Environmental Economics and Policy, Livestock Production/Industries,

Adom, F.

Clayton-Niederman, Z.

Kellogg, W.

Kemper, Nathan

Matlock, M.

Pilgrim, R.

Popp, Jennie S. Hughes

Shonnard, D.

Thoma, Greg

Ulrich, Rick

English

Research Papers in Economics

Factors Influencing the Green House Gas Footprint of US Dairy Farms 
 
 
 
Jennie Popp, Ph.D, corresponding author 
Department of Agricultural Economics and Agribusiness 
University of Arkansas 
Fayetteville, AR 72701 
hrodrig@uark.edu, jhpopp@uark.edu 
 
 
Greg Thoma, Ph.D.;  Rick Ulrich, Ph.D.;  M. Matlock, Ph.D; W. Kellogg, Ph.D.;  
Z. Clayton-Niederman; N. Kemper, and R. Pilgrim  
University of Arkansas 
Fayetteville, Arkansas 
 
D. Shonnard, Ph.D and F. Adom 
Michigan Technological University 
Hougton, Michigan 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Poster prepared for presentation at the  
Agricultural & Applied Economics Association 2010 
AAEA,CAES, & WAEA Joint Annual Meeting, Denver, Colorado, July 25-27, 2010 
Copyright 2010 by [authors]. All rights reserved. Readers may make verbatim copies of 
this document for non-commercial purposes by any means, provided that this copyright 
notice appears on all such copies. Factors Influencing the Green House Gas Footprint of US Dairy Farms
J. Popp†, G. Thoma†, R. Ulrich†, M. Matlock†, W.  Kellogg†,  D. Shonnard††, Z. Clayton-Niederman†, N. Kemper†, R. Pilgrim† and F. Adom††
† University of Arkansas † † Michigan Technological University
INTRODUCTION
In 2008, Dairy Management Inc.(DMI) commissioned and jointly
conducted with the University of Arkansas a life cycle assessment (LCA)
of the dairy fluid milk supply chain focused on defining greenhouse gas
(GHG) emissions. LCA is a tool to evaluate environmental impacts of a
product or process throughout its entire life cycle, from crop cultivation,
through to food processing, use and disposal of wastes associated with
its final end-use. This includes identifying and quantifying energy and
materials used and wastes released calculating their environmental
RESULTS
Of those surveyed 536 (roughly 10%) responded. Responses were
fairly evenly distributed across the three size categories. However,
significant differences (p <0.0001) across regions did exist. Region 3
represented nearly half (47%) of all respondents. Larger farms made up a
larger percentage of overall farms in Region 4 than in other regions.
For 75% of the farms, mature cows did not receive the majority of
forage intake from past re at an time that ear Region 4 had the smallest
Figure 1. Dairy Production Regions Used for the Study Table 1. Survey Respondents by Region and Herd Size
Herd Size
Region
One Two Three Four Five Total
Small 43 8 109 25 10 195
Medium 37 13 87 26 12 175
materials used and wastes released, calculating their environmental
impact, interpreting results, and evaluating improvement opportunities.
The dairy supply chain is broadly divided into 8 stages; each
receiving separate analyses that were combined to provide the life cycle
footprint. These stages are: feed production; milk production; delivery to
processor; processing; packaging; distribution; retail; and
consumption/disposal. This poster focuses on the farm level - feed and
milk production - stages of the analysis only.
forage intake from pasture at any time that year. Region 4 had the smallest
percentage (15%) of farms using some pasture; Region 2 had the largest
percentage (67%) of farms using some pasture. Data suggest the larger
the herd size, the less likely that cows are placed on pasture on the farm.
Nearly 45% of all farms used no type of production enhancement
practice in 2008 (Table 2). Rumensin was the most popular practice
adopted; it was used by 44% of respondents on at least some of their herd
for at least some part of the year. Other more commonly reported
practices were three times a day milking (27%) and rBST (23%).
Producers provided information related to both the type of manure
Table 2: Use of Production Enhancement Practices
Large 25 6 55 38 42 166
Total 105 27 251 89 64 536
Figure 2 : Range of Footprints Calculated for the Farm Survey Respondents
Black Horizontal Line is the Mean; Red Horizontal Line is the Weighted Mean
Practices Used in 2008
OBJECTIVES
The purpose is three-fold:
• to present information from a nationwide survey of dairy producers
regarding current demographics, milk production practices and
manure management practices,
• to present estimates of the farm level GHG footprint, and
• to identify important factors that influence the farm-level GHG
footprint.
Producers provided information related to both the type of manure
managed (dry, liquid and/or slurry) and type of practices (18 different
practices) used. Of the 54 practices (18 practices for 3 types of manure),
the 10 most commonly reported practices are shown in Table 3.
Comparing regionally, 6 practices ranked in the top 10 in all regions.
Carbon Footprint Analysis
Figure 2 presents the range of values for the on-farm, fuel, enteric
methane, feed, manure and total farm prints associated with the farms
represented by the survey data. The open box represents the 25th to 75th
percentile for each category; the gray boxes represent the 10th and 90th
Practice
Practices Used in 2008
Yes No
Photoperiod 83 453
Increased milking efficiency 
for fresh cows 
44 492
rBST 125 411
Milk 3 times a day 145 391
RESEARCH METHODS
A 2008 production year survey comprised of 48 questions in 9
sections solicited information for relevant to the calculation of the farm-
level footprint: 1) the dairy facility (location, herd and milk production), 2)
farm energy use, 3) animal housing and milking parlor information, 4)
feed and grazing practices, 5) crop production, and 6) manure
management. Surveys were targeted to 5415 producers in five regions
(Fig. 1) and across three herd sizes (less than 100 cows, 100 to 499
percentile for each category; the gray boxes represent the 10th and 90th
percentile; and the redline represents the weighted mean value. Enteric
methane and manure management practices were generally the largest
contributors to the farm-level footprint. Most farm footprints ranged from
0.70kg to 2.0 kg CO2e per kg FPCM.
Five variables explained nearly 67% percent of the variation in the
farm print (Table 6): inefficiency, managing volatile solids (VS) from
manure with deep cattle bedding, pasture feed fraction, managing VS with
an uncovered lagoon and region. Increases in inefficiency (that is the more
kg of feed it takes to produce one kg of milk), pasture feed fraction
(percent of annual feed that comes from pasture) and use of cattle deep
Table 3. Top Ten Reported Manure Management Practices
Type of Practice Type of 
Manure
Number of 
Farms 
Reporting 
Practice
Solid Storage Stacks†††† Dry 242
Rumensin 236 300
No enhancements 241 295
Table 4. Factors that Influence the Overall Footprint of the Farm
Variable
Parameter 
Estimate
Standard 
Error
tV a l u e P r>| t |
95% Confidence 
Limits
Intercept 0.20 0.053 3.71 0.0002 0.09 0.30
Inefficiency
cows, 500 or more cows).
These data were with others collected from USDA National
Agricultural Statistics Service and Economic Research Service,
technical literature and consultation with experts. SimaPro© 7.1 was
used as the primary modeling software; the EcoInvent database
provided information on the ‘upstream’ burdens associated with
materials. The on-farm footprint was calculated as the sum of the
individual footprints associated with enteric methane, fuel use, manure
management systems and feed production. The unit of analysis was
kilograms of CO e associated with the production of one kilogram of fat
(percent of annual feed that comes from pasture), and use of cattle deep
bedding and/or a lagoon each can increase the footprint. The regional
impact suggests that farms in Regions 2 and 4 are likely to have higher
prints than those in Regions 1 and 3. But the influence of region is much
smaller than the potential influence of most of the other variables.
CONCLUSIONS
Through this study we have amassed the most recent and
comprehensive data set for dairy facilities across the US These data have
Solid Storage Stacks Dry  242
Dry Lot Dry 187
Cattle Deep Bedding, Stored for 
more than 1 Month†††† Dry 187
Daily Spread†††† Dry 170
Earthen Ponds/Tanks with 
Natural Crust Cover Slurry 160
Earthen Ponds/Tanks with 
Natural Crust Cover†††† Liquid 143
Earthen Ponds/Tanks without 
Natural Crust Cover†††† Liquid 132
Inefficiency 1.21 0.055 21.95 <.0001 1.10 1.32
Deep Cattle Bedding >1 
Month (0.1% to 33.33%) 0.09 0.026 3.48 0.0005 0.04 0.14
Deep Cattle Bedding >1 
Month (33.34% to 66.67%) 0.35 0.052 6.86 <.0001 0.25 0.46
Deep Cattle Bedding >1 
Month (66.67% to 100%) 0.97 0.081 11.90 <.0001 0.81 1.13
Uncovered Anaerobic 
Lagoon (0.1 to 33.33%) 0.09 0.037 2.37 0.018 0.01 0.16
Uncovered Anaerobic 
Lagoon (33.334 to 66.66%) 0.21 0.057 3.68 0.0003 0.10 0.32
Uncovered Anaerobic 
Lagoon (66.67% to 100%) 0.47 0.061 7.61 <.0001 0.35 0.59 kilograms of CO2e associated with the production of one kilogram of fat
protein corrected milk (FPCM). Further details regarding the calculation
of the footprint are available from the authors.
Regression analysis was conducted to determine the influence of a
number of factors on the overall footprint of the farm. The 30+ factors
included in this analysis are: region, herd size, pasture use, production
enhancements, fuel usage, manure management practices, animal
breed, crop production, and efficiency (ratio of feed intake to milk
production).
comprehensive data set for dairy facilities across the US. These data have
offered a snapshot of dairy production practices across five regions and
three herd sizes in the US for 2008. The LCA indicates that overall footprint
of the farm is comprised of the footprints associated with feed production,
enteric methane, fuel use and manure management practices. Statistical
analysis suggests there are opportunities to influence the farm footprints
through changes in some manure management practices and efficiencies
in milk production.
For more information contact: Jennie Popp, PhD. Department of Agricultural Economics and Agribusiness,
University of Arkansas, 479-575-2279, jhpopp@uark.edu
Natural Crust Cover††††
Cattle Deep Bedding, Stored for 
less than 1 Month†††† Dry 123
Earthen Ponds/Tanks  without 
Natural Crust Cover Slurry 101
Uncovered Anaerobic Lagoon† Liquid 99
Top ten practice in: †Regions 3 and 4 only; †† Regions 1 through 4
††† Regions 2 through 5 †††† All regions
Percent Pasture Time 0.004 0.0005 6.81 <.0001 0.003 0.005
Region 1 -0.16 0.040 -4.08 <.0001 -0.24 -0.09
Region 2 0.07 0.060 1.22 0.22 -0.04 0.19
Region 3 -0.11 0.036 -3.06 0.0023 -0.18 -0.04
Region 4
0.00 0.042 0.09 0.93 -0.08 0.09

Factors Influencing the Green House Gas Footprint of US Dairy Farms

Factors Influencing the Green House Gas Footprint of US Dairy Farms

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