Keeping Feed Energy Out Of The Atmosphere

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With more talk than ever about greenhouse gases and with fingers pointing at feedlots as a source, researchers are finding innovative ways to reduce emissions from cattle production.

A team of scient ists at Agr icul ture and Agr i -Food Canada’s Lethbridge Research Centre is adding corn dried distillers grain (DDG) and tannin to feedlot cattle diets to assess the environmental impact of the supplements.

The good news from previous studies is that distillers grain reduces the amount of methane gas released by cattle. The downside is an increase in ammonia.

Now researchers are testing a combination treatment of distillers grain with products that have a high level of tannins – plant compounds that can bind or shrink proteins – to see if the added supplement will reduce the amount of ammonia emitted from cattle.

Research scientist Karen Koenig studies protein nutrition and nitrogen metabolism, while Karen Beauchemin studies methane production and the performance of cattle. Sean McGinn is

“There are studies saying people should eat less beef to reduce methane, but methane is just one component of the bigger issue of greenhouse gas emissions”

also involved in methodology and the environmental impact of livestock production.

“Around the world there is concern about cattle contributing to methane and greenhouse gas production,” says McGinn. “There are studies saying people should eat less beef to reduce methane, but methane is just one component of the bigger issue of greenhouse gas emissions.”

While previous studies show a 20 per cent reduction in methane from feedlot cattle when distillers grain is part of the diet, the other issue is too much protein. The nitrogen from the excess protein is excreted in the urine, which is then readily converted to ammonia and lost into the atmosphere, says Koenig.

Ammonia is a problem because it is a precursor to the formation of fine aerosols, which are a concern especially for those with respiratory issues.

By adding tannin, researchers hope to see a reduction in methane as well as ammonia. First, though, they need to know what level of tannin can be fed without impacting feed intake by cattle.

The study is being conducted at the research centre’s feedlot, which has 48 pens, with 10 to 15 animals in each pen. It is essentially a scaled-down version of a standard industry feedlot.

For the purposes of measuring emissions, though, a whole pen of cattle is moved to an isolated pen. There methane and ammonia can be measured without interference from nearby pens.

Researchers measure methane emissions by putting a modified halter on the cattle to sample the air coming out of the nostrils, not the other end of the animal as often portrayed by media cartoons.

A second measurement is taken using lasers to monitor methane concentrations around the pen.

To measure ammonia, samplers are placed on each side of the pen at four different heights to monitor levels from the animals and the manure in the pen.

Economics favourable

Depending on grain prices, it can be very economical for the feedlot industry to feed distillers grain to cattle. There is also an added potential benefit of better feed conversion. That is, if methane emissions are reduced, then the cattle can use that energy instead for feed conversion.

“The primary objective of this study is to reduce the environmental impact of cattle production, which is good news for feedlot operators,” says Beauchemin, especially if the reduction can be documented and used for carbon credit exchanges in the future.

The continued use of distillers grain will depend on the ethanol industry. With ongoing government support for the industry, it can be assumed that distillers grain will be available as animal feed for a while. Some newer plants, however, are looking at ways to extract the oil to sell separately, which may reduce the benefit of feeding distillers grain, says Beauchemin.

Most of the distillers grain coming from the United States is corn-based, while the distillers grain from Western Canada is from wheat.

This study started about two months ago and will continue until mid-July when the research feedlot animals are finished. Then the data will be analyzed and results will be published.

“It’s all part of a larger initiative to look at the environmental aspects of cattle production,” says Beauchemin.

The Lethbridge Research Centre has been working in this area for the past 10 years and is actively exploring other avenues and methods of greenhouse gas reduction. Studies are done at animal, herd and whole-farm scales. At the animal scale, researchers can also analyze nutrient digestion, rumen fermentation and microbial activity.

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