Browsing by Subject "Feedlots"
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Item An economic analysis of waste management for Texas cattle feedlots: an analysis of system alternatives and policy implications(Texas Tech University, 1994-08) Glover, Teresa P.Over 20 percent of the nation's fed cattle are finished each year in the Texas High Plains. Each animal that is fed produces approximately one dry ton of collectable manure. This equals about two dry tons of collectable manure per year per head of feedlot capacity. Given the amount of cropland in crop production on the High Plains, there is a potential demand for all manure produced. The general objective of this thesis was to determine efficient waste management strategies which would be environmentally benign while benefiting agricultural producers. Specific objectives were sought with respect to the physical aspects, cost of manure management, derivation of manure demand curves, and possible policy implications. Mathematical optimization models for two study areas in the Texas Panhandle were developed with the objective of maximization of net returns. The primary differences between the Northern Farm Area and the Transition Farm Area were the addition of cotton production in the Transition Farm Area as well as decreased farm size. Crop supply and input demand functions were determined using duality theory.Item Behavioral and environmental management of feedlot cattle(Texas Tech University, 2000-08) Mitlöhner, Frank Michael. Feeding large numbers of cattle in feedlots is a challenge in many respects including nutrition, health, transport, and slaughter. A field of growing importance is animal wellbeing and environmental aspects. The two main challenges for environmental management in the feedlot industry are to lower climatic stress, and to improve air quality. This dissertation covers the areas of a) ethological sampling methods for feedlot cattle, b) environmental management practices that lower heat stress in feedlot cattle, and c) behavioral management practices of cattle that control dust in feedlots. In the first study, 64 crossbred heifers were used to determine and validate accurate, precise, and efficient behavioral sampling techniques. When focal animal sampling, scan sampling, and time sampling were compared to continuous sampling, it was found that scan sampling in 10-min intervals as well as focal animal sampling were accurate and precise methods to quantify behavior of feedlot cattle. In the second study, a total of 112 crossbred heifers were used in the Texas Tech University feedlot in the summers of 1998 and 1999. The objective was to assess the impact of heat stress and its relief by shade and (or) water misting on behavior, physiology, performance, and carcass traits. Cattle without shade had a physiological and behavioral stress response to heat that negatively affected production. Providing shade significantly decreased heat stress and lowered the negative effects of heat on performance, whereas misting with water was largely ineffective. The objective of the third study, was to decrease the aerial dust concentration in a commercial feedlot by modifying dust-generating behaviors of feedlot cattle. It was hypothesized that through changes in feeding management practices, cattle activity patterns that result in high quantities of dust might be redirected towards feeding and ruminating behaviors that generate significantly less dust. It was found that changing the feeding regimen of cattle to their natural feeding times redirected the cattle away from dustgenerating behaviors and thereby decreased considerably aerial dust concentrations closer to legal limits. The understanding of the behavior of feeder cattle can help in the management of feedlots in a more animal welfare friendly manner. The modification of the feedlot environment by providing, e.g., shade should not only improve the well-being of the animals but also the profit of the operation.Item Constructed wetlands for agricultural wastewater treatment(Texas Tech University, 1998-08) Ancell, Michael EdwardA 23-tank, 43 m , pilot-scale constructed wetland system was loaded daily with 136.2 liters of cattle feedlot wastewater to measure the nitrogen removal effectiveness and to compare this removal to nitrogen removal models. The 23-tanks were separated into six different treatment series, and the effects of four different total nitrogen (TN) loading rates were investigated with three different series surface areas and detention times. The four TN loading rates were 11.4, 8.0, 2.3, and 0.5 g TN/day. All four loading rates were tested in treatment series consisting of four tanks. Additionally, the 2.3 g TN/day loading rate was tested in a series with two tanks and a series with five tanks. The removal of nitrogen constituents from wastewater is dominated by maximizing the permanent removal processes inherent to the nitrogen cycle. Although the nitrogen cycle is a complex interaction of biological and chemical phenomena, maximizing its inherent removal processes is attainable in the wetland environment. The primary facilitator of this nitrogen removal is the root-zone aeration of the predominantly anaerobic environment surrounding the wetland soil. Given proper amounts of dissolved oxygen, the microbiota of nitrification can oxidize ammonia to nitrate, and denitrification can take place in the anaerobic environment, ultimately removing nitrogen from the wastewater in the form of nitrogen gas. An additional permanent nitrogen removal pathway in wetlands is defined by the plant uptake of ammonia and/or nitrate. However, maximizing this removal pathway requires plant harvesting, which can be costly in the full scale wetland treatment settmg and does not always yield an appreciable amount of nitrogen removal.Item Effects of feeding direct-fed microbials and prebiotics on receiving calf performance, health, and fecal shedding of pathogens(Texas Tech University, 2001-08) Abney, Michael D.Not availableItem Engineering analysis of the air pollution regulatory process impacts on the agricultural industry(Texas A&M University, 2008-10-10) Lange, Jennifer MarieThe EPA press release dated February 23, 2004 states that the three Buckeye Egg Farm facilities had the potential to emit more than a combined total of 1850 tons per year of particulate matter (PM). This number was based on flowrate calculations that were three times higher than those measured as well as a failure to include particle size distributions in the emissions calculations. The annual PM emission for each facility was approximately 35 tons per year. The EPA was unjustified in requiring Buckeye Egg Farm to obtain Title V and PSD permits as the facilities could not have met the thresholds for these permits. Engineers need to be concerned with correctly measuring and calculating emission rates in order to enforce the current regulations. Consistency among regulators and regulations includes using the correct emission factors for regulatory permitting purposes. EPA has adopted AERMOD as the preferred dispersion model for regulatory use on the premise that it more accurately models the dispersion of pollutants near the surface of the Earth than ISCST3; therefore, it is inappropriate to use the same emission factor in both ISCST3 and AERMOD in an effort to equitably regulate PM sources. For cattle feedlots in Texas, the ISCST3 emission factor is 7 kg/1000 hd-day (16 lb/1000 hd-day) while the AERMOD emission factor is 5 kg/1000 hd-day (11 lb/1000 he-day). The EPA is considering implementing a crustal exclusion for the PM emitted by agricultural sources. Over the next five years, it will be critical to determine a definition of crustal particulate matter that researchers and regulators can agree upon. It will also be necessary to develop a standard procedure to determine the crustal mass fraction of particulate matter downwind from a source to use in the regulatory process. It is important to develop a procedure to determine the particulate matter mass fraction of crustal downwind from a source before the crustal exclusion can be implemented to ensure that the exclusion is being used correctly and consistently among all regulators. According to my findings, the mass fraction of crustal from cattle feedlot PM emissions in the Texas High Plains region is 52%.Item The economic and environmental implications of feedlot manure utilization in the Texas High Plains(Texas Tech University, 1996-12) Johnson, Jason LaurenceEnvironmental regulations and rising fertilizer costs have made livestock waste management issues important to cattle feedlots, farmers and consumers. These problems are especially evident in the Texas High Plains (THP), an area where vast numbers of cattle are fed alongside a large farm base. The objective of this research was to determine efficient patterns of feedlot manure utilization in the THP that would protect the environment and benefit both feedlot operators and crop producers. Spatial optimization procedures were used to model the economic and environmental implications of utilizing feedlot manure in predominant cropping practices of the THP. The data for this research was constructed from the 5-year average predominant crop acreages and the locations and capacities of 93 individual feedlots in the 29 county THP region. Estimated costs and returns were estimated for each cropping activity, alternative fertilization rate, and soil types predominant in the THP. Expected crop yields, water requirements, and residual nitrogen and phosphorous levels were estimated with the Erosion-Productivity Impact Calculator (EPIC) biological crop/growth simulation model.Item Water pollution from cattle feedlots(Texas Tech University, 1970-08) Malouf, John BorjisNot available