Beef life cycle assessment shows greenhouse gas opportunities
Results provide a baseline on the issue and insights toward mitigation strategies
Posted: July 16, 2013
At a time when everything from 'credits' and 'offsets' to 'environmental footprints' are making news and creating new expectations for livestock production, a new tool has emerged to help beef producers and their industry drive progress and find solutions.
Researchers at Agriculture and Agri-Food Canada (AAFC) have conducted a first-of-its kind life cycle assessment for GHG emissions from beef production in Canada. This landmark development that sets the stage for a much better understanding of what Canada's beef sector contributes and what can be done to minimize emissions while upholding a productive and competitive industry.
The assessment was conducted through a multi-faceted research effort that involved using the leading-edge 'Holos' modeling software program, which is designed as a tool to estimate and reduce greenhouse gas emissions from farms. The assessment captures a comprehensive, whole farm view of what contributes to emissions from beef operations during the full life cycle of beef cattle. It quantifies and dissects the sources of emissions from all inputs and components related to production, providing a sophisticated look at the hurdles and potential opportunities for GHG reduction.
"The issue of GHG emissions has been particularly challenging for the beef industry in part because of the multiple production levels and different approaches that exist within the beef sector," says Dr. Karen Beauchemin of AAFC Lethbridge, a lead researcher on the project. "With the life cycle assessment of GHG emissions from beef production, integrated with Holos, we now have a much clearer picture of this issue and what some of the best options might be to improve our efficiency and meet the rising pressures and expectations around this issue."
For strong progress to occur, any changes or fine tuning to production approaches need to make sense for beef operations on levels other than simply emissions reduction, says Beauchemin. "With the assessment in place, the focus as we look further at mitigation opportunities is finding ways to reduce emissions that also have economic benefits or other advantages for the producers. We're encouraged that the findings show the Canadian beef sector is already highly efficient and there is good potential for further improvements that fit this 'win-win' scenario."
Sophisticated Holos analysis
The assessment was a major study conducted over multiple years to capture the complete life span of beef cattle. Western Canada was selected as the model location, as the region with the highest level of beef production in Canada.
It was based on a "whole farm system model" approach that involved examining all factors that contribute to GHG emissions in the on-farm beef production system. This includes not only the emissions associated with the livestock themselves, but emissions associated with providing the feed for these animals. Also incorporated into the assessment are the factors involved with growing the crops to feed these animals.
Information was gathered to provide a valid representation of typical, real-world, commercial values for different levels and components of production in the region, including data from on-farm surveys, research and consultation with beef production advisors.
Anchoring the project was use of the Holos whole-farm modeling software. "Holos was developed specifically for the purpose of providing estimates of GHG emissions from farms," says Shannan Little, AAFC Holos Coordinator. "It can also be used to test different practice change or production approach scenarios, to quantify and compare differences in the GHG emission outcomes. It's really an excellent tool that is arguably the most sophisticated of its kind in the world. It offers many advantages to help us understand and address the issue of GHG emissions."
The researchers used the information gathered to develop values that could be used with Holos to generate a "simulated farm" model representing the complete beef production system and beef cattle life cycle.
"Our objective was to develop a model that would provide a solid, complete-system representation of commercial conditions in Western Canada," says Beauchemin. "Our simulated 'farm' included both a cow-calf operation and a feedlot, along with cropland needed to supply all feed and bedding for the cattle."
The simulated farm was situated in conditions like those in the county of Vulcan in southern Alberta. The beef herd was comprised of 120 cows, four bulls, and their progeny, with the progeny fattened in a feedlot modeled after those present in southern Alberta. The life cycle assessment was conducted over an eight-year period to represent the period from birth to slaughter of the breeding stock.
This model provided a sophisticated quantification of GHG emissions and a tool for running a variety of scenarios to project the impact of different changes to production approaches. Emissions were quantified and analysis was conducted on a beef basis - in other words, based on the emissions required to produce specific unit levels of beef.
The beef emissions picture
The results of the baseline scenario that emerged from the Holos analysis show several types of GHG emissions related to beef production. Enteric methane accounts for 63 percent of emissions, while nitrous oxide from manure makes up 23 percent. Other emissions include methane from manure at 5 percent, carbon dioxide from energy use at 5 percent and nitrous oxide from soil at 4 percent.
Perhaps most eye-opening were the results comparing emissions from the different life cycle stages of beef production. The cow-calf component of the life cycle – which comprised the cows and bulls in the system during the period they are producing calves - accounted for 61 percent of emissions.
Breeding stock – which represented the cows and bulls in the breeding stock while they are calves and immature animals – accounted for 19 percent. In other words, 19 percent of the emissions from producing a kg of beef were attributed to simply growing the mother and father of the beef animals to maturity. Emissions related to finishers made up 12 percent and backgrounders at 8 percent.
"The cow calf system accounted for about 80 percent of total GHG emissions and the feedlot system for only 20 percent, dividing roughly equally between the backgrounding and finishing phases," says Beauchemin. "In reality, this breakdown might vary somewhat, depending on the specific management practices used. In Western Canada, for example, weaned calves are sometimes fed forage-based diets over winter and placed back onto pasture the following summer before entering the feedlot, rather than being placed directly into feedlots as in our simulation. Such variations, however, are unlikely to displace the cow-calf system as the primary source of GHG emissions resulting from beef producing farms."
Cow-calf emissions higher than feedlot
About 84 percent of enteric methane was from the cow-calf system, mostly from mature cows. "Feedlots tend to be the target when people talk about environmental footprint and emissions concerns," says Beauchemin. "However, when you consider emissions on a per kilogram of beef produced basis, feedlots are actually extremely efficient. We found the feedlot system actually accounts for only a relatively small fraction of enteric methane from overall beef production. Animals are at the feedlot stage for a relatively short time and the grain-based diets are very efficient for producing beef."
The results point to enteric methane as a main target for potential mitigation strategies, particularly at the cow-calf stage. "Improvements at any stage are good but the 'bang for the buck' in terms of overall emissions reduction is greater from the cow-calf sector," says Beauchemin. "For example, based on our estimated breakdown, a proportional reduction in emissions from the cow-calf system – say, a 10 percent reduction - would reduce whole-farm emissions by about four times as much as the same reduction in the feedlot system."
Opportunities for progress
As for what are the best ways to reduce emissions, many options are on the table, says Beauchemin. In particular, the results indicate opportunities for dietary strategies that decrease enteric methane production from forage-based diets, as well as other management practices that improve efficiency of feed conversion. For example, a basic option identified is to add more oils to feedlot diets while a more complex opportunity is to apply new approaches for enhancing rumen function.
Also, because the emissions were quantified and analyzed on a meat basis, the researchers observed that any issues with reproductive performance or death loses have a major negative impact on the emissions picture. "Anything we can do to enhance the reproductive performance of cows, or decrease death losses of calves, can significantly improve the overall numbers," says Beauchemin.
Example of GHG mitigation opportunities evaluated recently by AAFC researchers include extending the backgrounding phase, extending the finishing phase, feeding oilseeds, feeding distillers dried grains, improving forage quality for breeding stock, increasing the number of calves weaned, and changes in land management such as seeding previously cropped land for use as pasture.
The key to moving forward is to have more concerted focus on evaluating any potential practice changes or fine tuning of production approaches in the context of what it means for overall GHG emissions, says Beauchemin. "The baseline established with this life cycle assessment, combined with our ongoing use of the Holos tool, provides us with an excellent opportunity to continually build our knowledge base. When we learn new things, we can add that new data to the Holos program to see how that changes the outcomes projected by the model."
The life cycle integrated with Holos can also play a key role in identifying priorities for further research, says Little. "It can provide a strong anchor to research direction, which in turn will provide new knowledge to help the model continually improve. It's a tremendous asset for Canada to support our GHG emissions strategies for agriculture."
Keeping a healthy perspective
There is potentially a broad range of strategies and options that have the potential to improve efficiencies in ways that reduce emissions and benefit the producer.
However, it's important to keep a healthy perspective on what is needed and what makes sense, says Beauchemin.
The life cycle assessment reinforced that Canada is already in the top-tier of efficient beef production systems in the world. "We can always get better, but the bottom line is we are doing very well already," she says. "The approach to beef production common in Canada and the U.S. is the most efficient in the world at producing beef."
Also, while the figures point to enteric methane from cow-calf production as a major emissions source, there are other mitigating factors to consider before pushing for substantial changes based on emissions targets alone. For example, because the cow-calf system relies extensively on pastures and forage crops, it has a beneficial role in preserving or augmenting soil carbon and preserving rangeland biodiversity and wildlife habitat.
"This is the type of next level question we can get a better handle on using a sophisticated modeling tool such as Holos, she says. "When we see opportunities that have benefits for beef producers and the efficiency, productivity or competitiveness or meat production, that also happen to have a GHG emissions benefit, we are in a safe zone. But we need to be careful about pushing any changes based on livestock emissions targets alone without considering an even broader environmental context."