Tackling beef industry's biggest methane emitter: Cattle on range

It's a sustainability and a production issue, with significant efficiency losses

Posted: July 16, 2013

It'll be a bit of a surprise to a lot of people but lifecycle analysis research shows that the cow calf sector, seen by many as the most environmentally friendly part of the beef business, is in fact the largest greenhouse gas (GHG) emitter in the sector.

Now, new research at Agriculture and Agri-Food Canada's Lethbridge Research Centre Onefour Ranch, is setting out to put numbers to enteric methane loss from cattle grazing on range. The goal, says Sean McGinn, lead researcher on the project, is to build a knowledge base to tackle efficiency and build a more sustainable industry long term.

It's not news that the cow calf industry depends heavily on grasslands. Most cattle producers will be quick to say their industry is a sustainable one with low environmental impact. For example, cattle on grasslands is a system that preserves soil carbon and maintains wildlife habitat.

But what a lot of producers may not know today is that grazing also comes with detrimental environmental effects which are not so visible, says McGinn. Although ruminants can use grasslands to produce high quality food for humans, grazing cattle are associated with high enteric methane emissions due to low digestibility of grasses. Low digestibility and the need for greater fermentation, increases enteric methane.

Globally, there is a move to mitigate GHG in agriculture, so there is some urgency to understand the impact of strategies that reduce the loss of methane from ruminants, says McGinn. The potential is significant. Worldwide, grasslands occupy 25 percent of the earth's surface, 30 percent of the total farm area in Canada with 86 percent on the Prairies.

Countries such as New Zealand, which faces more than 50 percent of its GHG production from agriculture, is leading in terms of tackling GHG, says McGinn.

Value to Canadian producers

Why does this matter to the Canadian beef producer?

"It's all related to sustainability," says McGinn. "In the public's mind the environmental component is becoming more important, so agriculture has to tackle greenhouse gas production from all sectors, including beef.

"The important thing for producers to understand is that if we can measure methane emissions effectively, this is a win-win for producers and environmentalists. Greenhouse gas emissions represent a loss of efficiency. Between two percent and 12 percent of energy from methane production is lost to emissions. If we can reduce that we've increased the value of feed. And if we manipulate diet without much cost to the producer, then it's really a win-win."

McGinn says it's important to note all this is not saying the cow calf part of the beef industry is not a sustainable system. "Cow calf brings all sorts of value like land stewardship and carbon reserves in the soil. But we need more to get numbers on the emissions situation to be clear."

Research targets

The Onefour research targets are based on what was learned from life cycle analysis of the western Canada beef herd. That research showed 84 percent of methane emissions were associated with the cow-calf grazing phase of the beef system.

"Research to date had been focused on feedlot and in dairy sectors where emissions can be controlled with diet manipulation," says McGinn, "but clearly there is a need to consider grazing practices when investigating strategies to reduce enteric methane production from cattle."

The Onefour Ranch research will help the industry understand whether beef cattle grazing mixed grasses are a net sink or source of the carbon-based greenhouse gases in the beef production system of southern Alberta. Basically grazing systems sequester carbon and from year to year carbon changes. At Onefour, McGinn explains, peak carbon intake to the system is July, but starting in August it drops through the fall and winter period. It's important to know that change from year to year. If you superimpose on that methane and carbon loss, you get a true value of the carbon balance of the grazing system.

New ways to measure methane

One of the challenges of setting up this new research was that there was not reliable ways to measure methane emissions in grazing cattle. In feedlots and dairies, where the bulk of this measurement work had been done, scientists use lasers set up upwind and downwind to measure concentrations of methane.

"That doesn't work with grazing because we don't have the same concentration of animals," says McGinn. "So we put together one hectare paddocks and grazed 40 animals for three days in each paddock. We put the lasers close to the paddocks so were able to measure concentrations. To do that required knowing exactly where cattle were in the paddock, so each animal was fitted with a GPS collar. So every 10 minutes we knew where these animals were and were able to measure net emissions."

These data are eventually incorporated into Holos, a Canadian designed calculator built to measure whole farm emissions. One of the challenges with Holos has been that to date the bulk of the data used in that tool is international, which does not necessarily provide an accurate value for Canadian lands, says McGinn. These new data will help provide a more accurate reflection of the Canadian situation.

The Australian connection

One of the collaborators in the range research is the Australian beef industry. That industry has a northern beef herd of about 25 million animals compared to 13 million for Canada, says McGinn, so they want to get a handle on GHG emissions. Part of the range study has been done in Australia and Australians have sponsored some of the study in Canada. The collaboration emphasizes the international nature of GHG research in beef production.