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Recommended African swine fever holding time more than doubles

Further research into swine virus transmission through imported feed shows African swine fever can survive much longer than originally thought.

Dr. Dave Pyburn with the National Pork Board says while looking at holding times as a potential mitigant, the initial study focused on Seneca virus because very few labs could work with ASF.

“The reason we thought Seneca would be a good one is because Seneca is a very hardy virus. It’s known to survive very well in the environment.”

The results indicated Seneca could survive in feed around 50 days.

He tells Brownfield the Pork Board, National Pork Producers Council, and American Association of Swine Vets then secured the necessary funding to examine African swine fever.

“And surprisingly to us, it has shown that African swine fever lasts even longer than Seneca Valley. It’s even hardier than Seneca at least in a feed environment.”

At a temperature of 54 degrees, Pyburn says the average half-life of ASF in conventional soybean meal is about 125 days.

“And even in organic soybean meal, and I can’t explain this, but in organic soybean meal it was even longer, 168 days.”

Because of the cost of storage, he suggests the best mitigant might be an approved feed additive like short-chain fatty acids or formaldehyde.

And Pyburn encourages producers to find out where their feed suppliers are sourcing soybean meal.  If it’s coming from a country that is ASF-positive, he recommends asking that they don’t bring it in.