Environmental impact

Peer-Reviewed Scientific Articles​

Animal source foods: Sustainability problem or malnutrition and sustainability solution? Perspective matters

URL: https://www.sciencedirect.com/science/article/pii/S2211912419300525?via%3Dihub

Journal: Global Food Security

Publication Date: 10/2019

Summary: Globally, two billion people suffer from micronutrient deficiencies, 151 million children under five suffer from stunting, and millions more have impaired cognitive development related to poor nutrition. This is partly due to insufficient consumption of animal-sourced foods (ASF), which supply multiple bioavailable nutrients that are lacking in the cereal-based diets of the poor. Yet, reports like the one recently published by the EAT-Lancet Commission, solely focus on the threat of ASF consumption on sustainability and human health, overestimate and ignore the tremendous variability in the environmental impact of livestock production, and fail to adequately include the experience of marginalized women and children in low- and middle-income countries whose diets regularly lack the necessary nutrients. Yet animal-source foods have been described by the World HealthOrganization as the best source of high-quality nutrient-rich food for children aged 6–23 months. Livestock and ASF are vital to sustainability as they play a critical role in improving nutrition, reducing poverty, improving gender equity, improving livelihoods, increasing food security, and improving health. The nutritional needs of the world’s poor, particularly women and children, must be considered in sustainability debates.

Key Takeaways

2 billion people suffer from micronutrient deficiencies, which results in poor physical and cognitive development. Animal sourced foods are have been named the best high quality nutrient rich foods for developing infants, yet the EAT Lancet Commission continues to focus animal sourced foods as an environmental and health threat.

Impacts of soil carbon sequestration on life cycle greenhouse gas emissions in Midwestern USA beef finishing systems

URL: https://www.sciencedirect.com/science/article/pii/S0308521X17310338

Journal: Agricultural Systems

Publication Date: 05/2018

Summary: Beef cattle have been identified as the largest livestock-sector contributor to greenhouse gas (GHG) emissions. Using life cycle analysis (LCA), several studies have concluded that grass-finished beef systems have greater GHG intensities than feedlot-finished (FL) beef systems. These studies evaluated only one grazing management system – continuous grazing – and assumed steady-state soil carbon(C), to model the grass-finishing environmental impact. However, by managing for more optimal forage growth and recovery, adaptive multi-paddock (AMP) grazing can improve animal and forage productivity, potentially sequestering more soil organic carbon (SOC) than continuous grazing. To examine impacts of AMP grazing and related SOC sequestration on net GHG emissions, a comparative LCA was performed of two different beef finishing systems in the Upper Midwest, USA: AMP grazing and FL. We used on-farm data collected from the Michigan State University Lake City AgBioResearch Center for AMP grazing. Impact scope included GHG emissions from enteric methane, feed production and mineral supplement manufacture, manure, and on-farm energy use and transportation, as well as the potential C sink arising from SOC sequestration. Across-farm SOC data showed a 4-year C sequestration rate of 3.59 Mg C ha−1 yr−1 in AMP grazed pastures. After including SOC in the GHG footprint estimates, finishing emissions from the AMP system were reduced from 9.62 to −6.65 kg CO2-e kg carcass weight (CW)−1, whereas FL emissions increased slightly from 6.09 to 6.12 kg CO2-e kg CW−1 due to soil erosion. This indicates that AMP grazing has the potential to offset GHG emissions through soil C sequestration, and therefore the finishing phase could be a net C sink. However, FL production required only half as much land as AMP grazing. While the SOC sequestration rates measured here were relatively high, lower rates would still reduce the AMP emissions relative to the FL emissions. This research suggests that AMP grazing can contribute to climate change mitigation through SOC sequestration and challenges existing conclusions that only feedlot-intensification reduces the overall beef GHG footprint through greater productivity.

Key Takeaways

Adaptive multi-paddock grazing is a rotational grazing system for cattle in which cattle graze on an area of land, while other areas recover, and then the cattle are moved to fully recovered paddocks so that the one they were just on can recover. This type of grazing system reduce the carbon footprint of cattle production by increasing the amount of carbon sequestered by the soil.

Sustainability of holistic and conventional cattle ranching in the seasonally dry tropics of Chiapas, Mexico

URL: https://www.sciencedirect.com/science/article/pii/S0308521X13000607

Journal: Agricultural Systems

Publication Date: 09/2013

Summary: Conventional cattle ranching in the lowlands of Chiapas, Mexico typically employs extensive grazing, annual pasture burns and frequent applications of agrochemicals, threatening biodiversity and long-term productivity. A small group of innovative ranchers in the Central Valleys are converting to holistic management through careful land-use planning, rotational grazing, diversified forage, and diminished use of purchased inputs. We compared the sustainability of 18 conventional and seven holistic, dual-purpose ranches, using three sets of sustainability metrics. First, we combined semistructured interviews and field observations to better describe the two productions systems and to calculate an “Organic Conversion Index” (OCI), combining economic, social, technological and environmental indicators. Holistic ranchers have more pasture divisions, higher grazing pressure, greater lengths of time between pasture burns, greater milk productivity, larger forest reserves, lower cow and calf mortality, purchase less hay and feed, and use less herbicides and pesticides than their conventional neighbors (T-tests and Fisher’s Exact Tests; all p < 0.05). OCI was greater (T-test, p < 0.0005) for holistic ranches (81.8 ± 4.6% compliance with organic standards), than for conventional ranches (32.1 ± 9.0% compliance), with holistic ranches demonstrating superiority for nine of ten OCI indicators. Second, drawing on data from the same interviews, we conducted “emergy” analysis to quantify the embodied energy of inputs, outputs and sustainability of the ranching systems. The Emergy Yield Ratio, an index of a systems emergy throughput relative to the emergy in purchased inputs, was marginally higher in holistic ranches (T-test; p = 0.07), but became significant when only ranches ⩾40 ha were analyzed (p = 0.04) and when government assistance (mostly in the form of machinery) was removed from the calculations (p = 0.008). Holistic ranches exhibited marginally higher Emergy Sustainability Indices, a measure of system yield relative to environmental impact, for all ranches combined (p = 0.07) and for ranches ⩾ 40 ha (p = 0.06). Third, we sampled vegetation and soils on seven holistic and seven conventional ranches. We found higher soil respiration, deeper topsoil, increased earthworm presence, more tightly closed herbaceous canopies (all p < 0.05), and marginally greater forage availability (p = 0.053) in holistic ranches. Other variables, including soil compaction, soil chemistry and pasture tree cover, did not differ significantly between groups. These data are a snapshot of long, complex processes. Nonetheless, these complementary metrics combine to suggest that holistic management strategies are leading to greater ecological and economic sustainability. This production model merits further study for potential broader application as well as greater attention from decision makers concerned with ranching and the environment.

Key Takeaways

Holistic cattle ranching in Mexico utilizes rotational grazing, more diverse forage, and less use of purchased inputs such as chemicals and fertilizers. When compared to conventional cattle ranches, the holistic ranches had less pasture burns, healthier cattle, less use of pesticides, more/healthier topsoil, and had to purchase less hay. Overall, holistic ranches were more sustainable than conventional ranches.

Managing grazing animals to achieve nutrient cycling and soil improvement in no-till integrated systems

URL: https://link.springer.com/article/10.1007/s10705-010-9360-x

Journal: Nutrient Cycling in Agroecosystems

Publication Date: 11/2010

Summary: Crop-livestock systems are regaining their importance as an alternative to unsustainable intensive farming systems. Loss of biodiversity, nutrient pollution and habitat fragmentation are a few of many concerns recently reported with modern agriculture. Integrating crops and pastures in no-till systems can result in better environmental services, since conservation agriculture is improved by system diversity, paths of nutrient flux, and other processes common in nature. The presence of large herbivores can positively modify nutrient pathways and soil aggregation, increasing soil quality. Despite the low diversity involved, the integration of crops and pastures enhances nature’s biomimicry and allows attainment of a higher system organization level. This paper illustrates these benefits focusing on the use of grazing animals integrated with crops under no-tillage systems characteristic of southern Brazil.

Key Takeaways

Combining grazing animals such as cattle with crops by integrating the pastures with the growing fields can produce a no-till agriculture system with increased biodiversity, increased nutrient density, and increased soil quality.


URL: https://academic.oup.com/jas/article-abstract/96/4/1519/4833918

Journal: Journal of Animal Science

Publication Date: 04/2018

Summary: To ensure long-term sustainability and ecological resilience of agroecosystems, agricultural production should be guided by policies to ensure regenerative cropping and grazing management protocols. Changing current unsustainable high-input agricultural practices to low-input practices that regenerate ecosystem function will be necessary for sustainable, resilient agroecosystems. Effective soil management provides the greatest potential for achieving sustainable use of agricultural land with rapidly changing, uncertain and variable climate. With appropriate management of grazing enterprises, soil function can be regenerated to improve essential ecosystem services and farm profitability. Affected ecosystem services include carbon sequestration, water infiltration, soil fertility, nutrient cycling, soil formation, biodiversity, wildlife habitat, and increased ecosystem stability and resilience. Collectively, conservation agriculture managed regeneratively supports ecologically healthy, resilient agroecosystems and enhances watershed function. To accomplish this, it is important for scientists to partner with farmers who have improved the environment and excel financially to convert experimental results into sound environmental, social, and economic benefits regionally and globally. Benefits include addressing questions at commercial scale; integrating component science into whole-system responses; identifying emergent properties and unintended consequences; incorporating pro-active management to achieve desired goals under changing circumstances; and including the potential of the human element to achieve superior economic and environmental goals. Developing and implementing regenerative management protocols that include ruminant grazing animals will be necessary to ensure long-term sustainability and ecological resilience of agroecosystems.

Key Takeaways

Sustainable agricultural practices require utilization of grazing animals and crop production in an integrated way. Proper execution of sustainable agriculture practices can sequester carbon from the atmosphere, improve soil fertility, improve water supply, improve nutrient availability, and improve resilience of the land.

Impacts of holistic planned grazing with bison compared to continuous grazing with cattle in South Dakota shortgrass prairie

URL: https://www.sciencedirect.com/science/article/pii/S0167880919300301

Journal: Agriculture, Ecosystems & Environment

Publication Date: 07/2019

Summary: We assess holistic planned grazing outcomes in shortgrass prairie of the Northern Great Plains of North America. We compared key ecosystem functions on the ranch managed using adaptive multi-paddocks (AMP) grazing by bison with those on neighboring ranch paddocks managed using set stocked light continuous (LCG) and heavy continuous grazing (HCG) grazed by cattle. Sites on the neighboring ranches in each grazing category were paired for sampling by soil type and landscape position. In all paddocks, management practices had been constant for more than a decade. Positive results with AMP grazing include increased fine litter cover (P <  0.05), improved water infiltration (P <  0.06), two to three times the available forage biomass (P <  0.001), improved plant composition (P <  0.05), decrease in invasive plants (P <  0.05), and decrease in bare ground (P <  0.05). Higher infiltration occurred with AMP on soils having higher permeability but not on soils having a high clay content. Differences were greatest between AMP and HCG management with LCG being intermediate. Counterintuitively, herbaceous biomass in LCG was less than that of the more heavily stocked HCG (P <  0.05). This was due to decades of heavy continuous grazing resulting in HCG being dominated by invasive herbaceous plants of no forage value in contrast to LCG paddocks that had a greater proportion of palatable forages. The HCG paddocks were dominated by unpalatable invasive plants that were avoided by cattle. Soil carbon stocks increased under the AMP grazing but not on all soils. Total carbon stocks (TC), summing organic carbon and inorganic carbon, were not different between the AMP and LCG grazing strategies (P >  0.63) but both had higher TC values across all soils than HCG (P <  0.001). There were no differences in TC among grazing treatments on the different soils (P >  0.46) except on the Norrest silty clay loam soil that had the highest permeability. On this soil there were differences between AMP and HCG (P < 0.0001) and LCG and HCG (P <  0.0001). There were significantly lower TC levels at all soil depths with HCG than with AMP and LCG (P <  0.05). Using holistic planned grazing protocols with AMP grazing effectively limited overstocking and overgrazing by adjusting animal numbers to match available forage amounts and grazing for short periods followed by adequate recovery after grazing. This study indicated ecological improvements by AMP grazing on the 777 Bison Ranch compared to HCG pastures is contributing to improvements in this semi-arid short grass ecosystem.

Key Takeaways

Multi-paddock grazing involves moving livestock from pasture to pasture to allow for the pastures to recover between grazing periods. This approach is more sustainable and improves amount of available forage, increases water influx, improves soil composition, and decreases invasive plant species when compared to traditional continuous grazing practices. More carbon is also sequestered from the atmosphere in multi-paddock grazing than heavy continued grazing.

Sustainable livestock systems to improve human health, nutrition, and economic status

URL: https://academic.oup.com/af/article/9/4/39/5575470

Journal: Animal Frontiers

Publication Date: 9/2019

Summary: Sustainable livestock systems contribute to food security, economic and environmental stewardship, and sociocultural needs and are vital for achieving most of the United Nation’s Sustainable Development Goals. Livestock production contributes to sustainability through use of uncultivable land for food production, conversion of energy and protein sources that cannot be used by humans into highly nutritious animal-sourced food and reduction of environmental pollution with agroindustrial by-products, while generating income and supporting livelihoods of millions of people all over the world. Some livestock systems are particularly effective at carbon sequestration and hence reducing greenhouse gas emissions that contribute to global warming. Livestock production offers the greatest potential to reduce greenhouse gas emissions from agriculture and animal scientists have devised several effective strategies that can reduce such emissions from livestock systems by up to 30%. Most of the current discourse on sustainability focuses on one albeit important factor—the environment. Equally important factors are the need to ensure food and nutritional security for the growing global population in a culturally acceptable manner that ensures its accessibility, affordability, and safety. While livestock systems generally contribute to sustainability, poorly managed livestock systems may have adverse effects on the environment and human and animal health and welfare.

Key Takeaways

Livestock production done properly can be a sustainable way to provide high quality nutrition to the population while simultaneously reducing pollution. Poorly managed livestock systems can have negative effects on the environment and human health, so it is important that we develop sustainable systems.

Environmental footprints of beef cattle production in the United States

URL: https://www.sciencedirect.com/science/article/pii/S0308521X18305675

Journal: Agricultural Systems

Publication Date: 02/2019

Summary: This study aimed to quantify important environmental impacts of beef cattle production in the United States. This study is the most detailed, yet comprehensive, study conducted to date to provide baseline measures for the sustainability of U.S. beef.

Key Takeaways

The average annual greenhouse gas and reactive N emissions associated with beef cattle production over the past five years were determined to be 243 ± 26 Tg carbon dioxide equivalents (CO2e) and 1760 ± 136 Gg N, respectively. Total fossil energy use was found to be 569 ± 53 PJ and blue water consumption was 23.2 ± 3.5 TL.

Assessing the Role of Cattle in Sustainable Food Systems

URL: https://journals.lww.com/nutritiontodayonline/Fulltext/2018/07000/Assessing_the_Role_of_Cattle_in_Sustainable_Food.5.aspx

Journal: Nutrition Today

Publication Date: 07/2018

Summary: Currently, livestock produces more than one-third of the world’s protein, and ruminant animals (ie, cattle, sheep and goats) have the unique capacity to convert nondigestible biomass (ie, grasses and forages) into high-quality protein. These factors highlight the need for prudent use of ruminants to optimize land use for production of adequate quantity and quality of protein. Any recommendations for changes in agriculture should consider impact on climate but must also focus on making optimal use of natural resources for creating healthy diets.

Key Takeaways

Ruminant animals such as cattle, sheep, and goats contain multiple stomachs, which gives them the unique ability to convert grass and other forage-able biomass into high quality protein for human nutrition.

Livestock: On our plates or eating at our table? A new analysis of the feed/food debate

URL: https://doi.org/10.1016/j.gfs.2017.01.001

Journal: Global Food Security

Publication Date: 09/2017

Summary: An analysis of livestock food intake and meat production. 86% of livestock feed is inedible for humans. 2.8 kg of human edible food is required to produce 1 kg of boneless meat in ruminants and 3.2 kg is required in monogastrics.

Key Takeaways

Most of the feed given to animals is not edible for humans, thus this food would be wasted if not fed to livestock. About 3 kg of food that is edible by humans can produce 1 kg of meat.

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