Research on Viral Transmission in Feedstuffs Yields New Information

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October of 2018, based on the historical research had been done, we were able to calculate a half-life for virus survivability.


Don Wick


Paul Sundburg, Executive Director, Swine Health Information Center




Don Wick: 00:00 From the Pork Checkoff in Des Moines, Iowa, it’s Pork Pod. Pork Pod, a look at the hot topics in today’s pork industry. The Pork Checkoff is working for you through various forms of research, promotion and consumer information projects. I’m Don Wick speaking on behalf of the Pork Checkoff. And today our guest is Dr. Paul Sundberg, executive director of the Swine Health Information Center. We’ve had research that details the viability of a virus, a virus like a African swine fever or other foreign animal diseases in feed, feed ingredients. Dr. Sundberg, can you bring us up to date on some of the latest research here?

Paul Sundberg: 00:37 Yeah, so initially last October, October of 2018, based on the historical research had been done, we were able to calculate a half-life for virus survivability. And a half life is defined as, the time that it takes for natural degradation, or inactive of viruses in feed components over time. So, we know that as a viruses load of viruses put in feed stuffs over a certain period of time, half of it will be gone and it naturally degrades. And then if you take the next half-life, half of the half will be gone. So it will continue to go down and go down and go down. So, it’s based on the initial research that we did with the survivability of these viruses in feed components, we were able to calculate an estimated half-life. And that’s a very important point. It was an estimated half-life based on preliminary research back in October of 2018. That half-life then was used to calculate a projected holding time and that holding time would be such that it would allow natural degradation of the virus until it was 99.99% gone.

Paul Sundberg: 02:00 Whenever it started with was 99.99% would be gone. And that was the initial holding time. We knew that that was initial and we knew that was preliminary and based on preliminary research. So, with the American Feed Industry Association, we funded research at South Dakota State University to do a better job of calculating half-life of virus in different feed components. And that research is the basis now for this revised half-life information or holding time information. South Dakota State University did this and we looked at it with three different temperatures. We looked at the half life in different feed components at about 40 degrees at approximately 60 degrees and a little bit over 70 degrees. So, by Celsius it was 4, 15, and 30 degrees centigrade or about 40, about 50 and about 70 some degrees Fahrenheit. And we looked at that and got a half-life, pretty scientifically sound half-life by which now we can do a better job of giving some better information about suggested holding times based on that research.

Don Wick: 03:23 So has it changed significantly from what we were talking about previously?

Paul Sundberg: 03:28 Yeah. You know, the good news is that it’s gone down. The initial research was a fairly lengthy half-life, a fairly lengthy holding time for, for the viruses. This new research now has decreased it significantly and I think that’s good in a couple of ways. One is that initially we told everybody it was an estimate and we said, we’re going to do better. And so that happened. The other part of it is though that initially I think we erred on caution on the side of caution and while that was approximately 78 days, say at one temperature for ingredients like vitamins, pre-mixes, amino acids. We’ve done a much better job now of focusing on different temperatures and different feed ingredients and the amount of days that it would take for holding time for natural degradation as little as 30, as little as 20 some days, as little as 30 days. It varies.

Paul Sundberg: 04:35 There’s a length there for those types of components. As a general rule, however, things like soybean meal and DDGs, which we’d continue to import from areas of the world that have ASF, those types of things have the longest holding time, whether it was back in October or whether it is now. And so that’s an important differentiation of those products, like vitamins, amino acids, that type of thing and all of that research. All of that holding time calculation can be found on the swine health information website.

Don Wick: 05:21 As we’ve talked before, it’s really important to know the origin of the feed ingredients that you have. How does a pig farmer do that today?

Paul Sundberg: 05:30 Yeah, yeah. You see, here’s the thing. If, if we have a risk from feed and we believe that there is, that’s not quantified. So there, I’m sure there are other risks that may be more a higher risk than what feed is, but we believe there’s a risk of feed there. And in order to mitigate that risk, there’s a number of things that have to happen. One is either apply a holding time to help degrade the viruses. We’re doing research on feed ingredients that could be added to feed as it’s milled that would decrease that. A third and very important piece is to talk to your feed supplier to make sure you know where your feed components come from and the biosecurity conditions under which they’re manufactured. So if you start with a clean ingredient to begin with and it’s maintained clean throughout the process, you know you’re going to have a clean ingredient when you mill it.

Paul Sundberg: 06:33 And so that’s an important thing to start that conversation with your feed supplier. And those questions that producers and their veterinarians can use to start that conversation are also available on the website. All of those resources are right there. If all of those things can’t happen, then we suggest that producers consider if they should be sourcing those components from areas of the world that have ASF or other foreign animal diseases. We know that for certain things like certain vitamins, they have to come from China for example, because that’s the only place in the world they’re manufactured. And so if that’s the case, you can’t source them from other places, then you have to apply one of those other mitigations. So, I think starting that conversation with your feed supplier based on those questions that are on is exactly the thing that has to happen for pork producers.

Don Wick: 07:35 How important is it that we have this coordinated approach from Pork Board, Pork Producers Councils, swine veterinarians, feed industry. How important is that to really be working together as we are?

Paul Sundberg: 07:50 Yeah. You know what, we are held to the lowest common denominator for all producers and anybody that’s raising pigs. If, if we get ASF for example, in the country, it makes no difference at that ASF happens in somebody that has 10 pigs or 100,000 pigs. We still would be positive for ASF in the US and our foreign markets would close. So we all have to work together and National Pork Board, NPPC, National Pork Producers Council, American Association of Swine Veterinarians and the American Feed Industry Association, and the other feed associations all have different audiences and there’s a lot of overlap of course, but we want to make sure that we covered the whole ocean of audiences out there because everybody needs to work together on this. The pork producer is the last point of biosecurity to keep the ASF virus and other foreign animal diseases out of their pigs and we all have a stake in this no matter what kind of production we have, nor how big our farms are.

Paul Sundberg: 09:03 Everybody’s held to the same standard. You know, the other message here is that we’ve done that research, and this is a technical point, but we’ve done that research with Seneca Valley virus because our initial research on that show that SVA or Seneca Valley virus had the longest half-life of all of them and including African swine fever. So, if we do the half-life in the holding time for all of these based on Seneca valley, we’ll catch them all. More research is happening with African swine fever to make sure that that is in fact the case. And it’s possible that we could even update this based on African swine fever in another six, eight months or so. So, look for more information that will come out. As we go along, we reserve the right to learn more and we reserve the right to know more and pass that along. The other very important piece of this is that what we’re doing is communicating research results. We can’t really make recommendations or set standards for pork producers. It’s up to them to decide if they want to implement this in the best interest of themselves and of the pork industry. But we’re at least communicating the research results. So, producers are informed about the research and then can take actions for mitigation if they so choose.

Don Wick: 10:30 Thank you for listening to this edition of Pork Pod. For more information on this topic or the Pork Checkoff itself visit