MINTO, Man. – Of the four legal options for disposing of dead cattle in Manitoba, producers could find that composting is one of the easiest and most affordable, says James Hood, a land stewardship specialist with Manitoba Agriculture.
During a recent information meeting for beef producers in Minto, Hood outlined a method for composting dead cattle that requires little time or expense on the part of the producer. The composting method he described involves straw and his presentation offered tips on how to get the best results.
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The composting begins with choosing a site. According to environmental regulations in Manitoba, the site must be a minimum of 100 metres from wells and waterways such as drainage ditches and streams. The site must also be at least that far from roads and property lines.
Oxygen is important when composting a dead cow, calf or bull, so the site should be in a well drained location, Hood said. A low lying area where water can pool is not advisable since it could cause saturation of the composting material, restricting the oxygen needed by the bacteria that break down the carcass.
Once the site is chosen, establish a layer of straw that is two feet (0.7 metre) deep and will extend at least two feet around the animal.
Hood said the straw should be packed to ensure it will remain that thick once the dead animal is placed on it.
The straw base will act as a sponge for the fluids released as the carcass breaks down and it will also allow air through to the carcass, he said. Wheat or barley straw is preferred because it will break down more easily than straw from other crops.
“You want the straw to break down,” said Hood. “That’s how the composting works.”
Once the straw base is finished, place the dead animal on top of it, making sure the straw extends the minimum of three-quarters of a metre beyond the body, legs and head.
Hood recommends making an opening in the chest and abdominal cavities of the animal so that gases can escape slowly while the carcass is composting.
“We’re not talking about a pin hole but it doesn’t have to be a gaping hole either.”
The openings can help prevent a rupturing of the intestinal cavity during composting that can release foul odours.
The next step is to wet the body down with water and then cover it with a layer of straw at least three-quarters of a metre thick. The straw on top also allows air to circulate during the composting while curbing odours.
“That layer of straw is very effective at controlling the odour,” Hood said. “It really does work.”
“There’s nothing really sophisticated here. There’s nothing high tech. It’s just a pile of straw.”
Chopping the straw can provide even greater odour control, said Hood.
Wetting the straw later on in the process is usually not necessary.
“There’s a fair amount of water in the animal and that’s usually enough to keep the composting going.”
Turning the compost after three months can help speed the process by breaking up clumps of material and improving air circulation.
A more precise way to tell when to turn the compost is to use a temperature probe. The composting is at its most intense once temperatures inside the pile are between 40-65 C.
When the temperature drops off, that’s an indication the compost should be turned. By that time, most of the flesh on the carcass will typically have been broken down.
In Manitoba, it usually takes at least six months of warm weather for composting to completely break down the cattle carcass, although larger bones such as the skull could remain.
Because six months of warm weather is rare on the Prairies, it is more likely that a full year will pass before the composting is complete.
If a cow, bull or calf dies in the winter and the producer wants to compost it, an option is to establish the straw base, place the animal on it and then cover it with straw and snow until milder weather returns.
In the spring, top up the layer of straw covering the carcass so it is at least three-quarters of a metre thick.
Starting a compost in the middle of winter can be difficult or even impossible, especially if the carcass is frozen, Hood said.
Scavengers need to be kept away from the composting animal.
Hood suggested covering the pile with chicken wire anchored with posts or planks.
Another option is to establish a more permanent composting site, enclosed on three sides, open on the top and gated across the front in a way that will keep out scavengers.
If there are skulls and long bones left after the rest of the composting is complete, producers should avoid spreading the bones on the land, Hood said.
“It doesn’t look good for the industry if we have skulls scattered across the land and it’s really not necessary.”
The composted material could be applied to hay or crop land, he said, but not pastures, so that the remains of a dead ruminant are not consumed up by another ruminant.
The other legal options in Manitoba for disposing of dead cattle include rendering, incineration or burial, although those are not always practical for producers.
