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Study measures methane in belching

“What we want to find out is, what is the safe level of corn to supplement without having to compromise the productivity of the cow, and what happens to methane.”


Less methane is belched into the atmosphere by grain-fed cattle, but that doesn’t necessarily translate to lower greenhouse gas reduction.

A study at the University of Manitoba has been measuring the amount of methane belched out by some test cows in a dairy research farm. Each week, the diets of the cattle are changed. Grain-fed cattle belch out less methane and belching accounts for 98 per cent of all methane released from cattle.

The research began in 2004 and results are to be published soon.

But noticeably absent from the report is the extrapolation of all energy used to produce the grain and transport it to the cattle, something farmers who have grass-fed cattle would not need to consider.

The belief that grass-fed cattle are less of a contributor to global warming, is not necessarily true according to the research conducted by the project’s lead researcher Ermias Kebreab. This study only considers the diet, and is not a complete carbon cycle analysis.

The research, funded by the Dairy Farmers of Canada and Engineering Research Council, has shown the grass-fed cattle produce more methane, less milk and less red meat than their grain-fed counterparts.

The research requires the cattle to be fed with their heads in a chamber that provides oxygen and measures methane. The diet is changed weekly, and research subjects spend eight hours in the chamber. The same cow that receives a grain diet will be fed a more grass-based diet. While it is not good for the cow to be on a strict corn-based diet as the corn can cause rumen disorder, Kebreab wants to find out what level of corn is safe to be added to the diet.

“What we want to find out is, what is the safe level of corn to supplement without having to compromise the productivity of the cow, and what happens to methane,” he said. “We are looking at some additives that reduce methane in the lab.”

Kebreab said grass has much more fibre, which is harder to break down and digest than grain. Methane is also produced when the undigested grass decomposes in the feces of grass-fed cattle.

It is estimated that agriculture in Canada is responsible for 8.3 per cent of the total greenhouse gas emissions with 32 per cent of that attributed to methane produced by cattle. Worldwide it is thought to be one of the important sources of methane production.

Kebreab hopes this will help develop new standards for measuring methane production in cattle.

He said the U. S. is using standards based on some of the research done here, but Canada has yet to adopt it. “We developed the model here, but the Americans are the ones using it,” he said.

One problem with a more grain-based diet is the economics. Kebreab said right now this type of diet may not be economically feasible due to current prices.

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