Quarantine window for feed ingredients may reduce hog disease risk

Foreign animal diseases (FAD) are top of mind as the ongoing outbreaks of African swine fever (ASF) in China, Belgium and elsewhere, have raised the stakes to implement new practices designed to minimize disease transmission. On the plus-side, lessons learned from the porcine epidemic diarrhea virus’ (PEDV) entry into the US has provided insight into protection measures against future disease exposure. Among those is the fact that feed and feed ingredients shipped from other countries can serve as a pathway to harbor viable viruses.

To that end, research has provided some insight into how long certain feed ingredients should be stored to reduce virus-exposure risks and when they can be released for use. The modelling program in the peer-reviewed research¹ has made clear that it’s possible for swine disease viruses to survive in shipments of certain feed ingredients during transoceanic shipping to US ports and even to inland points of feed manufacture.

Based on this current research, a holding time of 78 days after the date of manufacture/bagging or sealing  to prevent additional contamination (aka the “born on date”) for amino acids, minerals or vitamins will degrade 99.99% of viral contamination.

The holding time extends to 286 days for bulk/unsealed ingredients such as soybean meal to allow for similar viral degradation, once shipped to prevent additional contamination.

“Working with your feed supplier to get this type of information is yet another way to help protect your pigs from potential infection from a foreign animal disease,” said Dave Pyburn, DVM, National Pork Board’s (NPB) senior vice president of science and technology. “It’s just one more tool in our arsenal against African swine fever and other diseases. We hope it will offer US producers more protection against this growing global threat.”

The feedstuffs that were studied and shown to have the potential to support virus survival include: conventional soybean meal¹, distiller’s dried grains with solubles¹, lysine hydrochloride¹, choline chloride¹, vitamin D¹, pork sausage casings¹, dry and moist dog food¹, organic soybean meal¹, soy oil cake¹, moist cat food¹ and porcine-based ingredients². Researchers note that there may be other untested feedstuffs that could allow survival of pathogenic viruses. Scientific study and proof-of-concept work in this area continues. To date, without an organized surveillance program, pathogenic swine viruses are not being identified in imported feedstuffs.

“It’s clear from the research that certain feed ingredients can support viral survival during conditions modeled after either trans-Atlantic or trans-Pacific shipping to US ports,” said Paul Sundberg, DVM, director of the Swine Health Information Center (SHIC). “Based on these findings, we think it’s prudent that the entire U.S. pork industry look at this research and consider taking action to help us prevent an FAD from entering this country through this route.”

It’s worth noting that FADs are not the only diseases that could pose future risks. SHIC offers the Disease Matrix on its website at swinehealth.org, listing emerging diseases, a risk score and potential impact.

In a related area of disease prevention, the NPB, National Pork Producers Council (NPPC), American Association of Swine Veterinarians (AASV) and SHIC recommend that producers talk to their feed suppliers to get information about seven key areas.

1. Describe the facility’s biosecurity program to minimize the spread of pathogens from people, vehicles and ingredients.
2. Describe the facility’s employee training on feed safety.
3. Describe the facility’s pest-control program.
4. Describe the facility’s traceability program.
5. Describe the facility’s supplier-approval program.
6. Is the facility certified by a third-party certification body for food safety? Third-party certification programs may include the Feed Additives Manufacturers (FAMI-QS), the International Organization for Standardization (ISO), the Safe Quality Food (SQF), Safe Feed/Safe Food, etc.
7. Does the facility utilize ingredients that were manufactured or packaged outside of the US?

To get a better handle on your farm’s risk of FAD transport via a feed ingredient, Sundberg suggests producers use the newly developed “virus transport in feed ingredients decision tree matrix.” “It was developed to help producers work with their feed suppliers to minimize risk from feed ingredients,” he added.

Aside from the specific feed-related ways to reduce disease risk, Tom Burkgren, DVM, AASV executive director, advises producers to review their current on-farm biosecurity plan with their veterinarian. “While this is always a good thing to do periodically, it’s critically important now to find any potential weaknesses in your production practices so that you can take immediate steps to fix them to help protect your animals.”

The four swine groups continue to collectively reach out to USDA officials, including Chief Veterinary Officer Jack Shere, to see what can be done to enhance the protection of the domestic swine herd from ASF and all FADs.

“U.S. agriculture must bolster its defenses against the spread of animal disease as we face heightened risk,” said Liz Wagstrom, chief veterinarian for the NPPC. “These measures should include private-sector efforts like those that have informed this feed directive as well as publicly funded programs to guard against disease outbreaks that would immediately close export markets and threaten prosperity in rural America.”

¹Dee., S., F. Bauermann, M. Niederwerder, A. Singrey, T. Clement, M. DeLima, C. Long, G. Patterson, M. Shehan, A. Stoian, V. Petrovan, C.K. Jones, J. De Jong, J. Ji., G Spronk, J. Hennings, J. Zimmerman, B. Rowland, E. Nelson, P. Sundberg, D. Diel, and L. Minion. 2018. Survival of viral pathogens in animal feed ingredients under transboundary shipping models. PLoS ONE. 13(3): e0194509. https://doi.org/10.1371/journal.pone.0194509

²Cochrane, R., S. S. Dritz, J. C. Woodworth, and C. K. Jones. 2015. Evaluating chemical mitigation of PEDV in swine feed and ingredients. J. Anim. Sci. 92(E2)090.