The cow is dead. Now what?
It costs money to summon the renderers, and burning or burying a carcass takes time and effort.
Faced with a dead animal, many cattle producers want to try composting the body, but success depends on proper methods.
Alberta Agriculture beef research scientist Kim Stanford explained those methods Nov. 17 during a webinar sponsored by the Beef Cattle Research Council.
She has seen cattle legs protruding from would-be compost piles and the heads of pigs staring out of such piles with most features still intact.
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That’s the wrong way to go about it, she told the webinar.
“If you can see the faces of the animals that you’re trying to compost … you’re not making good compost,” she said.
Protruding legs are related to improper placement of the carcass. It should be placed on its side, and if there is more than one carcass, they should not be touching.
However, Stanford said that before that happens, a good location and a proper base are vital to effective compost. The site should be accessible year-round and convenient for adding material such as straw, manure and sawdust.
It should be well-drained and at least 100 metres from water sources, wells and buildings and separated from livestock.
Stanford recommended starting with an 145-centimetre-thick base of old straw, sawdust or woodchips to provide the necessary carbon. The material should be fairly dry.
Carcasses should be completely covered with the waste material, which may include more of the ingredients that were in the base layer, plus manure, soil, spoiled silage and other waste material.
Build a windrow approximately two metres high so no part of the carcass is showing.
“You can use a lot of different things to build your compost,” she said.
“Build it in layers. It’s kind of like a really strange sandwich. You just use whatever you’ve got on hand.”
Material used to cover the carcasses should have 35 to 60 percent moisture, but no more than that.
The compost process requires nitrogen, and dead stock contain plenty of it. Manure is a good material for covering the carcasses, but a covering of only soil is unlikely to contain enough nitrogen and carbon.
“Stick with things that have a bit of nitrogen and some carbon in, for amendments,” said Stanford.
Oxygen is the other requirement. Lack of it is often the reason that compost efforts fail. Oxygen allows the pile to heat, and it will be limited if the material is too wet.
Stanford outlined “the three Ts” of composting: time, turning and temperature. It takes about nine months to fully degrade a 500 to 1,400 pound animal. To achieve that, the pile should be turned three times over that nine-month period. A tractor with a bucket will do the job.
Other disposal methods include natural exposure, burial, incineration and burning.
Natural exposure invites scavengers and possibly predators. Dead stock also attracts flies, stinks and can contaminate the water table.
It is legal in Alberta to leave dead stock out in the open, but it could draw complaints.
As for burial, the hole must be more than a metre deep and 150 metres from a water well, barn or home. The water table, soil type and topography have to be considered.
Most cattle are too big for incinerators, and the units are not legal in some municipalities. There are air quality issues and the fuel needed can be costly. Setting the body on fire also causes air pollution. It requires supervision and can take quite awhile, said Stanford. It isn’t legal to burn carcasses in some regions.
