For swine producers, biosecurity is nothing new; it’s always on the mind. As concerns about African Swine Fever virus grow, experts are taking a closer look at protocols in every step of the production process.

During the virtual Swine Day, Kansas State University researchers examined and explained biosecurity measures and virus transmission within feedmills.

“Feed may not be viewed as the highest risk vector of transmission, but it could have the largest reach, ” said Jason Woodworth, K-State research associate professor.

Woodworth explained feedmills are built to receive ingredients from around the world and later distribute those ingredients to a number of locations, potentially spreading a destructive virus far and wide.

“We need to acknowledge how feedmills can be a hub for transferring viruses to other locations,” Woodworth said. “Trucks going back and forth from farms to the mills, and then trucks entering and exiting ingredient facilities and subsequently to other feed mills and farms really creates a great pathway for disease transmission.”

Research in the mill

The big question: how and when could ASFv enter the United States? A qualitative assessment by the USDA showed feed-based entry of ASFv into the United States was unlikely, although the uncertainty of this is high.

“The research we have is very preliminary,” said Cassie Jones, K-State associate professor of animal sciences and industry. “I think we need to continue to work in this area and understand how substantial is the risk, and if so what are the things we can be doing to manage it.”

To better understand the risks of ASFv transmission through feed, K-State researchers built a miniature feedmill within the Biosecurity Research Institute.

“The first question we wanted to evaluate was, if we introduce ASFv to the environment of a feedmill, where does it go and how long does that contamination persist?” Jones said.

Researchers outlined the four zones that could potentially be contaminated with the virus: surfaces in direct contact with feed, surfaces within 1 meter of equipment, surfaces greater than 1 meter away from equipment and transient surfaces, such as employee clothes and shoes.

To simulate a feedmill, researchers ran batches of feed through a mixer and bucket elevator before discharging the final product into biohazard bags.

“We did that initially with a batch of feed that did not contain ASFv,” Jones said. “Just a normal batch of feed, because you can imagine there’s some level of dust and feed residue that remains on the manufacturing equipment and we wanted to have as realistic conditions as we could.”

The second batch of feed was intentionally contaminated with ASFv by adding an ingredient laced with the virus. The following three batches were made with feed that had not been contaminated. Then all batches of feed and all surfaces within the feedmill were tested for ASFv.

“What we found was very similar to what we had previously seen with PEDv,” Jones said. “As soon as we introduce ASFv to the manufacturing environment, that contamination begins to be distributed throughout the manufacturing environment, not just food contact surfaces.”

Contamination persisted in the feed, on non-direct surfaces and on transient surfaces following the initial introduction of ASFv.

“That means that contamination has the potential to extend to multiple pigs and/or multiple farms,” Jones said. “We’re not just talking about the high risk product manufactured during that specific batch, but subsequent batches of feed that are being delivered potentially to different farms and different facilities.”

What can be done?

A multifaceted approach is key to mitigating the risk of ASFv entering the United States through feed, Jones said.

“I suggest we continue to exclude high-risk ingredients,” Jones said.“We’ve made a strong case for extending biosecurity practices from farms to mills.”

In cases of concern, active mitigation, such as chemical or thermal treatments, is also available.

To help producers better understand the threat ASFv poses, and what they can be doing on their operations, KSU has feed safety bulletins and producer publications posted on www.KSUSwine.org

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