Ask an Expert: Feed's Role in Swine Virus Mitigation

Swine viruses such as African Swine Fever (ASF), Porcine Epidemic Diarrhea virus (PEDV), and Porcine Reproductive and Respiratory Syndrome (PRRS) are detrimental to animal health and performance, severely impacting producer productivity and profitability.

While PEDV and PRRS are endemic, causing reduced productivity in sows and growers, ASF continues to spread throughout the world, leading to significant economic losses. Feed plays a crucial role in the health and welfare of swine, and recent global disease outbreaks have sparked interest in understanding feed as a potential carrier for viral pathogens. Given that feed and feed ingredients are sourced globally and brought directly to farms, it is important to understand and acknowledge the potential virus transmission risk associated with swine feed.

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We sat down with Dr. Francisco Domingues to answer some of our most frequently received questions.

Is feed a fomite for swine viruses?

There is a significant body of evidence evaluating the survival of viral pathogens in feed and feed ingredients. Studies have confirmed that viruses can survive in feed matrices, and shown that some feed ingredients or feed products are more suitable to virus survival than others. For example, in one experiment designed to simulate transoceanic shipment, ASFV demonstrated a half-life in feed ranging from 9.6 to 14.2 days. The significance? After two weeks under shipment conditions, the viable virus concentration would only decay by half its original level.

More recent studies have identified feed as an infectious vehicle and a credible risk to biosecurity. Studies using real-world conditions to simulate virus transmission in feed confirmed that PEDV and PRRSV can be recovered from contaminated feed and are capable of causing disease in pigs under experimental conditions. Similar studies looking at ASFV transmission via feed found that the infectivity of contaminated feed is heightened due to repeated exposure, or in other words repeated herd exposure to contaminated feed reduces the viral load required for infection.

What are some mitigation strategies for bacterial and viral contamination of swine feed?

Effective mitigation of swine viruses, such as PEDv, PRRS and ASFV, in swine feed involves rigorous measures at various stages. Initially this typically includes careful selection of feed ingredients from reputable sources with stringent biosecurity protocols and implementing testing and certification procedures to ensure viral-free ingredients. Additional measures such as heat treatment can be used to deactivate viruses. However, new research has found that some viruses can withstand heat up to 100°C. Many producers have found that incorporating proven feed additives that target viral pathogens further enhances protection against viral contamination in swine feed.

Managing feed as a fomite and achieving animal performance and productivity goals require that producers reduce microbial loads and the prevalence of pathogens in feed and feed ingredients. Producers milling and utilizing clean feed are better prepared to achieve operational performance and productivity goals due to lower feed-source pathogen prevalence, reduced microbial load and spoilage-causing organisms.

Chemical treatments in the form of feed additives offer varying levels of effectiveness and control, enabling producers to tailor feed pathogen control to their specific operational risks. By effectively controlling feed pathogens, producers enhance feed safety, bolster biosecurity measures in livestock production, optimize animal performance, and safeguard the integrity of the entire food chain.

What is the impact of clean feed on endemic viruses like PEDV and PRRSV?

Clean feed supports pig performance and potentially mitigates the impact of endemic viruses such as PEDV and PRRSV by reducing the entry of bacterial and viral contaminants into the animal production system. Animals exposed to lower and more consistent microbial loads through clean feed are better equipped to establish stable gut microbiomes, which support robust immune function and overall health. This reduction in viral and bacterial challenges helps minimize the incidence and severity of diseases like PEDV and PRRSV.

Comprehensive biosecurity measures, including the use of feed pathogen control solutions, further enhance the effectiveness of clean feed in protecting against virus transmission, thereby promoting better animal health outcomes and optimizing production efficiency.

Producers wanting to take effective action to protect their animals against contamination can get more information by contacting a clean feed expert today.

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