Swine production represents approximately 40% of the world's meat production, and its wastes contain high concentrations of organic carbon, nitrogen (N), and phosphorus (P). Anaerobic digestion is an increasingly popular technology for treating animal wastes while simultaneously generating energy. Its propagation and ability to solubilize organic N and P make adding a struvite recovery process attractive. Recovering struvite (MgNH4PO4) from anaerobically digested swine waste can address global P shortages, meet P discharge guidelines, and produce slow-release fertilizer, which can be sold for revenue. Anaerobic digesters were operated with at organic loading rates of 3.4-3.9 g volatile solids per liter per day to provide consistent effluent for struvite precipitation studies. Three research questions about struvite precipitation were addressed in this study, specifically what is the (1) required Mg:PO4 ratio, (2) effect of organic matter, and (3) effect of storage time and conditions on struvite precipitation from effluent of anaerobically digested swine manure? Mg:PO4 ratios between 1.3-1.8 were determined to be the economic optimum and precipitated 81-90% of P from synthetic wastewater with calcium phosphate minerals dominating. Under P-limited conditions, a chemical equilibrium model (Visual MINTEQ v.3.0) predicted over 99% P removal with a precipitate mixture of struvite, calcium phosphates, and magnesite. Synthetic wastewater experiments without organic matter removed approximately 85% P with a precipitate mixture of struvite, dolomite, calcite, brucite, and calcium phosphates. Real swine effluent removed more than 95% of P and had a similar mixture of precipitates as synthetic wastewater, but in different concentrations. Organic acids were suspected to prevent struvite formation. Stored anaerobically digested swine wastewater under varying conditions all suggest calcium phosphates form naturally over time. Precipitation of struvite is best carried out as soon as possible to increase the purity of struvite. Although struvite recovery was possible, the conditions for struvite precipitation must be controlled carefully to obtain highly pure struvite.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In order to assess the use of high grain diets, corn or sorghum offered as the entire form or ground, the termination in male animals in confinement, crossbred dairy origin, an essay was conducted at the Escola de Medicina Veterinária e Zootecnia (EMVZ) the Universidade Federal do Tocantins (UFT), in the municipality of Araguaína, in the North region of Brazil, between October 2013 and January 2014, lasting 109 days. It was used 28 crossbred steers whole, from crosses of European breeds with zebu breeds, with an average age of 30 months and average weight of 238 ± 6,1 kg. Four treatments were tested: MGI) whole corn; MGM) Grounded Corn; SGI) Whole Sorghum; and SGM) Grounded sorghum. These diets were formulated targeting an average daily weight gain of 1,5 kg/day/animal, with 100 % concentrate, on a dry matter basis. After a period of 109 days, the animals were slaughtered and subsequently to this period, were made evaluations of temperature, pH, carcass conformation, based on muscular expression and physiological maturity, based on ossification of the vertebrae and ribs. The marbling assessments, color and texture of meat were held. Chemical composition of the meat was performed on sample taken from caudal face of the Longissimus dorsi. The steaks were undergone by evaluators trained in sensory analysis panel. It was evaluated the levels of dry matter, crude protein, ether extract, neutral detergent fiber, acid detergent fiber, non-fiber carbohydrate, total carbohydrates and total digestible nutrients, and their respective apparent digestibility. It was also evaluated the total weight gain, average daily gain, feed efficiency and feed conversion. The experiment was conducted as a completely randomized design with the treatments distributed in a factorial arrangement 2 x 2, being used seven replications (animals) per treatment. According to analyzes carried out by this study, it is concluded that the best performances of average daily intake, feed conversion and body condition score were obtained in diets that used kernel of corn in the ground form, while the meat and carcass performance, treatment with sorghum grain in the entire form, obtained better results. / Com o objetivo de avaliar o uso de dietas de alto grão, milho ou sorgo, fornecidos nas formas inteira ou moída, na terminação em confinamento de animais machos, mestiços de origem leiteira, foi realizado um experimento na Escola de Medicina Veterinária e Zootecnia (EMVZ) da Universidade Federal do Tocantins (UFT), localizada no município de Araguaína, situada na região Norte do Brasil, entre outubro de 2013 e janeiro de 2014, com duração de 109 dias. Utilizou-se 28 novilhos mestiços inteiros, provenientes de cruzamentos de raças taurinas com raças zebuínas, com idade média de 30 meses e peso médio inicial de 238 ± 6,1 Kg. Foram testados quatro tratamentos, MGI) Milho inteiro; MGM) Milho Moído; SGI) Sorgo inteiro; e SGM) Sorgo Moído, essas dietas foram formuladas visando um ganho de peso médio diário de 1,5 kg/dia/animal, apresentando 100% de concentrado, com base na matéria seca. Depois do período de 109 dias os animais foram abatidos, e posteriormente a este período foram feitas avaliações de temperatura, pH, conformação, baseada na expressão muscular e maturidade fisiológica, baseada na ossificação das vértebras e costelas. Foram realizadas as avaliações de marmoreio, coloração e textura da carne. A composição química da carne foi realizada em amostra retirada da face caudal do Longíssimus dorsi. Os bifes foram submetidos a avaliações através de avaliadores treinados no painel de análise sensorial. Avaliou-se os níveis de matéria seca, proteína bruta, extrato etéreo, fibra em detergente neutro, fibra em detergente ácido, carboidratos não fibrosos, carboidratos totais e nutrientes digestíveis totais, além de suas respectivas digestibilidades aparentes. Também foram avaliados o ganho de peso total, ganho médio diário, eficiência alimentar e conversão alimentar. O experimento foi realizado com delineamento inteiramente casualizado, sendo os tratamentos distribuídos em arranjo fatorial 2 x 2, sendo utilizado sete repetições (animais) por tratamento. De acordo com análises realizadas através desse estudo, conclui-se que os melhores desempenhos de consumo médio diário, conversão alimentar e escore de condição corporal foram obtidos nas dietas que utilizaram grão de milho na forma moída, enquanto que no desempenho de carne e carcaça, o tratamento com grão de sorgo na forma inteira, obteve melhores resultados.

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Master of Science / Department of Agronomy / Jay M. Ham / The potential environmental impact of animal feeding operations on air quality has created the need for accurate air emissions measurements. Of particular concern are ammonia emissions from cattle feedlots, operations that contribute a large portion of the agricultural ammonia emissions inventory. Micrometeorological methods are ideal for emissions measurements from large, open-source areas like feedlot pens; however, theoretical assumptions about the boundary layer must be made, which may not hold true above the heterogeneous, fetch-limited surface of the feedlot. Thus, the first objective of this work was to characterize the surface boundary layer of an open-air cattle feedlot and provide insight into how micrometeorological techniques might be applied to these non-ideal sites. Eddy covariance was used to measure fluxes of momentum, heat, water, and carbon dioxide from a commercial cattle feedlot in central Kansas. Data supported the use of eddy covariance and similar methods (i.e., relaxed eddy accumulation) for flux measurements from both cattle and pen surfaces. The modeled cumulative source area contributing to eddy covariance measurements at a 6 m sample height was dominated by just a few pens near the tower, making the characteristics of those pens especially important when interpreting results. The second objective was to develop a system for measuring ammonia fluxes from feedlots. A new type of relaxed eddy accumulation system was designed, fabricated, and tested that used honeycomb denuders to independently sample ammonia in up-moving and down-moving eddies. Field testing of the relaxed eddy accumulation system at a feedlot near Manhattan, KS showed fluxes of ammonia ranged between 60 and 130 μg m-2 s-1 during the summer of 2007. Even in the high ammonia environment (e.g., 300-600 μg m-3), the honeycomb denuders had enough capacity for the 4-hour sampling duration and could be used to measure other chemical species that the denuders could be configured to capture. Results provide a foundation for emissions measurements of ammonia and other gases at cattle feedlots and help address some of the challenges that micrometeorologists face with any non-ideal source area.