Tag: enteric methane

Posted on

Sustainability of the Dairy Industry in the United States

Purpose

The U.S. dairy industry recognizes its environmental impact and has committed to achieving carbon neutrality by 2050, aiming to significantly reduce greenhouse gas (GHG) emissions while maintaining production efficiency. The primary sources of dairy-related emissions include enteric methane from cows, manure management, feed production, and energy use on farms.

Improvements in feed efficiency and manure management have already led to reductions in emissions per unit of milk produced. For instance, Idaho has successfully reduced enteric methane emissions per unit of milk by 25% since 1990, and methane emissions from manure per unit of milk have declined by about 20% (O’Hara, 2022). However, the total emissions from manure have increased by 20% due to herd growth in Idaho. These figures highlight the challenge of balancing productivity with environmental stewardship. Despite these difficulties, advancements in animal nutrition, manure management, and emerging technologies provide a promising path toward sustainability.

What Did We Do?

Over the past several decades, remarkable advancements in dairy farming have significantly improved milk production efficiency. Since the 1940s, the industry has nearly quadrupled milk output per cow through genetic improvements, optimized nutrition, and better overall management. This increase in productivity has allowed farmers to produce more milk with fewer cows, reducing the environmental footprint of each unit of dairy produced. Beyond improvements in feed efficiency, nutritional interventions such as adding feed additives like 3-NOP (3-nitrooxypropanol), seaweed, and oilseeds have been shown to reduce enteric methane emissions by altering rumen microbial activity. Research suggests that 3-NOP, for instance, can reduce methane emissions by up to 30% without negatively affecting milk yield or composition (Hristov, 2021).

Manure management is another critical area of focus. Technologies such as anaerobic digesters, composting systems, and improved storage techniques have been implemented to mitigate methane emissions from manure. Anaerobic digesters convert manure into biogas, which can be used as a renewable energy source, reducing the reliance on fossil fuels and lowering overall carbon emissions. Other strategies, such as mechanical separators and compost-bedded pack barns, have also been explored as effective methods for reducing methane release from stored manure.

What Have We Learned?

Several key strategies have emerged as effective pathways for improving dairy sustainability. The first is continued advancements in genetics, which allow farmers to breed more productive cows that require fewer resources per unit of milk produced. Selective breeding programs targeting low-methane-emitting cows could further contribute to sustainability efforts. Precision feeding techniques, which ensure cows receive the optimal balance of nutrients without overfeeding, are also crucial for reducing emissions. Feed additives such as tanniferous forages, alternative electron sinks like nitrates, and certain types of fats have shown potential in mitigating enteric methane production. However, long-term research is still needed to assess their effectiveness and potential side effects on animal health and productivity.

Another significant finding is the role of manure management systems in influencing overall farm emissions. Studies indicate that farms implementing covered liquid slurry storage and anaerobic digesters experience lower methane emissions compared to traditional open-lagoon systems. Additionally, manure treatment systems that integrate composting or separation techniques have been identified as key factors in reducing GHG emissions. Beyond farm-level practices, the industry has recognized the importance of collaboration across the supply chain. Processors, retailers, and policymakers must work together to promote sustainable practices, invest in research, and provide incentives for farmers to adopt new technologies.

Future Plans

Moving forward, the dairy industry will continue to focus on increasing milk production efficiency as a means of reducing emissions per unit of milk produced. Advances in genetics, feed optimization, and herd management will further contribute to sustainability efforts. Additionally, manure management will play a pivotal role in achieving sustainability goals. Expanding the use of anaerobic digesters and nutrient recycling technologies will help reduce emissions while providing renewable energy and valuable soil amendments.

Investment in research and innovation will be essential for identifying new strategies and improving existing ones. Research into alternative feed additives, precision agriculture, and digital monitoring tools will enable farmers to make data-driven decisions that enhance both productivity and environmental sustainability. Policy support and financial incentives will also be critical in accelerating the adoption of sustainable practices. Government programs and industry initiatives should continue to provide funding for technology adoption, carbon offset programs, and educational resources for farmers. Ultimately, the U.S. dairy industry is well-positioned to make significant strides toward its sustainability goals. By leveraging innovation, research, and collaboration, the industry can continue to provide essential nutrition while reducing its environmental footprint and working toward carbon neutrality by 2050.

Authors

Presenting & corresponding author

Mark A. McGuire, University Distinguished Professor, Department of Animal, Veterinary and Food Sciences, University of Idaho, mmcguire@uidaho.edu

Additional Information

Capper, J. L., Cady, R. A., & Bauman, D. E. (2009). The environmental impact of dairy production: 1944 compared with 2007. Journal of Animal Science, 87(6), 2160–2167. https://doi.org/10.2527/jas.2009-1781

El Mashad, H. M., Barzee, T. J., Franco, R. B., Zhang, R., Kaffka, S., & Mitloehner, F. (2023). Anaerobic digestion and alternative manure management technologies for methane emissions mitigation on Californian dairies. Atmosphere, 14(1), 120. https://doi.org/10.3390/atmos14010120

Godber, O. F., Czymmek, K. J., van Amburgh, M. E., & Ketterings, Q. M. (2024). Farm-gate greenhouse gas emission intensity for medium to large New York dairy farms. Journal of Dairy Science. https://doi.org/10.3168/jds.2024-25874

Hristov, A. N., Melgar, A., Wasson, D., & Arndt, C. (2021). Symposium review: Effective nutritional strategies to mitigate enteric methane in dairy cattle. Journal of Dairy Science, 105(10), 8543–8557. https://doi.org/10.3168/jds.2021-21398

Innovation Center for U.S. Dairy. (2022). U.S. Dairy Sustainability Report 2021-2022. Retrieved from https://www.usdairy.com/about-us/innovation-center

Kreuzer, M. (2024). Feed additives for methane mitigation: Introduction—Special issue on technical guidelines to develop feed additives to reduce enteric methane. Journal of Dairy Science.

Nguyen, B. T., Briggs, K. R., & Nydam, D. V. (2023). Dairy production sustainability through a one-health lens. Journal of the American Veterinary Medical Association, 261(1). https://doi.org/10.2460/javma.22.09.0429

O’Hara, J. K. (2022). State-level trends in the greenhouse gas emission intensity of U.S. milk production. Journal of Dairy Science, 106(10), 5474–5484. https://doi.org/10.3168/jds.2022-22741

Rotz, C. A. (2017). Modeling greenhouse gas emissions from dairy farms. Journal of Dairy Science, 101(7), 6675–6690. https://doi.org/10.3168/jds.2017-13272

U.S. Farmers & Ranchers in Action (USFRA). (2024). Potential for U.S. Agriculture to Be Greenhouse Gas Negative. Retrieved from https://www.usfraonline.org

Acknowledgements

Supported by USDA-NIFA SAS 2020-69012-31871

Posted on

Livestock Methane Emissions Estimated and Mapped at a County-level Scale for the Contiguous United States


Proceedings Home | W2W Home w2w17 logo

Purpose         

This analysis of methane emissions used a “bottom-up” approach based on animal inventories, feed dry matter intake, and emission factors to estimate county-level enteric (cattle) and manure (cattle, swine, and poultry) methane emissions for the contiguous United States.

What did we do? 

Methane emissions from enteric and manure sources were estimated on a county-level and placed on a map for the lower 48 states of the US. Enteric emissions were estimated as the product of animal population, feed dry matter intake (DMI), and emissions per unit of DMI. Manure emission estimates were calculated using published US EPA protocols and factors. National Agricultural Statistic Services (NASS) data was utilized to provide animal populations. Cattle values were estimated for every county in the 48 contiguous states of the United States. Swine and poultry estimates were conducted on a county basis for states with the highest populations of each species and on a state-level for less populated states. Estimates were placed on county-level maps to help visual identification of methane emission ‘hot spots’. Estimates from this project were compared with those published by the EPA, and to the European Environmental Agency’s Emission Database for Global Atmospheric Research (EDGAR).

What have we learned? 

Overall, the bottom-up approach used in this analysis yielded total livestock methane emissions (8,888 Gg/yr) that are comparable to current USEPA estimates (9,117 Gg/yr) and to estimates from the global gridded
EDGAR inventory (8,657 Gg/yr), used previously in a number of top-down studies. However, the
spatial distribution of emissions developed in this analysis differed significantly from that of
EDGAR.

Methane emissions from manure sources vary widely and research on this subject is needed. US EPA maximum methane generation potential estimation values are based on research published from 1976 to 1984, and may not accurately reflect modern rations and management standards. While some current research provides methane emission data, a literature review was unable to provide emission generation estimators that could replace EPA values across species, animal categories within species, and variations in manure handling practices.

Future Plans    

This work provides tabular data as well as a visual distribution map of methane emission estimates from enteric (cattle) and manure (cattle, swine, poultry) sources. Future improvement of products from this project is possible with improved manure methane emission data and refinements of factors used within the calculations of the project.

Corresponding author, title, and affiliation        

Robert Meinen, Senior Extension Associate, Penn State University Department of Animal Science

Corresponding author email    

rjm134@psu.edu

Other authors   

Alexander Hristov (Principal Investigator), Professor of Dairy Nutrition, Penn State University Department of Animal Science Michael Harper, Graduate Assistant, Penn State University Department of Animal Science Richard Day, Associate Professor of Soil

Additional information                

None.

Acknowledgements       

Funding for this project was provided by ExxonMobil Research and Engineering.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

Posted on

Evaluation of a Model to Predict Enteric Methane Production from Feedlot Cattle


Proceedings Home | W2W Home w2w17 logo

Purpose

Continual refinement of methods estimating enteric methane production in beef finishing cattle provides a more accurate assessment of the environmental impact of the beef industry.  The USDA-OCE publication “Quantifying Greenhouse Gas Fluxes in Agriculture and Forestry: Methods for Entity-Scale Inventory” identified conservation practices and management strategies for reducing greenhouse gas emissions while improving agriculture production (Eve et al., 2014).  In Chapter 5 a new method to estimate effects of nutrition and management on enteric methane production of feedlot cattle is provided.  The system recommends using adjustment factors to correct the IPCC (2006) tier 2 Methane Conversion Factor (Ym) of 3.0% of gross energy intake to an adjusted Ym.  Adjustment factors are used for dietary grain and fat concentrations, grain type and processing method, and ionophore use.  These adjustment factors let beef producers more accurately determine the enteric methane production associated with their individual finishing operation.

What Did We Do?

To evaluate this new model, we developed a database consisting of 36 refereed publications, with 75 treatment means.  The focus of this database was to identify published research relating to high concentration beef finishing that provided methane as a percent of gross energy, or provided enough information for calculation.  Treatments containing greater than 20% forage were excluded, as they are not representative of a high concentration finishing diet.  Additionally, treatment diets utilizing a methane mitigation agent were excluded from the database. 

What Have We Learned?

This database encompassed 75 treatment means containing a wide range in weight, intake and protein of the diets.  Body weight, dry matter intake, and dietary crude protein concentrations for the database ranged from 150 to 723 kg, 4.78 to 12.9 kg, and 9.4 to 23%, respectively.  Predicted Ym had a significant but relatively low correlation (r = 0.31, P = 0.0077) to actual Ym.  However, when one experiment (4 treatments) with very high methane values (likely a result of manure CH4) was removed, the correlation improved (r = 0.62, P < 0.0001), resulting in the following relationship:  Predicted Ym = 2.23 + (0.41 * actual YM) (r2 = 0.39, RMSE = 0.58).  Predicted g of CH4 produced daily were highly correlated to actual g of CH4/d (r2 = 0.63, RMSE = 22.61), and predicted CH4 produced, as a percentage of digestible energy intake, was highly correlated to actual CH4 per kcal of digestible energy intake, DEI (r2 = 0.46, RMSE = 0.61).  Under the conditions of this investigation, the new model moderately predicted enteric methane production from feedlot cattle fed high-concentrate diets.

Future Plans

The database will be expanded as refereed publications suitable to the selection criteria are identified.  Trials with greater forage inclusion will be evaluated to test the robustness of the model and evaluate the correlation to IPPC (2006) estimations. 

Corresponding author (name, title, affiliation) 

Tracy D. Jennings, Associate Research Scientist, Texas A&M AgriLife Research

Corresponding author email address  

Tracy.Jennings@ag.tamu.edu

Other Authors 

Kristen Johnson, Professor, Washington State University; Luis Tedeschi, Professor, Texas A&M University; Michael Galyean, Provost, Texas Tech University, Richard Todd, Soil Scientist, USDA-ARS; N. Andy Cole, Retired Animal Scientist, USDA-ARS

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

Posted on

Effects of Corn Processing Method and Dietary Inclusion of Wet Distillers Grains with Solubles (WDGS) On Enteric Methane Emissions of Finishing Cattle

Waste to Worth: Spreading science and solutions logoWaste to Worth home | More proceedings….

Abstract

The use of wet distiller’s grains with solubles (WDGS) in feedlot diets has increased as a result of the growing U.S. ethanol industry.  However, few studies have evaluated the use of WDGS in finishing diets based on steam-flaked corn (SFC), the processing method used extensively in the Southern Great Plains.  The effects of corn processing method and WDGS on enteric methane (CH4) production, carbon dioxide (CO2) production and energy metabolism were evaluated in two respiration calorimetry studies.  In Exp. 1, the effects of corn processing method (SFC or dry rolled corn – DRC) and WDGS inclusion (0 or 30% of diet dry matter- DM) were studied using a 2 x 2 factorial arrangement of treatments and four Jersey steers in a 4 x 4 Latin square design.  In Exp. 2, the effects of WDGS inclusion rate (0, 15, 30, or 45% of diet DM) on CH4 and CO2 production were measured in a 4 x 4 Latin square design. Results indicate that cattle consuming SFC-based diets produce less enteric CH4 and retain more energy than cattle fed  DRC-based diets.  When dietary fat levels were held constant, dietary inclusion of WDGS at 15% of diet DM did not affect enteric CH4 production, WDGS inclusion at 45% of diet DM significantly increased enteric CH4 production and WDGS inclusion at 30% of diet DM had variable effects on enteric CH4 production.

Purpose

Our objectives were to determine the effects of corn processing method and WDGS inclusion rate on enteric methane losses from finishing cattle using respiration calorimetry.

What Did We Do?

Steer in open circuit respiration calorimetry chamber.

Eight steers were used in two studies.  In each study steers were fed one of four diets at 2 x maintenance energy requirements in a 4 x 4 Latin square design.  Each period of the Latin squares included a 16 d adaptation period followed by 5 days of total fecal and urine collection and measurement of gas exchange in respiration chambers.  In Experiment 1 dietary treatments consisted of corn processing method (steam flaked -SFC or dry rolled -DRC) and WDGS inclusion rate (0 or 30% of DM).  All diets were balanced for ether extract.   In Exp. 2, cattle were fed SFC-based diets containing 0, 15, 30 or 45% WDGS (DM basis).  The calorimetry system consisted of 4 chambers with an internal volume of 6500 L.   Outside air was pulled through chambers using a mass flow system.  Gas concentrations were determined using a paramagnetic oxygen analyzer and infrared methane and carbon dioxide analyzers (Sable Systems, Las Vegas, NV)  Data were statistically analyzed using the Mixed procedure of SAS.

What Have We Learned?

In Exp. 1. no iteractions between grain processing method and WDGS inclusion were detected (P > 0.47).  Cattle fed DRC-based diets had greater (P < 0.05) CH4 production (L/steer, L/kg of DMI, % of gross energy intake, and % of digestible energy intake) than cattle fed SFC-based diets probably the result of differences in ruminal fermentation and ruminal pH.  Methane losses as a proportion of GE intake (2.47 and 3.04 for SFC and DRC-based diets, respectively) were similar to previous reports and to IPCC (2006) values but were somewhat lower than EPA (2012) values.  Grain processing method did not affect CO2 production (13 to 14 Kg/d).  WDGS  inclusion rate did not affect CH4 or CO2 production.  In Exp. 2, CH4 production (L/d) increased quadratically (P = 0.03) and CH4 production as L/kg of DMI and as a proportion of energy intake increased linearly (P < 0.01) with increasing concentrations of WDGS in the diet.  Feeding WDGS did not affect (P > 0.23) total CO2 production.  Conclucions: Our results indicate that cattle consuming DRC-based finishing diets produce approximately 20% more enteric CH4 than cattle fed SFC-based diets.  When WDGS comprised 30% or less of the diet and diets were similar in total fat content, feeding WDGS had little effect on enteric CH4 but when fed at higher inclusion rates enteric CH4 production was increased by approximately 40%.

Future Plans

Over 80% of the enteric methane emissions of the U.S. beef cattle herd are produced by cows, calves, and yearling on pasture.  Therefore, additional research will study the effects of supplementation strategies and forage quality on enteric methane production by cattle.

Authors

N. Andy Cole; Research Animal Scientist/Research Leader; USDA-ARS-CPRL, Bushland, TX andy.cole@ars.usda.gov

Kristin E. Hales, Research Animal Scientist, USDA-ARS-MARC, Clay Center, NE

Richard W. Todd, Research Soil Scientist, USDA-ARS-CPRL, Bushland, TX

Ken Casey, Associate Professor, Texas AgriLife Research, Amarillo, TX

Jim C. MacDonald, Associate Professor, Dept. of Animal Science, Univ. of NE, Lincoln

Additional Information

Hales, K. E. , N. A. Cole, and J. C. MacDonald.  2013. Effects of increasing concentrations of wet distillers grains with solubles in steam-flaked corn-based diets on energy metabolism, carbon-nitrogen balance, and methane emissions of cattle. J. Anim. Sci. (in press)

Hales, K. E. , N. A. Cole, and J. C. MacDonald.  2012. Effects of corn processing method and dietary inclusion of wet distillers grains with solubles on energy metabolism, carbon-nitrogen balance, and methane emissions of cattle. J. Anim. Sci. 90:3174-3185.

Acknowledgements

Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA.  USDA is an equal opportunity provider and employer.

We wish to thank USDA-NIFA for partial funding through Project # TS-2006-06009 entitled “Air Quality: Odor, Dust and Gaseous Emissions from Concentrated Animal Feeding Operations in the Southern Great Plains”

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

Proudly powered by WordPress