Escherichia coli O157: H7, Salmonella spp., as well as viruses including highly pathogenic avian influenza, foot-and-mouth disease, Newcastle disease and porcine epidemic diarrhea, Akdeniz says.

Composting also eliminates the risk of contaminating other sites because diseased animals are not transported to a different location. On-farm management is always preferred, she adds.

Although composting has not been used in a swine disease outbreak yet, it was used successfully in the avian influenza outbreak in 2015-16.

“ASF is resistant to low temperatures, so we have to use heat treatment,” Akdeniz says. “If done properly, [composting] can eliminate pathogens quickly.”

The challenge with composting is that it needs to be done properly. 

“We can’t just put animals there and assume they will be composted by themselves. It requires some experience and time commitment,” she adds.

When it comes down to it, one method alone won’t work. Akdeniz says USDA is looking at many methods to dispose of animal mortalities should a foreign animal disease like ASF come to the United Sates. Some of the alternative methods include above ground burial, horizontal grinders to grind carcasses to reduce volume before composting and sending some carcasses to the landfill.

“Depending on the area and size of the outbreak, we won’t be able to compost all mortalities because there is not enough carbon source on hand,” Akdeniz says. 

Communications and support
During a time of crisis, communication is critical. She says it’s important for producers to communicate how they will respond to these situations to the public, she adds.

“Producers need to remember they are not alone,” Costa says. “They have resources and support available. When it comes time, they won’t have to make these tough decisions on their own. There are plenty of specialists in the field available to help them through these times.”

In the meantime, Akdeniz advises producers to take advantage of educational opportunities to learn more about mortality disposal methods and to start thinking about how they will depopulate and dispose their animals if needed. 

“Think about it, be prepared, and let’s do everything we can to keep ASF out,” Akdeniz says. “If you are traveling abroad, follow biosecurity protocols so you don’t bring it back.

“A review of the animal disease outbreaks and biosecure animal mortality composting systems” was published in the journal, Waste Management in May.

For more on ASF news and prevention, read

Neslihan Akdeniz is a clinical assistant professor with a research and an extension appointment and Tiago Costa is a graduate student in the department of Agricultural and Biological Engineering at University of Illinois at Urbana-Champaign. 

Read more from Farm Journal’s PORK:
A Mortality Composting How-To

Mortality Composting: Making Happy Microbes

How To Dispose of Mortalities in Livestock Production