29 October 2018 – It might be generally assumed that animal viruses in feed ingredients cannot resist the long durations of transoceanic voyages. But research in the U.S. has shown the possibility that African Swine Fever (ASF) could survive transboundary shipment in feed and feed ingredients. And in light of recent events many in the U.S. livestock industry are calling for, or are moving forward with, measures which some believe will mitigate the risks of ASF transmission via imported feed ingredients.
The research concerning the transmission of ASF via transocean shipments, issued jointly by the National Pork Board, National Pork Producers Council, Swine Health Information Center and the American Association of Swine Veterinarians echoes scientific findings published earlier this year in Plos One, which according to lead researcher Dr. Scott Dee, Director of Research for Pipestone Veterinary Services, presented for the first time the possibility of certain feed ingredients to serve as vehicles for survival and potential movement from place to place and country to country.
In this study, he conducted molecular analysis and compared isolates of PEDV during a US outbreak that began in 2013. His work suggested that a close relationship between strains found in China and in the US existed and that the possibility of feed ingredients serving as a vehicle for transmitting the pig disease.
To simulate the environmental conditions that feed ingredient cargoes could encounter during the trip from Beijing to Des Moines, Iowa, Dee used an environmental chamber to reproduce temperature and humidity fluctuations on a daily basis. Meanwhile, Dr. Eric Nelson of South Dakota State University provided insight on how to spike samples of feed ingredients known to be imported from China with PEDV. They used representative transport times and environmental conditions and tested the samples at different points along the path to determine what viruses could survive the long journey.
The study grew and the Swine Health Information Center became involved. They expanded the testing across an additional 11 viruses, including ASF. The results of this further multi-virus study confirmed Dee’s initial findings on the survival of PEDV in feed, as well as the survival of several viral pathogens in multiple feed ingredients or feed products.
It was concluded that viruses can survive in feed, but survival is variable and depends on specific properties of each virus. Moreover, certain feed ingredients or feed products present a better matrix for virus survival than others.
But on a more reassuring note, ASF is thought to die out when held in dry conditions. And there is also the fact that viruses are killed during some feed ingredient manufacturing processes.
Dr. Dee shared the information at the Allen D. Leman Swine Conference in September and urged for the industry to be vigilant and adopt a multi-pronged approach.
“We are in such a different place with ASF than we were when PEDV hit”, Dee said. “We are not infected. We are all focused. We have data that we can use proactively”.
But with the ASF situation intensifying in China and in Eastern Europe, and Japan detecting the virus in one imported sausage, U.S. government officials are now also urging that the US livestock industry increases its ability to test for ASF and come up with a plan to respond quickly if a case is identified. In turn, U.S. pork producers are ramping up safety procedures and it is understood that various feed ingredients imported from China are being kept in storage for longer periods.
Minnesota hog farmer Randy Spronk told Reuters earlier this week that he asked feed brokers and manufacturers about the origin of the vitamins and feed additives he buys for his herd, adding that if the products came from China, he wanted them kept in storage.
Hugh Welsh, president of DSM North America, meanwhile, also told Reuters that DSM does not quarantine products from China to prevent ASF because it takes 120 days to reach the U.S. market. That is thought to be long enough for the virus become ineffective.
And New Fashion Pork is asking feed companies to keep ingredients from China in storage for at least 30 days, said owner Brad Freking. After that New Fashion Pork will hold the products in storage for another 45 days. “We have asked our supplier to basically quarantine those ingredients”, Freking commented.
In a statement sent to Feedinfo News Service, Cargill Animal Nutrition said: “The ingredients we buy today have all gone through heat treatment steps to control ASF risk. The time factor during shipment, adds an additional buffer and comfort for our customers”.
“ASF is not new to us, we have effectively operated in Europe where ASF has been present for more than three years and in Russia for more than 10 years. We have a long standing dedicated team in China whose job is to work with suppliers to improve quality, food safety and now help ensure the risk ASF is properly managed”, the company added. “Our team of experts continues to monitor animal disease outbreaks such as ASF in all countries and implement appropriate measures when needed. Cargill will continue to work closely with suppliers and review the supply chains to help control potential hazards for animal and human health”.
The additional days of storage, however, raises all sorts of logistical and financial questions. Indeed, keeping feed in storage raises costs for the livestock producers because it requires them to have more supplies on hand. It also takes up more storage space in warehouses.
The larger importers are naturally aware of this issue which they plan to mitigate.
Cargill Animal Nutrition commented: “Although there are additional costs associated with quarantines, we believe we can manage these complexities for our customers”.
African Swine Fever will be the subject of a lunchtime briefing on day 2 of Feed Additives Americas in Miami, from December 12-13. For more information on the content of this conference, click here.