Riparian buffers in agricultural landscapes are designed to trap pollutants in overland flow by slowing, filtering, and infiltrating surface runoff entering the buffer via sheet flow. However, observational evidence suggests that concentrated flow is prevalent from agricultural fields. Also, over time sediment can accumulate in riparian buffers forming berms that restrict sheet flow from moving into the buffers; these berms ultimately back up surface runoff, resulting in an eventual breakthrough which concentrates runoff. Breakthrough by concentrated flow can lead to gully formation that may reduce the filtering capacities of buffer systems by providing direct conduits to stream channels. This study explores the frequency of concentrated flow paths in riparian buffers at both the field and watershed scale. At the field scale, intensive topographic surveys were conducted at 10 field sites in southern Illinois to characterize concentrated flow paths, accumulated berm sediments, and field area drained by concentrated flow. Detailed digital elevation models (DEMs) were created for each site and riparian buffer and agriculture field characteristics were analyzed to assess the development and occurrence of concentrated flow paths. At each site, soil samples were analyzed to characterize sediment deposition patterns within the buffer. To assess the prevalence of concentrated flow paths at the watershed scale, three watersheds in southern Illinois were selected for walking stream surveys. Five stream segments, approximately 1000 m long, were randomly selected within each watershed and surveyed for the occurrence and size of concentrated flow paths. These data were analyzed with respect to riparian buffer vegetation, buffer width, and surrounding land cover data. Concentrated flow paths were identified in all topographic surveys and all walking stream surveys indicating a common occurrence in agricultural watersheds of southern Illinois. Among field scale sites, concentrated flow accounted for 82.5-100% of the drainage areas contributing to riparian buffers. Results from the watershed scale analysis suggest that concentrated flow paths are significantly more abundant in agricultural land cover, than forested land. Current riparian buffer design principles are based on the assumption that sheet flow is the primary form of surface runoff entering buffers. Furthermore, buffers are installed and not maintained which can lead to berm accumulation and buffer failure. Results from this study indicate that concentrated flow was the prevalent form of runoff at field scale sites. Managers need to consider the occurrence of concentrated flow paths when designing riparian buffers to protect stream water quality.

Field scale research shows concentrated flow paths (CFPs) are prevalent in agricultural watersheds. They are an important source of soil erosion in cropland and significantly contribute to the transport and delivery of agricultural pollutants such as sediment and nutrients to nearby water resources. High resolution LiDAR data have enabled the investigation of the prevalence of concentrated flow at a large geographic extent. This study focused on identifying CFPs in 389 agricultural fields in Jackson County in southern Illinois and estimating the contribution of the CFPs to drainage of the fields. Addressing the lack of literature on factors influencing CFP characteristics, this study also investigates various topographical and soil factors that influence CFP development. LiDAR derived DEMs with a cell resolution of 3 meters were used to identify areas of flow concentration and delineate a drainage basin of each CFP using the Hydrology tools in the Spatial Analyst toolbox in ArcMap 10.3.1. Information on the topographical and soil characteristics were obtained from the DEMs and SSURGO database using the Soil Data Viewer 6.2 extension for ArcMap. Multiple regression analysis in SAS v. 9.4 was used to identify factors influencing CFP characteristics, while CART analysis in R v. 3.3.1 was conducted to detect linear dependencies among predictor variables. An average of 5 CFPs per agricultural field were observed in the study area with a minimum of 0 and maximum of 17 CFPs, but only two fields had no CFPs indicating a high prevalence of CFPs throughout the study area. The mean percent of field area drained by CFPs was estimated to be 81 percent with minimum of 36 percent and ii maximum of 100 percent. The majority of the fields, 85 percent, had more than 70 percent of their area drained by CFPs. Statistically significant regression equations were found for all CFP characteristics with slope, LS factor, K factor and organic matter as the factors influencing CFP characteristics. However, the factors only explained 2 to 22 percent of variation observed. Both multiple regression and CART analysis indicated slope as the most important influencing factor. Variation in CFP characteristics followed regional trends with higher values in the floodplain region and lower values in the rough hills region suggesting residual variation could be explained by other environmental factors along with topographical and climatological factors which were not included in the study. Results from this study highlight the prevalence of CFPs at a regional scale and their substantial contribution to field drainage identifying a need for research in quantifying the impacts of CFP on soil loss and water quality. This study also reports a need of future research to identify important factors controlling CFP formation and development that could help build empirical and physical models to accurately predict CFP locations and morphology. Such information could be useful in designing and targeting conservation practices that protect both soil health and water quality.

Made available in DSpace on 2016-12-23T13:53:39Z (GMT). No. of bitstreams: 1 Thiago Jaccoud Machado.pdf: 1172469 bytes, checksum: adc200abdf68ac3f3c2306b567b5f258 (MD5) Previous issue date: 2013-07-24 / The objective of this research was to evaluate the ingestive behavior and nutrient intake of Santa Inês crossbred lambs fed Tifton 85 hay supplemented with concentrate. Twenty lambs, not neutered, with an initial live weight of 20.3 ± 3.6 kg, in a completely randomized design, with five repetitions were used. Four treatments were studied constituted by Tifton 85 hay associated to four concentrate levels (0.0%; 0.66; 1.33 e 2.0% LW). The diets were provided ad libitum twice a day and the animals were submitted to observation by 24 hours integral periods, in ten-minute intervals, to assess behavioral activities. Dry matter intake (DMI) was estimated through the external indicator technique using the LIPE®. Was no effect of concentrate level on DMI and CPI, over the time spent feeding (TAL) and rumination (TRU), in min/day and min/kg of DM, NDF and CP, and time spent with leisure (TOC) in min/day. The feeding and rumination efficiencies in grams of DM and CP increased linearly with the increasing in the concentrate levels. Conversely, none of the regression models if adjusted to data the efficiency of feeding and rumination expressed in g NDF. In parallel, it was study a correlation between estimates of lambs intake by using external indicator LIPE® and the weight difference between food offered and remains of the diet by interpolations from the behavioral variable feeding time. It was observed a high association between the methodologies for estimating intake of DM and CP, which suggests its use to estimate the individual consumption of feedlot lambs / Objetivou-se com esta pesquisa avaliar o comportamento ingestivo e o consumo de nutrientes de cordeiros mestiços da raça Santa Inês alimentados com feno de Tifton 85 suplementado com concentrado. Foram utilizados 20 cordeiros, não castrados, com peso vivo inicial de 20,3 ± 3,6 kg, em delineamento inteiramente casualizado, com cinco repetições. Foram estudados quatro tratamentos constituídos por feno de Tifton 85 associado a níveis crescentes de suplemento concentrado (0,0%; 0,66; 1,33 e 2,0% PV). As dietas foram fornecidas ad libitum duas vezes ao dia. Os animais foram submetidos à observação por períodos integrais de 24 horas, em intervalos de dez minutos, para avaliação das atividades comportamentais. O consumo de matéria seca (CMS) foi estimado por meio da técnica LIPE®. Houve efeito dos níveis de concentrado sobre o CMS e o CPB, além do tempo despendido com a alimentação (TAL) e com a ruminação (TRU), em min/dia e min/kg de MS, FDN e PB, e tempo despendido com o ócio (TOC), em min/dia. As eficiências de alimentação e ruminação em g de MS e PB apresentaram ajuste linear com o incremento do nível de concentrado. No entanto, nenhum dos modelos de regressão se ajustou aos dados de eficiência de alimentação e ruminação expressa em g de FDN. Paralelamente foi estudada a correlação existente entre as estimativas de consumo individual de cordeiros pelo método do indicador externo LIPE® e pela diferença de peso entre o alimento ofertado e as sobras da dieta por interpolações a partir da variável comportamental tempo de alimentação. Observou-se alta associação entre as metodologias para as estimativas de consumo de MS e PB, o que sugere que ambas podem ser usadas para estimar o consumo de cordeiros em confinamento

abstract: Thermodynamic development and balance of plant study is completed for a 30 MW solar thermochemical water splitting process that generates hydrogen gas and electric power. The generalized thermodynamic model includes 23 components and 45 states. Quasi-steady state simulations are completed for design point system sizing, annual performance analysis and sensitivity analysis. Detailed consideration is given to water splitting reaction kinetics with governing equations generalized for use with any redox-active metal oxide material. Specific results for Ceria illustrate particle reduction in two solar receivers for target oxygen partial pressure of 10 Pa and particle temperature of 1773 K at a design point DNI of 900 W/m2. Sizes of the recuperator, steam generator and hydrogen separator are calculated at the design point DNI to achieve 100,000 kg of hydrogen production per day from the plant. The total system efficiency of 39.52% is comprised of 50.7% hydrogen fraction and 19.62% electrical fraction. Total plant capital costs and operating costs are estimated to equate a hydrogen production cost of $4.40 per kg for a 25-year plant life. Sensitivity analysis explores the effect of environmental parameters and design parameters on system performance and cost. Improving recuperator effectiveness from 0.7 to 0.8 is a high-value design modification resulting in a 12.1% decrease in hydrogen cost for a modest 2.0% increase in plant $2.85M. At the same time, system efficiency is relatively inelastic to recuperator effectiveness because 81% of excess heat is recovered from the system for electricity production 39 MWh/day and revenue is $0.04 per kWh. Increasing water inlet pressure up to 20 bar reduces the size and cost of super heaters but further pressure rises increasing pump at a rate that outweighs super heater cost savings. / Dissertation/Thesis / Doctoral Dissertation Mechanical Engineering 2018

Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-04-12T19:16:29Z No. of bitstreams: 1 WANDERSON MAGNO PAIVA BARBOSA DE LIMA – DISSERTAÇÃO (PPGEM) 2017.pdf: 3865442 bytes, checksum: 6806587d90f466df06ed6f2d8853c1cc (MD5) / Made available in DSpace on 2018-04-12T19:16:29Z (GMT). No. of bitstreams: 1 WANDERSON MAGNO PAIVA BARBOSA DE LIMA – DISSERTAÇÃO (PPGEM) 2017.pdf: 3865442 bytes, checksum: 6806587d90f466df06ed6f2d8853c1cc (MD5) Previous issue date: 2017-09-01 / O processo de secagem consiste na remoção de umidade de um material através do aquecimento, envolvendo mecanismo simultâneo de transferência de calor e massa entre o material e o ar de secagem, sendo uma importante etapa na conformação de um material cerâmico e argiloso. Neste sentido, este trabalho objetiva a simulação da secagem de sólidos vazados e com forma arbitraria. Para descrever o processo de secagem de materiais porosos utilizou-se o método da capacitância global. A aplicação tem sido feita para a secagem de materiais cerâmicos afim de obter resultados cinéticos de perda de massa e calor dos mesmos. Foram simulados diferentes casos variando-se a forma do corpo, de onde obteve-se as cinéticas de secagem (perda da umidade) e aquecimento do sólido (aumento de temperatura). Observou-se que o processo de perda de umidade ocorre numa menor velocidade que o aquecimento do material cerâmico, pois a sua difusividade térmica é muito superior a difusividade de massa, e que o formato do sólido, particularmente a sua relação área/volume afeta fortemente os fenômenos de transporte de calor e massa. / The drying process consists of the removal of moisture from a material through heating, involving simultaneous heat and mass transfer between the material and the drying air, being an important step in the formation of a clay and ceramic material. In this sense, this work aims at simulating the drying of cast and cast solids. To describe the drying process of porous materials, the global capacitance method was used. The application has been made for the drying of ceramic materials in order to obtain kinetic results of loss of mass and heat of the same. Different cases were simulated by varying the shape of the body, from which the kinetics of drying (loss of moisture) and heating of the solid (temperature increase) were obtained. It was observed that the process of moisture loss occurs at a slower rate than the heating of the ceramic material, because its thermal diffusivity is much higher than mass diffusivity, and that the shape of the solid, particularly its area / volume ratio strongly affects The phenomena of heat and mass transport.

The electrolyte is a crucial part of any lithium battery, strongly affecting longevity and safety. It has to survive rather severe conditions, not the least at the electrode/electrolyte interfaces. Current commercial electrolytes based on 1 M LiPF 6 in a mixture of organic solvents balance the requirements on conductivity and electrochemical stability, but they are volatile and degrade when operated at temperatures above ca. 70°C. The salt could potentially be replaced with e.g. LiTFSI, but corrosion of the aluminium current collector is an issue. Replacing the graphite negative electrode by Li metal for large gains in energy density challenges the electrolyte further by exposing it to freshly deposited Li, leading to poor coulombic efficiency (CE) and consumption of both Li and electrolyte. Highly concentrated electrolytes (up to > 4 M) have emerged as a possible remedy, by a changed solvation structure such that all solvent molecules are coordinated to cations – leading to a lowered volatility and melting point, an increased charge carrier density and electrochemical stability, but a higher viscosity and a lower ionic conductivity. Here two approaches to highly concentrated electrolytes are evaluated. First, LiTFSI and acetonitrile electrolytes with respect to increased electrochemical stability and in particular the passivating solid electrolyte interphase (SEI) on the anode is studied using electrochemical techniques and X-ray photoelectron spectroscopy. Second, lowering the liquidus temperature by high salt concentration is utilized to create an electrolyte solely of LiTFSI and ethylene carbonate, tested for application in Li metal batteries by characterizing the morphology of plated Li using scanning electron microscopy and the CE by galvanostatic polarization. While the first approach shows dramatic improvements, the inherent weaknesses cannot be completely avoided, the second approach provides some promising cycling results for Li metal based cells. This points towards further investigations of the SEI, and possibly long-term safe cycling of Li metal anodes. / Elektrolyten är en fundamental del av ett litiumbatteri som starkt påverkar livslängden och säkerheten. Den måste utstå svåra förhållanden, inte minst vid gränsytan mot elektroderna. Dagens kommersiella elektrolyter är baserade på 1 M LiPF 6 i en blandning av organiska lösningsmedel. De balanserar kraven på elektrokemisk stabilitet och jonledningsförmåga, men de är lättflyktiga och bryts ned när de används vid temperaturer över ca. 70°C. Saltet skulle kunna bytas ut mot t.ex. LiTFSI, vilket ökar värmetåligheten avsevärt, men istället uppstår problem med korrosion på den strömsamlare av aluminium som används för katoden. Genom att byta ut grafitanoden i ett Li-jonbatteri mot en folie av litiummetall kan man öka energitätheten, men då litium pläteras bildas ständigt nya Li-ytor som kan reagera med elektrolyten. Detta leder till en låg coulombisk effektivitet genom nedbrytning av både Li och elektrolyt. Högkoncentrerade elektrolyter har en mycket hög saltkoncentration, ofta över 4 M, och har lags fram som en möjlig lösning på många av de problem som plågar denna och nästa generations batterier. Dessa elektrolyter har en annorlunda lösningsstruktur, sådan att alla lösningsmedelsmolekyler koordinerar till katjoner – vilket leder till att de blir mindre lättflyktiga, får en ökad täthet av laddningsbärare, och en ökad elektrokemisk stabilitet. Samtidigt får de en högre viskositet och lägre jonledningsförmåga. Här har två angreppssätt för högkoncentrerade elektrolyter utvärderats. I det första har acetonitril, som har begränsad elektrokemisk stabilitet och ett högt ångtryck, blandats med LiTFSI för en uppsättning av elektrolyter med varierande koncentration. Dessa har testats i Li-jonbatterier och i synnerhet den passiverande ytan på grafitelektroder har undersökts med både röntgen-fotoelektronspektroskopi (XPS) och elektrokemiska metoder. En markant förbättring av den elektrokemiska stabiliteten observeras, men de inneboende bristerna hos elektrolyten kan inte kompenseras fullständigt, vilket skapar tvivel på hur väl detta kan fungera i en kommersiell cell. Med det andra angreppssättet har hög saltkoncentration nyttjats för sänka smältpunkten för en elektrolyt baserad på etylenkarbonat, som annars inte kan används som enda lösningsmedel. Dessa elektrolyter har testats för användning i Limetall-batterier genom långtidstest, mätning av den coulombiska effektiviteten och analys av deponerade Li-ytor med svepelektronmikroskop. Resultaten är lovande, med över 250 cykler på 0.5 mAh/cm2 och en effektivitet på över 94%, men framförallt observeras en mycket jämnare deponerad Li-yta, vilket kan möjliggöra säker cykling av Li-metall-batterier. Ett logiskt nästa steg är studier av Liytan med t.ex. XPS för att utröna vad som skiljer den från ytan som bildats i en 1 M referenselektrolyt.

Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2014-12-04T18:22:28Z No. of bitstreams: 2 Tese- Elis Aparecido Bento - 2013.pdf: 1240390 bytes, checksum: 353acfa530fd79da0d59d4a48a1572c4 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-12-04T18:46:46Z (GMT) No. of bitstreams: 2 Tese- Elis Aparecido Bento - 2013.pdf: 1240390 bytes, checksum: 353acfa530fd79da0d59d4a48a1572c4 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-12-04T18:46:46Z (GMT). No. of bitstreams: 2 Tese- Elis Aparecido Bento - 2013.pdf: 1240390 bytes, checksum: 353acfa530fd79da0d59d4a48a1572c4 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-03-22 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / The objective of the present study was to evaluate the performance, carcass characteristics and digestibility of diets with low or no bulk food inclusion in Dorper X Santa Ines lambs finished in a feedlot. The treatments consisted of five complete diets: Commercial Feed Corte Confina® (CCONF), commercial Concentrate Corte 20® plus Bagasse (CB), commercial Concentrate plus Corn and Bagasse (CMB), commercial Concentrate plus Corn, Soybean hulls and Bagasse (CMCSB) and commercial Concentrate plus Soybean hulls and Bagasse (CCSB). The performance study was carried out in the Goat and Sheep Sector at the Federal Institute Goiano - Campus Rio Verde – Goiás - Brazil. Twenty intact F1 Dorper x Santa Ines lambs were used, average age 60 days and average weight 20.34±39 kg at the start of the experiment. A complete randomized design was used. The experiment lasted 85 days and the animals were weighed every 21 days. The digestibility experiment was carried out in the experimental installations at the Food Analysis Laboratory of the Animal Production Department at the Veterinary and Animal Science College of the UNIVERSIDADE FEDERAL DE GOIÁS Goiânia – Brazil. A 5 x 5 Latin square was used to evaluate the apparent digestibility and intake performance. Samples of the diets used in the performance experiment were incubated to evaluate the in vitro dry matter degradability. The means were compared by the Fisher DMS test (α = 0.05). The diet did not affect (P>0.05) either performance, where the mean general weight gain was 232.4 g/day for 4.78 food conversion, or the carcass characteristics. The fatty acid profile of the carcass was altered. The intake performance was not affected and the food conversion was not altered. / O objetivo foi avaliar o desempenho, as características de carcaça e a digestibilidade de dietas com baixa ou nenhuma inclusão de alimento volumoso em cordeiros Dorper x Santa Inês terminados em confinamento. Os tratamentos foram constituídos por cinco rações completas: ração comercial Corte Confina® (CCONF), concentrado comercial Corte 20® mais bagaço de cana (CB), concentrado comercial mais milho e bagaço de cana (CMB), concentrado comercial mais milho, casca de soja e bagaço de cana (CMCSB) e concentrado comercial mais casca de soja e bagaço de cana (CCSB). O estudo de desempenho foi conduzido no Setor de Caprinos e Ovinos do Instituto Federal Goiano – Campus Rio Verde; foram utilizados 20 cordeiros não castrados F1 Dorper x Santa Inês com idade média de 60 dias e peso médio de 20,34±0,39 kg no inicio do experimento. Utilizou-se delineamento experimental inteiramente casualizado. O período experimental teve duração de 85 dias. Os animais foram pesados a cada 21 dias. O experimento de digestibilidade foi conduzido no Galpão experimental e no Laboratório de Análise de Alimentos do Departamento de Produção Animal da Escola de Veterinária e Zootecnia da Universidade Federal de Goiás. Trabalhou-se com um quadrado latino 5x5 avaliando a digestibilidade aparente e o comportamento ingestivo. Amostras das dietas usadas no experimento de desempenho foram incubadas para avaliar a degradabilidade in vitro da matéria seca. As médias foram comparadas pelo teste DMS de FISHER (α = 0,05). As dietas não promoveram efeitos (P>0,05) tanto no desempenho, em que o ganho de peso médio geral foi 232,4 g/dia para uma conversão alimentar de 4,78, quanto nas características de carcaças. Houve alteração do perfil de ácidos graxos da carcaça. O comportamento ingestivo não foi afetado e a Conversão Alimentar não alterou.

Com o objetivo de estudar o uso de inóculo de fezes em substituição do conteúdo ruminal de bubalinos na técnica in vitro de produção de gases, este presente trabalho comparou as avaliações realizadas em três ensaios. Foram utilizados três bubalinos da raça Mediterrâneo, machos, adultos, castrados, fistulados no rúmen com média de peso vivo de 450 (± 18,7) kg. Estes animais receberam uma dieta basal, composta de silagem de milho (70%) e concentrado (30%). Estes animais foram os doadores dos 2 tipos de inóculos, que foram conteúdo ruminal (CR) e fezes. O primeiro ensaio realizado foi com alimentos concentrados: grão de milho, farelo de soja, farelo de trigo e farelo de algodão; o segundo ensaio foi com leguminosas forrageiras: alfafa (Medicago sativa L. ), estilosantes pioneiro (Stylosanthes macrocephala cv. Pioneiro), soja perene (Neonotonia wightii) e leucena (Leucaena leucocephala); e o terceiro e último ensaio foi realizado com gramíneas forrageiras: capim braquiarão (Brachiaria brizantha cv. Marandu), capim buffel (Cenchrus ciliaris L. cv. Biloela), estrela africana (Cynodon plectostachyus) e capim mombaça (Panicum maximum Jacq. cv. Mombaça). Os valores médios obtidos de produção potencial de gases em cada ensaio foram menores (P<0,05) para as amostras fermentadas com inóculos de fezes que com conteúdo ruminal, sendo respectivamente, para concentrados (140,23 e 194,08 mL.g-1MS), gramíneas (161,99 e 230,25 mL.g-1MS) e leguminosas (141,78 e 170,70 mL.gm-1MS). Conclui-se que inóculos de fezes não apresentam condições satisfatórias para substituição do inóculum com conteúdo ruminal para uso na técnica de produção in vitro de gases. / In order to study the use of faeces as inoculum as alternative for buffalo rumen contents in the in vitro gas production technique, the present work evaluations of three tests. We used three Mediterranean buffalos, male, adult, neutered, fistulated in the rumen, with an average live weight of 450 (± 18.7) kg. These animals received a basal diet composed of corn silage (70%) and concentrated (30%). These buffalo were the donors of the two types of inocula, rumen content (CR) and faeces. The first test was carried out with concentrate foods: corn grain, soybean meal, wheat bran and cottonseed meal, the second test was with legumes: alfalfa (Medicago sativa L. ), Pioneiro estilo (Stylosanthes macrocephala cv. Pioneiro) , perennial soybean (Neonotonia wightii) and leucaena (Leucaena leucocephala) and the third and last test was carried out with grasses: Marandu grass (Brachiaria brizantha cv. Marandu), buffel grass (Cenchrus ciliaris L. cv. Biloela), African Star grass (Cynodon plectostachyus) and Mombasa grass (Panicum maximum Jacq. cv. Mombasa). The average values of potential production of gas in each test were lower (P<0.05) for samples fermented with an inoculum of faeces with rumen contents, being respectively, for concentrates (140.23 and 194.08 mL.g-1MS), grasses (161.99 and 230.25 mL.g-1MS) and legumes (141.78 and 170.70 mL.g-1MS). It follows that fecal inoculum unsatisfactory condition for replacing the inoculum with rumen technique for use in the in vitro production of gases technique.

Vinte e quatro cordeiros machos não castrados, Santa Inês x Dorper, com aproximadamente 90 dias de idade e peso vivo médio inicial de 27,0 ± 4,4kg, foram alimentados com uma dieta com elevada proporção de concentrado com 20% de pelete proteico-mineral (Grano Entero®), 5% de feno de capim coast cross e 75% de milho, na forma de milho grão inteiro (MGI), milho grão moído (MGM) ou milho grão úmido (MGU). Os animais foram distribuídos em um delineamento em blocos ao acaso, de acordo com o peso vivo inicial, com três tratamentos e oito repetições. Os alimentos e as sobras foram pesados diariamente e os animais, a cada 14 dias, sem jejum de alimentos ou água. Após 65 dias de confinamento, os animais foram abatidos com peso vivo médio final (PVF) de 47,97 ± 5,13kg e obteve-se o peso de carcaça quente (PCQ), o pH (pH1h) e a temperatura (T1h). Após 24 horas de refrigeração, o peso de carcaça fria (PCF), o pH (pH24h) e a temperatura (T24h) foram novamente aferidos. As carcaças foram serradas entre a 12ª e 13ª costelas para a realização das medidas na carcaça de área de olho de lombo (AOL) e espessura de gordura subcutânea (EGS). Três amostras do músculo Longissimus dorsi de cada animal foram coletadas, para as análises de maciez, cor e perda por cocção (PAC). Os efeitos dos tratamentos foram analisados usando-se o procedimento GLM do SAS®. O ganho de peso médio diário e a eficiência alimentar (kg ganho/kg IMS) não diferiu (P>0,05) entre as dietas, com média de 0,33kg e 0,28kg, respectivamente. Não houve diferença (P>0,05) entre os tratamentos, quanto à ingestão diária de matéria seca em kg (1,20kg) ou em percentagem de peso vivo (3,17%). Em relação ao PCQ, animais que receberam MGM apresentaram diferenças de peso das carcaças (P<0,05) em relação aos animais que receberam MGU, e semelhança de pesos com os animais que receberam MGI com respectivas médias de 23,90 kg, 21,35 kg e 23,15 kg. O rendimento de carcaça quente (47,5%), rendimento de carcaça fria (46,25%), a AOL (15,6cm2) e EGS (2,7mm) também não foram afetados pelos tratamentos. Observou-se aumento (P<0,05) do PCF nos animais que receberam MGM e MGI, quando comparados aos animais que receberam MGU, com médias de 22,97kg, 22,84kg e 20,81kg. Não foram observadas diferenças (P>0,05) para as variáveis qualitativas de maciez, cor e PAC. O processamento dos grãos de milho não teve influência acentuada sobre as características de desempenho ou de carcaça, exceto para PVF, PCQ e PCF. No entanto, o MGI apresentou ganho de peso significativo em relação aos outros tratamentos, além de ser mais prático na sua utilização não apresentando despesas de processamento. / Twenty four Santa Inês x Dorper crossbred not castrated lambs, approximately 90 days old and average initial weight of 27.07 ± 4.36kg were fed a high concentrate diet 20% protein-mineral pellet (Grano Entero®), 5% coast cross hay and 75% corn as whole corn grain (WCG), grounded corn grain (GCG) or high moisture corn (HMC). The animals were assigned to a randomized block design. Feed and orts were weighted daily and each 14 days the animals were also weighed. After 65 days feeding the animals were slaughtered with an average final weight (AFW) of 47.97 ± 5.13kg and hot carcass weight (HCW), pH (pH1h) and temperature (T°1h) were measured. After 24 hours of chilling the cold carcass weight (CCW), pH (pH24h) and temperature (T°24h) were again measured, thus obtaining the hot carcass yield (HCY) and cold carcass yield (CCY). The carcasses were ribbed between 12th and 13th ribs to measure the loin eye area (LEA) and the subcutaneous fat thickness (SFT). Three samples of the Longissimus muscle of each animal were collected for analyzes of tenderness, color and weight loss due to cooking (WLC). Effects of treatments were analyzed using the GLM procedure of SAS®. The average daily weight gain and feed efficiency (kg gain/kg DMI) of the animals did not differ between diets (P>0.05), with an average of 0.33kg and 0.28kg, respectively. There was no difference between treatments (P>0.05) for DMI in kg (mean = 1.20) or when expressed as a percentage of live weight (mean=3.17 %). In relation to the CCW, animals that received GCG had greater carcass weight (P<0.05) compared to animals receiving HMC, and similar weights with animals receiving WCG with respective averages of 23.90kg, 21.35 and 23.15kg. Treatments WCG and HMC did not differ among themselves. HCY (mean=47.5%), CCY (mean=46.25%), LEA (mean=15.6cm2) and SFT (mean=2.7mm) were not affected by treatments. The same result was observed for cold carcass weight (P<0.05), averaging 22.97kg, 22.84kg and 20.81kg. There were no differences (P>0.05) for qualitative variables of softness, color and WLC. Corn grain processing had no influence on the performance or carcass characteristics except for AFW, HCG and CCY. However, whole corn showed significant weight gain compared to other treatments, since it has no processing expenses.

Aditivos são amplamente utilizados em dietas ricas em concentrado para prevenir distúrbios metabólicos. A alga calcária, Lithothamnium calcareum, produto natural e renovável, fonte de carbonato de cálcio, pode ser uma alternativa na prevenção destes distúrbios. Este estudo foi desenvolvido para avaliar o efeito das fontes de cálcio, com ou sem monensina sódica na dieta, no controle da acidose ruminal de bovinos Nelore recebendo de forma abrupta uma dieta com elevada proporção (92,3%) de concentrado. Oito bovinos portadores de cânulas ruminais foram distribuídos em um delineamento quadrado latino (4x4) duplo. Os tratamentos foram a adição a dieta base com diferentes fontes de cálcio, calcário calcítico (CC) ou produto a base de alga calcária (AC), com (CMO) ou sem (SMO) a presença de monensina. A inclusão de CC, AC e monensina foi, respectivamente, de 7,1 g/kg, 7,4 g/kg e 30 mg/kg MS. Não houve efeito das fontes de cálcio e da monensina sobre o consumo alimentar e concentração total dos ácidos graxos de cadeia curta. Os tratamentos com AC resultaram em maior pH ruminal médio (P=0,039), menor tempo com pH ruminal abaixo de 5,2 (P<0,001) e um maior pH sanguíneo (P=0,006). Os tratamentos com monensina apresentaram menor tempo com pH ruminal abaixo de 5,2 (P=0.023). O produto a base de alga calcária pode ser uma boa alternativa para prevenir distúrbios metabólicos em animais submetidos a mudanças abruptas para dietas com elevada proporção de concentrado. / Additives are used in high concentrate diets in order to prevent metabolic disorders. Calcareous algae (Lithothamnium calcareum), a natural and renewable product, may be an alternative to prevent these disorders. This study was designed to evaluate the effect of calcium sources and monensin in the control of ruminal acidosis of Nellore cattle, abruptly fed a high (92.3%) concentrate diet. Eight cannulated steers were randomly assigned to a doubled 4x4 Latin square design. The treatments were the inclusion of different sources of calcium to the basic diet, limestone or calcareous algae, with or without the presence of monensin. The inclusion of limestone, calcareous algae and monensin was, respectively, 7.1 g/kg, 7.4 g/kg and 30mg/kg DM. There was on effect of calcium source (P=0.607) and monensin (P=0.294) on feed intake and in the short chain fatty acids concentration. Treatments with calcareous algae based product resulted in greater ruminal pH mean (P=0.039), lower time rumen pH remained below 5.2 (P<0.001) and better control of blood pH (P=0.006). Treatments with the presence of monensin also resulted in lower time of rumen pH below 5.2 (P=0.023). Calcareous algae may be an alternative to be used in pH control of beef cattle fed high concentrate diets.