Environmental Footprints of Beef Production in the Kansas, Oklahoma and Texas Region

Why Look at the Environmental Footprint of Livestock?

Both producers and consumers of animal products have concern for the environmental sustainability of production systems. Added to these concerns is the need to increase production to meet the demand of a growing population worldwide with an increasing desire for high quality protein. A procedure has been developed (Rotz et al., 2013) that is now being implemented by the U.S. beef industry in a comprehensive national assessment of the sustainability of beef. The first of seven regions to be analyzed consisted of Kansas, Oklahoma and Texas.

What did we do? 

A survey and visits of ranch and feedyard operations throughout the three state region provided data on common production practices. From these data, representative ranch and feedyard operations were defined and simulated for the climate and soil conditions throughout the region using the Integrated Farm System Model (USDA-ARS, 2014). These simulations predicted environmental impacts of each operation including farm-gate carbon, energy, water and reactive nitrogen footprints. Individual ranch and feedyard operations were linked to form 28 representative cattle production systems. A weighted average of the production systems was used to determine the environmental footprints for the region where weighting factors were determined based upon animal numbers obtained from national agricultural statistics and survey data. Along with the traditional beef production systems, Holstein steers and cull animals from the dairy industry in the region were a lso included.

What have we learned?             

The carbon footprint of beef produced was 18.4 ± 1.7 kg CO2e/kg carcass weight (CW) with the range in individual production systems being 13.0 to 25.4 kg CO2e/kg CW. Footprints for fossil energy use, non precipitation water use, and reactive nitrogen loss were 51 ± 4.8 MJ/kg CW, 2450 ± 450 liters/kg CW and 138 ± 12 g N/kg CW, respectively. The major portion of the carbon, energy and reactive nitrogen footprints was associated with the cow-calf phase of production (Figure 1).

Beef footprints

Beef footprints

Future Plans   

Further analyses are planned for the remaining six regions of the U.S. which will be combined to provide a national assessment. Cattle production data will be combined with processing, marketing and consumer data to complete a comprehensive life cycle assessment of beef production and use.

Authors       

C. Alan Rotz, Agricultural Engineer, USDA-ARS al.rotz@ars.usda.gov

Senorpe Asem-Hiablie and Kim Stackhouse-Lawson

Additional information                

Rotz, C. A., B. J. Isenberg, K. R. Stackhouse-Lawson, and J. Pollak. 2013. A simulation-based approach for evaluating and comparing the environmental footprints of beef production systems. J. Anim. Sci. 91:5427-5437.

USDA-ARS. 2014. Integrated Farm System Model. Pasture Systems and Watershed Mgt. Res. Unit, University Park, PA. Available at: http://www.ars.usda.gov/Main/docs.htm?docid=8519. Accessed 5 January, 2015.

Acknowledgements    

This work was partially supported by the Beef Checkoff.

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. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

 

 

Combustion of Poultry Litter: A Comparison of Using Litter for On-Farm Space Heating Versus Generation of Electricity

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Abstract

This presentation will compare using litter as a replacement for LP gas for on-farm space heating with using litter to generate electricity. The comparison includes heating system efficiency, amount of LP off-set possible, value of plant nutrients in the litter, quantity and value of plant nutrients in the litter ash, impact of brokerage, and costs of producing the energy. It was concluded that using litter on-farm as a source of space heat and using the litter ash as fertilizer could provide a potential value of $48 per ton of litter. However, on-farm combustion of litter to produce electricity resulted in a loss of about – $3/ton of litter. Therefore, if a heating and ash management system can be implemented in a cost-effective manner use of litter to off-set 90% or more of the heating energy requirements would be the better of these two alternatives.

Why Is Energy Use Important in Poultry Production?

Modern poultry production requires substantial amounts of energy for space heating (propane/LP gas), ventilation, feed handling, and lighting. It was determined that annual LP gas consumption in broiler houses can range from 150 to 300 gallons of LP per 1000 square feet of floor space with an average of about 240 gal LP/1000 ft2 observed in South Carolina. Similarly, broiler production in South Carolina requires about 2326 kWh/1000 ft2 of house area. As a result, a 6-house broiler farm in SC uses about 30,240 gallons of LP and 293.076 kWh of electricity annually. The cost for energy for a 6-house farm is on the order of $57,456 per year for LP ($1.90/gal LP) and $35,169 per year for electricity ($0.12/kWh). Energy costs have more than doubled over the last decade and as a result producers are very interested in ways to reduce on-farm energy costs by using the energy contained in the litter. The objective of this study was to compare using litter as a replacement for LP gas for on-farm space heating with using litter to generate electricity.

What Did We Do?

Our analysis included heating system efficiency, amount of LP off-set possible, value of plant nutrients in the litter, quantity and value of plant nutrients in the litter ash, impact of brokerage, and costs of producing the energy.

What Have We Learned?

It was concluded that using litter on-farm as a source of space heat and using the litter ash as fertilizer could provide a potential value of $46 to $55 per ton of litter. However, on-farm combustion of litter to produce electricity resulted in a loss of about $3/ton of litter. Therefore, if a heating and ash management system can be implemented in a cost-effective manner use of litter to off-set 90% or more of the heating energy requirements would be the better of these two alternatives.

Future Plans

This information is being used in extension programs that target poultry producers.

Authors

Dr. John P. Chastain, Professor and Extension Agricultural Engineer,  School of Agricultural, Forestry, and Environmental Sciences, Clemson University, jchstn@clemson.edu

Additional Information

Chastain, J.P., A. Coloma-del Valle, and K.P. Moore. 2012. Using Broiler Litter as an Energy Source: Energy Content and Ash Composition. Applied Engineering in Agriculture Vol 28(4):513-522.

Acknowledgements

Support was provided by the Confined Animal Manure Managers Program, Clemson Extension, Clemson University, Clemson, SC.

 

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.