BEEF SPECIES-RUMINANT NUTRITION CACTUS BEEF SYMPOSIUM: A role for beef cattle in sustainable U.S. food production

Abstract

The increasing global population, limited resource availability, and global focus on reducing greenhouse gas (GHG) emissions put pressure on animal agriculture industries to critically evaluate and optimize the role they play in a sustainable food production system. The objective of this review is to summarize evidence of the various roles that the U.S. beef industry plays in the U.S. and global agricultural systems. As the world's largest beef producer, the United States reaps considerable economic benefit from the beef industry through strong domestic and international demand, as well as employment opportunities for many Americans. Beef production contributes to GHG emissions, land use, and water use, among other critical environmental impacts but provides an important source of essential micronutrients for human consumption. The U.S. beef industry provides sufficient product to meet the protein, vitamin B12, omega-3 and -6 fatty acid requirements of 43, 137, 47, and 487 million people, respectively. In the United States, beef production was estimated to account for 53% of GHG emissions from U.S. animal agriculture and 25% of GHG emissions from all of U.S. agriculture. Footprinting studies suggest that much of the land use and water use associated with beef production are attributed to the development of feed crops or pastureland. On a global scale, beef from U.S. origin is exported to numerous developed and developing countries, representing an important international nutrient routing. Along with other prominent beef-producing nations, the United States continues to pursue a greater level of sustainability in its cattle industry, which will bear important implications for future global food security. Efforts to reduce the environmental impacts of beef production will likely be the strongest drivers of enhanced sustainability.

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1Based on presentation given at the Beef Species-Ruminant
Nutrition Cactus Beef Symposium titled “Nutritional and
environmental impacts of removing beef cattle from US agri-
culture” at the 2018 Annual Meeting of the American Society
of Animal Science held in Vancouver, BC, Canada, July 8–12,
with publication sponsored by the Journal of Animal Science
and the American Society of Animal Science.
2Corresponding author: rrwhite@vt.edu
Received December 12, 2018.
Accepted July 26, 2019.
BEEF SPECIES-RUMINANT NUTRITION CACTUS BEEF SYMPOSIUM:
Arole for beef cattle in sustainable U.S.food production1
ClaireB. Gleason and RobinR. White2
Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061
ABSTRACT: The increasing global population,
limited resource availability, and global focus on
reducing greenhouse gas (GHG) emissions put
pressure on animal agriculture industries to crit-
ically evaluate and optimize the role they play in
a sustainable food production system. The ob-
jective of this review is to summarize evidence
of the various roles that the U.S. beef industry
plays in the U.S.and global agricultural systems.
As the world’s largest beef producer, the United
States reaps considerable economic benet from
the beef industry through strong domestic and
international demand, as well as employment
opportunities for many Americans. Beef produc-
tion contributes to GHG emissions, land use, and
water use, among other critical environmental im-
pacts but provides an important source of essen-
tial micronutrients for human consumption. The
U.S.beef industry provides sufcient product to
meet the protein, vitamin B12, omega-3 and -6
fatty acid requirements of 43, 137, 47, and 487
million people, respectively. In the United States,
beef production was estimated to account for 53%
of GHG emissions from U.S.animal agriculture
and 25% of GHG emissions from all of U.S.agri-
culture. Footprinting studies suggest that much of
the land use and water use associated with beef
production are attributed to the development of
feed crops or pastureland. On a global scale, beef
from U.S. origin is exported to numerous devel-
oped and developing countries, representing an
important international nutrient routing. Along
with other prominent beef-producing nations, the
United States continues to pursue a greater level
of sustainability in its cattle industry, which will
bear important implications for future global
food security. Efforts to reduce the environmental
impacts of beef production will likely be the
strongest drivers of enhanced sustainability.
Key words: beef industry, environmental impact, human nutrition, sustainability
© The Author(s) 2019. Published by Oxford University Press on behalf of the American Society of
Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
J. Anim. Sci. 2019.97:4010–4020
doi: 10.1093/jas/skz173
INTRODUCTION
The global population is expected to exceed
9.8 billion by the year 2050 (UN DESA, 2017).
Along this same timescale, improved afuence in
developing nations is expected to increase global
demand for meat and milk (Seale, 1998; Delgado,
2003). Globally, land and water availability are al-
ready limited (Gomiero etal., 2011; Hertel, 2011).
As a result, concern exists about the opportunity
to rely on food production, as it currently func-
tions, to meet this demand increase. Agricultural
food production also contributes to atmospheric
concentrations of greenhouse gases (GHGs) like
methane (CH4), nitrous oxide (N2O), and carbon
dioxide (CO2) (United States Environmental
Protection Agency (EPA), 2018). The current
challenge requires food production to improve
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4011
A role for beefcattle
land and water use efciency and decrease GHG
emissions while developing adaptive capacity in the
face of climate variability (Nardone et al., 2010).
Acommonly proposed solution to these challenges
is to improve “sustainability” of food production
systems (Gomiero etal., 2011). Sustainability is de-
ned as a balance between social acceptability, en-
vironmental responsibility, and economic viability
(Brundtland, 1991; Committee on Incorporating
Sustainability in the U.S. Environmental Protection
Agency et al., 2011; Committee on Sustainability
Linkages in the Federal Government et al., 2013).
By improving sustainability, ideally, the envir-
onmental impact of a system can be reduced so
that societal demands for food can be met within
the bounds of resource availability and climate
conditions.
CONTRIBUTIONS OF BEEF TO U.S.
AGRICULTURE
Beef production in the United States is a
socioeconomically valuable system (USDA/NASS,
2018). The United States is not only the largest net
consumer of beef globally, but it also houses the
largest fed cattle industry in the world (OECD,
2014). The beef production system is comprised of
3 sectors: the cow-calf, stocker/backgrounder, and
feedlot. Cow-calf operations breed cows and bulls
and sell weaned calves. Stocker operations pur-
chase weaned calves, feed them on pasture, and sell
yearlings. Backgrounding operations feed weaned
calves forage-based rations out of feed bunks in
preparation for entry into a feedlot. Feedlots pur-
chase weaned calves from cow-calf operations,
cull dairy calves or yearlings from stocker/back-
grounder operations, and market nished animals
for harvest. Studies have cataloged the environ-
mental impact of each sector (Beauchemin et al.,
2010) and comparisons among sectors can be useful
in highlighting opportunities to improve the overall
role beef production plays in the agricultural envir-
onmental footprint.
Sustainability, however, must consider more
than just environmental impact. Sustainability
balances economic, environmental, and social
concerns; therefore, assessments of sustainability
should encompass metrics for each of these areas
of focus. This review characterizes the human nu-
tritional, environmental, and economic roles that
the beef industry plays in the U.S.and global agri-
cultural systems with an emphasis on how the in-
dustry might consider continual adaptation to
optimize thoseroles.
Nutritional Contributions
Contributions of beef cattle to the supply of
human-edible nutrients provided by U.S. agricul-
ture are summarized in Table 1 and were derived
from the data presented previously (White and
Hall, 2017). Along with other animal products,
beef meets the denition of a “complete protein”
because it contains all 9 amino acids that must be
obtained via the human diet. Very few plants pro-
vide all essential amino acids. Beef is therefore con-
sidered a higher quality protein source than the vast
majority of plant-based protein foods. Surprisingly,
beef provides only 5% of the protein available for
consumption in the United States today (Table
1). Amino acids from beef production range be-
tween 3.7% and 7% of the total domestic supplies,
with Lys, Met, and His being in the greatest sup-
plies (Table 1). Lys is indispensable for its role in
protein synthesis. Additionally, it supports the pro-
cess of beta-oxidation as a precursor to carnitine
(Tanphaichitr and Broquist, 1973). Cereal grains
possess low quantities of Lys, frequently making
Lys the limiting amino acid in human and animal
diets. As a precursor to succinyl-CoA and a host
of other biologically relevant molecules, Met is
another essential amino acid. It is involved in ac-
tivities ranging from fat metabolism to disease pre-
vention (Martínez etal., 2017). Histidine was once
thought to be only essential for children but is now
considered essential in all life stages because it is the
precursor to the neurotransmitter histamine, which
is involved in appetite regulation, fat mobilization,
and metabolic rate (DiNicolantonio etal., 2018).
Besides amino acids, beef also provides notable
quantities of vitamin B3, vitamin B6, and vitamin
B12. Vitamin B3, or niacin, serves as a precursor
to co-enzymes vital to metabolism (Surjana etal.,
2010). Vitamin B6 (pyridoxine) is important for
proper immune, nervous, and endocrine function.
Deciencies of B6 have been linked to neurological
disorders and birth defects (Ahmad et al., 2013).
Also known as cobalamin, vitamin B12 is essen-
tial for proper metabolic function as well as DNA
synthesis and modication (Green et al., 2017).
Interestingly, vitamin B12 is only synthesized by
microorganisms, making it an essential nutrient
to absorb from the diet. Naturally synthesized
vitamin B12 can only be obtained through the con-
sumption of animal-origin foods. Beef and other
ruminant animal products are especially valuable
sources of B12 owing to the large quantities of
microbes inhabiting the ruminant gastrointestinal
tract that are capable of cobalamin synthesis (Gille
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4012 Gleason and White
and Schmid, 2015). Following synthesis, cobalamin
storage takes place in the animal’s muscle and liver
tissue (Martens etal., 2002). Although severe cases
are uncommon in developed countries, vitamin
B12 deciencies are most often noted in individ-
uals who restrict or eliminate the consumption of
animal products, or who lack proper access to these
foods (Pawlak etal., 2013; Green etal., 2017). Well-
established manifestations of deciency include
neurologic and psychiatric disorders, as well as an-
emia (Bar-Shai etal., 2011).
Beef is a rich source of dietary minerals, pro-
viding 2.7% of the iron, 2.5% of the selenium, and
6.6% of the zinc available for human consumption
in the United States (Table 1). While signicant
quantities of minerals may be found in plant-based
foods, they are typically less biologically available
than those present in animal products. Heme iron
in meat, for instance, is more readily absorbed than
the nonheme iron present in plants. As myoglobin is
digested, the heme iron released is maintained in an
optimal state for absorption by the nearby products
of globin degradation. Iron deciency is therefore
less common in populations that consume ad-
equate amounts of meat or offal (Uzel and Conrad,
1998). According to Solomons (2001), poor zinc
uptake has been noted in both whole grain- and
soy-based diets. The impaired bioavailability of
zinc in plants is attributed to antinutritional factors
such as tannins and phytic acid. Beef and other
animal meats are devoid of such compounds and
just 100g of beef contain approximately 45.3% of
an adult male’s daily zinc requirement (Solomons,
2001). Akey micronutrient in proper immune and
reproductive function, selenium from beef has also
been reported as highly available to humans (Van
Table 1. Contributions of beef cattle to U.S.nutrient supplies
Nutrient
Human nutrient requirement years
supplied, millions1Percent of total U.S.supply2
Percent of total
U.S.requirement3
Energy 14.9 2.30 4.70
Protein 43.1 4.98 13.62
Linoleic acid 5.0 0.75 1.57
alpha-Linolenic acid 20.4 3.31 6.45
Calcium 0.8 0.24 0.26
Iron 19.5 2.66 6.17
Magnesium 5.8 0.75 1.84
Phosphorus 23.3 1.97 7.38
Potassium 6.7 1.98 2.12
Zinc 45.8 6.58 14.50
Copper 9.4 0.87 2.96
Selenium 35.3 2.49 11.15
Thiamin 8.5 0.89 2.68
Riboavin 17.4 2.19 5.50
Niacin 28.7 4.05 9.07
Folate 2.1 0.46 0.68
Vitamin B6 29.0 3.32 9.17
Vitamin B12 137.0 15.53 43.33
Cysteine 55.6 3.67 17.58
Histidine 69.9 5.79 22.11
Isoleucine 50.9 5.15 16.09
Leucine 45.3 4.70 14.33
Lysine 58.9 7.04 18.64
Methionine 50.8 5.74 16.06
Phenylalanine or
tyrosine
32.2 4.00 10.19
Threonine 60.3 5.62 19.08
Tryptophan 61.3 4.91 19.38
Valine 43.1 4.63 13.65
EPA+DHA 47.0 10.45 14.85
AA 486.6 7.52 153.93
1Value indicates the number of people (millions) whose annual requirement of each nutrient would be supplied by beef.
2Value indicates the percent of the total amount of each nutrient supplied by the U.S.agricultural system coming from beef.
3Value indicates the percent of the total U.S.population’s requirement for each nutrient that would be satised from beef.
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4013
A role for beefcattle
Der Torre etal., 1991). According to Holden etal.
(1991), beef is “the most abundant single food
source of selenium in the North American diet.”
Broccoli is also rich in selenium, but the complex
food matrix in which the mineral is bound may sig-
nicantly lower its bioavailability when consumed
(Thiry etal., 2012).
Beef has often been criticized as having detri-
mental effects on the heart due its saturated fatty
acid (SFA) content. However, this claim has recently
come under scrutiny and a considerable amount of
research has been unable to link SFA intake to in-
creased risk of cardiovascular disease (Lawrence,
2013). Indeed, many years’ worth of recommenda-
tions to reduce red meat consumption have not led
to improved health in the U.S.population. Beef in-
stead remains a signicant source of heart healthy
cis-monounsaturated fatty acids and the long-chain
omega-3 fatty acids eicosapentaenoic acid (EPA )
and docosahexaenoic acid (DHA) (Vahmani etal.,
2015). As identied in White and Hall (2017), beef
contributes to U.S.food supplies by providing over
10% of the EPA+DHA and 7% of the arachidonic
acid (AA) available in the nation. Furthermore, beef
provides fatty acid biohydrogenation products such
as rumenic and vaccenic acids. These fatty acids
have been identied as possessing hypolipidemic
and anticarcinogenic properties (Vahmani et al.,
2015).
When considering the role of beef in providing
a high-quality nutrient supply to the United States,
the provision of these critical nutrients is an im-
portant aspect. Continuing to ne-tune manage-
ment to optimize product quality and fatty acid
composition may be an important area of work to
reinforce this nutritional contribution in the future.
Economic Contributions
The United States is currently the largest beef-
producing country in the world. Between 2014 and
2018, the United States was responsible for nearly
20% of global beef production, averaging approxi-
mately 12.0 million metric tons in carcass weight
equivalent annually (USDA/ERS, 2018c; USDA/
FAS, 2018a). Domestic beef consumption in the
United States is also larger than consumption in
any other country, averaging 12.1 billion kg in total
weight annually between 2002 and 2015 (USDA/
ERS, 2018b). When compared to other meats, do-
mestic beef consumption exceeds both domestic
pork (USDA/ERS, 2013a) and poultry consump-
tion (USDA/ERS, 2013b). Unsurprisingly, beef
production is one of the nation’s most important
industries, generating $67.4 billion in direct cash re-
ceipts in 2017 (USDA/ERS, 2018a).
The United States is currently the world’s
fourth largest exporter of beef, totaling over 1.26
million metric tons of product in 2017 with a dollar
value of $7.3 billion (USMEF, 2017; USDA/FAS,
2018a). The United States is also the top global im-
porter, with over 1.35 million metric tons of foreign
beef imported in 2017 (USDA/FAS, 2018a). Export
value, however, exceeded import value by $1.6 bil-
lion due to the fact that the United States mainly
imports inexpensive lean beef trimmings for ham-
burger rather than high-priced cuts (Speer, 2018).
Leading importers of U.S. beef, including beef
variety meats, are listed in Table 2. At the time of
this writing, beef exports are following an upward
trend in practically every market (USMEF, 2018).
Markets including Canada, South Korea, and
Japan are forecasted to import more U.S.beef due
to a combination of competitive prices, abundant
supply, and decreased Australian exports (USDA/
FAS, 2018a). Strong foreign demand has led to
record-breaking volume and value of exports with
Asian markets being the major drivers of this in-
crease. Increased afuence and a growing middle
class in many Pacic nations have helped fuel the
demand for American beef and greater market ac-
cess has allowed the United States to prot from
this demand. The recent reopening of the Chinese
market to U.S.beef in June of 2017 yielded an ex-
port of 3,655 metric tons valued at $33 million
during the rst half of 2018. Closed to U.S. beef
for 13 yr, China has become the world’s second
largest beef importer, growing from $275 mil-
lion in imports during 2012 to $2.5 billion in 2016
(USDA/FAS, 2017a; USDA/FAS, 2018a). Growing
demand for American beef has also been noted in
the Indonesian market. Increased ease of export to
Indonesia as well as advocacy efforts on the parts
of the USDA Foreign Agricultural Service and
the U.S. Meat Export Federation have resulted in
a record of $53.7 million in exports to Indonesia
Table 2. Major importers of U.S.beef and beef var-
iety meats in 20171
Market Import volume, metric tons Dollar value, millions
Japan 307,559 1,890
Mexico 237,972 980
South Korea 184,152 1,220
Hong Kong 130,726 884
Canada 116,561 796
Taiwan 44,800 410
1Adapted from USMEF (2017).
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4014 Gleason and White
in 2017, an increase of almost 40% from the pre-
vious year (USDA/FAS, 2018b). Because of the sig-
nicant impact U.S.beef makes in foreign markets
and food supplies, decisions to change aspects of
our domestic beef production must be made with
the awareness that foreign consumers may also be
impacted.
The animal agriculture industry in the United
States employs over 1 million people among animal
food manufacturing, animal production, and
animal processing (USDL/BLS, 2014). Due to its
signicance for the U.S.economy, beef production
takes a prominent position in these sectors. The
USDA National Agricultural Statistics Service’s
most recent agricultural census reported 727,906
beef cattle farms (including ranches and research
farms) in operation (USDA/NASS, 2012). Raising
beef cattle therefore provides a livelihood for a sig-
nicant number of Americans. The cattle feeding
industry also employs numerous professionals,
which cumulatively reect a substantial economic
impact on the U.S.economy.
At present, the major economic roles of beef
cattle include generating export income and pro-
viding jobs for Americans. As the industry con-
tinues to develop, focus should be put on developing
high-quality jobs. Continued integration of tech-
nology into production is critical for this gener-
ation of high-quality jobs but will require shifts in
the workforce development strategy and continuing
workforce education. Optimizing the role of the
U.S. industry as an exporter of beef has been a
focus for decades and the success of this effort is
demonstrable in the statistics on income from ex-
port. As the industry evolves, continuing to con-
sider the benets of this export-driven economy in
the context of collateral social and environmental
concerns is essential.
Environmental Contributions
Beef cattle account for 52% of emissions from
animal agriculture and 25% of all agricultural emis-
sions in the United States (Mitloehner, 2016; White
and Hall, 2017). Emissions attributed to beef cattle
production include CO2 emissions from synthesis
of commercial fertilizer, herbicide, seed, and other
cropping-system inputs; on-farm CO2 emissions
from land management and transportation; CH4
emissions from enteric fermentation and manure
storage; direct and indirect N2O emissions from
manure storage; CO2 emissions from infrastructure
upkeep; and other sources. Beef cattle remain the
predominant contributors of CH4 emissions and
were responsible for 71% of total enteric CH4 emis-
sions from livestock in 2016 (EPA, 2018). System
boundaries for establishing a carbon footprint for
beef production typically extend from the inputs to
the cropping system through the feedlot or slaugh-
terhouse gate. For most U.S.beef production en-
terprises, the cow-calf operation contributes the
greatest to the whole-system emission primarily
because of enteric fermentation from the cow herd
(Beauchemin et al., 2010; Asem-Hiablie et al.,
2018).
Water use from beef cattle production varies
considerably based on accounting approach and
production system and is typically estimated be-
tween 200L/kg and 4,000 L/kg depending on the
different sources of water included (Beckett and
Oltjen, 1993; Oltjen and Beckett, 1996; White etal.,
2014). Some estimates of beef production water
use are over 10,000L/kg when accounting for all
sources of water (Mekonnen and Hoekstra, 2012).
Water use is broadly classied into 3 categories:
blue water includes surface and ground water;
green water refers to rainwater; and gray water
refers to the volume of freshwater required for
diluting pollutants to adequate water quality stand-
ards (Mekonnen and Hoekstra, 2012). Sources of
direct water use on beef operations typically in-
clude irrigation water; sanitation and processing
water; and animal drinking water. Irrespective of
the water footprint estimate, most studies agree that
land-applied water is the greatest contributor to a
C-footprint (Beckett and Oltjen, 1993; White and
Capper, 2013). In 2013, 81.2 billion liters of water
was applied to crops in the United States (USDA/
NASS, 2013). Globally, only 10% to 30% of irriga-
tion water is utilized by plants for growth (Wallace,
2000), suggesting that improving efciency of irri-
gation water use within crop production would have
notable impacts on the water footprint of beef. By
comparison to the irrigation water usage for feed
production, the 4 to 15 liters of water per kg feed
intake consumed directly by livestock (Winchester
and Morris, 1956; Mader and Davis, 2004), or 123
liters of daily drinking water per kg of beef (White
etal., 2014), is a minimal contribution.
Land use associated with beef cattle produc-
tion is considered both a resource use and a benet
associated with production. Biodiversity preserva-
tion on rangeland is important and the impacts of
herbivory on healthy grasslands have clearly been
demonstrated. Oltjen and Beckett (1996) noted that
most assessments of land use in beef production in-
correctly assume that all land used for beef produc-
tion could also be used for human food production.
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A role for beefcattle
Estimates of land use for beef production range
from roughly 15 m2 for intensive systems (Nguyen
etal., 2010) to nearly 100 m2/kg for grass-nishing
systems (Capper, 2012). In most U.S. production
systems, a substantial amount of that land foot-
print (e.g., roughly 66% in White and Capper, 2013)
is associated with grazing. It is difcult to estimate
the number of cattle housed on rangeland and pas-
tureland that is not croppable in the United States
but it is expected to be the majority of beef cows.
This assumption implies that the majority of im-
provements in beef land use could be accomplished
by optimizing stocking density in grazing systems.
A key requirement of stocking density optimiza-
tion is improvement in the efciency of forage use,
which can be achieved through the employment of
specic grazing systems such as rotational or strip
grazing. Strip grazing, for example, may result in
upwards of 80% forage use efciency when util-
ized (Stewart etal., 2012). Finding the best grazing
management or forage optimization strategy is
likely something that must be accomplished on the
individual farm scale considering constraints like
capital, labor, climate, and other factors.
BEEF CATTLE AS RECYCLING ENGINES
Use of Nonhuman-Edible Resources
A critical aspect of beef cattle production that
is unique among livestock systems in the United
States is the extensive use of land area that could not
otherwise be harvested for food production (Oltjen
and Beckett, 1996). In particular, beef cattle are the
primary species used to graze the 96 million acres
of rangeland (USDA Forest Service, 2018) avail-
able in the United States. Forage accounts for ap-
proximately 80.8% of the feed needed to produce
market-ready beef and the total amount of forage
needed to produce 1 grain-nished feedlot animal
is estimated at 6,411kg on a dry matter (DM) basis
(NASEM, 2016). The amount of grain required
is estimated at less than 10%, or 793.4 kg DM
(NASEM, 2016). The remaining 10% or more of
the life-cycle diet is comprised of by-products of
the various grain and pulp processing industries.
Consumption of these human-inedible resources
likely exceeds 800 kg DM per animal. Optimizing
the conversion of human-inedible feed resources
into human-edible food is crucial for solidifying the
role of beef in a sustainable human diet.
For some time, beef production has been touted
as a critical way to generate high-quality human-
edible protein from human-inedible products.
However, when the analysis by White and Hall
(2017) is assessed specically for beef product con-
tributions, beef production in the United States
only provides sufcient protein to meet the require-
ments of 14% of the population (Table 1). Other
essential micronutrients like vitamin B12 and AA
appear to be more important contributions of beef
than protein and individual amino acids (Table 1).
As such, when discussing the role of beef cattle in
producing human-edible products from nonhuman-
edible resources, there is likely a need to identify
more important contributors toward these nutrient
supplies.
As mentioned above, a critical cost of the
ruminant animal’s unique ability to synthesize
human-edible nutrients from low-quality forage is
the production of methane. Along history of me-
thane research (Johnson and Johnson, 1995) and
models of methane prediction (Mills et al., 2003;
Ellis etal., 2010) all agree that forage-based diets
generate higher methane production than grain-
based diets. This suggests that converting cows
from forage (range, pasture, or stored forage) diets
to feedlot rations might be an efcient way to re-
duce methane emissions; however, the economic
and social ramications of this approach and the
associated resource use make it simply infeas-
ible. The USDA/NASS (2018) estimates there are
roughly 32 million beef cows in the United States.
On a pasture-based diet (13kg/d DMI), the equa-
tion of Moe and Tyrell (1979) predicts a 567 kg
beef cow to produce 371g of CH4 per day. If the 32
million cows in the United States each emit 371g of
CH4 per day, their annual emissions equate to 4.3
million metric tons of CH4. If instead, they were
emitting closer to 180g of CH4 per day (as might be
expected from a grain-based ration), their net an-
nual emissions would equate to 2.1 million metric
tons of CH4. This reduction equates to over 50 mil-
lion metric tons of CO2 equivalents. Considering
that total U.S.emissions in 2016 were estimated at
6.5 billion metric tons of CO2 equivalents, a 50 mil-
lion metric ton decrease is less than a 1% change in
national emissions. This example goes to show that
although methane emissions are an important agri-
cultural issue, even a halving of methane emissions
from beef cattle has a small marginal result in terms
of national effects.
The above example uses only 1 strategy to es-
timate methane emissions and it is important to
note that there are several equations available. The
NASEM (2016) cites the Intergovernmental Panel
on Climate Change (IPCC) as one of the only CH4
prediction equations tailored to predict emissions
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4016 Gleason and White
at high and low levels of dietary forage inclusion.
Under the IPCC (2006) equations, at 13kg of in-
take with a gross energy concentration of 4.16
Mcal/kg, a cow on a high-forage diet would be
expected to product 264g of CH4 per day. On a
grain-based diet consuming the same level of gross
energy emissions would be expected to be 122g/d.
Although the absolute values vary between the pre-
diction methods, the proportional change in emis-
sions (51% to 53%) is very similar suggesting the
net effect discussed above is supported across me-
thane prediction approaches.
A logical next question when discussing the
trade-offs associated with the ruminant animal is
more subjective—are the environmental costs worth
the nutritional benet? To address this question, it
is tempting to look at the environmental impact
per unit of human-edible nutrient produced; how-
ever, such an analysis fails to address the system
feasibility of meeting human requirements for par-
ticular nutrients with the food products produced
in a manner divorced from the food production
system. As elaborated in White and Hall (2017),
comparison of the importance of different products
really must be done in the context of the production
system. Beef production uses by-products from nu-
merous other industries (dairy, corn, soy, etc.) and
the question of whether the environmental costs of
beef production are worth the nutritional benet
cannot be answered without more holistic, systemic
assessment of these specic nutrient uxes.
The continued search for strategies that re-
duce environmental impacts of beef production
in an economically viable and socially acceptable
manner is likely the most important way to ensure
the sustainability of beef production in the United
States. Anumber of studies have been conducted on
strategies to reduce environmental impact of beef
production systems (Pelletier etal., 2010; Capper
and Hayes, 2012; Stackhouse etal., 2012; White
etal., 2015; Rotz etal., 2019). In general, any agri-
cultural system with enhanced efciency will also
have improved environmental impact (Capper and
Bauman, 2013). Given the structure of the beef
industry in the United States, the most substantive
improvements in environmental impact must be
realized in the cow-calf sector (Beauchemin etal.,
2010; White et al., 2014). The need for focus on
the cow-calf production system presents a chal-
lenge because of the practical, economic, and so-
cial constraints placed on the cow-calf production
system. More diverse than the other beef industry
segments, the cow-calf sector is composed of op-
erations varying considerably in size, protability,
and productive output. In the United States, cow-
calf production is and will likely remain a forage-
based enterprise. As such, improving the efciency
of cow-calf production will undoubtedly involve
forage management. This will likely be challen-
ging, however, as the cow-calf sector is generally
slower at adopting new technologies and manage-
ment practices. Greater extension efforts therefore
should be geared toward the adoption of more
efcient forage management practices. A number
of reviews exist about factors inuencing prod-
uctivity of grazing beef cattle (Walmsley et al.,
2018) and pasture and soil responses to herbivory
(Drewry etal., 2008). Rather than duplicate con-
tent found in these other resources, we will focus
this discussion on the implications of optimizing
land use efciency in beef production.
Figure 1 compares the ability of beef to meet
the annual nutrient requirements of an average
American with that of other food sources in terms
of GHG emissions intensities. When evaluating
nutrient output per unit of GHG input, beef does
not have an advantage compared with most other
animal or nonanimal products, even for those nu-
trients for which beef is an important source (Fig.
1). The utility of beef production is thought to be
making use of land that cannot be used for other
food production endeavors. However, when the
croppable land use efciency of beef is compared
05000 10000 15000 20000 25000 30000 35000
Energy
Protein
Linoleic acid
alpha-Linolenic acid
Iron
Zinc
Vitamin B12
CO2-e Required to Meet Annual Requirements of 1 Person for Each Indicated
Nutrient
Beef Animal VegetableNut Legume Grain Fruit
Figure 1. Greenhouse gas emissions intensities of producing suf-
cient product (beef, animal products, vegetables, nuts, legumes, grains,
or fruits) to meet the nutrient (vitamin B12, zinc, iron, alpha-linolenic
acid, linoleic acid, protein, and energy) requirements of an average
American for 1 yr. Arachadonic acid and EPD+DHA results are not
shown due to lack of concentrations in nonanimal source products.
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4017
A role for beefcattle
to other food types (Fig. 2), more humans can be
fed from other land use options. The values in Fig.
2, reecting the number of people whose annual
nutrient requirements could be met from a single
acre producing each food type, are derived from
White and Hall (2017) and the beef numbers may
not reect true land use efciencies. Comparison
of croppable land use efciency is somewhat im-
perfect because it assumes that all croppable pas-
ture and half of hay land is croppable and used
for beef production. The estimate of 50% of hay
land is based on the assumption that an average
cow consumes 2% of body weight in hay for 90 d
out of the year. This estimation yields an annual
consumption of hay at 28.8 million tons, which
is approximately 50% of the annual hay produc-
tion in the United States in 2016 (USDA/NASS,
2018). To better understand the implications of
this assumption, the analysis was duplicated as-
suming no hay land (15%) or all hay land (85%)
should be assigned to beef cattle. What this ana-
lysis suggests is that a critical step in optimizing
the role of beef production in U.S.agriculture is
to nd ways to eliminate competition between re-
sources for nonanimal source food production
and beef production to reinforce the role of beef
cattle as a recycling engine.
GLOBAL CONSIDERATIONS FOR BEEF
PRODUCTION
Beef Production Worldwide
The largest foreign producer of beef is Brazil,
which produced over 9.5 million metric tons of
beef and veal in 2017. It is the world’s largest ex-
porter, with 1.86 million metric tons sold in 2017.
Continued expansion of the Brazilian beef industry
has been propelled by strong domestic demand and
gains in important Asian markets (USDA/FAS,
2018a). China, the second-largest consumer of beef,
is third in production (Zan etal., 2015). Beef de-
mand has increased rapidly along with the nation’s
economic strides. However, a depressed cattle in-
ventory has made it impossible for the Chinese beef
industry to keep pace with this demand, resulting in
higher prices and an increased need to import from
other countries (Li et al., 2018). India’s beef and
water buffalo meat (or carabeef) exports have risen
substantially since the late 2000s, even surpassing
Brazil in 2014. Acombination of a large inventory,
strong demand for cheap carabeef in poorer Asian
nations, and development of the meat processing
sector has fueled India’s ascent to the top tier of
global beef producers (Landes etal., 2016). The re-
building of Argentine beef herds has led to gains
in both the domestic market and exports. Indeed,
Argentina’s 2018 exports are predicted to reach a
9-yr high at 350,000 tons carcass weight equivalent
(USDA/FAS, 2017b). Sixth in beef production glo-
bally, Australia’s severe drought conditions have
resulted in considerable herd liquidation (USDA/
FAS, 2018a). The duration of the current drought
will most likely determine when herd rebuilding can
commence. The Mexican beef industry, however,
has experienced steady growth and is projected to
continue this trend through its close integration
with the U.S.beef industry and efforts to appeal
to foreign markets (USDA/FAS, 2018c). With their
nancial and scientic resources, the world’s top
beef producers described here continue to pave the
way toward more sustainable practices of beef pro-
duction. These efforts are a key factor in securing
the global food supply and increasing beef access
for populations with serious nutrient deciencies.
Considering the global trends in beef demand,
an essential consideration for the U.S.beef industry
is how to optimize its role in supplying efciently
produced beef. Beef production in the United
States is, environmentally, one of the most efcient
production systems in the world. Correspondingly,
there is some logic to exporting U.S. beef to
0.05.0 10.0 15.020.025.030.035.040.045.
05
0.
0
Energy
Protein
Linoleic acid
alpha-Linolenic acid
Iron
Zinc
Vitamin B12
Number of Human's Annual Nutrient Requirements Met From an Acre
Beef, 85% Hay Beef, 50% Hay Beef, 15% Hay Vegetable
Nut Legume GrainFruit
Figure 2. The number of average Americans whose yearly nutrient
requirements could be met from an acre of land producing each food
type. Opportunities to meet human nutrient requirements through
beef production were calculated assuming 15% of hay land, 50% or
hay land, or 85% of hay land were attributable to beef production.
Arachadonic acid and EPD+DHA results are not shown due to lack
of concentrations in nonanimal source products.
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4018 Gleason and White
developing countries whose beef production sys-
tems are less environmentally efcient. However,
there is concern about this approach because it is
unclear whether the export income provides suf-
cient societal benet to justify the externalities asso-
ciated with production. Additional work assessing
this trade-off is critical to further considering the
role of U.S.beef production in the growing global
market.
CONCLUSIONS
Along with other top beef producers, the
U.S. beef industry plays an important role in
delivering essential nutrients to both domestic and
foreign consumers. Beef production maintains a
prominent position in the nation’s livestock in-
dustry, offering signicant economic and employ-
ment opportunities. Beef cattle account for 52% of
emissions from animal agriculture and 25% of all
agricultural emissions in the United States (White
and Hall, 2017). Enhancing resource use of beef
production requires improved land management,
focused on optimizing the calf weight produced per
unit of land while considering conservation, bio-
diversity, and soil health interests. Perhaps most
critically, efforts must focus on nding ways to elim-
inate competition between resources for nonanimal
source food production and beef production to
reinforce the role of beef cattle as a recycling en-
gine. Population forecasts and environmental con-
cerns underscore the importance of current efforts
to improve productive output and sustainability of
the U.S.beef industry. Indeed, the future of global
food security will depend on today’s decisions made
regarding the direction of beef production and the
food industry as a whole.
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