Subject: Grass-finished Beef Methane Emissions
James,
I recently read your article, “Bellying up to Environmentalism” in The Washington Post. I generally, agree with your premises, but question your dismissal of alternative pasture-based livestock production as an environmentally sound and humane alternative to the industrial CAFO model. I was driven to email you after being intrigued with your sources for many of the facts you presented in the article.
I have extensively researched grass-finished beef both in the university and independently, and currently work for an organization promoting environmentally sustainable grazing systems in Kansas. Many of the numbers and percentages you present in your article are so drastically outside the existing research literature that I am familiar with, that I am very curious what your sources are for the facts you presented in your article.
One particular fact that you presented is of particular interest to me. You stated that grass-finished beef produces four times the amount of methane that grain-finished beef produces. I have personally been searching for research studies making this very comparison. There does not seem to be much literature on this, but what little research I found was very inconclusive. Some studies pointed to the lower average gains of grass-finished beef implying that grass-finished beef will be slightly older at slaughter, thus producing more methane over their lifespan. Other research indicates that a high roughage diet may shift the microbe community in the cattle’s gut, reducing methane eructation.
So, if there is research out there suggesting grass-finished beef produces 4-times the amount methane than grain-finished beef, I would like to know of this research. From a net greenhouse grass emissions standpoint, I think a convincing argument could be made for grass-finished beef has a net GHG emission lower than grain-finished beef and most grain production. Grass-finished beef produced from perennial pastures with legumes (removing the need for nitrogen fertilizer), ends up being carbon neutral due to the tremendous carbon sink of a healthy perennial grassland and the minimal fossil fuels need in the production life cycle.
I would be honored if you would share your sources of information with me.
Thank you,
Jason Schmidt
Kansas Rural Center
Topeka, Kansas
_______________________________________________________________
Subject: RE: Grass-finished Beef Methane Emissions
I recently read your article, “Bellying up to Environmentalism” in The Washington Post. I generally, agree with your premises, but question your dismissal of alternative pasture-based livestock production as an environmentally sound and humane alternative to the industrial CAFO model. I was driven to email you after being intrigued with your sources for many of the facts you presented in the article.
I have extensively researched grass-finished beef both in the university and independently, and currently work for an organization promoting environmentally sustainable grazing systems in Kansas. Many of the numbers and percentages you present in your article are so drastically outside the existing research literature that I am familiar with, that I am very curious what your sources are for the facts you presented in your article.
One particular fact that you presented is of particular interest to me. You stated that grass-finished beef produces four times the amount of methane that grain-finished beef produces. I have personally been searching for research studies making this very comparison. There does not seem to be much literature on this, but what little research I found was very inconclusive. Some studies pointed to the lower average gains of grass-finished beef implying that grass-finished beef will be slightly older at slaughter, thus producing more methane over their lifespan. Other research indicates that a high roughage diet may shift the microbe community in the cattle’s gut, reducing methane eructation.
So, if there is research out there suggesting grass-finished beef produces 4-times the amount methane than grain-finished beef, I would like to know of this research. From a net greenhouse grass emissions standpoint, I think a convincing argument could be made for grass-finished beef has a net GHG emission lower than grain-finished beef and most grain production. Grass-finished beef produced from perennial pastures with legumes (removing the need for nitrogen fertilizer), ends up being carbon neutral due to the tremendous carbon sink of a healthy perennial grassland and the minimal fossil fuels need in the production life cycle.
I would be honored if you would share your sources of information with me.
Thank you,
Jason Schmidt
Kansas Rural Center
Topeka, Kansas
_______________________________________________________________
Subject: RE: Grass-finished Beef Methane Emissions
Jason,
Below is just some of the info I relied upon for my methane info. Please let me know if/why anything below is wrong. I'm well aware that "grass fed" is a blanket term that might obscure more than it reveals. But writing for the popular press does not allow for splitting hairs and making qualifications--generalizations are inevitable. It is thus in all sincerity that I ask you to tell me why you think I was wrong to cite the figure as a general reflection of the whole. II write about this stuff all the time and would hate to make the mistake again, if indeed I was mistaken. I don't spend a lot of time researching this--in fact none. I rely on others. So, thanks.
James
For overall GHG emissions I relied on a 2008-9 study by Dalhousie University scientist, Nathan Pelletier. His work is summarized in this article: http://www.sciencenews.org/view/generic/id/40934/title/AAAS_Climate-friendly_dining_..._meats. An excerpt:
Many environmentalists have argued that finishing up the fattening of beef cattle on corn is worse for the environment than cattle that are raised solely on pasture grass. Pelletier says his team’s analysis finds that at least from a climate perspective, the opposite is true. “We do see significant differences in the GHG intensities [of grass vs grain finishing]. It’s roughly on the order of 50 percent higher in grass-finished systems.”When an audience member questioned whether he had heard that right, that grass-fed cattle have a higher carbon footprint, Pelletier reiterated, “higher. Yes.” The reason: “It’s related to the much higher volumes of feed throughput and associated methane and nitrous-oxide [GHG] emissions.” He added that most pastures were highly managed, and subject to “periodic renovations and also fertilization.” Finally, with grass-fed cattle “there is also a high [grass] trampling rate. So the actual land area that you need to maintain magnifies that [GHG] difference,” Pelletier said. As for the methane problem specifically--I relied on this: http://discovermagazine.com/2008/aug/08-fighting-cow-methane-at-the-source, as well as the work of John Robbins, who writes,
And there are other environmental costs [with grass fed]. Next to carbon dioxide, the most destabilizing gas to the planet's climate is methane. Methane is actually 24 times more potent a greenhouse gas than carbon dioxide, and its concentration in the atmosphere is rising even faster. The primary reason that concentrations of atmospheric methane are now triple what they were when they began rising a century ago is beef production. Cattle raised on pasture actually produce more methane than feedlot animals, on a per-cow basis. Then there's this, from a 1999 Journal of Animal Science piece: http://jas.fass.org/cgi/content/abstract/77/6/1392 (note this line: "These measurements clearly document higher CH4 production (about four times) for cattle receiving low-quality, high-fiber diets than for cattle fed high-grain diets.")
And Here's this by Peter Singer, who felt comfortable putting the figure at 3x:
To the Editor:Nicolette Hahn Niman (“The Carnivore’s Dilemma,” Op-Ed, Oct. 31) is simply wrong in suggesting that grass-fed beef produces less methane than feed-lot meat. It is the other way around, with grass-fed animals producing up to three times more methane. It may be true that in some trials scientists have found ways to reduce methane emissions from cattle, but until these methods are in widespread use, they are simply not relevant to the consumer choices we face.In any case, globally, only 8 percent of all meat is produced in natural grazing systems, and there is little available unforested land suitable for such systems. To replace factory-farmed meat without further tropical forest destruction is impossible. Hence the call to cut down or eliminate meat-eating, especially beef, should be supported by everyone concerned about the future of our planet.Peter SingerGeoff Russell Barry Brook New York, Nov. 3, 2009Peter Singer is a professor of bioethics at Princeton University and the author of “The Ethics of What We Eat.” Geoff Russell is the author of “CSIRO Perfidy.” Barry Brook is a professor of climate change at the University of Adelaide, Australia
___________________________________________________________________
Subject: RE: Grass-finished Beef Methane Emissions
Below is just some of the info I relied upon for my methane info. Please let me know if/why anything below is wrong. I'm well aware that "grass fed" is a blanket term that might obscure more than it reveals. But writing for the popular press does not allow for splitting hairs and making qualifications--generalizations are inevitable. It is thus in all sincerity that I ask you to tell me why you think I was wrong to cite the figure as a general reflection of the whole. II write about this stuff all the time and would hate to make the mistake again, if indeed I was mistaken. I don't spend a lot of time researching this--in fact none. I rely on others. So, thanks.
James
For overall GHG emissions I relied on a 2008-9 study by Dalhousie University scientist, Nathan Pelletier. His work is summarized in this article: http://www.sciencenews.org/view/generic/id/40934/title/AAAS_Climate-friendly_dining_..._meats. An excerpt:
Many environmentalists have argued that finishing up the fattening of beef cattle on corn is worse for the environment than cattle that are raised solely on pasture grass. Pelletier says his team’s analysis finds that at least from a climate perspective, the opposite is true. “We do see significant differences in the GHG intensities [of grass vs grain finishing]. It’s roughly on the order of 50 percent higher in grass-finished systems.”When an audience member questioned whether he had heard that right, that grass-fed cattle have a higher carbon footprint, Pelletier reiterated, “higher. Yes.” The reason: “It’s related to the much higher volumes of feed throughput and associated methane and nitrous-oxide [GHG] emissions.” He added that most pastures were highly managed, and subject to “periodic renovations and also fertilization.” Finally, with grass-fed cattle “there is also a high [grass] trampling rate. So the actual land area that you need to maintain magnifies that [GHG] difference,” Pelletier said. As for the methane problem specifically--I relied on this: http://discovermagazine.com/2008/aug/08-fighting-cow-methane-at-the-source, as well as the work of John Robbins, who writes,
And there are other environmental costs [with grass fed]. Next to carbon dioxide, the most destabilizing gas to the planet's climate is methane. Methane is actually 24 times more potent a greenhouse gas than carbon dioxide, and its concentration in the atmosphere is rising even faster. The primary reason that concentrations of atmospheric methane are now triple what they were when they began rising a century ago is beef production. Cattle raised on pasture actually produce more methane than feedlot animals, on a per-cow basis. Then there's this, from a 1999 Journal of Animal Science piece: http://jas.fass.org/cgi/content/abstract/77/6/1392 (note this line: "These measurements clearly document higher CH4 production (about four times) for cattle receiving low-quality, high-fiber diets than for cattle fed high-grain diets.")
And Here's this by Peter Singer, who felt comfortable putting the figure at 3x:
To the Editor:Nicolette Hahn Niman (“The Carnivore’s Dilemma,” Op-Ed, Oct. 31) is simply wrong in suggesting that grass-fed beef produces less methane than feed-lot meat. It is the other way around, with grass-fed animals producing up to three times more methane. It may be true that in some trials scientists have found ways to reduce methane emissions from cattle, but until these methods are in widespread use, they are simply not relevant to the consumer choices we face.In any case, globally, only 8 percent of all meat is produced in natural grazing systems, and there is little available unforested land suitable for such systems. To replace factory-farmed meat without further tropical forest destruction is impossible. Hence the call to cut down or eliminate meat-eating, especially beef, should be supported by everyone concerned about the future of our planet.Peter SingerGeoff Russell Barry Brook New York, Nov. 3, 2009Peter Singer is a professor of bioethics at Princeton University and the author of “The Ethics of What We Eat.” Geoff Russell is the author of “CSIRO Perfidy.” Barry Brook is a professor of climate change at the University of Adelaide, Australia
___________________________________________________________________
Subject: RE: Grass-finished Beef Methane Emissions
James,
Thank you very much for your quick and honest response to my email. I appreciate your openness and the sources you shared with me.
The study by Harper et al., 1999 proposed a convincing argument for grass-fed beef emitting more methane than grain-fed beef. However, I noticed a serious flaw in the study. The pasture grazing in the study was very low in forage quality (Crude protein between 3.5% to 11.7% with low digestibility). This forage quality is well below the quality needed for finishing beef cattle, while the grain diet was a high quality finishing diet. It is likely that finishing beef cattle would actually lose weight on pasture of this poor quality, and would have to eat large quantities just for maintenance. The study concludes that feed quality has a greater influence on CH4 production than previous studies have indicated. Six other studies cited found much smaller differences between grain-fed and grass-fed methane emission, although Harper et al. claims the differences between other studies and this study may be due to different CH4 measurement procedures.
I would argue that the poor pasture quality may have been the largest factor contributing to the 4-fold difference in methane production. The study does suggest that cellulose fermentation from forage diets produces more methane than carbohydrate digestion from grain diets, but I suggest a high quality forage diet required for finishing beef cattle with high digestibility and crude protein levels around 20% would increase ruminal passage leading to methane emissions similar to a grain diet. DeRamus et al. (J Environ Qual. 2003 Jan-Feb;32(1):269-77) reports that heifers grazing high quality ryegrass produced one-tenth the amount of methane than heifers grazing low quality bermudagrass and bahiagrass. Similarly, an ongoing study in Vermont reported in The New York Times (http://www.nytimes.com/2009/06/05/us/05cows.html?_r=3&adxnnlx=1244226134-VCIralBRQR6L/gumIykDvA&pagewanted=all) is investing high quality spring grasses as forages that will potentially lower methane emissions below those of grain diets. In addition, tannin-rich forages or tannin supplements decrease methane emissions (Beauchenmin et al., 2007 – J Anim Sci 2007.85:1990-1996).
I am still searching for net life cycle GHG emission from healthy grazed grasslands. I found some preliminary research from the Netherlands (Jacobs et al., 2007), but the study still hadn’t factored cattle emissions into the equation for grasslands. A follow up study to this research by Soussana et al. (Agriculture, Ecosystems and Environment 121 (2007) 121–134) studied 9 sites in Europe and concluded that even with accounting for the methane emissions of grazing ruminants, grasslands are still CO2-C equivalent sink.
As for other arguments for grass-finished beef being better for the environment, I see increasing grazing management skills among grass-finished beef producers. Missouri research now indicates that well managed rotational grazing can be more efficient at harvesting grass than even mechanical harvesting. Grass-finished beef producers also must maintain high forage quality, perennial forages, and low-inputs (no or very little fertilizer and pesticides) to stay profitable and to produce a satisfactory product.
I do stand corrected that there is convincing research out there concluding that methane emissions are higher on a per cow basis for grass-fed compared to grain-fed cattle. However, I think these differences can be greatly exaggerated, and can be (and are) mitigated with high quality forage diets. I do strongly believe that cattle finished on a healthy perennial grassland will have a much lower net GHG emission than feedlot finished cattle, not to mention all the other environmental and health benefits, and hope to see more research in this area.
Personally, I would like to see large areas of the Great Plains region converted back to grasslands in the near future. Ecological speaking this region needs grasslands and grazers to be a balanced and healthy ecosystem.
Thank you for your interest in our food. I fully agree that our personally habits of how we eat have a huge impact on our environment and we need to closely examine where our food comes from and how it is produced. Please do not hesitate to ask me question about grass-finished beef in the future.
Thank you,
Jason Schmidt
Thank you very much for your quick and honest response to my email. I appreciate your openness and the sources you shared with me.
The study by Harper et al., 1999 proposed a convincing argument for grass-fed beef emitting more methane than grain-fed beef. However, I noticed a serious flaw in the study. The pasture grazing in the study was very low in forage quality (Crude protein between 3.5% to 11.7% with low digestibility). This forage quality is well below the quality needed for finishing beef cattle, while the grain diet was a high quality finishing diet. It is likely that finishing beef cattle would actually lose weight on pasture of this poor quality, and would have to eat large quantities just for maintenance. The study concludes that feed quality has a greater influence on CH4 production than previous studies have indicated. Six other studies cited found much smaller differences between grain-fed and grass-fed methane emission, although Harper et al. claims the differences between other studies and this study may be due to different CH4 measurement procedures.
I would argue that the poor pasture quality may have been the largest factor contributing to the 4-fold difference in methane production. The study does suggest that cellulose fermentation from forage diets produces more methane than carbohydrate digestion from grain diets, but I suggest a high quality forage diet required for finishing beef cattle with high digestibility and crude protein levels around 20% would increase ruminal passage leading to methane emissions similar to a grain diet. DeRamus et al. (J Environ Qual. 2003 Jan-Feb;32(1):269-77) reports that heifers grazing high quality ryegrass produced one-tenth the amount of methane than heifers grazing low quality bermudagrass and bahiagrass. Similarly, an ongoing study in Vermont reported in The New York Times (http://www.nytimes.com/2009/06/05/us/05cows.html?_r=3&adxnnlx=1244226134-VCIralBRQR6L/gumIykDvA&pagewanted=all) is investing high quality spring grasses as forages that will potentially lower methane emissions below those of grain diets. In addition, tannin-rich forages or tannin supplements decrease methane emissions (Beauchenmin et al., 2007 – J Anim Sci 2007.85:1990-1996).
I am still searching for net life cycle GHG emission from healthy grazed grasslands. I found some preliminary research from the Netherlands (Jacobs et al., 2007), but the study still hadn’t factored cattle emissions into the equation for grasslands. A follow up study to this research by Soussana et al. (Agriculture, Ecosystems and Environment 121 (2007) 121–134) studied 9 sites in Europe and concluded that even with accounting for the methane emissions of grazing ruminants, grasslands are still CO2-C equivalent sink.
As for other arguments for grass-finished beef being better for the environment, I see increasing grazing management skills among grass-finished beef producers. Missouri research now indicates that well managed rotational grazing can be more efficient at harvesting grass than even mechanical harvesting. Grass-finished beef producers also must maintain high forage quality, perennial forages, and low-inputs (no or very little fertilizer and pesticides) to stay profitable and to produce a satisfactory product.
I do stand corrected that there is convincing research out there concluding that methane emissions are higher on a per cow basis for grass-fed compared to grain-fed cattle. However, I think these differences can be greatly exaggerated, and can be (and are) mitigated with high quality forage diets. I do strongly believe that cattle finished on a healthy perennial grassland will have a much lower net GHG emission than feedlot finished cattle, not to mention all the other environmental and health benefits, and hope to see more research in this area.
Personally, I would like to see large areas of the Great Plains region converted back to grasslands in the near future. Ecological speaking this region needs grasslands and grazers to be a balanced and healthy ecosystem.
Thank you for your interest in our food. I fully agree that our personally habits of how we eat have a huge impact on our environment and we need to closely examine where our food comes from and how it is produced. Please do not hesitate to ask me question about grass-finished beef in the future.
Thank you,
Jason Schmidt
