Swine feed holding times updated to prevent the spread of viruses

AMES, Iowa — With research confirming that swine viruses can be transmitted through feed and feedstuffs, new studies are looking at how to prevent the spread of foreign animal diseases, such as African swine fever (ASF).

Based on new research, the Swine Health Information Center (SHIC), the National Pork Board, the National Pork Producers Council and the American Association of Swine Veterinarians have revised the information for feed holding times (see adjacent table).

The new details decrease holding times over the initial estimations, which were calculated in October 2018 based on the available research, and give additional assurances of further viral degradation if the feed ingredients are contaminated.

“The science on viral transmission through feed and feedstuffs is still relatively young, but it has yielded some interesting and potentially useful information on mitigating the spread of costly viruses, such as ASF,” said Paul Sundberg, DVM, Swine Health Information Center executive director.

Lots of variations

But not all imported feedstuffs are manufactured and handled in the same way, Sundberg cautioned. “It’s important to know whether ingredients are produced under biosecure conditions and how they were shipped.”

“Variations of the same feed components might cause disparity in holding time confidence,” added David Pyburn, DVM, National Pork Board senior vice president, science and technology.

For example, according to research using Senecavirus A (Seneca Valley virus), which is suggested to have the longest holding time of studied viruses, increasing holding times by an additional 30% would give an opportunity for 99.999% degradation of contaminating viruses, Pyburn said.

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.

What to watch

“Continued diligence on feedstuffs origin, the manufacturing processes, the shipping methods and ‘born on date’ is essential,” Liz Wagstrom, DVM, National Pork Producers Council chief veterinarian, said.

“Feedstuffs manufactured, sealed, handled, and shipped under biosecure conditions produces an ingredient free of pathogens and reduces the risk of post-processing contamination, resulting in little to no risk to animal health.”

For example, vitamins and amino acids are typically shipped in sealed or secure containers. Anything produced under unknown conditions or unsealed can pose an animal health risk.

Imported soybean meal and DDGS are often transported in non-sealed or non-secure containers. Knowing the origin of ingredients and the disease status of the region or country is essential.