Composting could help control the spread of a serious disease from dead farm animals, although more research is required.
Researchers are studying the potential of composting to destroy the prions associated with scrapie in sheep. Scrapie is the equivalent of BSE in cattle and chronic wasting disease in elk.
While refining the techniques for composting, the researchers also want to learn more about its merits for disposing of large numbers of livestock in the event of an infectious disease outbreak, such as the recent avian flu epidemic in British Columbia.
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Lloyd Spencer, a retired research scientist with the Canadian Food Inspection Agency, is leading the work on composting’s ability to destroy scrapie prions.
He said there is evidence that prions can be destroyed in that way, but more research is needed to ensure there is no risk of other animals becoming infected from material left once an infected carcass is composted.
“That’s going to take us some time,” said Spencer, who now works as a consultant for the CFIA.
“We’re not looking for something that could be recommended tomorrow for the industry, but we’re moving in that direction.”
Tim McAllister, a research scientist with Agriculture Canada in Leth-bridge, is involved with the study of composting.
There are two main themes to his research. The first is to better define the conditions and techniques needed to cause the decomposition of animals as quickly as possible.
“The second is looking at the containment structure we would use in an infectious outbreak and to make sure that that doesn’t interfere with the composting process.”
Under the second scenario, the carcass and other composting material are sealed within plastic and the pile is shored up with large straw bales. Air reaches the composting material only through a perforated pipe placed at the bottom of the pile to allow passive aeration.
McAllister said the research has shown that composting will break down an entire animal carcass, including the bones, within 200 days. He views it as the most economical way to dispose of deadstock, at least when it comes to small numbers of animals.
“A lot of people don’t really realize that composting is an option. There’s a little bit of education that has to be done in terms of doing it properly.”
Producers with dead animals typically have had four options for disposal, including composting, burial, incineration or sending the carcasses to a rendering plant.
Spencer said the avian flu outbreak in British Columbia showed that composting can effectively dispose of large volumes of livestock, at least for poultry.
It was an approach taken by the CFIA as the numbers of dead birds began to mount in the Fraser Valley.
“Initially they were burning the carcasses and they still had the manure to deal with,” Spencer said.
“What we want to do is to be able to have the technology in place so that if there was any disease of this nature that was highly infectious, that we could move in and take care of the animals and their waste that was potentially infected at the site so that none of this infected material leaves the site.”
Also collaborating on the composting research is Kim Stanford, an Alberta Agriculture researcher specializing in beef production.
