Feed found to play a part in spreading bird flu

Poultry feed should be considered a potential vector for avian influenza, with the virus able to survive in raw materials, especially when protected by organic material such as faeces.

Addressing a breakfast meeting at the International Production and Processing Expo in Atlanta, Georgia, poultry veterinarian Haroldo Toro from Auburn University said that finding AI in feed is like “looking for a needle in a haystack”. “But if it’s there, then birds will find it.”

Studies by the US Department of Agriculture following last year’s US outbreak of high pathogenic AI suggested feed did have a role to play in the spread of the disease, particularly via the inclusion of home-grown grain in the ration.

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This view was endorsed by Gino Lorenzoni, technical director at pathogen control company Anitox.

“We’re looking for multiple vectors,” he said. “Migratory birds are widely accepted to be responsible for inter-continental and inter-state spread. The answer as to how individual farm biosecurity is being breached, though, is more complex. 

“There are multiple mechanical vectors under the spotlight, with feed appearing on that list for two reasons. 

“Firstly, migratory birds settle and shed on feed raw materials such as corn. Any protection normally offered by heat in the pelleting process is absent, as layers and turkeys are predominantly fed mash.”

Dr Lorenzoni also pointed to the fact the virus survives in watercourses and vermin, such as birds and rats, frequently move between water and feed stores, “effectively building a bridge between migratory birds and farmed poultry”.

“We might not have all the pieces of the jigsaw in place. But we have enough of a picture for me to be convinced feed should be treated as part of an effective biosecurity programme.”

Dr Lorenzoni then explained that trials carried out at Auburn University, jointly funded by the US Poultry and Egg Association, showed that treating feed with the long-established additive Termin-8 could eradicate almost all the AI virus present within one hour.