Environmental Sustainability of Livestock Production

The environmental impact of livestock production has become an important and controversial global issue, pri- marily due to reported impacts on global warming. This concern applies to all meat animals, but especially beef cattle due to their emission of enteric methane. Livestock production contributes to global warming, but the importance of its contri- bution may be overstated. Its effect on climate is primarily through methane production, which does not have a long-term effect on the atmosphere. Global livestock numbers and emissions from their manure are increasing, so there is a short-term effect through increased rate of emission. Other effects of meat production may be of more concern for long-term sustain- ability. Through a full life cycle of meat, the dominant impact is loss and waste, which adversely effects all measures of sustainability. An important environmental concern is reactive nitrogen losses, among which ammonia emission from manure is of most concern. Global estimates suggest that 63% of all ammonia emissions come from agriculture, with 44% of the total from livestock manure. Ammonia emissions have adverse effects related to acidification of ecosystems, eutrophication of surface waters, and human toxicity through formation of small particulate matter in the air we breathe. Water consumption is another important concern. Global estimates suggest that agriculture uses about 70% of freshwater withdrawals, with 20% used for livestock feed production. Although livestock production is not a large energy consumer, fossil fuels are a limited resource, and conservation is important. Many technologies and strategies exist for mitigating environmental impacts of livestock production, but finding economical solutions is challenging. Mitigation must start with the reduction of consumer waste. Other livestock impacts are best reduced using intensive practices to produce animals in less time and with fewer resources. Diets that accurately meet animal nutrient needs are an important mitigation option for efficient and sustainable meat production

Management characteristics of beef cattle production in the Northern Plains and Midwest regions of the United States

A comprehensive life cycle assessment of United States beef will provide benchmarks and identify opportunities for improvement. On-going region-specific data collection is characterizing cattle production practices for a more accurate assessment. This study reports production information obtained via online surveys and on-site visits from 2 of 7 regions: the Northern Plains (Nebraska, North Dakota, and South Dakota) and Midwest (Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, and Wisconsin). Ranch responses (n = 512) represented 1.6% of beef cows maintained in both regions with operation sizes varying from 1 to 12,500 cows. Feedlot responses (n = 120) represented 9.6 and 3.7% of cattle finished in the Northern Plains and Midwest, respectively. Ranch herd sizes increased and stocking rates decreased moving westward. Average animal BW increased from south to north. Also recorded were bull and replacement heifer numbers; housing facilities; feed production and use; and machinery, energy, and labor use. Feedlot characteristics including entering and final BW, background and finish feeding periods, crop area per animal, and labor were similar across the regions, but the Northern Plains reported larger feedlots than the Midwest. Diets were similar across regions except that slightly more distillers grain and less corn were fed in the Northern Plains. Ninety-three percent of feedlots produced most of their feed (corn grain, corn silage, and alfalfa). Cropland producing feed received most of the manure produced, but a few large feedlots reported composting and export. Information gathered provides production system characteristics and inventory for conducting a comprehensive United States beef life cycle assessment

An environmental assessment of cattle manure and urea fertilizer treatments for corn production in the northern Great Plains

Nitrogen (N), phosphorus (P), and carbon (C) emissions from livestock systems have become important regional, national, and international concerns. Our objective was to use process-level simulation to explore differences among manure and inorganic fertilizer treatments in a corn production system used to feed finishing cattle in the Northern Great Plains region of the U.S. Our analysis included model assessment, simulation to compare treatments under recent climate, and comparisons using projected midcentury climate. The Integrated Farm System Model was evaluated in representing the performance and nutrient losses of corn production using cattle manure without bedding, manure with bedding, urea, and no fertilization treatments. Two-year field experiments conducted near Clay Center, Nebraska; Brookings, South Dakota; and Fargo, North Dakota provided observed emission data following these treatments. Means of simulated emission rates of methane, ammonia, and nitrous oxide were generally similar to those observed from field-applied manure or urea fertilizer. Simulation of corn production systems over 25 years of recent climate showed greater soluble P runoff with use of feedlot and bedded manure compared to use of inorganic fertilizers, but life-cycle fossil energy use and greenhouse gas emission were decreased. Compared to feedlot manure, application of bedded pack manure generally increased N and P losses in corn production by retaining more N in manure removed from a bedded housing facility and through increased runoff because a large portion of the stover was removed from the cornfield for use as bedding material. Simulation of these treatments using projected midcentury climate indicated a trend toward a small increase in simulated grain production in the Dakotas and a small decrease for irrigated corn in Nebraska. Climate differences affected the three production systems similarly, so production and environmental impact differences among the fertilization systems under future climate were similar to those obtained under recent climate

Nitrogen–climate interactions in US agriculture

Agriculture in the United States (US) cycles large quantities of nitrogen (N) to produce food, fuel, and fiber and is a major source of excess reactive nitrogen (Nr) in the environment. Nitrogen lost from cropping systems and animal operations moves to waterways, groundwater, and the atmosphere. Changes in climate and climate variability may further affect the ability of agricultural systems to conserve N. The N that escapes affects climate directly through the emissions of nitrous oxide (N2O), and indirectly through the loss of nitrate (NO3-), nitrogen oxides (NOx) and ammonia to downstream and downwind ecosystems that then emit some of the N received as N2O and NOx. Emissions of NOx lead to the formation of tropospheric ozone, a greenhouse gas that can also harm crops directly. There are many opportunities to mitigate the impact of agricultural N on climate and the impact of climate on agricultural N. Some are available today; many need further research; and all await effective incentives to become adopted. Research needs can be grouped into four major categories: (1) an improved understanding of agriculturalNcycle responses to changing climate; (2) a systems-level understanding of important crop and animal systems sufficient to identify key interactions and feedbacks; (3) the further development and testing of quantitative models capable of predicting N-climate interactions with confidence across a wide variety of crop-soil-climate combinations; and (4) socioecological research to better understand the incentives necessary to achieve meaningful deployment of realistic solutions

Beef production from feedstuffs conserved using new technologies to reduce negative environmental impacts

End of project reportMost (ca. 86%) Irish farms make some silage. Besides directly providing feed for livestock, the provision of grass silage within integrated grassland systems makes an important positive contribution to effective grazing management and improved forage utilisation by grazing animals, and to effective feed budgeting by farmers. It can also contribute to maintaining the content of desirable species in pastures, and to livestock not succumbing to parasites at sensitive times of the year. Furthermore, the optimal recycling of nutrients collected from housed livestock can often be best achieved by spreading the manures on the land used for producing the conserved feed. On most Irish farms, grass silage will remain the main conserved forage for feeding to livestock during winter for the foreseeable future. However, on some farms high yields of whole-crop (i.e. grain + straw) cereals such as wheat, barley and triticale, and of forage maize, will be an alternative option provided that losses during harvesting, storage and feedout are minimised and that input costs are restrained. These alternative forages have the potential to reliably support high levels of animal performance while avoiding the production of effluent. Their production and use however will need to advantageously integrate into ruminant production systems. A range of technologies can be employed for crop production and conservation, and for beef production, and the optimal options need to be identified. Beef cattle being finished indoors are offered concentrate feedstuffs at rates that range from modest inputs through to ad libitum access. Such concentrates frequently contain high levels of cereals such as barley or wheat. These cereals are generally between 14% to 18% moisture content and tend to be rolled shortly before being included in coarse rations or are more finely processed prior to pelleting. Farmers thinking of using ‘high-moisture grain’ techniques for preserving and processing cereal grains destined for feeding to beef cattle need to know how the yield, conservation efficiency and feeding value of such grains compares with grains conserved using more conventional techniques. European Union policy strongly encourages a sustainable and multifunctional agriculture. Therefore, in addition to providing European consumers with quality food produced within approved systems, agriculture must also contribute positively to the conservation of natural resources and the upkeep of the rural landscape. Plastics are widely used in agriculture and their post-use fate on farms must not harm the environment - they must be managed to support the enduring sustainability of farming systems. There is an absence of information on the efficacy of some new options for covering and sealing silage with plastic sheeting and tyres, and an absence of an inventory of the use, re-use and post-use fate of plastic film on farms. Irish cattle farmers operate a large number of beef production systems, half of which use dairy bred calves. In the current, continuously changing production and market conditions, new beef systems must be considered. A computer package is required that will allow the rapid, repeatable simulation and assessment of alternate beef production systems using appropriate, standardised procedures. There is thus a need to construct, evaluate and utilise computer models of components of beef production systems and to develop mathematical relationships to link system components into a network that would support their integration into an optimal system model. This will provide a framework to integrate physical and financial on-farm conditions with models for estimating feed supply and animal growth patterns. Cash flow and profit/loss results will be developed. This will help identify optimal systems, indicate the cause of failure of imperfect systems and identify areas where applied research data are currently lacking, or more basic research is required

Modelling responses of forages to climate change with a focus on nutritive value

European livestock agriculture is extraordinarily diverse, and so are the challenges it faces. This diversity has contributed to the development of a fragmented set of research communities. As a result, livestock research is often under-represented at policy level, despite its high relevance for the environment and food security.Understanding livestock systems and how they can sustainably adapt to global change requires inputs across research areas, including grasslands, nutrition, health, welfare and ecology. It also requires experimental researchers, modellers and stakeholders to work closely together.Networks and capacity building structures are vital to enable livestock research to meet the challenges of climate change. They need to maintain shared resources and provide non-competitive arenas to share and synthesize results for policy support.  Long term strategic investment is needed to support such structures. Their leadership requires very different skills to those effective in scientific project coordination

A generalized approach to increased mixing efficiency for viscous liquids.

Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering.Microfiche copy available in Archives and Engineering.Includes bibliographical references.M.S