When it comes to biosecurity on the farm, there isn’t any one thing that you can do that’s 100% effective, says Paul Sundberg, DVM, executive director of the Swine Health Information Center. That’s why putting multiple biosecurity procedures – hurdles – in place on the farm is the best thing producers can do to keep disease out.
“Putting a series of hurdles in the way decreases the chance of a virus getting to our pigs with each hurdle,” Sundberg says. “Showering in will decrease the probability by some percentage, putting on farm-specific boots will decrease it by another percentage, passing through UV lights may decrease it again, etc.”
Recent research funded by SHIC and IFEEDER, the research arm of the American Feed Industry Association, led to SHIC, the National Pork Board, the National Pork Producers Council and the American Association of Swine Veterinarians revising feed holding time calculation is one more hurdle producers can place between their pigs and viruses on the outside.
“If we don't look at biosecurity and feed, what we end up with is an open pipeline between the outside and our pigs,” he adds. “If you bring in imported feed ingredients that are contaminated with a virus, they will be mixed and go directly into our pigs. We’ve got to minimize that risk the best we can.”
Viral Transmission Through Feed
Although the science on viral transmission through feed and feedstuffs is relatively young, Sundberg says it has yielded some interesting and useful information. In a recent study, South Dakota State University evaluated the half-life of Seneca Valley virus. The half-life is the amount of time that it takes for half of a virus that may be contaminating feed or a feed ingredient to die off naturally. Current research suggests that Seneca Valley virus has the longest half-life of all of those researchers looked at, including African swine fever (ASF).
Researchers compared the half-life of Seneca Valley virus at three different temperatures based on seasonal weather norms – 36.9, 59, and 86 degrees Fahrenheit in conventional soybean meal, distillers dried grains with solubles, Vitamin D and lysine.
The updated holding times are based on this half-life research, Sundberg says. He stresses that they aren’t making recommendations, but rather providing research results for producers to consider when implementing feed biosecurity practices.
To account for variability within feedstuffs (even though they are manufactured in the same way, different lots can have different chemical characterization that can affect the half-life), Sundberg says consideration could be given to holding the feed longer.
More research would be needed to confirm that the results could be extrapolated to other feed ingredients in like classes to those studied. The updated information shows new holding times details for general informational and educational purposes. They should not be considered as to be recommending or advocating any specific course of action.
“Unfortunately, there isn't any one thing that will guarantee that a contaminated feed product will be completely safe,” Sundberg says. “So we can't guarantee that a feed is sterile, but we can say that, based on this research, holding time decreases any contamination significantly.”
That’s one more biosecurity step we can take to help protect our pigs and U.S. animal agriculture from importing viruses that we don't want, he adds.
The Last Hurdle is You
Rest assured our country is doing everything possible to put national biosecurity hurdles out to keep diseases from the U.S. pig herd, Sundberg says. Customs and Border Protection agents are protecting our airports and ports of entry on ships. USDA is inspecting garbage feeders out on farms to ensure that they are boiling anything that has meat in it for 30 minutes.
“But it’s important that producers know they are the last hurdle in that national biosecurity chain,” he says. “Even if these viruses get into the country, which most probably happens, our producers on the farm are the last hurdle in that national biosecurity chain. Because if they can keep things out, then it never gets to the pig. It’s a big responsibility.”
Sundberg says that the National Pork Board has funded half-life work to be done directly on ASF.
“We want to ensure that we are right in our assumption that Seneca Valley virus has the longest half-life,” he says. “We're going to continue to get smarter. And we're going to continue to verify and make sure that we are doing everything we can to not miss anything.”
For more information on biosecurity practices, visit porkbusiness.com/resources/biosecurity.
Research on Viral Transmission in Feedstuffs Yields New Information