alanr1 – Livestock and Poultry Environmental Learning Community

Why Model Environmental Impacts of Livestock?

Quantifying the long term environmental impacts of dairy and beef production is complex due to the many interactions among the physical and biological components of farms that affect the amount and type of emissions that occur. Emissions are influenced by climate and soil characteristics as well as internal management practices. Software models are needed to perform an integrated and comprehensive assessment of all important environmental and economic effects of farm management and mitigation strategies. Related: Manure value & economics

What Did We Do?

Figure 1. The Integrated Farm System Model simulates the performance, determines the economics, and predicts the air and water emissions of farm production systems.

Software tools were created that perform whole-farm analyses of the performance, economics and environmental impact of dairy and beef production systems. The Integrated Farm System Model (IFSM) is a comprehensive research tool that simulates production systems over many years of weather to quantify losses to the environment and the economics of production. From the simulated performance and losses, environmental footprints are determined for carbon, energy use, water use and reactive nitrogen loss. Crop, dairy and beef producing farms can be simulated under different management scenarios to evaluate and compare potential environmental and economic benefits. The Dairy Gas Emissions Model (DairyGEM) provides a simpler educational tool for studying management effects on greenhouse gas, ammonia and hydrogen sulfide emissions and the carbon, energy and water footprints of dairy production systems.

What Have We Learned?

Analyses with either the IFSM or DairyGEM tools illustrate the complexity of farming systems and the resultant effect of management choices. Although IFSM was primarily developed and used as a research tool, it is also used in classroom teaching and other education applications. DairyGEM provides an easier and more graphical tool that is best suited to educational use.

Future Plans

Figure 2. DairyGEM is an educational tool for evaluating management effects on air emissions and environmental footprints of dairy production systems.

Development of these software tools continues. Work is currently underway to add the simulation of VOC emissions to both models. Routines are also being implemented to better represent the performance and emissions of beef feed yards.

Acknowledgements

Many people have contributed to the development of these models and software tools. Although they can not all be listed here, they are acknowledged in each software program.

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.

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Why Study the Environmental Footprint of Beef?

As a major contributor in food production, beef production provides a major service to our economy that must be maintained. Production of cattle and the associated feed crops required also impact our environment, and this impact is not well understood. Several studies have determined the carbon footprint of beef, but there are other environmental impacts that must be considered such as fossil energy use, water use, and reactive nitrogen loss to the environment. Because of the large amount of data available to support model evaluation, production systems of the U.S. Meat Animal Research Center were simulated with the Integrated Farm System Model for the purpose of evaluating the environmental impact of the beef cattle produced.

What Did We Do?

The environmental footprints of beef produced at the U.S. Meat Animal Research Center (MARC) in Clay Center, Nebraska were determined with the objective of quantifying improvements achieved over the past 40 years. Relevant information for MARC operations was used to establish parameters representing their production system with the Integrated Farm System Model. The MARC farm, cow calf and feedlot operations were each simulated over recent historical weather to evaluate performance, environmental impact and economics. The current farm operation included 2,078 acres of alfalfa and 2,865 acres of corn to produce feed predominately for the beef herd of 5,500 cows, 1200 replacement heifers and 3,724 cattle finished per year. Spring and fall cow calf herds were fed on 24,000 acres of pastureland supplemented through the winter with hay and silage produced by the farm operation. Feedlot cattle were backgrounded 3 mo on hay and silage and finished over 7 mo on a diet high in corn grain and wet distiller’s grain.

What Have We Learned?

Model simulated predictions for weather year 2011 were within 1% of actual records for feed production and use, energy use, and production costs. A 25-year simulation of their current production system gave a carbon footprint of 10.9 lb of CO₂ equivalent units per lb body weight (BW) sold, and the energy required to produce that beef was 11,400 Btu/lb BW. The total water required was 2,560 gallon/lb BW sold, and the water footprint excluding that obtained through precipitation was 335 gallon/lb BW. Reactive N loss was 0.09 lb/lb BW, and the simulated total cost of producing their beef was $0.96/lb BW sold. Simulation of the production practices of 2005 indicate that the use of distiller’s grain in animal diets has had a small impact on environmental footprints except that reactive N loss has increased 10%. Compared to 1970, the carbon footprint of beef produced has decreased 6% with no change in the energy footprint, a 3% reduction in the reactive N footprint, and a 6% reduction in the real cost of production. The water footprint, excluding precipitation, has increased 42% due to greater use of irrigated corn production.

Future Plans

Now that the modeling approach has been shown to appropriately represent beef production systems, further simulation analyses are planned to evaluate beef production systems on a regional and national scale.