Fossil Fuel Input to Grow Beef Cattle New Zealand Vs Us

• Journal List
• Animals (Basel)
• v.2(two); 2012 Jun
• PMC4494320

Animals (Basel). 2012 Jun; 2(ii): 127–143.

Is the Grass E'er Greener? Comparing the Environmental Impact of Conventional, Natural and Grass-Fed Beef Product Systems

Received 2012 Jan 22; Revised 2012 Mar 27; Accepted 2012 Mar 31.

Abstract

Uncomplicated Summary

The ecology impact of three beefiness product systems was assessed using a deterministic model. Conventional beef product (finished in feedlots with growth-enhancing engineering) required the fewest animals, and least country, h2o and fossil fuels to produce a set up quantity of beefiness. The carbon footprint of conventional beef product was lower than that of either natural (feedlot finished with no growth-enhancing technology) or grass-fed (forage-fed, no growth-enhancing engineering) systems. All beef production systems are potentially sustainable; yet the environmental impacts of differing systems should exist communicated to consumers to let a scientific ground for dietary choices.

Abstract

This study compared the environmental impact of conventional, natural and grass-fed beefiness product systems. A deterministic model based on the metabolism and nutrient requirements of the beef population was used to quantify resource inputs and waste material outputs per ane.0 × 10⁹ kg of hot carcass weight beef in conventional (CON), natural (NAT) and grass-fed (GFD) production systems. Product systems were modeled using characteristic management practices, population dynamics and production data from U.Due south. beef production systems. Increased productivity (slaughter weight and growth charge per unit) in the CON organization reduced the cattle population size required to produce 1.0 × x⁹ kg of beef compared to the NAT or GFD system. The CON organization required 56.3% of the animals, 24.viii% of the water, 55.3% of the state and 71.4% of the fossil fuel free energy required to produce 1.0 × 10^nine kg of beef compared to the GFD system. The carbon footprint per 1.0 × ten^nine kg of beefiness was everyman in the CON system (xv,989 × x³ t), intermediate in the NAT system (18,772 × ten³ t) and highest in the GFD arrangement (26,785 × 10^three t). The challenge to the U.S beefiness industry is to communicate differences in system ecology impacts to facilitate informed dietary choice.

Keywords: beefiness, carbon footprint, environmental touch on, greenhouse gas, productivity, feedlot, corn, grass-fed

1. Introduction

Sustainability is often divers as "meeting society'southward present needs without compromising the ability of future generations to meet their ain needs" and comprises three interlinked facets: environmental responsibleness, economical viability and social acceptability [1]. In this context, the sustainability of beef production comes under considerable scrutiny. Global food security and environmental problems are significant considerations for governments and policy-makers who are conscious non only of the proportion of their national population that is currently nutrient-insecure, but also of the prediction that the global population will increment to over 9.5 billion people past the year 2050 [2]. The greatest population increases are predicted to occur in developing regions such as Africa, China and Republic of india, and, by 2050, these nations are predicted to enjoy a per capita income like to that currently seen within Europe and North America [three]. Equally incomes increase, so does the demand for high-quality fauna proteins such as meat, milk and eggs, thus the Food and Agriculture Organisation of the Un (FAO) suggests that food requirements will increment by lxx% by 2050 [ii]. In the effect of considerable population growth, future competition for h2o, state and free energy between livestock production and human activities will increase. The global beef industry volition therefore confront a pregnant claiming in fulfilling consumer demand for meat products, using a finite resource base. This issue is not confined to a future scenario—current concern over dwindling natural resources, climate change and the social acceptability of beef production practices leads to debate every bit to whether the U.S. beefiness manufacture should continue to intensify and ameliorate productivity to feed the increasing population, or adopt extensive production systems often perceived past consumers to have a lower environmental touch [4].

Advances in nutrition, genetics and management have conferred considerable advances in reducing the ecology impact of beef product over time: Capper [5] demonstrated that compared to beefiness production systems characteristic of 1977, modern beefiness production in 2007 used 19% less feed, 12% less water, 33% less country and exhibited a 16% decrease in the carbon footprint per unit of beef. The improvements in efficiency conferred past modern management practices and technology employ facilitate the production of economically-affordable beef [6,7]. Nevertheless, the social acceptability of specific beef production practices, specifically finishing inside feedlots and the use of applied science to meliorate growth rate, may be perceived as undesirable by the consumer due to concerns relating to animal welfare [8,ix], human being health [10] or environmental sustainability [eleven]. Beefiness produced without the utilize of growth-enhancing technology (GET; "natural" beef), or finished on a forage-based diet ("grass-fed") may therefore proceeds market share [12]. The aim of this study was to evaluate the comparative ecology impacts (divers as resources utilize and greenhouse gas (GHG) emissions) of conventional, natural and grass-fed beef production using a deterministic whole system model based on ruminant nutrition and metabolism.

two. Experimental Section

This report utilized data from existing reports and databases and required no Animate being Care and Utilize Committee approval. A deterministic environmental impact model (EIM) based on the nutrient requirements and metabolism of animals within all sectors of the beefiness production system was used to quantify the environmental impact of iii U.S. beefiness product systems: "Conventional", (CON) "Natural" (NAT) and "Grass-fed" (GFD). The CON system represented the beef production arrangement characteristic of the bulk of beef operations. A myriad of definitions be for "natural" beef, thus in this study management practices in the CON and NAT system were identical, relieve for the utilize of Arrive the CON organization (where approved by the FDA) at 100% adoption rate, compared to cipher adoption in the NAT system. The GFD system was defined by the USDA-AMS standard for grass-fed beef [13], which prescribes a forage-based diet from birth to slaughter without grain or other non-forage supplementation. No prohibition of GET exists in the USDA-AMS standards for grass-fed beefiness production, but such technologies are seldom compatible with marketing claims for grass-fed beef, therefore they were non employed in the current comparison. Environmental impact was calculated past comparing almanac resources inputs and waste output of each beefiness production system, expressed per i.0 × 10⁹ kg of beefiness (hot carcass weight) produced in 365 d.

2.1. The Beefiness Product System Ecology Model

A deterministic EIM of beef production was created within Microsoft Excel. The EIM contained four different sub-models: the beefiness population, the animal arrangement, the cropping organization and the transportation system (Figure 1).

Simplified schematic representation of the sub-systems inside the environmental impact model.

2.one.one. The Beef Population Sub-Model

The model worked step-wise backwards through the production chain. The functional unit of measurement (1.0 × 10⁹ kg of hot carcass weight beef) and the slaughter characteristics of the diverse beefiness populations determined the number of slaughter animals required and thus the total beef population size. The numbers of animals inside each of the six sub-systems (cow-calf unit, stocker operation, pre-grass-finishing system, feedlot, grass-finishing organization and dairy population) independent within the animal system sub-model (ASSM; Figure two) were derived from the total slaughter population size according to sub-arrangement-specific productivity metrics (mortality, growth rate) equally detailed in Section 2.ii and Department 2.3, and pro-rated on an annual footing according to the number of days spent within each organisation.

Schematic representation of the animate being systems modeled within the study.

ii.1.ii. The Animate being System Sub-Model

The ASSM contained half dozen sub-systems. The cow-calf unit of measurement contained beef breed animals (Angus cows, Hereford bulls and Angus × Hereford offspring) that served to support population dynamics (lactating and dry cows, pre-weaned calves, replacement heifers, adolescent bulls, yearling bulls and mature bulls). The stocker operation and pre-grass-finishing system contained weaned beefiness breed steers and heifers fed until they reached sufficient weight to be placed into the feedlot or the grass-finishing system. The feedlot contained calf-fed beef and dairy (Holstein) animals that enter the feedlot at weaning (beef calves) or four months of age (dairy calves); and yearling-fed beef breed animals that enter the feedlot after the stocker stage. Within the feedlot, cattle were fed until the desired weight and status were accomplished. A dairy system was also independent within the CON and NAT systems for the purposes of supplying dairy-bred calves and cull dairy cows and for consequent resource allotment of resources and emissions between the beefiness and dairy system. The grass-finishing organization independent beef breed steers and heifers fed until the desired weight and condition was accomplished.

Food requirements and feed intakes for each class of animals were calculated using AMTS Cattle Pro [14], a commercial cattle diet conception software package based on the Cornell Internet Carbohydrate and Protein System. Diets were formulated to fulfill the requirements of animals within each class and sub-system according to historic period, sex, breed, liveweight, average daily proceeds, production system characteristics and GET use (where appropriate) to within one% of predicted metabolizable free energy and poly peptide requirements. Outputs from AMTS Cattle Pro (growth rate, DMI, dietary composition, dietary fiber characteristics, manure output, N and P excretion) were then inputted into the ASSM. Voluntary water intake for mature cows was modeled according to Beckett and Oltjen [15], with water intakes for all other classes of animal calculated from the equation derived by Meyer et al. [16]. Total manure output, N and P excretion were calculated as the sum totals from each animal class within the ASSM expressed per part unit of measurement of output (i.0 × ten⁹ kg beef). Total carbon emissions from the ASSM comprised CH_four and Northward_twoO from both enteric fermentation and manure. Dietary soluble residue, hemicellulose and cellulose intakes were used to calculate enteric CH₄ product from all animals within each sub-system, including pre-weaned calves [17]. The fraction of nitrogen emitted as enteric N₂O was modeled using information reported by Kaspar and Tiedje [18] and Kirchgessner et al. [19]. Emissions of CH_four from manure were estimated using methodology prescribed by the U.S. Environmental Protection Agency [20] based on the quantity of volatile solids excreted, maximum CH_four-producing potential (0.24 cubic meters per kg of volatile solids), and a conversion factor specific to either pasture or feedlot systems. Intergovernmental Console on Climatic change [21] emission factors were used to summate N₂O emissions from manure.

ii.1.3. The Cropping System Sub-Model

Quantities of feedstuffs required to support beef production were derived from the ASSM co-ordinate to dietary conception, daily DMI for each animal class and animate being numbers. State use was calculated according to feedstuff requirements and cropping yields. Ingather yields and inputs (fertilizers, herbicides, insecticides, fuel use) were derived equally detailed past Capper [5]. Irrigation h2o use for crop production was calculated from awarding rates and proportions of crops irrigated according to the Census of Agriculture Ranch and Irrigation Survey [22]. Carbon emissions from feedstuff production comprised N_iiO and CO₂ from crop production expressed as CO₂-equivalents. Emissions of Northward₂O from fertilizer application, manure application to crops, and manure applied while grazing were estimated from the factors published by the IPCC [21]. Emissions of CO₂ from fertilizer and pesticide manufacture were derived from West and Marland [23], and similar emissions from fossil fuel combustion for ingather production were calculated from The states EPA [24]. Biogenic carbon, which rotates continuously through a wheel comprising uptake of atmospheric carbon by crops followed by a return to the atmosphere through beast respiration, was considered to be neutral with respect to GHG emissions. Carbon sequestration into soil and CO₂ produced through animal respiration were considered to exist equivalent and were therefore non specifically accounted for.

ii.i.4. The Transportation Sub-Model

The assumptions underlying the transportation sub-model are described within Capper [5]. Carbon emissions from animal transport were derived from animate being numbers, the carrying capacity of haulage vehicles dependent upon animal liveweight and vehicle size, distances between fauna sub-systems and fuel efficiency. Within the CON and NAT systems, animals were transported an average of 483 km between sub-systems and 161 km to the butchery. Animal transport within the GFD arrangement was confined to the transport of animals from the grass-finishing organisation to the slaughterhouse (161 km) as animals were causeless to stay within the aforementioned farm premises from birth to slaughter. Within the CON and NAT systems, feed (corn and soy) was transported 558 km to the feedlot (underlying assumptions described by Capper [5]), with carbon emissions dependent upon feedstuff requirements, vehicle conveying capacity and fuel efficiency. All forages within the GFD arrangement were causeless to be domicile-grown, thus no feed ship costs were assigned to this system.

two.ii. Conventional and Natural Beef Production System Characteristics

The CON and NAT beef production systems comprised cow-calf, stocker and feedlot operations modeled co-ordinate to characteristic U.S. production practices [25,26,27,28] with population characteristics unaffected by GET use every bit detailed in Capper [5]. Briefly, these included a 365 d calving interval, a 207 d lactation, and a calving rate of 91.5% with 96.5% of cows producing a live calf. Replacement heifers were included in the population at a charge per unit of 0.27 heifers per moo-cow with an almanac replacement rate of 12.9% and a 24-month age at first calving. Bulls were included in the population at a ratio of one bull per 25 cows.

Diets for animals in the CON and NAT supporting populations (lactating and dry cows, replacement heifers, mature and adolescent bulls) were formulated based on pasture, grass hay and straw, adjusted for a predominantly pasture-based diet during leap and summer, with conserved forage supplementation during autumn and winter. Prior to weaning at 207 d [26], calves suckled from the dam and consumed pasture and starter feed (flaked corn and soybean meal). Post-weaning, 83.5% of calves [5] entered the stocker sub-arrangement where they were fed primarily pasture-based diets with supplemental grass hay, corn silage, flaked corn and soybean meal according to seasonal pasture availability. At 386 kg bodyweight (BW; steers) or 340 kg BW (heifers), stocker cattle entered the feedlot as yearling-fed finishing animals.

Diets for yearling-fed feedlot steers and heifers were counterbalanced for predicted dry matter intake (DMI) and growth rates (Table one) and comprised corn grain, soybean meal, alfalfa hay and vitamin/mineral supplements. A total of 16.5% [5] of weaned beef calves entered the feedlot straight as calf-fed finishing animals and were fed a nutrition containing the same base ingredients as the yearling-fed animals, formulated for predicted DMI and average growth rates as documented in Table one.

Table 1

Mean product information for sub-classes of growing and finishing animals inside three beef production systems: conventional (CON), natural (NAT) or grass-fed (GFD) ^a.

	System	Time in sub-system (d)	Growth rate (kg/d)	Weight change (kg)	Stop weight (kg)	Slaughter data
						Historic period (d)	Weight (kg)
Pre-weaned beef calf	CON	207	0.98	203	245	North/A	Northward/A
	NAT	207	0.98	203	245	Northward/A	N/A
	GFD	207	0.88	183	226	Northward/A	N/A
Pre-weaned dairy dogie b	CON	56	0.92	51	92	Due north/A	N/A
	NAT	56	0.92	51	92	N/A	N/A
Stocker	CON	123	0.99	122	367	Northward/A	N/A
	NAT	159	0.77	122	367	North/A	N/A
Pre-grass finishing	GFD	159	0.42	67	293	N/A	Due north/A
Dogie-fed beef in feedlot	CON	203	1.61	326	571	410	571
	NAT	203	1.xx	244	489	435	489
Calf-fed dairy in feedlot	CON	259	one.74	449	541	315	541
	NAT	259	1.48	383	476	315	476
Yearling-fed beefiness in feedlot	CON	110	one.86	204	571	440	571
	NAT	110	one.48	163	530	440	530
Grass-finished	GFD	313	0.61	192	486	679	486

The CON and NAT beef systems included animal inputs from the U.South. dairy manufacture in terms of choose cows, plus male person and dairy female calves at iii d of age. The question of resource and waste allotment between interlocking systems (in this instance the dairy and beefiness populations) has been extensively debated [29]. Resources inputs and waste material output between the dairy and beef systems were calculated based upon a biological allocation method. A deterministic model of resource utilise and environmental touch within dairy product was previously developed by Capper et al. [30], based upon the same nutrition and metabolism principles as the electric current beef model. Employing the model described by Capper et al. [30] to appraise the environmental affect of dairy inputs to the beefiness industry inside the current study ensured that resource input information for both models were sourced from similar information, thus minimizing methodological conflict betwixt the models. The dairy model was used to decide the proportion of total resource inputs and waste output owing to growth in Holstein heifers from nascence upwardly to 544 kg (the weight at which they would be sold as beef animals if they did not enter the dairy herd). These totals represented the environmental toll attributed to dairy choose cows inbound the beef marketplace and were added to the appropriate beef product system according to the number of choose cows within said organization. The impact of producing male and female dairy calves for calf-fed rearing was calculated by partitioning out the proportion of full resources inputs and waste output attributable to pregnancy in lactating and dry dairy cows. This cost was adjusted for the number of dairy calves in the beef system and thus the number of cows required, earlier application to the beef product system. Use of this allocation method ensured that the dairy manufacture was credited for past-product animals that were ultimately destined to produce meat within the beef production organisation.

A total of 12.9% of animals within the CON and NAT feedlot finishing systems originated from dairy production, comprising xi.five% dairy steers and ane.4% dairy heifers [5,15]. Within the model, dairy calves were fed milk replacer and a calf starter ration (flaked corn and soybean meal) until weaning at 56 d. Dairy calves entered the feedlot on a calf-fed footing and were finished on a standard feedlot diet similar to that fed to the calf-fed beef animals, balanced for predicted DMI and growth rate (Table 1).

The CON arrangement included the use of Get in terms of steroid implants, in-feed ionophores (monensin sodium, lasalocid sodium) in-feed hormones (melengestrol acetate, MGA) and beta-adrenergic agonists (ractopamine hydrochloride, zilpaterol hydrochloride, βAA). Ionophore utilize in lactating and dry beef cows was modeled co-ordinate to Sprott et al. [31] with a 10.2% reduction in feed intake while maintaining performance. AMTS Cattle Pro [fourteen] has a congenital-in module within the software that corrects feed intake, efficiency and growth rate for the apply of steroid implants and ionophores in growing cattle, therefore this was employed when formulating diets for stocker and feedlot animals. Due to a lack of data for the effects of implant use in pre-weaned calves and the characteristically depression adoption charge per unit of this engineering science inside this animal class [25], this technology was non included in the pre-weaned calf groups. The effects of MGA use in heifers were modeled according to data from Perrett et al. [32] and Sides et al. [33,34,35,36,37] that showed a fundamental trend towards a 3.5% increase in feed intake compared to non-supplemented animals. Research relating to the productivity effects of βAA demonstrated a cardinal tendency to increase growth rate past 18.4% during the supplementation period (28 d for ractopamine hydrochloride, twenty d for zilpaterol hydrochloride) beyond all classes of supplemented fauna [34,35,36,37,38,39,40,41,42,43,44]. The dressing per centum for animals supplemented with βAA (CON) averaged 63.8% compared to 63.3% for non-supplemented animals (NAT) [34,35,36,37,38,39,42,43,44,45].

Slaughter populations for the CON and NAT systems comprised calf-fed and yearling-fed beef-breed animals; calf-fed dairy animals and choose animals from the beef and dairy sectors. Sub-classes of feedlot-finished animals were taken to the aforementioned number of days on feed within both models, for instance, 110 days on feed for yearling-fed beef steers in both the CON and the NAT systems, equally shown in Table one. The average slaughter weight beyond all brute categories was 569 kg in the CON system and 519 kg in the NAT system, at average ages of 444 d (CON) and 464 d (NAT).

ii.iii. Grass-Fed Beefiness Production Organisation Characteristics

The GFD production system included a cow-dogie functioning, a pre-grass-finishing operation and a grass-finishing operation. Supporting population characteristics unaffected by applied science use (calving interval, age at first calving, calving rate, lactation length, replacement heifer:cow ratio and bull:cow ratio) were as detailed in Capper [5] and briefly described in Section two.two.

All animals in the GFD system were supplied with a forage-based diet formulated based on pasture, alfalfa hay, grass hay and wheat straw, adjusted for a pasture-based nutrition during jump and summertime, with conserved fodder supplementation during fall and wintertime. All diets were formulated co-ordinate to AMTS Cattle Pro [fourteen] based on predicted DMI and growth charge per unit. Prior to weaning at 207 d, calves suckled from the dam and consumed pasture. Postal service-weaning, all weaned calves entered the pre-grass-finishing sub-system where they were fed pasture, alfalfa hay and grass hay diets according to seasonal pasture availability. Cattle entered the grass-finishing organization at 12 mo of age to coincide with bound grass availability.

As dairy calves entering the beefiness system are characteristically finished within feedlots and cull dairy cows would non be eligible to be sold as grass-fed beef, the GFD arrangement did not include any animals from the dairy industry. Slaughter populations for the GFD organization therefore comprised grass-finished steers and heifers, plus cull beef brood cows and bulls. The average slaughter weight across all animal categories was 486 kg at 679 d of age, with a 57.5% dressing percentage.

iii. Results and Discussion

Productivity is a major driver of environmental impact via the "dilution of maintenance" effect [5]. This concept is demonstrated by the results of the current study. Animals inside the CON arrangement had an boilerplate slaughter weight of 569 kg and took a total of 444 d to raise from birth to slaughter; compared to 519 kg slaughter weight per animal later on a like time period (464 d) in the NAT arrangement; and 486 kg after 679 d in the GFD system. As slaughter weight increases, concurrent decreases are exhibited in the number of finished beef animals required to produce a set quantity of beef, and the number of non-productive animals required to maintain the supporting beef population. Thus, the CON arrangement required 7,046 × ten³ animals in the population to produce one.0 × ten⁹ kg of beef compared to 8,257 × 10³ animals (a 17.1% increase) and 12,510 × 10³ animals (a 77.5% increase) in the NAT and GFD systems respectively (Tabular array 2).

Table 2

Resource inputs, waste output and environmental impact associated with producing one.0 × ten^nine kg of beefiness from a conventional (CON), natural (NAT) or grass-fed (GFD) organization ^a.

System	CON	NAT	GFD
Animals
Supporting population b (×10iii)	5,539	six,265	8,482
Stockers/Pre-finishing (×103)	628	920	1,378
Finishing animals (×103)	2,334	two,640	3,045
Total animals slaughtered c (×103)	2,756	3,117	3,580
Total population d (×teniii)	vii,046	8,257	12,510
Diet resource
Population energy requirement e (MJ × 10half dozen)	228,651	254,841	353,484
Feedstuffs (t × xiii)	54,476	67,263	106,166
Land (ha × xthree)	v,457	6,678	9,868
Water (liters × 10half-dozen)	485,698	572,477	1,957,224
Fossil fuel free energy (MJ × 106)	8,773	x,304	12,290
Waste output
Manure (t × ten3)	36,976	45,431	74,392
Nitrogen excretion (t)	399,789	486,683	807,759
Phosphorus excretion (t)	37,190	46,897	76,567
Greenhouse gas emissions
Methane f (t)	501,593	586,729	854,561
Nitrous oxide grand (t)	7,532	nine,078	13,833
Carbon footprint h (t CO2-eq × xiii)	15,989	18,772	26,785

Improvements in growth charge per unit do not necessarily affect the size of the supporting beefiness population; however, the time elapsing from birth to slaughter has a notable issue upon the full population maintenance nutrient requirement. It is important to note that the growth rates inside this study are those predicted by the AMTS Cattle Pro [14] ration formulation software based on beast characteristics and dietary nutrient supply, and are not representative of any specific farm. Animal productivity varies considerably between and inside private systems, and it could exist argued comparisons betwixt private farms might evidence differing results than those exhibited in the current study. The average time from nascency to slaughter in the GFD system (679 d) is considered to exist a conservative approximate as it is at the lower finish of the range of finishing ages (671–915 d) quoted during personal communication with a grass-fed beefiness producer, Joel Salatin, Polyface Farm, Swoope, VA, USA, who is noted for a highly-successful forage-based system.

Equally shown in Tabular array ii, reducing slaughter weight and growth rate increases the population nutrient requirement of the CON system (228,651 × ten⁶ MJ ME) by eleven.v% in the NAT system (254,841 × 10^vi MJ ME) or 54.vi% in the GFD organization (353,484 × 10⁶ MJ ME). The population maintenance nutrient requirement can exist considered a proxy for both resource use and GHG emissions [v], thus, every bit shown in Table ii, environmental touch measured as a office of whatever measured parameter was reduced in the CON system compared to the NAT or GFD system. These results concur with those of a previous report evaluating the ecological impact of beef technology employ and production arrangement [46], which demonstrated considerable decreases in state apply and methyl hydride emissions, and increased habitat conservation in an intensive arrangement compared to a grass-fed system. Moreover, Pelletier [47] compared of diverse beefiness finishing systems using fractional life bike assessment, last that the greatest environmental impact was conferred by all-encompassing grass-finishing systems compared to intensive feedlot-finishing systems; with the everyman bear upon bestowed past systems with the shortest time interval from nativity to slaughter (calf-finished beefiness product).

Post-obit established historical trends, the quantity of arable land available per capita is predicated to decrease in accordance with the global population size, reaching a nadir at 0.15 ha/person in 2050 [48]. This is a consequence of increased demand for land used for non-agronomical purposes (east.g., industry, recreation, urban sprawl) and deposition of existing agronomics country [49]. Efficient land employ is crucial for agricultural sustainability, thus the CON system, which required 5,457 × 10^three ha of state per 1.0 × x^nine kg beef, appears to be more sustainable than either the NAT system which required 22.4% more state (6,678 × ten³ ha of country per 1.0 × 10⁹ kg beef) or the GFD arrangement at 80.8% more land to produce the same quantity of beef (9,868 × 10^three ha of land per i.0 × ten⁹ kg beef; Table ii). Existing argue as to the validity of using grains or legumes for animal feed that could be otherwise be used for human nutrient [fifty,51] is likely to intensify as the population increases. For example, despite its biological implausibility, a feed efficiency of 30 kg feed to one kg gain has recently been quoted as evidence of the unsustainability of beef production [52]. Monogastric animals have an improved efficiency of feed conversion into gain compared to ruminants. However, beef production systems that utilize range and pastureland (which is generally unsuitable for human food crop production [five]) gain a sustainability advantage over monogastric product systems that rely upon man-edible grains and legumes. This is discussed at length by Wilkinson [53], who redefined the conventional measures of feed efficiency (7.8 kg feed per kg of gain for feedlot-finished beef) to account for the human-edible free energy or poly peptide feed inputs compared to the human-edible energy or poly peptide output from the creature production system. Under these constraints, grass-finished beef (termed suckler beef in European systems) had a favorable human edible feed efficiency ratio whether expressed in terms of energy (1.nine MJ/MJ edible free energy in animal product) or protein (0.92 kg/kg edible poly peptide in creature production). Wilkinson's [53] results appear to imply that grass-fed beef would be environmentally advantageous if competition for feed/food crops is a defining criteria, yet, the quantity of state required for differing production systems must be taken into consideration. If the total U.South. beef produced in 2010 (xi.8 × x⁹ kg) was produced by a grass-fed system, the increase in state required compared to conventional production would exist 52.2 × 10⁶ hectares, equivalent to 75% the land area of Texas.

H2o utilize for agriculture is an surface area of growing business organisation within many regions and is predicted to be the primary limiting factor affecting agricultural productivity in futurity [54] as agronomical requirements conflict with industrial and urban utilize, and the rate of withdrawal from aquifers exceeds replenishment. Inside beef product, h2o is used within two major sub-systems: the brute sub-arrangement in terms of voluntary water intake, and the cropping sub-system, in which water is used for ingather and pastureland irrigation. As with other ecology measures, brute productivity has a considerable effect on h2o consumption equally a maintenance requirement for water may be partitioned out for each private brute. Thus increased growth rate and slaughter weight in the CON arrangement reduces water consumption to 485,689 × 10⁶ liters (CON) compared to a 17.9% increase in the NAT organisation (572,477 × 10⁶ liters per 1.0 × ten⁹ kg beefiness) or a 302% increase in the GFD organisation (1,957,224 × ten⁶ liters per i.0 × x⁹ kg beef; Tabular array two). However, irrigation h2o is the major contributor to total water consumption, thus the magnitude of the difference in h2o use between the CON and GFD systems (compared to the proportional differences in other environmental measures) is due to the assumption inside the model that fifty% of grassland used to finish cattle in the GFD organisation is irrigated. This is an surface area of uncertainty compared to the irrigation data for the feed ingather (corn, soy, alfalfa) components of the model. USDA irrigation surveys [22] provide information upon boilerplate water use per pastureland unit expanse and the pct of pastureland irrigated on a national basis, notwithstanding in that location is no data available every bit to how much irrigated pastureland is allocated to beef. If we change the original supposition (50% of pastureland used to finish cattle is irrigated) and run the model with 25%, fifteen% or 5% of land beingness irrigated, the total quantity of water used by the GFD system declines from 1,957,224 × 10^vi liters to 1,044,070 × 10^six liters (25%), 678,808 × 10⁶ liters (15%) or 313,547 × 10⁶ liters (five%). Thus, the model is sensitive to irrigation water use to the extent that if greater than 9.7% of state used to finish beefiness is irrigated (while holding irrigation h2o utilize within the CON system constant), the GFD system is less environmentally-desirable than the CON organization.

Food (Northward and P) excretion was primarily affected by animal productivity (Tabular array 2), with minor furnishings of nutrient supply vs. requirements. The quantities of Due north and P excreted from the population per one.0 × 10⁹ kg kg beef were reduced in the CON system (399,789 t N/kg beef and 37.190 t P/kg beef) compared to the NAT arrangement (486,683 t Due north/kg beef and 46,897 t P/kg beef) or GFD system (807,759 t N/kg beef and 76,567 t P/kg beefiness). Nutrient run-off into waster courses is a main business relating to P excretion, and N excretion is also associated with ammonia emissions to the atmosphere, particularly in confined animal systems. Variation in manure application rate, storage characteristics, climatic weather condition and pasture-based/housed beast management will have a considerable effect upon both nutrient run-off [55] and ammonia emissions [56]. It should therefore be noted that neither P nor N excretion provides a direct measure of nutrient run-off or ammonia emissions, simply simply act as a comparative mensurate for the potential for run-off or gaseous emissions to occur.

The carbon footprint (expressed as total GHG emissions in CO₂-equivalents per unit of beef) of livestock production systems is one of the well-nigh debated issues relating to environmental impact. Previous inquiry has demonstrated that improving productivity demonstrably reduces the carbon footprint of beef production [5,47,57,58,59,60], which concurs with the results revealed by the 17.4% increase in NAT system carbon emissions (xviii,772 t CO₂-eq per 1.0 × 10⁹ kg beef) compared to the CON system (15,989 t × 10³ CO₂-eq per 1.0 × 10^ix kg beefiness; Table two) within the current report. Notwithstanding, the perception remains that extensive, grass-based systems have a lower carbon footprint than intensive, confined systems. This is exemplified by a report from the Ecology Working Group [61] that states "Meat, eggs and dairy products that are certified organic, humane and/or grass-fed are by and large the least environmentally dissentious." Within the electric current study, the GFD system had a carbon footprint of 26,785 t CO_two-eq per 1.0 × x⁹ kg beefiness, which, is an increment of 67.5% compared to the CON organisation and would be equivalent to adding 25.two × x⁶ United states of america cars to the road on an annual ground based on average mileages and carbon emissions per mid-sized automobile from U.s. EPA [24]. The increase in carbon emissions was primarily affected by the increase in population size and time elapsed from birth to slaughter in the GFD population, however, provision of a forage-based nutrition also increased daily methane emissions per beast as noted by Johnson and Johnson [62] and Pinares-Patiño et al. [63].

The potential for carbon sequestration by well-managed pastureland may be a mitigating factor for carbon emissions within the GFD system, yet it was non accounted for throughout the current study due to a lack of sustentative data. Although the GFD organization is fodder-based throughout, the cow-calf and stocker sub-systems inside the CON and NAT production systems were also forage-based. In the absence of meaning differences in country conversion or management in these sub-systems, potential for carbon sequestration could therefore only be considered to be a mitigating gene within the grass-finishing system compared to the feedlot-finishing sub-system. Division out the carbon emissions from sub-systems reveals that the grass-finishing sub-organisation deemed for 6,868 t × 10ⁱⁱⁱ CO_two-eq per 1.0 × 10^nine kg beef. With a total country use of 1,392 × 10³ ha in the grass-finishing sub-arrangement and assuming carbon equilibrium for land used past the feedlot-finishing system, the pastureland used to finish cattle in the GFD system would need to sequester 4.93 t CO_ii per ha/yr, equivalent to i.35 t C per ha/yr, in guild to produce a finishing sub-organisation with a like carbon footprint to that of the CON organization. This appears to be a lofty target, given that Bruce et al. [64] suggest that the potential for carbon sequestration in well-managed pastureland is 200 kg/ha, whereas Conant et al. [65] report 540 kg/ha. Moreover, this does not have into consideration the increased land apply and carbon emissions from cow-calf and stocker populations in the GFD compared to the CON system. As moo-cow-calf and stocker operations tend to be located on unimproved rangeland or forage crops that do not achieve significant carbon sequestration [64], the estimate of the amount of carbon needed for the GFD system to achieve equal carbon emissions per unit of beefiness should be regarded every bit a considerable underestimate. Well-managed rotational grazing systems within the cow-dogie performance would lessen the impact of the cow-calf sub-arrangement on total carbon emissions per unit of measurement of beef, however, this mitigation is not bars to GFD systems and could equally exist practiced within the CON or NAT systems.

Feed and animal transportation are often considered to be a major factor affecting fossil fuel use in CON or NAT beef production systems, even so inside the electric current study ship accounted for 0.87% of the carbon footprint from the CON system, 0.83% of the NAT organisation's carbon emissions and 0.24% of total carbon emitted from the GFD organization, a result which is in agreement with the results published by Capper [v]. The increased contribution of transportation to the CON and NAT systems' carbon footprints resulted from the greater reliance upon feeds imported into the feedlot system, compared to increased proportional contributions of CH₄ emissions in the GFD arrangement. Fossil fuel use within the three systems followed a similar pattern to the previously discussed resource, with CON arrangement using less fossil fuel energy per ane.0 × 10⁹ kg beef (8,773 × 10⁶ MJ) compared to the NAT (x,304 × x⁶ MJ, an increment of 17.5%) or GFD (12,290 × 10⁶ MJ, an increase of twoscore%) systems. This is contrary to the pop belief that lesser fossil fuel utilize is a major ecology advantage of all-encompassing beefiness production systems. Inside the current study, cropping and harvesting practices are the major contributors to fossil fuel employ: decreases in full feed utilise and therefore cropping inputs and feed transportation resulting from improved animal productivity are demonstrated by the difference in fossil fuel energy between the CON and NAT systems. The greater apply of fossil fuel free energy in the GFD arrangement results from cropping and harvesting practices for conserved forages to support animals during winter months.

four. Conclusions

The United states of america beef industry faces a clear challenge in supplying the needs of the increasing population, while reducing environmental impact. Use of technologies that improve animal productivity in combination with intensive feedlot finishing systems demonstrably reduce both resource apply and GHG emissions per unit of beef. The beef industry is thus well placed to continue its tradition of ecology stewardship, still information technology faces considerable opposition in terms of consumer perceptions of intensive production systems that may accept a negative impact upon social sustainability. Demonization of specific sectors in favor of niche markets that intuitively appear to have a smaller carbon footprint further propagate the idea that big-scale production systems are undesirable, yet all systems that fulfill the three facets of sustainability have a place within the manufacture. It is important to communicate the relative environmental impacts of differing beef production systems to producers, processors and retailers in social club to maintain a variety of beefiness products within the marketplace and to provide consumers with a scientific basis for dietary choices.

Conflict of Interest

The author declares no conflict of interest.

References and Notes

2. How to Feed the World in 2050. FAO; Rome, Italy: 2009. [Google Scholar]

3. Tilman D., Cassman K.G., Matson P.A., Naylor R., Polasky S. Agricultural sustainability and intensive production practices. Nature. 2002;418:671–677. doi: 10.1038/nature01014. [PubMed] [CrossRef] [Google Scholar]

iv. Xue H., Mainville D., You Due west., Nayga R.M. Consumer preferences and willingness to pay for grass-fed beef: Empirical testify from in-store experiments. Food Quality Preference. 2010;21:857–866. doi: ten.1016/j.foodqual.2010.05.004. [CrossRef] [Google Scholar]

5. Capper J.L. The environmental impact of United States beef production: 1977 compared with 2007. J. Anim. Sci. 2011;89:4249–4261. doi: 10.2527/jas.2010-3784. [PubMed] [CrossRef] [Google Scholar]

half-dozen. Lawrence J.D., Ibarburu Thou. Economic Assay of Pharmaceutical Technologies in Mod Beef Production in a Bioeconomy Era. Iowa State University; Ames, IA, United states: 2007. [Google Scholar]

7. Capper J.L., Hayes D.J. The environmental and economic impact of removing growth-enhancing technologies from Us beef product. J. Anim. Sci. 2012 submitted. [PubMed] [Google Scholar]

viii. MacArthur Clark J.A., Pottera Thousand., Hardinga E. The welfare implications of fauna breeding and convenance technologies in commercial agriculture. Livest. Sci. 2006;103:270–281. doi: 10.1016/j.livsci.2006.05.015. [CrossRef] [Google Scholar]

9. Fraser D. Toward a global perspective on farm animal welfare. Appl. Anim. Behav. Sci. 2008;113:330–339. doi: x.1016/j.applanim.2008.01.011. [CrossRef] [Google Scholar]

x. Anderson S.A., Yeaton Woo R.Due west., Crawford L.M. Run a risk cess of the impact on human health of resistant Campylobacter jejuni from fluoroquinolone use in beef cattle. Food Control. 2001;12:13–25. doi: x.1016/S0956-7135(00)00014-1. [CrossRef] [Google Scholar]

eleven. Harrington L.1000.B., Lu Chiliad. Beef feedlots in southwestern Kansas: Local change, perceptions, and the global change contex. Global Environ. Change. 2002;12:273–282. doi: 10.1016/S0959-3780(02)00041-9. [CrossRef] [Google Scholar]

13. USDA/AMS. United States Standards for Livestock and Meat Marketing Claims, Grass (Provender) Fed Claim for Ruminant Livestock and the Meat Products Derived From Such Livestock—Docket No. AMS–LS–07–0113; LS–05–09. USDA; Washington, DC, USA: 2007. [Google Scholar]

xiv. Cattle Pro. Cornell Research Foundation; Ithaca, NY, USA: 2006. Agricultural Modeling and Training Systems (AMTS) [Google Scholar]

fifteen. Beckett J.L., Oltjen J.Due west. Estimation of the h2o requirement for beefiness production in the Us. J. Anim. Sci. 1993;71:818–826. [PubMed] [Google Scholar]

16. Meyer U., Stahl West., Flachowsky G. Investigations on the h2o intake of growing bulls. Livest. Sci. 2006;103:186–191. doi: 10.1016/j.livsci.2006.02.009. [CrossRef] [Google Scholar]

17. Moe P.Westward., Tyrrell H.F. Methyl hydride production in dairy cows. J. Dairy Sci. 1979;62:1583–1586. doi: 10.3168/jds.S0022-0302(79)83465-7. [CrossRef] [Google Scholar]

18. Kaspar H.F., Tiedje J.M. Dissimilatory reduction of nitrate and nitrite in the bovine rumen: Nitrous oxide production and effect of acetylene. Appl. Environ. Microbiol. 1981;41:705–709. [PMC costless article] [PubMed] [Google Scholar]

19. Kirchgessner Grand., Windisch W., Muller H.L., M K. Release of methane and of carbon dioxide by dairy cattle. Agribiol. Res. 1991;44:2–ix. [Google Scholar]

twenty. U.Southward. EPA. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990–2008. U.Southward. EPA; Washington, DC, United states: 2010. [Google Scholar]

21. IPCC. IPCC Guidelines for National Greenhouse Gas Inventories. Constitute for Global Environmental Strategies (IGES) for the IPCC; Kanagawa, Japan: 2006. [Google Scholar]

22. USDA/NASS. 2007 Census of Agriculture: Subcontract and Ranch Irrigation Survey. USDA; Washington, DC, USA: 2007. [Google Scholar]

23. West T.O., Marland G. A synthesis of carbon sequestration, carbon emissions, and internet carbon flux in agriculture: Comparing cultivation practices in the United State. Agr. Ecosyst. Environ. 2002;91:217–232. doi: x.1016/S0167-8809(01)00233-X. [CrossRef] [Google Scholar]

24. U.Southward. EPA. Light-Duty Automotive Applied science, Carbon Dioxide Emissions, and Fuel Economy Trends: 1975 Through 2009. US EPA; Washington, DC, USA: 2009. [Google Scholar]

25. USDA. Part I: Baseline Reference of Feedlot Management Practices, 1999. USDA:APHIS:VS, CEAH, National Animal Health Monitoring System; Fort Collins, CO, USA: 2000. [Google Scholar]

26. USDA. Beef 2007–08 Function I: Reference of Beef Cow-Calf Management Practices in the United states, 2007–08. USDA:APHIS:VS, CEAH, National Animate being Health Monitoring Organization; Fort Collins, CO, USA: 2009. [Google Scholar]

27. USDA. Beefiness 2007–08 Part II: Reference of Beef Cow-calf Management Practices in the United states of america, 2007–08. USDA:APHIS:VS, CEAH, National Beast Wellness Monitoring System; Fort Collins, CO, USA: 2009. [Google Scholar]

28. USDA. Office II: Baseline Reference of Feedlot Health and Wellness Management, 1999. USDA:APHIS:VS, CEAH, National Animal Wellness Monitoring Organization; Fort Collins, CO, The states: 2000. [Google Scholar]

29. Cederberg C., Stadig Chiliad. Arrangement expansion and allocation in life cycle assessment of milk and beef production. Int. J. LCA. 2003;eight:350–356. doi: 10.1007/BF02978508. [CrossRef] [Google Scholar]

thirty. Capper J.50., Cady R.A., Bauman D.Eastward. The environmental impact of dairy product: 1944 compared with 2007. J. Anim. Sci. 2009;87:2160–2167. doi: 10.2527/jas.2009-1781. [PubMed] [CrossRef] [Google Scholar]

31. Sprott L.R., Goehring T.B., Beverly J.R., Corah L.R. Effects of ionophores on cow herd production: A review. J. Anim. Sci. 1988;66:1340–1346. [PubMed] [Google Scholar]

32. Perrett T., Wildman B.K., Jim M.G., Vogstad A.R., Fenton R.K., Hannon S.L., Schunicht O.C., Abutarbush South.M., Booker C.W. Evaluation of the efficacy and price-effectiveness of Melengestrol Acetate in feedlot heifer calves in Western Canada. Vet. Ther. 2008;9:223–240. [PubMed] [Google Scholar]

33. Sides 1000.E., Swingle R.Southward., Vasconcelos J.T., Borg R.C., Moseley W.M. Effect of feeding Melengestrol Acetate, Monensin, and Tylosin on performance, carcass measurements, and liver abscesses of feedlot heifers. Profess. Anim. Scient. 2009;25:459–464. [Google Scholar]

34. Scramlin Southward.M., Platter W.J., Gomez R.J., Choat Westward.T., McKeith F.T., Killefer J. Comparative effects of ractopamine hydrochloride and zilpaterol hydrochloride on growth performance, carcass traits, and longissimus tenderness of finishing steers. J. Anim. Sci. 2010;88:1823–1829. doi: 10.2527/jas.2009-2405. [PubMed] [CrossRef] [Google Scholar]

35. Montgomery J.L., Krehbiel C.R., Cranston J.J., Yates D.A., Hutcheson J.P., Nichols W.T., Streeter One thousand.North., Bechtol D.T., Johnson E., TerHune T., Montgomery T.H. Dietary zilpaterol hydrochloride. I. Feedlot performance and carcass traits of steers and heifers. J. Anim. Sci. 2009;87:1374–1383. [PubMed] [Google Scholar]

36. Montgomery J.L., Krehbiel C.R., Cranston J.J., Yates D.A., Hutchseon J.P., Nichols Due west.T., Streeter One thousand.N., Swingle R.Due south., Montgomery T.H. Effects of dietary zilpaterol hydrochloride on feedlot functioning and carcass characteristics of beefiness steers fed with and without monensin and tylosin. J. Anim. Sci. 2009;87:1013–1023. [PubMed] [Google Scholar]

37. Elam North.A., Vasconcelos J.T., Hilton G.G., VanOverbeke D.L., Lawrence T.E., Montgomery T.H., Nichols W.T., Streeter 1000.N., Hutcheson J.P., Yates D.A., Galyean Grand.L. Effect of zilpaterol hydrochloride elapsing of feeding on functioning and carcass characteristics of feedlot cattle. J. Anim. Sci. 2009;87:2133–2141. [PubMed] [Google Scholar]

38. Laudert S., Vogel G., Schroeder A., Platter Westward., Van Koevering G. Effects of ractopamine fed to finishing steers. II. Summary of six studies—Carcass traits. J. Anim. Sci. 2005;83 (Suppl. 1):112. [Google Scholar]

39. Schroeder A.L., Polser D.M., Laudert S.B., Vogel G.J., Ripberger T., Van Koevering G.T. The Outcome of Optaflexx on Growth Performance and Carcass Traits of Steers and Heifers; Proceedings of the 19th Almanac Southwest Nutrition and Management Conference; Tempe, AZ, United states of america. 24–25 February 2004; pp. 65–81. [Google Scholar]

40. Laudert South., Vogel One thousand., Schroeder A., Platter W., Van Koevering 1000. Effects of ractopamine fed to finishing steers. I. Summary of six studies—Growth operation. J. Anim. Sci. 2005;83 (Suppl. i):112. [Google Scholar]

41. Abney C.S., Vasconcelos J.T., McMeniman J.P., Keyser Due south.A., Wilson K.R., Vogel G.J., Galyean M.Fifty. Effects of ractopamine hydrochloride on performance, rate and variation in feed intake, and acid-base residue in feedlot cattle. J. Anim. Sci. 2007;85:3090–3098. doi: 10.2527/jas.2007-0263. [PubMed] [CrossRef] [Google Scholar]

42. Gruber Southward.50., Tatum J.D., Engle T.E., Mitchell M.A., Laudert South.B., Schroeder A.L., Platter W.J. Effects of ractopamine supplementation on growth operation and carcass characteristics of feedlot steers differing in biological blazon. J. Anim. Sci. 2007;85:1809–1815. [PubMed] [Google Scholar]

43. Vogel M.J., Duff G.C., Lehmkuhler J., Beckett J.L., Drouilliard J.Due south., Schroeder A.50., Platter West.J., Van Koevering M.T., Laudert Due south.B. Event of ractopamine hydrochloride on growth performance and carcass traits in calf-fed and yearling Holstein steers fed to slaughter. Profess. Anim. Sci. 2009;25:26–32. [Google Scholar]

44. Anderson D.B., Moody D.East., Hancock D.L. Beta-Adrenergic Agonists. In: Swimming W.M., Bell A.W., editors. Encyclopedia of Animal Science. Marcel-Dekker Inc.; New York, NY, Us: 2005. [Google Scholar]

45. Baxa T.J., Hutcheson J.P., Miller M.F., Brooks J.C., Nichols W.T., Streeter M.N., Yates D.A., Johnson B.J. Additive effects of a steroidal implant and zilpaterol hydrochloride on feedlot operation, carcass characteristics, and skeletal muscle messenger ribonucleic acid affluence in finishing steers. J. Anim. Sci. 2010;88:330–337. [PubMed] [Google Scholar]

46. Avery A., Avery D. The Environmental Prophylactic and Benefits of Pharmaceutical Technologies in Beefiness Production. Hudson Institute, Heart for Global Food Issues; Washington, DC, Us: 2007. [Google Scholar]

47. Pelletier N., Pirog R., Rasmussen R. Comparative life cycle environmental impacts of 3 beef production strategies in the Upper Midwestern United States. Agr. Syst. 2010;103:380–389. doi: ten.1016/j.agsy.2010.03.009. [CrossRef] [Google Scholar]

48. Bauman D.E., Capper J.L. Future Challenges and Opportunities in Animal Nutrition; Proceedings of 26th Southwest Nutrition & Direction Conference; Tempe, AZ, USA. 24 February 2011. [Google Scholar]

49. Global Agriculture Towards 2050. FAO; Rome, Italy: 2009. [Google Scholar]

l. Garnett T. Livestock-related greenhouse gas emissions: Impacts and options for policy makers. Environ. Sci. Policy. 2009;12:491–503. doi: x.1016/j.envsci.2009.01.006. [CrossRef] [Google Scholar]

51. Pimentel D., Pimentel K. Sustainability of meat-based and found-based diets and the environment. Am. J. Clin. Nutr. 2003;78:660S–663S. [PubMed] [Google Scholar]

53. Wilkinson J.Grand. Re-defining efficiency of feed apply by livestock. Animal. 2011;five:1014–1022. doi: ten.1017/S175173111100005X. [PubMed] [CrossRef] [Google Scholar]

54. Godfray H.C.J., Beddington J.R., Crute I.R., Haddad 50., Lawrence D., Muir J.F., Pretty J., Robinson Due south., Thomas S.M., Toulmin C. Nutrient security: The challenge of feeding ix billion people. Science. 2010;327:812–818. [PubMed] [Google Scholar]

55. Harta M.R., Quin B.F., Nguyen 1000.Fifty. Phosphorus runoff from agricultural land and straight fertilizer effects: A review. J. Environ. Qual. 2004;33:1954–1972. doi: 10.2134/jeq2004.1954. [PubMed] [CrossRef] [Google Scholar]

56. Arogo J., Westerman P.W., Heber A.J., Robarge Due west.P., Classen J.J. Ammonia Emissions from Animal Feeding Operations. In: Rice J.M., Caldwell D.F., Humenik F.J., editors. Fauna Agriculture and the Environment: National Center for Manure and Animal Waste Management White Papers. ASABE; St. Joseph, MI, United states of america: 2006. [Google Scholar]

57. Beauchemin K.A., Janzen H.H., Little S.One thousand., McAllister T.A., McGinn S.M. Mitigation of greenhouse gas emissions from beef production in western Canada—Evaluation using farm-based life cycle assessment. An. Feed. Sci. Tech. 2011;166-167:663–677. doi: 10.1016/j.anifeedsci.2011.04.047. [CrossRef] [Google Scholar]

58. Cederberg C., Meyer D., Flysjo A. Life Bicycle Inventory of Greenhouse Gas Emissions and Use of Land and Free energy in Brazilian Beefiness Product. The Swedish Institute for Nutrient and Biotechnology; Gothenburg, Sweden: 2009. [Google Scholar]

59. Peters G.M., Rowley H.V., Wiedemann S., Tucker R., Curt 1000.D., Schultz Yard.Southward. Ruby meat production in Australia: Life cycle assessment and comparison with overseas studies. Environ. Sci. Technol. 2010;44:1327–1332. [PubMed] [Google Scholar]

60. Ridoutt B.G., Sanguansri P., Harper Grand.S. Comparison carbon and h2o footprints for beef cattle product in Southern Australia. Sustainability. 2011;three:2443–2455. doi: x.3390/su3122443. [CrossRef] [Google Scholar]

61. Meat Eater's Guide to Climate Change and Health. Environmental Working Group; Washington, DC, U.s.a.: 2011. [Google Scholar]

62. Johnson Thousand.A., Johnson D.E. Methane emissions from cattle. J. Anim. Sci. 1995;73:2483–2492. [PubMed] [Google Scholar]

63. Pinares-Patiño C.Due south., Waghorn G.C., Hegarty R.South., Hoskin S.O. Effects of intensification of pastoral farming on greenhouse gas emissions in New Zealand. Due north. Z. Vet. J. 2009;57:252–261. doi: 10.1080/00480169.2009.58618. [PubMed] [CrossRef] [Google Scholar]

64. Bruce J.P., Frome Chiliad., Haites East., Janzen H., Lal R., Pawtian K. Carbon sequestration in soils. J. Soil Water Conserv. 1999;54:382–389. [Google Scholar]

65. Conant R.T., Paustian K., Elliott Eastward.T. Grassland management and conversion into grassland: Effects on soil carbon. Ecol. Appl. 2001;11:343–355. doi: ten.1890/1051-0761(2001)011[0343:GMACIG]2.0.CO;2. [CrossRef] [Google Scholar]

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