Hans Deason, a Graduate Student in Mechanical Engineering with the University of Saskatchewan said Thermal Assisted Drying and Decontamination (TADD) is proving to be effective in deactivating pathogens in swine transport trailers but it requires some fine tuning.
As part of research on behalf of Swine Innovation Porc (SIP) aimed at developing an automated system for cleaning and disinfecting swine transport trailers scientists are assessing the value of TADD.
Deason said the goal of TADD, is to use heat to raise the interior surfaces of livestock transport trailers to high enough temperatures for specified amounts of time sufficient to deactivate dangerous pathogens.
“The target temperatures, the jury is still really out on that,” he said. “Right now it seems that 75 degrees Celsius for 15 minutes might be sufficient to kill even the most hardy pathogens out there. In terms of what types of pathogens we’re dealing with, its assorted bacteria and assorted viruses.
Deason said right now it seems like the most hardy and difficult pathogen to kill by means of heat is PED virus.
“One of the key challenges is to just make sure you get the entire surface of these trailers to the target temperature for the correct amount of time,” he said. “It might sound easier than it actually is. But, when you’re dealing with a 53 foot livestock transport trailer, there’s a lot of thermal mass there that you actually need to be able to heat up.”
Ultimately these systems use forced hot air that flows throughout the transport trailer so the challenge is, and it is vitally important to make sure this air reaches all of the areas of the trailer.
Deason said there is some fine tuning required to determine the most efficient combination of time and temperature to heat these trailers to. “Higher temperatures will require less time to deactivate pathogens but higher temperatures require higher amounts of energy, he said. “The biggest challenge, when using heat to kill diseases causing pathogens in swine transport trailers, is ensuring all surfaces reach a high enough temperature to kill the organisms.”
Deason said for instance right near the heat source at the back of the trailer, where the forced air is entering the trailer, there’s no problem heating up that surface to well over the target temperatures that people might be looking at.
“Generally the further away from that heat source that you get, the temperatures start to fall a little bit so that’s definitely one factor,” he said. “Another factor is behind any walls or obstructions inside these transport trailers where the forced air has a hard time reaching.
Typically temperatures in those locations can be a little bit lower as well.”
As Deason said earlier the jury is still out on the temperatures that should be targeted but, right now, it seems 75 degrees Celsius for 15 minutes might be sufficient to kill even the most hardy of pathogens.
Currently PEDv is on the minds of all pig producers, especially with the outbreaks in six additional facilities in the last month. He says it seems like the most hardy and difficult to kill pathogen by means of heat is the virus responsible for Porcine Epidemic Diarrhea.
The days of saying its good enough with one pass or a quick wash of that hog transporting trailer are long past.
PED Case #16 found in Manitoba finisher barn
On May 25, 2017, Dr. Megan Bergmann, Manitoba’s Chief Veterinary Officer (CVO) confirmed positive test results for PEDv from another finisher operation in southeast Manitoba. This farm is within the same area as the five farms that were previously confirmed positive for PED in May.
Manitoba Agriculture’s Emergency Operation Centre is continuing to operate and is assisting the affected producer and conducting a full disease investigation. All veterinarians with clients within the area are aware of the site’s location. •
— By Harry Siemens
