Air Emissions from Animal Feeding Operations Current Knowledge, Future Needs (2003) / Chapter Skim
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2. Livestock Agriculture and Animal Feeding Operations
2. Livestock Agriculture and Animal Feeding Operations
Pages 26-49
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From page 26... ...
It then turns to the general economics of livestock agriculture and the structure of the livestock industry. It ends with a discussion of the economics of emissions and manure management and potential methods of livestock operation emissions control and mitigation.
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· Hay is consumed by livestock and represented 3.8 percent of cash receipts from farm marketings of crops during this period. · Livestock agriculture is also the market or consumer for soybean meal and other oilseed meals.
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Producers respond to market prices for livestock and their products and to prices of feed ingredients by increasing production following periods of high profit and decreasing production following periods of losses. Biological lags in production response are a fundamental characteristic of livestock agriculture.
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Typical production contracts have the livestock owner (frequently, but not necessarily, a processor) provide livestock, feed, medication, and managerial and veterinary support, while farmers provide buildings, labor and management, land, manure management, utilities, repairs, and supplies in exchange for a fee per head or per pound produced.
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Of these, 16 percent were very small (<35 USDA animal units [AUs]
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Beef Cattle. The number of beef cattle in the United States peaked at 132 million head in 1975.
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indicates that 60 percent of chicken eggs are produced on farms owned by the processor and another 38 percent are produced under production contracts for the processor. Although not substantially concentrated economically in terms of being able to affect prices for their output, the animal feeding operations (as distinguished from the large processing firms, referred to as "integrators" in the case of swine and poultry)
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TABLE 2-2 Leading Livestock Production States by Animal Sector Sector Top Four States Percent Next Four States Percent Total Beef cattle TX, KS, NE, CO 60 IA, CA, OK, MN 16 76 Milk cows WI, CA, NY, PA 44 MN, TX, MI, ID 17 61 Swine IA, NC, MN, IL 57 IN, NE, MO, OH 21 78 Broilers GA, AR, MS, NC 48 TX, VA, DE, MO 16 64 SOURCE: EPA (2001a)
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USDA has a different definition of an animal unit, which can lead to confusion in comparing EPA and USDA statistics, including confusion in estimating air emissions because of differences in the animal base on which estimates of air emissions are predicated. The committee suggests that estimates of air emissions in the future be based on a modeling approach that is more flexible than has been TABLE 2-3 Number of Animals per EPA Animal Unit Animal Type Head Horses Slaughter or feeder cattle Mature dairy cow Pigs weighing 25 kg or more 2.5 Turkeys Chickens Sheep or lambs 1.0 0.7 55.0 100.0 10.0 0.5
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Cows are culled from the herd and slaughtered for low-grade meat production because of failure to become pregnant, low milk production, or chronic health issues. Calves, growing heifers, and dry cows are often housed separately from lactating cows.
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Nursery operations receive the weaned pigs and produce feeder pigs that are typically 10 to 11 weeks old and weigh 20-27 kilograms. Finishing operations receive feeder pigs and feed them to market
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Pig feed consists primarily of ground corn, soybean meal, and supplemental minerals and vitamins. Feed is often ground, mixed, and pelleted at large centralized feed mills, although some farms still grind their own corn and mix in soybean meal and vitamin-mineral premixes.
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Manure Management Manure management varies widely across species, region, and farm type. Since manure management can have a significant effect on emissions, attention is given here to some of the common systems.
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Manure management in feedlots varies with the range of facilities described previously. Earthen-floor pens are routinely scraped, and the solids are collected into mounds within the pens.
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The result of federal, state, and local regulations and stipulations is a checkerboard of manure management strategies. This creates confusion in the permitting process, may accommodate specific optimums by location, and may lead to a real or perceived disparity of requirements.
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Farm practices to limit emissions and manage manure can be considered in this context. Since manure management can affect rates and composition of emissions, it is given considerable attention in this and the following section.
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Emissions and manure management become a policy issue when not all costs and benefits of livestock production are realized by the farmer. Costs and benefits realized by others in the absence of a negotiated exchange (purchase or sale)
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are available. Regulatory requirements and nonregulatory guidelines are important to cost analyses of various manure management systems if they affect the rate at which
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The economic basis for measurement of emissions is that society cannot rationally decide how much cost to incur to decrease emissions without knowing the extent to which emissions will be decreased and the value of the benefits that will be generated by that decrease. Alternative Manure Management and Emission Mitigation Strategies Air emissions from livestock and poultry farms arise from many sources spread across the entire farm and the emissions are matters of concern.
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Discussion of possible emission modification or control strategies is presented in broad categories including strategies for animal feeding, animal health, and manure management. Animal Feeding and Animal Health Strategies.
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This need for updated data is apparent in attempts to budget nitrogen emission factors using dated estimates of nitrogen excretion. Manure Management Strategies.
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Recently, USDA NRCS initiated a project to identify and evaluate the emerging animal manure treatment technologies that will most likely be used by animal producers in the next 5 to 10 years. The following discussion includes manure handling and treatment technologies that have been identified by the project and have relevance to air emissions (Melvin, personal communication, 2002~.
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Costs, benefits, and emissions arising from sludge management must be considered. Solid-liquid separation is used on some farms now and is being considered as part of several alternative manure management systems.
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Other technologies and practices such as livestock housing design and operation affect air emissions. A considerable research and development effort has been devoted to evaluation of inexpensive filters for exhaust air from buildings and of "windbreak walls" to deflect and disperse the exhaust airstream from buildings.
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