Tesis: "Urea production"

1

Wheeler, Robert Alec. "Urea production and recycling in surgical neonates during convalescence". Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316464.

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Medeiros, João A. S. "Management alternatives for urea use in corn and wheat production". Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4533.

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Thesis (M.S.)--University of Missouri-Columbia, 2006.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February 9, 2007) Includes bibliographical references.

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3

Yan, Wei. "Nickel-based Catalysts for Urea Electro-oxidation". Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1391419479.

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4

Schiller, Tamar Marie. "Urea production capacity in the wood frog (Rana sylvatica) varies with season and experimentally induced hyperuremia". Oxford, Ohio : Miami University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1196441446.

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5

Xie, Rongjing. "Animal manures and urea as nitrogen sources for corn production in Québec". Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64482.

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6

Schiller, Tamar M. "Urea production capacity in the wood frog (Rana sylvatica) varies with season and experimentally induced hyperuremia". Miami University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=miami1196441446.

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7

Schindler, Frank Vincent. "Redistribution and fate of applied ??N-enriched urea under irrigated continuous corn production". Thesis, North Dakota State University, 1996. https://hdl.handle.net/10365/28973.

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Understanding the redistribution and fate of N is essential for justification of Best Management Practices (BMP). This project was conducted on a Hecla fine sandy loam (sandy, mixed, Aquic Haploboroll) soil at the BMP field site near Oakes, North Dakota. One objective of this investigation was to evaluate the residence times of N03- -N in 20 undisturbed lysimeters and its infiltration time through the soil profile to tile drains. Corn (Zea mays L.) was fertilized with 135 kg N ha -1 as ??N-enriched urea plus 13.5 and 48.1 kg N ha -1 preplant for 1993 and 1994, respectively. Urea-N was band applied to 20 and 10 undisturbed lysimeters at 2.0 and 5.93 atom percent (at %) ??N in 1993 and 1994, respectively. Average resident times of N03- -N in the lysimeters was 11.7 months. Lysimeter and tile drainage indicate the presence of preferential pathways. Residence times of N03- -N depend on frequency and intensity of precipitation events. Another objective was to determine what portion of the total N in the crop was from applied urea-N and what portion was from the native soil-N. Nitrogen plots received ??N enrichments of 4.25 and 5.93 at % ??N in 1993 and 1994, respectively. At the end of the 1993 and 1994 growing season, 41.5% and 35.7% of the labeled fertilizer N remained in the soil profile, while the total recovery of applied ??N in the soil-plant system was 86.2% and 75.4%, respectively. Low recoveries of applied N may have been the result of soil or aboveground plant biomass volatilization, or denitrification or preferential flow processes. Further research needs to be conducted with strict accountability of gaseous loss and the mechanism(s) responsible.
U.S. Bureau of Reclamation

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8

King, Rebecca Lynne. "Investigation of Anode Catalysts and Alternative Electrolytes for Stable Hydrogen Production from Urea Solutions". Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1275514221.

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9

Ottman, M. J. "Use of Agrotain to Prevent Urea Volotilization in Irrigated Wheat Production, Casa Grande 1996". College of Agriculture, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/202455.

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10

Lu, Fei. "Electrochemically Induced Urea to Ammonia on Ni Based Catalyst". Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1502235953529178.

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11

Moore, Jeffrey Allen. "Comparison of ESN, urea, and aqua ammonia as sources of nitrogen for corn production in Iowa". [Ames, Iowa : Iowa State University], 2008.

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12

Kgole, M. L. (Matlou Lebogang). "Factors affecting milk urea nitrogen and its relationships with production traits in South African Holstein cattle". Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/41116.

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The efficiency of utilization of dietary nitrogen can be monitored using milk urea nitrogen (MUN). Overfeeding or underfeeding of protein can be identified through the observation of deviations from target MUN concentrations. This will assist in lowering feed costs of dairy farms, and improving nutrition management of herds. Higher efficiency of utilization of dietary nitrogen might result in a reduction in environmental pollution. Non-genetic factors affecting variation in MUN were herd-test-day (HTD), lactation stage and year of calving. The contribution of HTD was the highest, ranging from 58.56% to 63.18% in parity 1 to 3. Lactation stage had the second largest contribution to the MUN variation. Differences in least squares means for MUN in various years of calving were observed. The heritability estimate for MUN was 0.09±0.01 in the first parity, and remained constant at 0.11±0.01 in the second and third parity. Heritability estimates for milk, fat and protein yield ranged from 0.40±0.01 to 0.43±0.01, 0.21±0.01 to 0.26±0.01, and 0.32±0.01 to 0.38±0.01, respectively. These estimates were within acceptable ranges for South African Holstein cattle. Genetic correlations between MUN and milk production traits were low and positive, ranging from 0.01±0.003 to 0.10±0.004 across parities. Phenotypic correlations ranged from 0.02±0.11 to 0.16±0.07, being generally higher than the genetic correlations. The positive associations between MUN and milk production traits are undesirable as the dairy cows would be less efficient in utilizing dietary protein and may result in increased environmental pollution. The genetic trend for MUN was 0.44, 0.007 and 0.049 mg/dl in the first, second and third parity, respectively. Results of the current study indicate that MUN has potential as a management tool in South African Holstein dairy herds. It might be a good indicator of the efficiency of dietary protein utilization of dairy herds, and has practical advantage as it is currently collected by the national dairy herd recording and improvement scheme.
Dissertation (MSc Agric)--University of Pretoria, 2013.
gm2014
Animal and Wildlife Sciences
unrestricted

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13

Malate, Andries. "Replacing sunflower oilcake with Sericea lespedezaand/or urea on feed digestibility and milk production of Saanen goats". Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/63293.

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In conditions where supplementation of poor quality diets is a major challenge, forage legumes such as Sericea lespedeza can be a good alternative supplement for protein at lower cost than most commercial concentrates. From studies done on Sericea lespedeza it is found plausible and valuable to supplement urea with Sericea lespedeza to strategically combat the deleterious effect of condensed tannins in the Sericea lespedeza and provide nitrogen in the rumen. This study was aimed to evaluate the effect of replacing sunflower oilcake with urea (a rumen degradable protein RDP source) or Sericea lespedeza (rumen undegradable protein RUP source) mixed with urea as nitrogen/protein sources on nutrient utilization, milk yield and milk composition of Saanen dairy goats. A digestibility and lactation study were conducted at the University of Pretoria Research Farm and chemical analysis performed at the University Nutrilab. A 30 days digestibility study was conducted on male Saanen goats after the lactation study, with 23 days adaptation and 7 days data collection period. Nine male goats were randomised and allocated to the three treatments in metabolism cages. In the lactation study 36 dairy goats were blocked according to milk collected on first month of lactation into high, medium and low milk yielders, then allocated to the three treatments of total mixed rations containing sunflower oilcake (T1) at 7% main protein source, T2 (urea at 1%) and T3- Sericea lespedeza at 12.5% mixed with urea according to a complete randomised block design (CRBD). Milk samples were collected from individual goats monthly at two consecutive milking’s. The samples were analysed for milk fat, protein, lactose, somatic cell count and milk urea nitrogen using a Milko-Scan analyser (at Irene Lacto lab). In the digestibility study, dry matter intake was significantly higher for goats fed on Sericea lespedeza with urea (T3) diet than goats fed on T1 and T2 diet. Goats on T3 diet had also significantly higher organic matter and crude protein intake than those goats fed on the other two TMR diets. The results also shows that the mean daily milk yields for the goats in the T1, T2 and T3 were 2.56, 2.46 and 2.52 kg per day respectively. T2 group had higher milk fat % (3.61) and higher milk urea nitrogen (MUN - 25.70 mg N/dl) than the other two treatments. T1 had significantly higher milk protein %. There was a great difference in milk composition of the afternoon milk as compared to the morning milk. The three TMRs had no significant difference in the nitrogen utilization and nitrogen excretion. It is then concluded that Sericea lespedeza mixed with urea can be used as subsititutes for sunflower oilcake in the diets of dairy goats since no negetive effect was found. However further investigations are needed.
Dissertation (MSc Agric)--University of Pretoria, 2017.
DAAD-NRF
International Foundation for Science (IFS)
Animal and Wildlife Sciences
MSc (Agric)
Unrestricted

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14

Dahabieh, Matthew Solomon. "Metabolic engineering of industrial yeast strains to minimize the production of ethyl carbamate in grape and Sake wine". Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/790.

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During alcoholic fermentation Saccharomyces cerevisiae metabolizes L-arginine to ornithine and urea. S. cerevisiae can metabolize urea through the action of urea amidolyase, encoded by the DUR1,2 gene; however, DUR1,2 is subject to nitrogen catabolite repression (NCR) in the presence of high quality nitrogen sources during fermentation. Being cytotoxic at high concentrations, urea is exported into wine where it spontaneously reacts with ethanol, and forms the carcinogen ethyl carbamate (EC). Urea degrading yeast strains were created by integrating a linear cassette containing the DUR1,2 gene under the control of the S. cerevisiae PGK1 promoter and terminator signals into the URA3 locus of the Sake yeast strains K7 and K9. The ‘self-cloned’ strains K7EC- and K9EC- produced Sake wine with 68% less EC. The Sake strains K7EC- and K9EC- did not efficiently reduce EC in Chardonnay wine due to the evolutionary adaptation of said strains to the unique nutrients of rice mash; therefore, the functionality of engineered yeasts must be tested in their niche environments as to correctly characterize new strains. S. cerevisiae possesses an NCR controlled high affinity urea permease (DUR3). Urea importing yeast strains were created by integrating a linear cassette containing the DUR3 gene under the control of the PGK1 promoter and terminator signals into the TRP1 locus of the yeast strains K7 (Sake) and 522 (wine). In Chardonnay wine, the urea importing strains K7D3 and 522D3 reduced EC by 7% and 81%, respectively; reduction by these strains was equal to reduction by the urea degrading strains K7EC- and 522EC-. In Sake wine, the urea degrading strains K7EC- and 522EC- reduced EC by 87% and 84% respectively, while the urea importing strains K7D3 and 522D3 were significantly less capable of reducing EC (15% and 12% respectively). In Chardonnay and Sake wine, engineered strains that constitutively co-expressed DUR1,2 and DUR3 did not reduce EC more effectively than strains in which either gene was expressed solely. Uptake of 14C-urea under non-inducing conditions was enhanced in urea importing strains; parental strains failed to incorporate any 14C-urea thus confirming the functionality of the urea permease derived from the integrated DUR3 cassette.

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15

Villalba, Hugo Abelardo González. "Blending polymer-sulfur coated and NBPT-treated urea to improve nitrogen use efficiency and grain yield in corn production systems". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-14082018-100857/.

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Blends of controlled release and stabilized nitrogen (N) fertilizer represent an alternative to provide N at all corn growth stages, and is an option to reduce costs compared to the use of solely controlled release N. In this context, field experiments were conducted in Southeast Brazil with the use of a blend of polymer-sulfur coated urea (PSCU) and NBPT-treated urea (NBPTU) at a 70:30 ratio, applied at corn planting and incorporated into the soil. The objectives of the study were: i) to quantify and measure each fertilizer-derived N fate in the plants, and determine the nitrogen recovery efficiency of each N source in the blend; ii) to evaluate corn grain yield response to N rates (blend) in contrasting cropping systems, and to assess the posibility of reducing N rate when applying a blend of two enhanced efficiency N fertilizers compared to the application of regular urea; iii) understand and monitor changes in plant biomass and N uptake during the growing season. Fertilizer N contributed with less than 50% of the total plant N uptake at all evaluated corn growth stages (V4, V12, R2, and R6). At V4 growth stage, most of the N in the plant derived from fertilizer (NPDF) was provided by NBPTU, while later in the season, most of the NPDF was provided by PSCU. At harvest, most of the plant N was allocated in the grains (59%). Of the total plant N, 64% was supplied by the native soil N pool, 26% was provided by PSCU, and 10% by NBPTU. Therefore, NBPTU provided N to corn early in the season, while PSCU played a crucial role supplying N later in the season, as plants demand for N increased. Soil N was the main N source at all GS and this fraction decreased as N rate increased. At harvest, 64% of the total plant N was derived from the soil native N pool, 26% derived from PSCU, and 10% from urea. The measured fertilizer NRE of urea was in average 36%, and the estimated NUE from PSCU was 51%. In the second study, corn grain yield varied between sites, probably due to soil and climate characteristics of each site. Corn grain yield, N uptake, and biomass production were greatly impacted by fertilizer N. Grain yield and N uptake showed a quadratic response to N rates (blend). The blend of PSCU and NBPTU, applied at corn planting and incorporated into the soil proved to be a great strategy to attain yields at N rates below those needed when using regular urea. The third chapter focused on corn biomass and N uptake and partitioning throughout the growing season, and it was demonstrated that the amount of N uptake after flowering can reach up to 50% of the total plant N, thus, N availability must be guaranteed in late vegetative corn growth stages, and especially in the reproductive stages, which can be achieved by adopting enhanced efficiency N fertilizers such as the blend of PSCU and NBPTU used in this study.
A mistura de fertilizantes nitrogenados de liberação controlada e estabilizados representa uma alternativa para fornecer nitrogênio (N) em todos os estádios da cultura do milho, além de ser uma opção válida para reduzir custos em comparação ao uso exclusivo de produtos de liberação controlada. Neste sentido, conduziram-se experimentos de campo na região Sudeste do Brasil com a aplicação de um blend de ureia revestida com enxofre e polímeros (UREP) e ureia tratada com NBPT (U-NBPT), na proporção 70:30, aplicada na semeadura do milho, de forma incorporada. Os objetivos do trabalho foram: i) avaliar o destino do N dentro das plantas de milho proveniente dos fertilizantes misturados e determinar a eficiência de recuperação de cada um; ii) avaliar a resposta do rendimento de grãos de milho a doses de N (blend) em sistemas de produção contrastantes e avaliar a possibilidade de reduzir as doses de N quando aplicado o blend em comparação à ureia convencional; iii) entender e monitorar as mudanças da biomassa e o nitrogênio dentro das plantas de milho ao longo do ciclo da cultura. No primeiro estudo, o N na planta proveniente da UREP, da U-NBPT, e do solo (N-Solo) variaram ao longo do ciclo do milho. Contudo os fertilizantes nitrogenados contribuiram com menos de 50% do N total da planta em todos os estadios avaliados (V4, V12, R2 e R6). No estádio V4, a maior parte do N na planta proveniente de fertilizante (NPPF) foi fornecido pela U-NBPT, enquanto que nos estadios seguintes, a maior parte do NPPF foi fornecido pela UREP. O N-Solo foi o maior fornecedor de N para a planta, mas a contribuição diminuiu com o aumento das doses de N. Na colheita, 59% do total do N da planta foi alocado nos grãos. Do total de N da planta, 64% foi proveniente do N-Solo, 26% foi fornecido pela UREP, e 10% pela U-NBPT. A eficiência de recuperação da UREP e U-NBPT foram, respectivamente, 51 e 36%. No segundo estudo, o rendimento de grãos de milho variou entre locais, provavelmente devido às condições edafo-climáticas de cada área experimental. A aplicação do fertilizante nitrogenado influenciou o rendimento de grãos de milho, a produção de biomassa e acúmulo de N em todos os locais. O rendimento de grãos e acúmulo de N mostraram uma resposta quadrática às doses de N (blend). A incorporação do blend de UREP e U-NBPT na semeadura do milho mostrou-se como uma ótima estratégia para evitar perdas massivas de N e mostrou que pode atingir produtividade similar a ureia convencional com doses de N menores. O terceiro capítulo, com foco no acúmulo e particionamento da biomassa e N nas plantas de milho ao longo do ciclo, desmonstrou que a quantidade de N absorvido após o florescimento pode chegar a 50% do total de N acumulado nas plantas, pelo que adequada disponibilidade de N deve ser garantida nos estádios vegetativos finais e nos estádios reprodutivos da cultura do milho, o que pode ser conseguido com o uso de misturas de UREP e U-NBPT.

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16

Armstrong, Christen Taylor. "Nitrogen Isotope Fractionation and Toxin Production during The Uptake of Micromolar Concentrations of Nitrate, Ammonium, and Urea By A Marine Dinoflagellate". W&M ScholarWorks, 2017. https://scholarworks.wm.edu/etd/1499449867.

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Despite an increased global interest in harmful algal bloom (HAB) species and eutrophication, the relationship between nutrient sources and changes in species composition or toxicity remains unclear. Stable isotopes are routinely used to identify and track nitrogen (N) sources to water bodies, as sources can be differentiated based on stable isotope values. While literature is available describing N fractionation by diatoms and coccolithophores, data are greatly lacking regarding isotope fractionation by dinoflagellates. Here we investigate the fractionation of nitrogen isotopes by saxitoxin-producing Alexandrium fundyense, to validate the use of the δ15N of particulate organic matter and identify the nitrogen source fueling a dinoflagellate bloom and its toxicity. The effects of N chemical form on isotope fractionation, toxin content, and toxicity, were investigated using isolates in single-N and mixed-N experiments. Growth on NO3-, NH4+, or urea, resulted in isotope fractionation of 2.761.48‰, 29.019.32‰, or 0.340.19‰, respectively, with the lowest cellular toxicity and toxin quotas reported during urea utilization. Toxin composition and growth rates, however, remained constant across all N treatments, showing no effects of NO3-, NH4+, or urea utilization. Alexandrium fundyense was then preconditioned to either NO3-, NH4+, or urea, and abruptly inoculated into mixed-N medium containing all three chemical forms. All treatments initially utilized NH4+ and urea upon inoculation into mixed medium, suggesting no effect of preconditioning. Cells only began utilizing NO3- after NH4+ decreased below 2-4 M in the medium. During the inhibition of NO3- uptake by NH4+ utilization, the cellular δ15N was at its lowest (-5‰), and through the course of the experiment, the δ15N continuously changed to mimic the isotope value of the most recent N source(s) being utilized. When utilizing multiple sources, the isotope signature of the cells fell between the signal of the two N sources. Together this suggests that in NO3- and urea rich environments, the 15NPOM would reliably look like the source or sources of nitrogen utilized, but that caution should be taken in NH4+ rich environments where the large value could lead to misinterpretation of the signal. Nutrients are only one factor influencing bloom dynamics, but information about the relative importance of natural or anthropogenic nutrients in the development and toxicity of bloom events is necessary to predict future shifts in phytoplankton species composition, density, and toxicity.

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17

Eriksson, Torsten. "Milk production from leguminous forage, roots and potatoes : effects on microbial protein supply and nitrogen efficiency /". Uppsala : Dept. of Animal Nutrition and Management, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/a422.pdf.

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18

Ouyang, Duosheng. "New fertilizer combinations for improved nitrogen and phosphorus use efficiency and reduced environmental damage in corn production". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0004/NQ30353.pdf.

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19

George, Mary. "Urea and Non-Protein Nitrogen Metabolism in Infants : With Special Reference to the Sudden Infant Death Syndrome (SIDS)". Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5141-1/.

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20

Nascimento, Rildo Santana do [UNESP]. "Fontes e épocas de aplicação de nitrogênio em feijoeiro de inverno em sistema plantio direto". Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/98912.

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O nitrogênio é o nutriente absorvido em maior quantidade pelo feijoeiro, sendo que o manejo da adubação nitrogenada pode interferir no desenvolvimento e na produtividade da cultura. Neste sentido, o trabalho foi desenvolvido na Fazenda Experimental da UNESP – Ilha Solteira localizada em Selvíria, Mato Grosso do Sul, com o objetivo de estudar o efeito de fontes e épocas de aplicação do nitrogênio no desenvolvimento e produtividade do feijoeiro de inverno no sistema plantio direto utilizando irrigação por aspersão em dois anos de cultivo (2006 e 2007). O solo do local é do tipo Latossolo Vermelho argiloso, a área foi cultivada nos 5 anos anteriores com milho no verão e feijão no inverno. O cultivar utilizado foi o Pérola e o delineamento experimental foi o em blocos casualizados com 16 tratamentos dispostos em esquema fatorial 2 x 8, sendo duas fontes de nitrogênio (uréia e sulfonitrato de amônio), aplicadas em sete ocasiões (30 dias antes da semeadura, 15 dias antes da semeadura, na semeadura, 15 dias após a semeadura, 30 dias após a semeadura, 1/3 na semeadura + 2/3 15 dias após a semeadura, 1/3 na semeadura + 2/3 30 dias após a semeadura) na dose de 90 kg de N ha-1, além da testemunha (sem aplicação de N). Os resultados obtidos revelaram influência das fontes na população de plantas somente no segundo ano de cultivo e a população média de plantas em cada ano de cultivo pode ter influenciado direta ou indiretamente as demais variáveis. Maiores valores de massa seca de plantas foram observados quando o nitrogênio foi aplicado em dose total na semeadura. O teor de nitrogênio foliar não apresentou diferença entre os tratamentos devido à fontes ou épocas de aplicação de N, porém em 2006 os tratamentos que receberam N foram superiores à testemunha. O número de vagens planta-1 e de grãos planta-1 não foram influenciados...
Nitrogen is the nutrient uptaken in larger amount in common bean, and the management of the nitrogen fertilization can interfere in common bean crop yield. The work was developed at experimental station of University of São Paulo State – Ilha Solteira - Campus, located in Selvíria, State of Mato Grosso do Sul – Brazil, on a dystrophic clayey Haplic Acrustox cultivated in the previous five years with corn in the summer and common bean in the winter. The objective was to study the effect of sources and time of N application in common bean growth cropped under no-tillage, irrigated by sprinkle. Pérola cultivar was used and the experimental design was a randomized complete blocks, with 16 treatments in a factorial scheme 2 x 8: two sources of nitrogen (urea and ammonium sulfonitrate - fertilizer with inhibitor of nitrification), applied in seven times (30 days before sowing, 15 days before sowing, at sowing, 15 days after sowing, 30 days after sowing, 1/3 at sowing + 2/3 15 days after sowing, 1/3 at sowing + 2/3 30 days after sowing) and the control (without N) in two cropping years (2006 and 2007). The obtained results only revealed influence of sources in the stand at the second cropping year and the medium stand obtained in each cropping year might have influenced direct or indirectly the other results. Higher values of plant dry mass were obtained when the nitrogen was applied in total dosage at sowing. The nitrogen content on the leaves did not present difference among treatments; however, in 2006 the treatments that received N were superior to the control. The number of pods per plant and seeds per plant were not influenced by treatments. The number of seeds per pod and the mass of 100 grains were influenced by times of nitrogen application in 2006; however, with apparent relation to other production components results. The sources and nitrogen time application did not influence the grain yield of winter common bean in no till system.

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21

Laberge, MacDonald Tammy. "Molecular Aspects of Nitrogen Metabolism in Fishes". Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_dissertations/668.

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Molecular aspects of nitrogen metabolism in vertebrates is an interesting area of physiology and evolution to explore due to the different ways in which animals excrete nitrogenous waste as they transition from an aquatic to a terrestrial lifestyle. Two main products of nitrogen metabolism in fishes are ammonia and urea. Ammonia is produced during protein catabolism and build up of ammonia is toxic. Some aquatic vertebrates convert ammonia into a less toxic compound urea via de novo synthesis through the ornithine-urea cycle (O-UC). Five enzymes are involved in the O-UC: carbamoyl phosphate synthetase (CPS), ornithine carbamoyl transferase (OCT), argininosuccinate synthetase (ASS), argininosuccinate lyase (ASL), and arginase (ARG). An accessory enzyme, glutamine synthetase (GS) also participates in the "fish-type" O-UC. Teleosts excrete ammonia passively over their gills into the aquatic environment. The teleost, Opsanus beta, has been shown to increase urea production after 48 hours of crowding. This thesis explored how crowding stress affected nitrogen metabolite levels of ammonia and urea and O-UC gene expression and enzyme activity in O. beta. Lungfishes while in an aquatic environment avoid ammonia toxicity by releasing excess ammonia across their gills, but when stranded on land they produce urea through the O-UC. Urea production via the O-UC has a metabolic cost of at least four ATP molecules. This thesis explored the response of a lungfish, Protopterus annectens, to six days of aerial exposure and re-immersion conditions by measuring concentrations of O-UC mRNA expression and enzyme activity and nitrogen metabolites ammonia and urea. CPS acts as the entry point to the O-UC and based on enzymatic studies, most aquatic vertebrates utilize one isoform of this enzyme (CPSIII) while terrestrial vertebrates utilize a different isoform of this enzyme (CPSI). Lungfishes are a particularly interesting group of air-breathing fishes, not only because of their link to the origins of tetrapods, but also because CPS I may have originated within this group. Both CPS III and CPS I have been enzymatically described within this group. This thesis uses phylogenetics to investigate how CPS nucleotide sequences in lungfishes evolved compared to other vertebrates.

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22

BISPO, Safira Valença. "Substituição total do milho e parcial do farelo de soja por palma forrageira e uréia para vacas em lactação". Universidade Federal Rural de Pernambuco, 2009. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/6913.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The experiment was carried out with the aim of assessing the effect of the total replacement of corn meal and partial replacement of soybean meal with spineless cactus and urea in the diet of 5/8 Holstein-Gir dairy cows on the milk yield and composition as well as intake and apparent digestibility of nutrients. Eight cows with a mean body weight and daily milk production of ±540 and ±14 kg, respectively, were distributed in two 4x4 Latin squares. The experimental diets were composed of increasing levels of spineless cactus (45, 50, 55 and 60% DM) plus urea, completely replacing corn meal and partially replacing soybean meal. Each experimental period lasted 15 days, 10 of which were for the adaptation of the animals and five were for the data and sample collection. The intake of dry matter, organic matter, neutral detergent fiber, total carbohydrates, non-fibrous carbohydrates; content and production (kg/day) of fat, protein, total dry extract of the milk, digestibility of the dry matter, crude protein or ether extract, neutral detergent fiber, total carbohydrates and non-fibrous carbohydrates, Plasma Urea Nitrogen, milk Urea Nitrogen and urinary excretion of urea were not affected by total replacement of corn meal and partial replacement of soybean meal with spineless cactus and urea, with medians of 6,72; 14,59; 6,79; 12,49; 5,76; 3,88; 0,48; 3,25; 12,47; 61,08; 66,52; 55,79; 49,61; 65,64; 83,03; 14,69; 14,92 e 589,55, respectively. The milk production was reduced linearly with the inclusion spineless cactus and urea in the diet, ranging from 13,51 kg/day to 11,54 kg/day. The total replacement of corn meal and partial replacement of soybean meal with spineless cactus and urea were not affected feeding and rumination time or feeding, rumination efficiency (kgDM/h), total mastication time and idle time. However, The rumination efficiency (kgNDF) showed a quadratic effect. The total mastication time and idle time were not affected by total replacement of corn meal and partial replacement of soybean meal with spineless cactus and urea. However, the depression of milk can be tolerated under certain economic conditions.
O experimento foi realizado com o objetivo de avaliar o efeito da substituição total do milho e parcial do farelo de soja por palma forrageira e uréia na alimentação de vacas leiteiras 5/8 Holandês-gir sobre a produção e composição do leite; consumo, digestibilidade aparente dos nutrientes e comportamento ingestivo. Foram utilizadas oito vacas com peso corporal médio e produção de leite média diária de ±540 e ±14kg, respectivamente, distribuídas em dois quadrados latino 4x4. As dietas experimentais eram compostas de níveis crescentes de palma forrageira (45, 50, 55 e 60% MS) mais uréia, substituindo totalmente o milho e parcialmente o farelo de soja. Cada período experimental teve duração de 15 dias, sendo 10 para adaptação dos animais e cinco para coleta dos dados e amostras. Os consumos de matéria seca, matéria orgânica, fibra em detergente neutro, carboidratos totais e carboidratos não fibrosos; teores e a produções, em kg/dia, de gordura, proteína e extrato seco total do leite e a digestibilidade da matéria seca, proteína bruta, extrato etéreo, fibra em detergente neutro, carboidratos totais e carboidratos não fibosos, nitrogênio uréico no plasma, nitrogênio uréico no leite e excreção de uréia na urina não foram influenciados pela substituição total do milho e parcial do farelo de soja por palma e uréia, apresentando médias de 16,72; 14,59; 6,79; 12,49; 5,76; 3,88; 0,48; 3,25; 12,47; 61,08; 66,52; 55,79; 49,61; 65,64; 83,03; 14,69; 14,92 e 589,55, respectivamente. A produção de leite diminuiu linearmente com a inclusão de palma e uréia, variando de 13,51 kg/dia para 11,54 kg/dia. A inclusão de palma gigante e uréia nãoinfluenciaram os tempos de alimentação e de ruminação e nem as eficiências de alimentação e de ruminação (kgMS/h). No entanto, a eficiência de ruminação (kg FDN/hora) apresentou comportamento quadrático. O tempo de mastigação total e o tempo de ócio não foram influenciados pela inclusão de palma na dieta. Porém, a substituição total do milho e parcial do farelo de soja por palma e uréia diminuiu a produção de leite, esta que pode ser tolerada sob certas condições econômicas.

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Nascimento, Rildo Santana do. "Fontes e épocas de aplicação de nitrogênio em feijoeiro de inverno em sistema plantio direto /". Ilha Solteira : [s.n.], 2008. http://hdl.handle.net/11449/98912.

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Orientador: Orivaldo Arf
Banca: Salatiér Buzetti
Banca: Rogério Peres Soratto
Resumo: O nitrogênio é o nutriente absorvido em maior quantidade pelo feijoeiro, sendo que o manejo da adubação nitrogenada pode interferir no desenvolvimento e na produtividade da cultura. Neste sentido, o trabalho foi desenvolvido na Fazenda Experimental da UNESP - Ilha Solteira localizada em Selvíria, Mato Grosso do Sul, com o objetivo de estudar o efeito de fontes e épocas de aplicação do nitrogênio no desenvolvimento e produtividade do feijoeiro de inverno no sistema plantio direto utilizando irrigação por aspersão em dois anos de cultivo (2006 e 2007). O solo do local é do tipo Latossolo Vermelho argiloso, a área foi cultivada nos 5 anos anteriores com milho no verão e feijão no inverno. O cultivar utilizado foi o Pérola e o delineamento experimental foi o em blocos casualizados com 16 tratamentos dispostos em esquema fatorial 2 x 8, sendo duas fontes de nitrogênio (uréia e sulfonitrato de amônio), aplicadas em sete ocasiões (30 dias antes da semeadura, 15 dias antes da semeadura, na semeadura, 15 dias após a semeadura, 30 dias após a semeadura, 1/3 na semeadura + 2/3 15 dias após a semeadura, 1/3 na semeadura + 2/3 30 dias após a semeadura) na dose de 90 kg de N ha-1, além da testemunha (sem aplicação de N). Os resultados obtidos revelaram influência das fontes na população de plantas somente no segundo ano de cultivo e a população média de plantas em cada ano de cultivo pode ter influenciado direta ou indiretamente as demais variáveis. Maiores valores de massa seca de plantas foram observados quando o nitrogênio foi aplicado em dose total na semeadura. O teor de nitrogênio foliar não apresentou diferença entre os tratamentos devido à fontes ou épocas de aplicação de N, porém em 2006 os tratamentos que receberam N foram superiores à testemunha. O número de vagens planta-1 e de grãos planta-1 não foram influenciados...(Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Nitrogen is the nutrient uptaken in larger amount in common bean, and the management of the nitrogen fertilization can interfere in common bean crop yield. The work was developed at experimental station of University of São Paulo State - Ilha Solteira - Campus, located in Selvíria, State of Mato Grosso do Sul - Brazil, on a dystrophic clayey Haplic Acrustox cultivated in the previous five years with corn in the summer and common bean in the winter. The objective was to study the effect of sources and time of N application in common bean growth cropped under no-tillage, irrigated by sprinkle. Pérola cultivar was used and the experimental design was a randomized complete blocks, with 16 treatments in a factorial scheme 2 x 8: two sources of nitrogen (urea and ammonium sulfonitrate - fertilizer with inhibitor of nitrification), applied in seven times (30 days before sowing, 15 days before sowing, at sowing, 15 days after sowing, 30 days after sowing, 1/3 at sowing + 2/3 15 days after sowing, 1/3 at sowing + 2/3 30 days after sowing) and the control (without N) in two cropping years (2006 and 2007). The obtained results only revealed influence of sources in the stand at the second cropping year and the medium stand obtained in each cropping year might have influenced direct or indirectly the other results. Higher values of plant dry mass were obtained when the nitrogen was applied in total dosage at sowing. The nitrogen content on the leaves did not present difference among treatments; however, in 2006 the treatments that received N were superior to the control. The number of pods per plant and seeds per plant were not influenced by treatments. The number of seeds per pod and the mass of 100 grains were influenced by times of nitrogen application in 2006; however, with apparent relation to other production components results. The sources and nitrogen time application did not influence the grain yield of winter common bean in no till system.
Mestre

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Miranda, Mariana Santos de. "Efeitos da substituição parcial do farelo de soja por uma fonte de proteína microbiana derivada de levedura, em dietas de vacas holandesas em lactação". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/74/74131/tde-01022016-135600/.

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Foi conduzido um estudo com vacas leiteiras no Centro de Análise e Pesquisa Tecnológica do Agronegócio - Bovinos de Leite, do Instituto de Zootecnia, em Nova Odessa, SP, com o objetivo de avaliar os efeitos da substituição parcial do farelo de soja da dieta por uma fonte de proteína microbiana derivada de levedura (PML), e a sua combinação com uma ureia de liberação lenta (ULL), sobre o consumo de MS, produção e composição do leite, bem como alguns parâmetros sanguíneos e o balanço nitrogenado. Foram utilizadas oito vacas primíparas da raça Holandês, distribuídas aleatoriamente em dois quadrados latinos 4x4 em tratamentos arranjados em esquema fatorial 2x2, sendo que cada período experimental foi composto por 28 dias com 21 dias de adaptação e 7 dias de coleta. Foram comparadas quatro dietas, compostas por 49% de volumoso (47% de silagem de milho e 2% de feno de Tifton) e 51% de concentrado, com teor médio de 16,8% de proteína bruta e 2,5Mcal/kg EM. Na dieta controle (CTL = sem PML e sem ULL) o farelo de soja foi a principal fonte proteica e nas outras três dietas o farelo de soja foi parcialmente substituído por 15 g/kg MS de PML (com PML e sem ULL) ou por 7,5 g/kg MS de ULL (sem PML e com ULL) ou ambos, 15 g/kg MS PML+ 7,5 g/kg MS de ULL (com PML e com ULL). Houve interação entre PML e ULL para o consumo de MS (P=0,0003) e produção de leite (P=0,0013). As vacas que receberam o tratamento ULL tiveram menor consumo de MS, sem afetar a produção de leite comparado às vacas que receberam o tratamento PML+ULL (P≤0,05). Não houve interação para os componentes do leite obtido, exceto para o extrato seco desengordurado (P=0,0086), as vacas que receberam o tratamento CTL tiveram os maiores teores de ESD no leite comparada as vacas que receberam o tratamento ULL (P=0,0002) e esses teores mais elevados foram iguais aos das vacas que receberam o tratamento PML (P=0,066). Apesar de não ter havido interação, as vacas que receberam os tratamentos sem ULL tiveram maiores teores de proteína, caseína e sólidos totais no leite comparado às vacas que receberam os tratamentos com ULL (P≤0,05). Não houve interação entre PML e ULL para eficiência na produção de leite (P=0,0694), porém a eficiência na produção de leite corrigida para energia foi maior para as vacas que receberam tratamentos com ULL do que as vacas que receberam os tratamentos sem ULL (P≤0,05). Não houve interação entre PML e ULL para os parâmetros sanguíneos analisados (P>0,05) exceto para o teor de K (P=0,0098). Os teores de hematócrito e hemoglobina foram maiores nas vacas que receberam tratamento com ULL comparado aos valores encontrados nas vacas que receberam tratamento sem ULL (P≤0,05), não afetando a homeostasia. O teor de N retido (balanço de N) foi maior para os animais que receberam o tratamento CTL devido a diferença encontradas no teor de N ingerido e excretado nas fezes (P≤0,05). A eficiência do uso de N aumentou com a substituição do farelo de soja por PML, ULL ou ambos (P≤0,05). A substituição do farelo de soja pela PML, ULL ou por ambos em dietas de vacas leiteiras, teve efeitos sobre o consumo de MS, a produção e composição do leite, bem como na ingestão de N, secreção de N no leite, excreção fecal de N e no balanço nitrogenado. De maneira geral, é possível fazer a substituição do farelo de soja pela PML, ULL ou ambos, sem afetar negativamente os parâmetros de produtividade. Os resultados obtidos foram similares ao tratamento CTL em relação ao consumo, produção de leite e balanço nitrogenado permitindo espaço para a inclusão de alimentos mais baratos e garantindo melhor fornecimento de energia.
This study was conducted to evaluate the effects of partial replacement in the diet of dairy cows of soybean meal by a yeast-derived microbial protein source (YMP) or a combination of YMP with a slow release urea (SRU), on dry matter intake, milk production and composition, blood parameters and nitrogen balance. Eight first lactation cows were distributed randomly into two 4x4 Latin squares, in a 2x2 factorial arrangement of treatments, with four periods with 28 days each one (21 days of adaptation and 7 days of collection). The base diet had 49% roughage (47% corn silage and 2% Tifton hay) and 51% concentrate, with an average of 16.8% crude protein and 2.5 Mcal/kg dry matter (DM). In the control diet (CTL = without YMP and without SRU) soybean meal was the main protein source and in the three other diets the soybean meal was partially replaced by 15 g/kg DM of YMP or 7.5 g/kg DM SRU, or both, 15 g/kg DM YMP plus 7.5 g/kg DM SRU. There was an interaction between YMP and SRU for DM intake (P=0.0003) and milk production (P=0.0013). The cows that received SRU treatment had lower DM intake not affecting milk production compared to cows that received the YMP+SRU treatment and differences among treatments for DM intake and milk production (P≤0,05). There was no interaction of the milk components, except for nonfat dry milk (P=0.0086), the cows that received CTL treatment had the highest nonfat dry milk compared to cows received the SRU treatment (P=0.0002) and these higher levels were equal to those of cows received the YMP treatment (P=0.066). Although there was no interaction, the cows that received the treatments without SRU had higher protein, casein and total solids in milk compared to cows received treatments SRU (P≤0.05). There was no interaction between YMP and SRU for milk production efficiency (P=0.0694), but efficiency in the milk production corrected for energy was greater for cows received SRU treatments than cows received treatments without SRU (P≤0.05). There was no interaction between YMP and SRU for the analyzed blood parameters (P>0.05) except for the K content (P=0.0098). The levels of hematocrit and hemoglobin were higher in cows that received treatment with SRU compared to cows that received treatment without SRU (P≤0.05), not affecting homeostasis. The nitrogen retained (N balance) was higher for animals that received CTL treatment due to differences in N content ingested and excreted in the feces (P≤0.05). The efficiency of use of N increased with the substitution of soybean meal for PML, ULL or both (P≤0.05). The substitution of soybean meal by YMP, SRU or both in dairy cow diets, had effects on DM intake, milk yield and composition, as well as N intake, milk secretion of N, fecal excretion of N and nitrogen balance. In general, it is possible to replace soybean meal for PML, ULL or both, without impacting negatively the production performance parameters. The results obtained in the CTL treatment in the consumption of dry matter, production of milk and nitrogen balance allowing the inclusion of cheaper feeds allowing for better energy supply.

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Teixeira, César Roberto Viana. "Ureia e sal mineral em suplementos para vacas mestiças leiteiras". Universidade Federal de Viçosa, 2014. http://locus.ufv.br/handle/123456789/5814.

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This study aimed to evaluate the use of supplements with different proportions of urea and mineral salt, for dairy crossbred cows fed with sugarcane on intake and digestibility of dry matter (DMI and DMD respectively) and its constituents ,milk production and composition, feed efficiency , excretion of nitrogenous compounds and microbial protein synthesis . Ten crossbred cows with average body weight of 480 kg (± 30) were used after lactation peak, distributed in a 5x5 Latin square design, duplicate, with four treatments of supplements with different percentages of urea and mineral salt, being these: 10:10; 10:20, 20:10 and 20:20, completed to 100% with corn meal, beyond the fifth treatment consisting only of mineral salt. The experiment lasted 14 days each, with the first seven days for adaptation and the other to collect data and samples. Data were analyzed using the MIXED procedure of SAS, adopting a significance level of 0.05. The use of supplements provided increased (P < 0.05) in total DMI, sugarcane, supplement and all constituents of DM. In percent of DM intake, supplementation increased the level of organic matter (OM), crude protein (CP) and non-fibrous carbohydrates (NFC) and decreased of neutral detergent fiber digestibility (NDFD). The increase of urea level in supplements caused lower DMI of supplement, total, OM and NFC, but increased the levels of OM, CP, NDFD, decreasing only content NFC. With the increase in the proportion of mineral salt in the composition of supplements decreased (P < 0.05) levels of OM and CP in the diet. The use of supplements increased (P < 0.05) the digestibility of DM, OM, CP and NFC and daily intake of DM, OM, CP, EE, NDFD and NFC digestible and, consequently, total digestible nutrients (TDN) and digestible energy consumed. The increased level of urea in supplements decreased (P < 0.05) consumption of DM, OM, EE and NFC digestible. The increased level of mineral salt did not change the parameters of digestibility and intake of digestible nutrients. The use of supplements resulted in maintenance of animals body weight, unlike the control diet, which was daily loss (P < 0.05) from 0.95 kg/day. The treatments with the presence of supplements showed higher (P < 0.05) milk production. Milk composition did not change (P> 0.05) for the diet. The use of supplements resulted in fewer values (P < 0.05) of somatic cell count (SCC) and total bacterial count (TBC) in milk. Supplements, when compared to control or mineral salt (0:100) had (P < 0.05) lower gCP/kgTDN ratio and increased urea nitrogen excretion in urine, blood plasma and milk. The increased level of mineral salt practically did not change the parameters of daily excretion of purine derivatives, microbial N compounds and concentrations of urea nitrogen, except to urinary nitrogen urea that reduced. Supplements can be used to correct nutritional deficiencies of sugarcane, resulting in increased intake, digestibility and milk production. Supplements with 20% urea (20:10 e 20:20) in its composition resulted in lower consumption with the same animal performance and can be concluded that these treatments showed better utilization efficiency.
Esse estudo teve como objetivo avaliar o uso de suplementos, com diferentes proporções de ureia e sal mineral, para vacas mestiças leiteiras alimentadas com cana-de-açúcar, sobre o consumo e digestibilidade da matéria seca (CMS e DMS, respectivamente) e dos seus constituintes, produção e composição do leite, eficiência alimentar, excreção de compostos nitrogenados e síntese de proteína microbiana. Foram utilizadas dez vacas mestiças, com peso corporal médio de 480 kg (± 30), após o pico de lactação, distribuídas em um delineamento em quadrado latino 5x5, duplicado, com quatro tratamentos de suplementos com diferentes porcentagens de ureia e sal mineral, sendo estas: 10:10; 10:20; 20:10 e 20:20, completados para 100% com fubá de milho, além do quinto tratamento composto somente de sal mineral. Os períodos experimentais tiveram duração de 14 dias cada, sendo os sete primeiros dias para adaptação e os demais para coleta de dados e amostras. Os dados foram analisados utilizando-se o procedimento MIXED do programa SAS, adotando-se um nível de significância de 0,05. O uso de suplemento proporcionou aumento (P<0,05) do CMS total, de cana, suplemento e de todos os constituintes da MS. Em porcentagem da MS consumida, a suplementação aumentou os teores de MO, PB e CNF e diminuiu de FDNcp. O aumento do teor de ureia no suplemento causou diminuição do CMS de suplemento, MS total, MO e CNF, porém aumentou os teores de MO, PB, FDNcp, diminuindo somente o teor de CNF. Com o aumento da proporção de sal mineral na composição do suplemento, houve redução (P<0,05) dos teores de MO e PB na dieta consumida. O uso de suplemento aumentou (P<0,05) a digestibilidade da MS, MO, PB e CNF e o consumo diário de MS, MO, PB, EE, FDNcp e CNF digestíveis e, consequentemente de nutrientes digestíveis totais (NDT) e energia digestível (ED) consumida. O aumento do nível de ureia no suplemento diminuiu (P<0,05) o consumo de MS, MO, EE e CNF digestíveis. O aumento do nível de sal mineral não alterou os parâmetros de digestibilidade e consumo de nutrientes digestíveis. O uso de suplementos resultou em manutenção do peso corporal dos animais, ao contrário da dieta controle, com a qual houve perda diária (P<0,05) de 0,95 kg/dia. Os tratamentos com presença de suplemento proporcionaram maior (P<0,05) produção de leite. A composição do leite não sofreu alteração (P>0,05) em função da dieta. O uso de suplemento resultou em menores valores (P<0,05) de contagem de células somáticas (CCS) e contagem bacteriana total (CBT) no leite. Os suplementos, quando comparados ao controle ou sal mineral (0:100), apresentaram (P<0,05) menor relação gPBmic/Kg NDT e maior nitrogênio ureico no soro sanguíneo (NUS), nitrogênio ureico na urina (NUU) e nitrogênio ureico no leite (NUL). O aumento do nível de sal mineral não alterou os parâmetros de excreção diária de derivados de purinas, produção de compostos nitrogenados microbianos e concentração de nitrogênio ureico,exceto o nitrogênio ureico na urina, que reduziu. Os suplementos podem ser usados para corrigir as deficiências nutricionais da cana-de-açúcar, resultando em maior consumo, digestibilidade e produção de leite. Os suplementos com 20% de ureia (20:10 e 20:20) em sua composição resultaram em menor consumo com mesmo desempenho dos animais, podendo-se concluir que esses tratamentos apresentaram melhor eficiência de utilização.

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Carareto, Rafaela. "Uso de uréia de liberação lenta para vacas alimentadas com silagem de milho ou pastagens de capim Elefante manejadas com intervalos fixos ou variáveis de desfolhas". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/11/11139/tde-10032008-180721/.

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Foram conduzidos 2 estudos com vacas leiteiras no Departamento de Zootecnia da ESALQ/USP com os objetivos de avaliar a utilização de fonte de uréia de liberação lenta (Optigen ®) e ID (intervalos de desfolhas) fixos ou variáveis em pastagens de capim Elefante. No Experimento 1, foram utilizadas 32 vacas no terço médio de lactação, produzindo 20,8 kg leite dia-1 e pesando 524 kg no início do período experimental. O tratamento controle (C) continha apenas farelo de algodão como suplemento protéico. No tratamento U30, 30 % da PB do farelo de algodão foi substituída por uréia. No tratamento O30, 30% da PB do farelo de algodão foi substituída pela uréia de liberação lenta e no tratamento O60, 60% da PB do farelo de algodão foi substituída pela uréia de liberação lenta. O delineamento experimental adotado foi o quadrado latino 4 x 4 com 8 repetições e as variáveis foram analisadas utilizando o PROC MIXED (SAS). A produção de leite não diferiu (P>0,05) entre os tratamentos C (20,2 kg dia-1), O30 (19,8 kg dia-1) e U30 (19,5 kg dia-1). No tratamento O60 a produção de leite foi reduzida (19,0 kg dia-1) em comparação aos tratamentos C e O30 (P<0,05) e U30 (P<0,06). Não houve diferenças (P>0,05) nos teores de gordura, proteína, lactose, sólidos totais e contagem de células somáticas entre os tratamentos. A concentração de uréia no leite (NUL) foi menor (P<0,05) no tratamento U30 (7,2 mg dL-1) em relação aos tratamentos O30 (9,3 mg dL-1), C (9,1 mg dL-1) e O60 (8,9 mg dL- 1). No Experimento 2 foram utilizadas 32 vacas no terço médio de lactação, produzindo 15 kg de leite dia-1, pesando 466 kg. A área experimental foi composta por 56 piquetes de Pennisetum purpureum cv. Cameroon, com 0,1 ha cada um. Os tratamentos corresponderam a duas estratégias de ID dos pastos de capim Elefante (ID fixos de 27 dias ou ID variáveis determinados pela altura do dossel de 1,0 m) e dois concentrados isoprotéicos com diferentes fontes de N (farelo de algodão e uréia de liberação lenta). Foi adotado o delineamento experimental em blocos aleatorizados e as variáveis foram analisadas utilizando o PROC MIXED (SAS). Não houve efeito (P>0,05) de fonte de N sobre os parâmetros avaliados. Houve diferença estatística (P<0,05) entre os tratamentos com ID fixos de 27 dias e os com ID variáveis para as alturas das pastagens no pré-pastejo (1,20 X 1,03 metros), no pós-pastejo (0,47 e 0,41 metros), nas massas de forragem pré-pastejo (6642 e 6209 kg MS ha-1), pós-pastejo (3666 e 3277 kg MS ha-1) e nas densidades volumétricas (55,04 e 60,06 kg MS ha-1 cm-1) para os tratamentos com ID fixos ou variáveis respectivamente. A produção de leite foi maior para os animais dos tratamentos com ID variáveis (12,59 e 12,06 kg leite dia -1) em relação aos tratamentos com ID fixos de 27 dias (10,94 e 10,66 kg leite dia -1). Os componentes do leite e taxas de ganho diário de peso não foram alterados com os tratamentos (P>0,05).
Two studies were conducted with lactating dairy cows at the Animal Sciences Department of the School of Agriculture \"Luiz de Queiroz\", University of São Paulo, to evaluate the use of a slow release urea source (Optigen®) and fixed or variable grazing intervals on Pennisetum purpureum pastures. The objective of Experiment 1 was to evaluate the partial replacement of cotton seed meal (CSM) by urea or by a slow release urea (Optigen®) on the performance of dairy cows fed corn silage. Thirty two mid lactating cows, averaging 20.8 kg of milk day-1 and 524 kg of BW at the beginning of the experimental period were used to compare the 3 treatments. The control treatment (C) contained cotton seed meal (CSM) as protein source, the U30 treatment had 30% of the CSM crude protein replaced by urea, the O30 treatment, had 30% of the CSM crude protein replaced by slow release urea and the O60 treatment, had 60 % of the CSM crude protein replaced by slow release urea. A 4x4 Latin Square design was used and the variables were analyzed using the PROC MIXED (SAS). Replacing 30% of CSM crude protein by urea (U30) or slow release urea (O30) had no effect (P>0.05) on milk yield (20.2, 19.5, and 19.8 kg day-1 respectively). However, replacing 60% of CSM crude protein by slow release urea (O60) (19.0 kg day-1) reduced milk yield compared to C and O30 (P<0.05) and U30 (P<0.06). Milk fat, milk protein, milk lactose, and milk total solids contents, and milk somatic cells counting were not different (P>0.05) among the treatments. The milk urea nitrogen (MUN) was lower (P<0.05) for the U30 treatment (7,2 mg dL-1) compared to the other treatments (9.3 mg dL-1 (O30); 9.1 mg dL-1 (C), and 8.9 mg dL-1 (O60)). On Experiment 2, were used 32 midlactating cows averaging 15 kg of milk day -1 and 466 kg of BW at the beginning of the trial. Experimental area contained 56 paddocks of Pennisetum purpureum cv. Cameroon, averaging 0.1ha each. Treatments were 2 grazing interval (fixed grazing intervals of 27 days or variable grazing intervals based on the dossel height of 1 m), and two protein supplement (CSM x slow release urea). A randomized block design was used and the variables were analyzed using PROC MIXED (SAS). There were no effects (P>0.05) for N source on the evaluated parameters. There were differences (P<0.05) between the fixed and variable grazing intervals (GI). Pre-grazing dossel height (1.03 x 1.2 m), post-grazing stubble height (0.41 e 0.47 meters), pre-grazing (6209 and 6642 kg DM ha-1) and post-grazing forage mass (3277 and 3666 kg DM ha-1) were lower (P<0.05) for variable GI compared to 27 days fixed GI. Volumetric density (55.04 and 60.06 kg DM ha-1 cm-1) was higher for variable GI (P<0.05). Cows grazing pastures managed with variable GI produced more milk (P<0.06) (12.32 and 10.8 kg milk day -1) than cows grazing pastures managed with fixed GI. Milk components and cow average daily gain were not affected by the treatments (P>0.05).

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Queiroz, Oscar Cezar Müller. "Associação de aditivos microbianos na ensilagem e o desempenho de vacas em lactação recebendo silagem de cana-de-açúcar comparada a volumosos tradicionais". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/11/11139/tde-05102006-142405/.

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O presente trabalho teve como objetivo avaliar o efeito de aditivos químicos, microbianos e a associação destes sobre a dinâmica fermentativa e a estabilidade aeróbia de silagens de cana-de-açúcar, além de avaliar o desempenho de vacas leiteiras de alto potencial produtivo recebendo rações com diferentes fontes de volumosos. No primeiro experimento silagens de cana-de-açúcar foram confeccionadas em silos laboratoriais de 20L, contendo válvula para escape de gases e coleta de efluente. O experimento seguiu o delineamento inteiramente ao acaso, em esquema fatorial sendo constituído por dois períodos de abertura (80 e 140 dias) com 8 tratamentos e 4 repetições. Os tratamentos avaliados foram: uréia 1%MV, 1,2- propanodiol 1%MS (1,2 p), L. L. buchneri 5x104 ufc/g (Lb), L. diolivorans em duas concentrações 1x105 ufc/g (Ld 105 e 1x10 6 ufc/g (Ld 106), L. diolivorans 1x106 ufc/g + L.buchneri 5x104 ufc/g (Ld+Lb) e 1,2-propanodiol 1%MS + L. diolivorans 1x 106 ufc/g (1,2 p+Ld 106). Após abertos os silos foram realizadas avaliações de estabilidade aeróbia em sala com ambiente controlado. Os tratamentos contendo L. diolivorans mais 1,2- propanodiol ou L. diolivorans mais L. buchneri apresentaram os menores valores de perda total de matéria seca 20,42% e 23,73%, respectivamente. Ambos tratamentos também resultaram nos menores teores de etanol, 2,1% e 3,93% da MS, e de perdas gasosas, 20,36% e 20,62%. Tanto para FDN quanto FDA, foram observados valores menores para os tratamentos contendo uréia, 1,2-p + Ld 106 Ld + Lb e Ld 105. Quanto à estabilidade aeróbia houve diferenças entre os períodos de abertura, sendo de 48,03h aos 140 dias e de 31,35h aos 80 dias. O microrganismo L. diolivorans se constituiu em uma alternativa capaz de trazer benefícios quanto às perdas fermentativas e composição bromatológica em silagens de cana-de-açúcar. O segundo experimento avaliou o desempenho de vacas recebendo rações contendo diferentes fontes de volumosos: cana-de-açúcar in natura, silagem de cana-de-açúcar inoculada com L. buchneri silagem de milho e proporções equivalentes de silagem de milho e cana-deaçúcar in natura (50:50). O experimento contou com 48 vacas Holandesas em estágio intermediário de lactação, distribuídas em múltiplos quadrados latinos 4x4 com períodos de 21 dias, sendo 14 dias de adaptação e 7 dias de coleta de amostras. Além da avaliação de desempenho, foram realizadas análises de composição bromatológica dos alimentos e do leite, e avaliações do comportamento ingestivo dos animais e da estabilidade aeróbia dos volumosos e das rações. Os dados de desempenho mostraram diferenças na ingestão de MS, com maiores valores observados para o tratamento silagem de cana-de-açúcar (23,5 kg/dia) e a mistura cana-de-açúcar mais silagem de milho (23,5 kg/dia). Todas as rações resultaram em produções elevadas de leite (22,65 kg/dia) as quais não diferiram entre si. A composição do leite variou somente para o teor de gordura, sendo maior para a silagem de milho (3,61%) e a mistura com cana (3,48%). A silagem de cana-de-açúcar mostrou-se como alternativa interessante frente à cana-de-açúcar in natura, e que ambas podem proporcionar elevadas produções desde que as rações sejam corretamente balanceadas.
The current study aimed to evaluate the effect of chemical and microbial additives and the combination over the fermentative dynamics and the aerobic stability in the sugarcane silage as well to study the performance of high producing dairy cows fed with different roughage sources. In the first trial, sugarcane silage was prepared in lab silos of 20L, with a gas relief valve and a device for collecting effluent. The experiment was randomly arranged, in a factorial design, with two openings 80 and 140 days, across 8 treatments and 4 replications. The treatments evaluated were: urea 1%, 1.2-propanediol 1%DM (1.2 p) L. buchneri 5x104 cfu/g (Lb), L. diolivorans in two concentrations 1x105 cfu/g (Ld 105) and 1x106 cfu/g (Ld 106), L. diolivorans 1x106 cfu/g plus L. buchneri 5x104 cfu/g (Ld+Lb) and 1.2- propanediol 1%DM plus L. diolivorans 1x 106 cfu/g (1,2 p+Ld 106). After opening the silos, the aerobic stability assay was performed in an environmental controlled room. The treatments containing Ld +1.2 p, or Ld 106 + Lb showed the lowest values of total DM loss, 20.42% and 23.73% respectively. Both treatments also showed the lowest levels of ethanol 2.1% and 3.93% of DM, and gases losses 20.36% and 20.62%. For both NDF and ADF, lower values were detected for the following treatments: urea, 1.2 p + Ld 106, Ld + Lb and Ld105. As for the aerobic stability, there were differences between the openings dates, 48.03h (140 days) and 31.35h (80 days). The microorganism L. diolivorans turn out to be promising alternative able to show positive results on the fermentative losses and nutritive value in sugarcane silage. The second experiment evaluated the performance of cows fed rations with different sources of roughage: fresh sugarcane, sugarcane silage, corn silage and mixture of corn silage and fresh sugarcane (50:50). Forty eight mid lactation Holstein cows were assigned to multiple latin square design 4x4, with 21-d period (14-d adaptation and 7-d the sample collection). As well the animal performance fed and milk compositions were evaluated and also ingestivo behavior of cows and the aerobic stability of forage and rations were analyzed. The performance data has shown differences in the dry matter intake (DMI), with the highest values observed for the sugarcane silage (23.5 kg/day) and the mixture (23.5 kg/day). All rations resulted in high milk production (22.65 kg/day) which did not differ among treatments. The milk composition varied only for the fat percentage, which was higher for the corn silage treatment (3.61%) and the mix (3.48%). Sugarcane silage was exhibited as an interesting forage alternative when compared to fresh sugarcane. Both options may support high milk yields by the adequacy of rations balancing.

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Mendes, Alcester. "Fornecimento de uréia na dieta de catetos (Pecari tajacu) e uso de isótopo estável 15N como marcador para estimativa da síntese de nitrogênio microbiano". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/64/64134/tde-10062009-113522/.

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A utilização racional da fauna silvestre é um processo benéfico, por resultar em vantagens econômicas e sociais, e ao mesmo tempo auxiliar no processo de conservação das espécies silvestres. Entre as espécies silvestres brasileiras com potencial zootécnico, destaca-se o cateto (Pecari tajacu), um animal que consome diversos tipos de alimentos e que produz carne e couro com elevada demanda nos mercados nacional e internacional, respectivamente. Uma característica desta espécie é a presença de um pré-estômago, onde ocorre fermentação microbiana que confere a esta espécie capacidade para digerir alimentos volumosos. Objetivou-se com o presente trabalho: (i) medir a capacidade digestiva usando doses crescentes de uréia como fonte de nitrogênio não protéico (NNP) na dieta de catetos; (ii) avaliar a eficiência da microbiota do pré-estômago de catetos em proceder à fermentação anaeróbica da dieta, através da técnica de produção de gases para diferentes doses de uréia; (iii) estimar a síntese de nitrogênio microbiano in vitro utilizando o isótopo estável 15N como marcador. O trabalho foi dividido em três capítulos. No primeiro foi utilizado delineamento com distribuição inteiramente aleatória, no qual as possíveis seqüências dos tratamentos (doses de uréia: 0,0; 1,0; 1,5; 2,0 %) foram atribuídas aleatoriamente em cinco ensaios com quatro animais cada. No segundo e terceiro capítulos, o delineamento empregado foi com distribuição inteiramente aleatória em arranjo fatorial 4 X 2, no qual foram utilizados quatro doses de uréia, duas fontes de inóculo (espécie animal: cateto e ovino) e cinco repetições. Os resultados para digestibilidade da MS, PB e FDN não foram influenciados (P>0,05) pelas doses de uréia, contudo, podem ter proporcionado incremento na síntese microbiana melhorando a digestibilidade da fibra. O BN cresceu linearmente com o incremento das doses de uréia (R2 = 0,97), apresentando retenção de 8,95 g dia-1 de N para maior dose e 5,22 g dia-1 de N para a dieta sem uréia, não havendo efeito significativo (P>0,01) para as perdas de N fecal e urinário. No segundo trabalho, houve produção de gases (197 mL g-1 MS) utilizando inóculo de cateto, contudo, não apresentou correlação com os tratamentos. A digestibilidade da MS (MSD), MO (MOD) e FDN (FDND) e a produção de gases em função da MSD, MOD e FDND apresentaram diferença significativa (P<0,01) para os tratamentos, havendo crescimento linear (P>0,01) para digestibilidade de FDN (R2 = 0,50) e regressão linear inversa para produção de gases em função da FDND (R2 = 0,51). A produção de gás metano em função da MS, MO, MSD e MOD utilizando inóculo de cateto, apresentou diferença significativa (P<0,01) para os tratamentos, porém com baixo coeficiente de correlação entre as doses crescentes de uréia. A síntese de nitrogênio microbiano para o inóculo de cateto, não apresentou efeito significativo (P>0,05) para os tratamentos. A produção de nitrogênio amoniacal foi significativa (P<0,01) para as diferentes doses de uréia com ajuste de regressão linear aditiva (R2 = 0,50). A produção de gases mostra que a dieta concentrada foi degradada devido à presença de microrganismos no inóculo de cateto. Estes microrganismos foram capazes de hidrolisar a uréia em amônia e esta, por sua vez, convertida em compostos nitrogenados para síntese microbiana, mostrando a eficiência da fisiologia digestiva deste animal no aproveitamento do NNP. Além disso, os resultados in vivo indicam que o pré-estômago dos catetos foi capaz de utilizar uréia como fonte NNP, podendo substituir parte da proteína dietética em sua alimentação
The rational use of wild fauna is a beneficial process, as it results in economical and social advantages, and at the same time helps in the conservation process of wild species. Among the wild Brazilian species with zootechnical potential, the collared peccary (Pecari tajacu) stands out as an animal that consumes several kinds of foods and produces meat and pelt with a high demand in national and international markets, respectively. A characteristic of this species is the presence of a forestomach, where the microbial fermentation occurs, which enables this species to digest coarse roughage. The objective of this study was (i) to measure the digestive efficiency in the using increasing doses of urea as source of non protein nitrogen (NPN) in the collared peccary diet; (ii) to evaluate the efficiency of collared peccary fore-stomach microorganisms in proceed to anerobic fermentation of diet, using the in vitro gas production technique at different urea doses; (iii) to estimate the in vitro microbial nitrogen synthesis using stable isotope 15N as marker.This study is divided into three chapters. In the first chapter, an experimental design with entirely randomized distribution was used where the urea doses (0.0; 1.0; 1.5; 2.0 %) were randomly used in five assays with four animals each. In the second and third chapters, the experimental design used had an entirely randomized distribution, resulting in a 4 x 2 factorial experiment, in which four urea doses, and two sources of inoculum (collared peccary and sheep) and five replications. The DM, CP, and NDF digestibility results were not influenced (P>0.05) by the urea doses, however, they may have increased the microbial synthesis, improving fiber digestibility. The NB increased linearly with the increasing doses of urea (R2 = 0.97), presenting an N retention of 8.95 g day-1, for the highest dose of urea and 5.22 g day-1 for a non urea diet, without significant effect (P>0.01) to the losses of fecal and urinary N. In the second study, there was gas production (197 mL g-1 DM) using the collared peccary inoculums; however there was no correlation with the treatments. The DM (DMD), OM (OMD) and NDF (NDFD) digestibility and gas production as a function of DMD, OMD and NDFD showed a significant difference (P<0.01) for the treatments, showing a linear increase (P>0.01) in NDF digestibility (R2 = 0.50) and inverse linear regression for gas production as a function of NDFD (R2 = 0.51). The methane gas production as a function of DM, OM, DMD, and OMD using peccary fore-stomach inoculum showed significant difference (P<0.01) for the treatments, but with a low correlation coefficient between increasing doses of urea. The microbial nitrogen synthesis for the peccary inoculum did not show significant effect (P<0.01) for the treatments, in contrast, the production of ammoniacal nitrogen was significant (P<0.01) at different urea doses with an adjustment of additive linear regression (R2 = 0.50). The gas production showed that concentrated diet was degraded because of microorganisms presents in the collared peccary inoculum. These microorganisms present in the inoculum could hydrolyse the urea in ammonia and this, in its turn, is converted into nitrogen compounds for microbial synthesis, showing the efficiency of this animal´s digestive physiology in NPN use. Furthermore, in vivo results show that the pre-stomach of the collared peccary was capable to use urea as source NPN, thus could substitute part of the dietary protein in his/her feeding

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Jiménez, Aliaga Ronald. "Uso de desperdicios de tubérculos de papa y de rastrojos de maíz tratados con urea en la alimentación estratégica de ovinos". Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2007. https://hdl.handle.net/20.500.12672/1247.

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Los efectos del tamaño de partícula (TP) y tipo de amonificación-conservación (TAC) fueron evaluados sobre la digestibilidad y consumo de rastrojos de maíz, en ovinos. En un segundo experimento, la óptima combinación TP-TAC fue usada como dieta base para evaluar el efecto de niveles crecientes de suplementación con subproducto de papa sobre la ganancia de peso vivo, en ovinos. En el primer experimento se emplearon cuatro ovinos criollos en un arreglo factorial 4 x 4: TP (1, 2, 3 y 4 cm) x AC [no amonificado ni ensilado (SS) y tres tratamientos amonificados con variantes de conservación en silo plástico: aéreo (SA), cubierto con tierra sobre el suelo (SC) y enterrado en poza de compostaje (SE)]; dando un total de 16 tratamientos, bloqueados por ovino (4). No se encontró efecto de TP, mientras que los tratamientos con amonificación (SA, SC, SE) obtuvieron mejor digestibilidad y consumo (p menor 0,01); además SA y SE fueron mejores para la digestibilidad de proteína y fibra. En suma, la amonificación del rastrojo de maíz picado a un tamaño cercano a los 2 cm y en SA se considera el más apropiado desde el punto de vista económico, práctico y técnico. En el segundo experimento se emplearon 120 ovinos Junín (69 hembras y 51 machos) en un arreglo factorial 2 x 5 (sexo x tipo de alimentación: pastoreo 8 h y cuatro tratamientos con 4 h/día de pastoreo más rastrojo de maíz amonificado (2 cm en SA) a discreción con adición de: 0, 200, 400 y 600 g/ovino/día de subproducto de papa) para un período de engorde de 24 días. La respuesta en ganancia de peso a la suplementación con subproducto de papa fue mayor para ovinos machos (p menor 0,01), en los cuales, el patrón de respuesta para los niveles crecientes de subproductos de papa fue de tipo cuadrático (p menor 0.05), donde un nivel de 570 g de subproducto de papa dio ganancias de peso e índices económicos similares a los del sistema pastoril (8 h/día). Se concluye que la inclusión de subproducto de papa en niveles de 570 g/ovino/día a dietas de pastoreo restringido (4 h/día) más rastrojo de maíz amonificado es una estrategia de alimentación viable y económica para engordar ovinos machos durante la estación seca en la Sierra Peruana.
-- The effects of particle size (PS) and type of ammoniation-preservation (AP) on the digestibility and intake of corn crop residues were evaluated using sheep as test animal. In a second experiment, the optimum PS-AP combination was used a basal diet for evaluating the effect of increasing levels of supplementation with potato by-products on sheep liveweight gain. PS (1, 2, 3, and 4 cm) and type of AP [non ammoniated no silage (NA), and three ammoniated treatments with different plastic silage: aerial silage on the soil (AS), silage on the soil covered with ground (SC) and silage interred in a compost pit (SI)] were arrangement in a 4 x 4 factorial blocked by sheep (4). There was no effect of PS. On the other hand, ammoniated silage treatments (AS, SC, SI) significantly (p less 0.01) improved the digestibility and intake of the corn crop residue. Particularly, AS and SI performed better in protein and fiber digestibility. In short, the 2 cm-AS combination was considered the most appropriate from an economic, practical and technical point of view. In the second experiment, 120 Junín sheep (69 female and 51 male) were used in a factorial arrangement 2 x 5 (sex x feeding type: 8 h/day of grazing and four treatments with addition of 0, 200, 400 and 600 g of potato by-products over a 2 cm-AS corn crop residue basal diet on a restricted, 4-h a day grazing systems for 24 days. Liveweight gains were higher (p less 0.01) for male sheep. The response pattern to the increasing levels of potato by-products suplementation was quadratic (p less 0.01) whith a level of 570 g of potato by-products giving a biological and economic performance similar to the full (8-h a day) grazing systems. Our data suggest that the inclusion of 570 g of potato by-products on ammoniated corn crop residues is a practical and economical feeding strategy for fattening male sheep on a 4-h a day restricted grazing regime during the dry season in the Peruvian Highland.
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Santiago, Alberto Magno Ferreira. "Uréia em dietas à base de cana-de-açúcar para vacas leiteiras". Universidade Federal de Viçosa, 2009. http://locus.ufv.br/handle/123456789/5810.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
We evaluated the effect of four levels of mixing urea:ammonium sulfate (9:1) (Urea) on sugarcane (0, 0.4, 0.8 and 1.2%, fed basis) on consumption, on the intake and diet digestibility, production performance, metabolism of nitrogenous compounds and economy of diets in dairy cows producing less than 15 kg/day. We used 12 Holstein cows distributed in three 4x4 Latin squares. Diets were formulated to be isonitrogenous initially containing 12.5% crude protein, dry matter basis. The concentrated feed has been supplied in proportion to the milk production, making it a ratio of 1 kg for every 3 kg of milk. The sugarcane used had 21.9 brix. No effect of urea level in cane sugar on the intake and digestibility of dietary constituents, as well as on the production and composition of milk. It was found that the increase in the level of urea in sugar cane increases (P < 0.05) linearly the concentration of nitrogen-urea at the plasma, urinary excretion of nitrogen-urea (NUU in g/day) and the contribution of nitrogen-urea in the urinary excretion of nitrogen and reduce (P < 0.05) milk production per unit of nitrogen excreted in the urine. Although there wasn't detected significant effects (P > 0.05) for urinary excretion of nitrogen (UN) and nitrogen balance (NB), there was an increase of 50.3% on the UN and the consequent reduction 112.8% for the BN with increasing from 0 to 1.2% urea in sugarcane. These results demonstrate that even using sugarcane with high sugar content (50.5% of CNFcp, DM basis), the increased level of urea extends ureogênese and losses of nitrogen (N) in urine, reducing the efficiency of use of N, increasing energy expenditure and environmental liability. From the sensitivity analysis of the balance with the price of urea, it was found that the use of the same is feasible when the price is equal to or less than R$ 2.0/kg, equivalent to 2.17 times the price of kg of soybean, fed basis. In addition, it was found that regardless of the price range between R$ 0.40 to R$ 2,0/kg, the urea level that maximizes the balance with supply remains at 1.20%, fed basis of sugarcane.
Avaliou-se o efeito de quatro níveis da mistura de uréia:sulfato de amônio (9:1) (uréia) na cana-de-açúcar (0; 0,4; 0,8 e 1,2%, base da matéria natural) sobre o consumo, sobre o consumo e digestibilidade da dieta, desempenho produtivo, metabolismo de compostos nitrogenados e economicidade das dietas em vacas leiteiras com produção abaixo de 15 kg/dia. Utilizou-se 12 vacas da raça Holandesa, distribuídas em três quadrados latinos 4 × 4. As dietas foram inicialmente formuladas para serem isonitrogenadas contendo 12,5% de proteína bruta, base da matéria seca. A ração concentrada foi fornecida proporcional à produção de leite, perfazendo-se uma relação de 1 kg para cada 3 kg de leite produzido. A cana-de-açúcar utilizada apresentou 21,9 oBrix. Não houve efeito do nível de uréia na cana-de-açúcar sobre o consumo e coeficiente de digestibilidade dos constituintes da dieta, bem como sobre a produção e composição do leite. Verificou-se que o aumento no nível de uréia na cana aumenta (P<0,05) linearmente a concentração de nitrogênio-uréico no plasma, a excreção urinária de nitrogênio-uréico (NUU, em g/dia) e a contribuição do nitrogênio-uréico na excreção urinária de nitrogênio, além de reduzir (P < 0,05) a produção de leite por unidade de nitrogênio excretado na urina. Apesar de não terem sidos detectados efeitos significativos (P > 0,05) para a excreção urinária de nitrogênio (NU) e para o balanço de nitrogênio (BN), verificou-se aumento de 50,3% na NU e, conseqüente, redução de 112,8% no BN com o aumento de 0 para 1,2% de uréia na cana. Esses resultados demonstram que mesmo utilizando-se cana-de-açúcar com alto teor de açúcar (50,5% de CNFcp, base da MS), o aumento do nível de uréia amplia a ureogênese e as perdas de compostos nitrogenados (N) na urina, reduzindo a eficiência de utilização dos N, elevando-se o gasto energético e o passivo ambiental. A partir da análise de sensibilidade do saldo com alimentação ao preço da uréia, verificou-se que o uso da mesma é viável quando o preço for igual ou inferior à R$ 2,0/kg, o que equivale a 2,17 vezes o preço do kg do farelo de soja, base da matéria natural. Em adição, verificou-se que independente da faixa de preço entre R$ 0,40 a R$ 2,0/kg, o nível de uréia que permite maximizar o saldo com alimentação permanece em 1,20%, base da matéria natural da cana-de-açúcar.

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Hipfner, J. Mark. "Egg production in the thick-billed murre (Uria lomvia) and razorbill (Alca torda) : a life-history perspective /". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0015/NQ55126.pdf.

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Almeida, Ana Ruth Estrela. "Coproduto de fecularia de mandioca e ureia protegida na alimentação de vacas em lactação". Universidade Estadual do Oeste do Paraná, 2016. http://tede.unioeste.br:8080/tede/handle/tede/1594.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
This study aimed to evaluate the efficiency of the of dehydration process of co-product of sun cassava starch manufacturer (CFM) and the effect of storage period on their nutritional and microbiological quality. CFM dehydration curve of sun and nutritional quality was performed for 0, 30, 60, 90, 120 and 180 days of storage and the microbiological quality, in addition to the aforementioned times was also evaluated the 15th day of storage. The nutritional quality and the population of CFM yeasts and enterobacteria were not affected by the 180 days but a quadratic effect (P <0.05) for the bacteria Clostridium genus was verified. The main fungi found were Aspergillus, Fusarium and Penicillium. In this context, the dehydration of CFM to the sun is an effective practice in the conservation of this material, allowing a high storage time. Another objective was to evaluate the levels of protected urea Optigen® II associated with the co-product of cassava starch manufacturer (CFM) for the feeding of dairy cows, for this a study was done using five lactating cows fed diets containing levels (0%, 0.4%, 0.8%, 1.2% and 1.6%) of protected urea Optigen® II in the concentrate. Cows were distributed in a 5x5 Latin square, evaluating the intake and digestibility of nutrients, milk production and composition, metabolic parameters, microbial synthesis and economic viability of diets. There was no significant effect (P>0.05) on the intake and digestibility of dry matter and other nutrients. Urea levels did not influence the production and composition of milk. For metabolic parameters, the glucose in serum had no effect between treatments, and no interaction between time and treatment, serum urea nitrogen did not differ between treatments, but there was the time effect and interaction between time and treatment. The synthesis of microbial protein showed a quadratic effect (P<0.05), maximum point estimated to be 158.19 g.kg-1 TDN assigned to the level of 0.78% protected urea. In this context, the level of 1.6% protected urea associated with the CFM did not affect dry matter intake, digestibility of dry matter and other nutrients, as well as the production and composition of milk ensuring economic return to the productive sector
Objetivou-se avaliar a eficiência do processo de desidratação ao sol do coproduto de fecularia de mandioca (CFM), bem como o efeito do período de armazenamento sobre sua qualidade nutricional e microbiológica. Realizou-se a curva de desidratação do CFM ao sol e a qualidade nutricional durante 0, 30, 60, 90, 120 e 180 dias de armazenamento e para a qualidade microbiológica, além dos tempos supracitados, foi avaliado também o 15° dia de armazenamento. A qualidade nutricional e a população de leveduras e enterobactérias do CFM não foram afetadas até os 180 dias, porém foi verificado efeito quadrático (P<0,05) para as bactérias do gênero Clostridium. Os principais fungos encontrados foram dos gêneros Aspergillus, Fusarium e Penicillium. Nesse contexto, a desidratação do CFM ao sol é uma prática eficiente na conservação desse material, permitindo um elevado tempo de armazenamento. Outro objetivo foi avaliar os níveis de ureia protegida Optigen® II associada ao coproduto de fecularia de mandioca (CFM) na alimentação de vacas em lactação. Para isso foi realizado um estudo utilizando cinco vacas lactantes alimentadas com dietas contendo níveis (0%, 0,4%, 0,8%, 1,2% e 1,6%) de ureia protegida Optigen® II no concentrado. As vacas foram distribuídas em um quadrado latino 5x5, avaliando-se a ingestão e a digestibilidade de nutrientes, a produção e composição do leite, os parâmetros metabólicos, a síntese microbiana e a viabilidade econômica das dietas. Não houve efeito significativo (P>0,05) na ingestão e digestibilidade da matéria seca e demais nutrientes. Os níveis de ureia não influenciaram na produção e composição do leite. Para os parâmetros metabólicos, a glicose no soro não apresentou efeito entre os tratamentos e nem interação entre tempo e tratamento, o nitrogênio ureico do soro não diferiu entre os tratamentos, no entanto houve efeito do tempo e interação entre o tempo e o tratamento. A síntese de proteína microbiana apresentou efeito quadrático (P<0,05), com ponto de máxima estimado em 158,19 g.kg-1 de NDT atribuído ao nível de 0,78% de ureia protegida. Nesse contexto, o nível de 1,6% de ureia protegida associada ao do CFM não afetou a ingestão de matéria seca, digestibilidade da matéria seca e demais nutrientes, bem como a produção e composição de leite garantindo retorno econômico ao setor produtivo

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Bentes, Jones Gomes. "Influência do espaçamento na produtividade de sementes de malva (Urena lobata L.) em terra firme no Amazonas". Universidade Federal do Amazonas, 2015. http://tede.ufam.edu.br/handle/tede/4671.

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CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
The Malva (Urena lobata L.) is currently the main species used for natural fiber production in the Amazonas State. However, seed supply remains a strategic and critical issue to the production chain of the fiber. Due to total lack of local production of seeds, Amazonas fiber producers depend on acquisition by the state govern of about 100 tons of seeds produced in other regions, each year. Thus become necessary studies to determine technical recommendations for the implementation of seed production systems adapted to local conditions, for the state to become self-sufficient in the supply of this raw material. This study aimed to evaluate the effect of different spacing on productivity of Malva plants for seed production. The experiment was conducted at the Experimental Farm of Federal University of Amazonas – UFAM, in Manaus. The experimental design was completely randomized with three treatments corresponding to the spacing of (T1) 1.0 x 1.0m, (T2) 1.5 x 0.5m (T3) 1.0 x 0.5 m with 10 repetitions, each repetition corresponding to the average of four plants. The following characteristics were evaluated: plant height, stem diameter, number of branches, number of flowers, number of green fruits and number of ripe fruit, the seed production and dry weight of plants. The results were submitted to analysis of variance by F test at 5% probability. For the phenological parameters, 1,5 x 0,5 was higher in stem diameter, fresh fruits and ripe fruit. The treatments 1,5 x 0,5 was also statistically superior for the variable of production of seed. It was concluded that for the establishment of U. lobata L. seed production systems in Amazonas, it is recommended to use 1.5 x 0.5m spacing, in which can be obtained about 1,700 kg of seed per hectare.
A Malva (Urena lobata L.) é atualmente a principal espécie utilizada para a produção de fibra natural no Estado do Amazonas. No entanto, o fornecimento de sementes continua a ser uma questão estratégica e fundamental para a cadeia de produção da fibra. Devido à falta total de produção local de sementes, produtores de fibras Amazonas dependem aquisição pelo governo estadual de cerca de 100 toneladas de sementes produzidas em outras regiões, a cada ano. Assim, tornam-se necessários estudos para determinar as recomendações técnicas para a implantação de sistemas de produção de sementes adaptadas às condições locais, para que o Estado se torne autossuficiente no abastecimento desse insumo. Este estudo teve como objetivo avaliar o efeito de diferentes espaçamentos na produtividade das plantas de Malva para produção de sementes. O experimento foi realizado na Fazenda Experimental da Universidade Federal do Amazonas - UFAM, em Manaus. O delineamento experimental foi inteiramente casualizado, com três tratamentos que correspondem aos espaçamentos de (T1) 1,0 x 1,0 m, (T2) 1,5 x 0,5m (T3) 1,0 x 0,5 m, com 10 repetições, cada repetição correspondendo à média de quatro plantas. As características avaliadas foram: altura da planta, diâmetro do caule, número de ramos, número de flores, número de frutos verdes e número de frutos maduros, a produção de sementes e peso seco das plantas. Os resultados foram submetidos à análise de variância pelo teste F a 5% de probabilidade. Para os parâmetros fenológicos, o tratamento 1,5 x 0,5 se desenvolveu mais em diâmetro do caule, frutas frescas e frutas maduras. O espaçamento 1,5 x 0,5 também foi estatisticamente superior para a variável da produção de sementes. Concluiu-se que, para o estabelecimento de sistemas de produção de sementes de U. lobata L. no Amazonas, recomenda-se a utilização de 1,5 x 0,5 m de espaçamento, em que pode ser obtido cerca de 1.700 kg de sementes por hectare.

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Maciel, Alexandre Chaves. "Tendências do cultivo da malva (Urena Lobata L.) por agricultores familiares em Manacapuru-AM". Universidade Federal do Amazonas, 2015. http://tede.ufam.edu.br/handle/tede/4081.

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CNPQ - Conselho Nacional de Desenvolvimento Científico e Tecnológico
This study was developed to evaluate insalubrities of the production process and factors of the mauve cultivation abandon (Urena lobata L.), for family farmers, resident in the community of São Sebastião, Rio Solimões in Manacapuru/AM, municipality; through the posing of socio-economic information which contribute to the abandonment of the cultivation of vegetable fibers. The data used for this research come from field surveys from the application forms with the participation of mauve producers of the Ilha Marrecão in the period between 2013 to 2014. The cultivation of this culture occurs on a lowland environments in the state of Amazonas, being an exacting culture in workmanship without technological advances and total dependence on external inputs, coupled with the innumerable insalubrities of its production chain ranging from planting to extraction fiber, contributing to the reduction in prices and leading to the abandonment by some Riverine families who are totally dependent on this activity genuinely Amazon. Through this research we seek to understand the obstacles that directly affect the organizational structure and production of these families, identifying relevant and critical points related to the decision making by the malvicultors as the abandonment of their crops, so that, they can act directly on the resolution of existing problems in its supply chain, focusing on maintaining their production systems in order to continue a genuinely Amazonian culture, weakened from their way of cultivation and gradual loss of profitability because it is a highly demanding culture in labor, favoring an increase in production costs and acting as the main and decisive reason for the abandonment and / or recovery of this type of cultivation by some riparian producers.
Está pesquisa foi desenvolvida objetivando avaliar as insalubridades do processo produtivo e os fatores de abandono do cultivo da malva (Urena lobata L.), por agricultores familiares residentes na comunidade de São Sebastião, rio Solimões, no município de Manacapuru/AM, através do levantamento de informações socioeconômicas que contribuem para a desistência do cultivo de fibras vegetais. Os dados utilizados nesta pesquisa são provenientes de levantamentos de campo a partir da aplicação de formulários com a participação dos produtores de malva da ilha do Marrecão, no período compreendido entre os anos de 2013 a 2014. O cultivo desta cultura ocorre em ambientes de várzea no estado do Amazonas, sendo uma cultura exigente em mão de obra, sem incremento tecnológico, com total dependência de insumos externos, aliado as inúmeras insalubridades de sua cadeia produtiva que vão desde o plantio até a extração da fibra, contribuindo para a redução dos preços e levando ao abandono por parte de algumas famílias ribeirinhas que são totalmente dependentes desta atividade genuinamente amazonense. Através desta pesquisa buscam-se entender os entraves que afetam diretamente a estrutura organizacional e produtiva dessas famílias, identificando-se pontos relevantes e decisivos referente à tomada de decisão por parte dos malvicultores quanto ao abandono de seus cultivos, para que se possa atuar diretamente na resolução dos problemas existentes em sua cadeia produtiva, com foco na manutenção de seus sistemas de produção, visando a continuidade de uma cultura genuinamente amazonense, fragilizada a partir de seu modo de cultivo e da perda gradativa de sua rentabilidade, por ser uma cultura altamente exigente em mão de obra, favorecendo o aumento dos custos de produção e atuando como a principal e determinante razão para o abandono e/ou retomada desse tipo de cultivo por parte de alguns produtores ribeirinhos.

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Rivera, Solé María Belén. "Efecto del nivel de suplementación energética sobre la respuesta metabólica y productiva, en vacas consumiendo praderas con alto contenido protéico". Tesis, Universidad de Chile, 2013. http://repositorio.uchile.cl/handle/2250/148402.

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Tesis para optar al Título Profesional de Ingeniero Agrónomo y al Grado de Magister en Ciencias Agropecuarias, Mención Producción Animal
Se realizó un ensayo en la Estación Experimental Oromo dependiente del Departamento de Producción Animal de la Facultad de Ciencias Agronómicas, Universidad de Chile. El objetivo de esta investigación fue evaluar el efecto de la suplementación energética sobre la respuesta metabólica y productiva, en vacas consumiendo praderas de un alto contenido proteico. El estudio fue realizado durante los meses de Noviembre y Diciembre del año 2011 y tuvo una duración de 21 días. Se utilizaron 15 vacas de la raza Holstein Neozelandés para analizar parámetros productivos y sanguíneos, las que fueron asignadas a un diseño completamente al azar con 3 tratamientos. Para el estudio de parámetros ruminales se utilizaron 3 vacas de la misma raza provistas de cánula ruminal, las que fueron asignadas a un diseño de cuadrado latino de 3x3, con tres tratamientos y tres periodos. Los tratamientos para ambos diseños fueron: T0, solo pastoreo; T2, pastoreo más 4 Kg diarios de concentrado compuesto en un 50% de maíz roleado al vapor y 50% avena entera y T3, pastoreo más 6 Kg diarios del mismo concentrado. Los animales fueron suplementados dos veces al día y realizaron pastoreo de tipo rotativo en franjas. El peso vivo y condición corporal fueron registrados durante todos los días. La producción de leche se registró los últimos cuatro días de cada semana y la composición de leche se analizó semanalmente. Las muestras de sangre y de líquido ruminal fueron recolectadas los dos últimos días de cada periodo, las muestras de sangre en la mañana y las ruminales durante mañana y tarde. En relación a parámetros metabólicos, el amoniaco ruminal disminuyó significativamente (P<0,05) con el aumento del nivel de concentrado (17,7; 15,0 y 13,9 mg·dl-1 para T0, T2 y T3). El amoniaco plasmático disminuyó (P<0,05) con la inclusión de concentrado pero no se observaron diferencias entre los niveles de concentrado (0,497; 0,416 y 0,391 mg·dl-1 para T0, T2 y T3). La concentración de urea plasmática disminuyó significativamente (P<0,05) al aumentar el concentrado (28,3; 26,2 y 21,8 mg·dl-1 para T0, T2 y T3). El peso vivo y la producción de leche no fueron afectados por los tratamientos (P>0,05). En términos de composición láctea, no se observaron diferencias estadísticamente significativas entre tratamientos (P>0,05), exceptuando la concentración de urea láctea, la que disminuyó significativamente (P<0,05) con el aumento de concentrado en la dieta (46,8; 42,3 y 36,3 mg·dl-1 para T0, T2 y T3) Bajo las condiciones en las que fue realizada esta investigación, se concluye que al aumentar el nivel de concentrado energético en la dieta de vacas lactantes consumiendo praderas de un alto contenido proteico, se reduce la concentración de amoniaco a nivel ruminal y sanguíneo, lo que provoca una disminución importante en los niveles de urea plasmática y láctea, sin provocar efectos significativos sobre los parámetros productivos.
A research was conducted at the Oromo Experimental Station, Department of Animal Production, Faculty of Agricultural Sciences, Universidad de Chile. The objective of this study was to evaluate the effect of energy supplementation on the metabolic and productive response of dairy cows fed pasture with high protein content and high degradability. The study was conducted during November and December of 2011 and lasted for 21 days. Fifteen Cows Holstein New Zealand randomly assigned to three treatments, were used to analyze blood, and productive parameter. For the study of rumen parameters three rumen fistulated cows were assigned to three treatments rotating during three periods under a 3 x 3 Latin square design. Treatments for both experiments were: T0, cows only grazing pasture; T2, grazing pasture plus 4 Kg/day of a concentrate composed of 50% corn and 50% oats and T3, grazing pasture plus 6 Kg/day of the same concentrate. Cows were supplemented twice a day and managed under a strip grazing system. Body weight and body condition were recorded every day. Milk production was recorded the last four days of each week and milk composition was analyzed weekly. Blood samples and ruminal fluid were collected the last two days of each period, blood samples in the morning and the rumen during morning and evening. Ruminal ammonia decreased significantly (P <0,05) as the level of concentrate was increased (17,7; 15,0 and 13,9 mg·dl-1 for T0, T2 and T3). Plasma ammonia decreased (P <0,05) with the inclusion of concentrate but no differences among levels of concentrate (0,497; 0,416 and 0,391 mg∙dl-1 for T0, T2 and T3) were found. Plasma urea concentration decreased significantly (P <0.05) as concentrate was increased (28,3 ; 26,2 and 21,8 mg∙dl-1 for T0, T2 and T3). Live weight and milk production were not affected by treatments (P>0,05). No statistical differences in milk composition, among treatments were found. (P> 0,05), except milk urea concentration, that decreased significantly (P <0.05) as concentrate was increased (46,8; 42,3 and 36,3 mg∙dl-1 for T0, T2 and T3). Under the conditions in which this research was conducted, it is concluded that increasing the level of an energy concentrate in the diet of lactating cows consuming pasture of a high protein content, reduces the concentration of ammonia in the rumen and blood, with a significant decrease in plasma urea and milk levels but without any significant effects on animal productive performance.

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Rech, Ioná. "Produção e avaliação da eficiência de ureia enriquecida com aditivos para o controle da liberação do nitrogênio". Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-19032014-111122/.

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Devido à importância do aumento da eficiência agronômica dos fertilizantes nitrogenados em função do custo cada vez maior dos fertilizantes na produção agrícola, o objetivo do presente estudo foi desenvolver formulações de fertilizantes nitrogenados a base de ureia com a adição de compostos inibidores de urease (NBPT, Cu, B), enxofre elementar e um argilomineral do grupo das zeolitas compondo os grânulos internamente, a fim de minimizar as perdas de N por volatilização de amônia e por lixiviação de amônio e nitrato. O primeiro experimento foi conduzido em casa de vegetação entre janeiro e março de 2013, no departamento de ciência do solo da ESALQ, onde foram avaliadas dez formulações produzidas no Laboratório de Tecnologia de Fertilizante da Embrapa Solos, mais alguns fertilizantes comerciais (FH Nitro Mais®, FH Nitro Gold®, Super N®, sulfato de amônio e ureia). Colunas de PVC com 15 cm de diâmetro por 45 cm de altura foram montadas e preenchidas com amostra de um Latossolo Vermelho Amarelo de textura média. A volatilização de amônia foi determinada através de uma câmara semi-aberta estática instalada na parte superior de colunas. A avaliação da lixiviação do nitrato e amônio foram feitas ao final do experimento de volatilização por meio da percolação de água, simulando chuva de 15 mm por 4 dias consecutivos, nestas mesmas colunas. Em seguida foi realizada coleta de solo nas camadas de 0-10, 10-20 e 20-45 cm com a finalidade de quantificar o teor de amônio e nitrato acumulado no perfil. Em outro experimento, conduzido em casa de vegetação entre abril e maio de 2013, foi testada a eficiência de uso de N pelas plantas de milho com quatro formulações produzidas e três fertilizantes comerciais, os quais apresentaram as menores perdas de N por volatilização, acrescidos do tratamento ureia comercial e controle, sendo avaliado o N acumulado e a massa seca produzida pelo milho cultivado em vasos com 6 kg de solo. As formulações produzidas com inibidores de urease (NBPT, B, Cu) incorporado nos grânulos e estes combinados com o argilomineral apresentaram maior eficiência na redução das perdas de N por volatilização em comparação aos fertilizantes comerciais com tecnologia de revestimento desses inibidores. Os resultados da lixiviação de amônio e nitrato e o acúmulo desses íons no solo não apresentaram diferenças expressivas entre os fertilizantes produzidos e os comerciais. O acúmulo de N nas plantas com a adubação referente aos fertilizantes produzidos foi similar aos fertilizantes comerciais, porém superior à ureia comercial. No entanto, é possível afirmar que a incorporação de inibidores de urease na ureia é mais eficiente na redução das perdas de N por volatilização, comparado aos fertilizantes produzidos com a tecnologia de revestimento desses mesmos aditivos.
Due to the importance of increasing the agronomic efficiency of nitrogen fertilizers and the increasing fertilizer costs in agricultural production, the aim of this study was to develop urea-based formulations of nitrogen fertilizer with the addition of urease inhibitors (NBPT, Cu, B), elemental sulfur and clay minerals of the zeolite group, composing beads internally to minimize N losses by volatilization and leaching of ammonium and nitrate. The first experiment was conducted in greenhouse from January to March 2013 in the Department of Soil Science of ESALQ, where was assessed ten formulations produced in the Fertilizer Technology Laboratory of Embrapa Solos and some commercial fertilizers (FH Nitro Mais®, FH Nitro Gold®, Super N®, ammonium sulfate and urea). PVC columns with 15 cm in diameter and 45 cm in height were assembled and filled with soil samples of Latossolo Vermelho Amarelo medium-texture. Ammonia volatilization was determined using a semiopen static chamber installed on the top of columns. Evaluation of nitrate and ammonium leaching was taken at the end of the volatilization experiment by water percolation, simulating a rain of 15 mm for 4 consecutive days. Furthermore, soil samples were collected at 0-10, 10- 20 and 20-45 cm depth layers in order to determine the concentration of ammonium and nitrate accumulated in the profile. Another experiment, conducted in greenhouse from April to May of 2013, was carried out to test N use efficiency by corn plants with four produced formulations and three commercial fertilizers which obtained the lowest N losses by volatilization, including urea and a control treatment, being assessed N accumulated and dry matter produced by corn grown in pots with a volume of 6 kg. The formulations produced with urease inhibitor alone (NBPT, B, Cu) embedded in beads and those inhibitors combined with the clay mineral showed greater efficiency in reducing losses by volatilization compared to commercial coated fertilizer with the same inhibitors. Ammonium and nitrate leaching and soil accumulation showed no significant differences between produced formulations and commercial fertilizers. The N accumulation in corn plants grown with the new formulations was similar to commercial fertilizer, being higher to commercial urea. However, it is clear that the incorporation of a urease inhibitor in urea fertilizer is more efficient in the reduction of losses by volatilization compared to coated fertilizers produced with the same additives.

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Padovani, Kathya Regina Fioravanti. "Ureia de liberação controlada, cinética e os produtos da fermentação in vitro de Brachiaria brizantha cv. Marandu em duas idades de rebrotação". Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/74/74131/tde-25092014-145017/.

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Foi realizado no Laboratório de Ciências Agrárias da Faculdade de Zootecnia e Engenharia de Alimentos, um bioensaio de fermentação in vitro para avaliar a inclusão de doses crescentes de ureia de liberação controlada (ULC) em lâminas foliares de Brachiaria brizantha cv. Marandu em duas idades de rebrotação. Amostras colhidas em duas idades de rebrotação (28 e 65 dias, S28 e S65, respectivamente) foram incubadas em frascos com doses crescentes de ureia de liberação controlada (ULC - D0, D5, D10 e D20), em três inóculos distintos. O delineamento experimental foi em blocos casualizados fatorial 2 x 4. Foram realizadas análise de regressão e comparação entre médias pelo teste Tukey 5%. Durante 96 horas de fermentação foram colhidas s informações de leitura da produção de gases (tempos 4, 8, 12, 18, 24, 30, 36, 48, 60, 72, 84 e 96 h), concentração de N-NH3 (tempos 6, 12, 24, 48 e 96 h), e AGCC no fluido ruminal (tempos 24 e 48 h), pH (tempo 0 e 96h) e desaparecimento da FDN e MO (tempos 24, 48 e 96 h). Foram calculadas e analisadas as variáveis matemáticas geradas a partir do modelo exponencial indicando tempo de colonização (L), assíntota da curva de produção de gases (A), taxa de fermentação (µ), relação entre os tempos 48 e 96 h (R1), relação entre o tempo 96 h e Assíntota A (R2), t ½ da curva de produção de gases, Fatos de Partição MOD e AGCCtot com a produção acumulada de gases. Não foi observado efeito de doses sobre a produção total ou fracionada de AGCC em 24 e 48 horas de fermentação. Houve efeito de substrato para a síntese de AGVCR - valerato, isovalerato e outros, sendo maiores para o substrato S28, em 24 e 48 horas, indicando maior fermentação proteica. Em 24 horas, frascos contendo substrato S28 mantiveram níveis mais baixos de N-NH3 no fluido ruminal que aqueles contendo substrato S65 para doses 0, 5 e 10. Em 48 horas, as concentrações de N-NH3 indicam que a fermentação do substrato S65 foi mais eficiente na utilização de N-NH3, com concentrações significativamente inferiores de N-NH3 no fluido. O pH encontrado ao final da incubação indica adequação do processo fermentativo favorecendo microrganismos celulolíticos no fluido ruminal. Em relação à cinética fermentativa, S28 apresentou menor tempo de colonização, menor potencial de produção de gases e maiores taxas de fermentação (µ) em todos os tempos estudados. DIVMO e DIVFDN apresentaram efeito cúbico de doses para o substrato S28 durante as 24 horas de incubação. Embora o substrato S65 tenha apresentado taxa fermentativa mais lenta e apresentado menor degradação de MO e FDN nos períodos de 24, 48 e 96 horas, foi mais eficiente quando avaliado quanto ao Fator de Partição. Em conclusão, o fornecimento de Ureia de Liberação Controlada em lâminas foliares de capim-marandu foi mais eficiente na redução de N-NH3 em substratos com 65 dias de idade de rebrotação entre 24 e 48 horas de fermentação, que pode indicar maior conversão em proteína microbiana.
Was conducted at the Laboratory of Agricultural Sciences, Faculdade de Zootecnia e Engenharia de Alimentos, a in vitro fermentation bioassay to assess the inclusion of increasing doses of urea slow-release ( USR ) in leaf blades of Brachiaria brizantha cv. Marandu in two regrowth ages. Samples collected in two regrowth ages (28 and 65 days, S28 and S65, respectively) were incubated with increasing doses of slow-release urea ( USR - D0, D5, D10 and D20 ), in three different inocula. The experimental design was a randomized block factorial 2 x 4. Regression analysis and comparison of means by Tukey test 5 % were performed. During 96 hours of fermentation were reading information by gas production (4, 8 ,12, 18, 24 ,30, 36, 48, 60, 72, 84 and 96 h), concentration of NH3-N ( 6, 12, 24, 48 and 96 h ), and SCFA in ruminal fluid (24 and 48h ), pH (time 0 and 96 h ) and disappearance of NDF and OM (24, 48 and 96 h ). Were calculated and analyzed the mathematical variables generated from the exponential model indicating colonization time ( L ), asymptote of gas production ( A), fermentation rate (µ), relationship between times 48 and 96 h ( R1 ), relationship between time 96 and asymptote A (R2), t½ of the gas production curve, Factors of Partition from MOD, FDNcD and AGCCtot with the total gas production. No dose effect was observed on total production of SCFA and fractionated at 24 and 48 hours of fermentation. An effect of substrate for the synthesis of AGVCR - valerate, isovalerate and others being higher for substrate S28, 24 and 48 hours, indicating higher protein fermentation. In 24 hours, flasks containing substrate S28 maintained lower levels of NH3-N in rúmen fluid than those containing substrate S65 for doses 0, 5 and 10. Within 48 hours, the concentrations of NH3-N indicate that fermentation substrate S65 was in more efficient use of NH3-N, with significantly lower concentrations of NH3-N in the fluid. The pH found at the end of the incubation indicates suitability of the fermentation process favoring cellulolytic microorganisms. Regarding the fermentation kinetics, S28 showed lower colonization time, less potential for gas production and higher fermentation rates ( µ ) at all time points. DIVMO DIVFDN and had a cubic effect doses for the substrate S28 at 24 hours of incubation. Although the substrate S65 has shown slower fermentation rate, and showed less degradation of OM and NDF in periods of 24, 48 and 96 hours, was more efficient when assessed for Factor Partition. On 24 and 48 hours of incubation was more efficient in the degradation of OM and NDF. At 96 hours remained greater efficiency for degradation of NDF, however, no significant differences for the degradation of MO. In conclusion, the supply of urea slow-release in leaf blades of Marandu-grass was more effective in reducing NH3-N substrates 65 days old regrowth between 24 and 48 hours of fermentation, which may indicate higher conversion protein microbial.

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38

Brouard, Christine. "Contribution à l'étude de la rétention de phénylurées (herbicides) par des adsorbants modèles et des sols". Angers, 1995. http://www.theses.fr/1995ANGE0006.

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Notre objectif était d'étudier la rétention d'herbicides de la famille des phenylurées sur des adsorbants minéraux et dans le sol. Les molécules retenues sont le chloroxuron, le chlortoluron, le metobromuron, l'isoproturon et le difenoxuron. Les adsorbants utilises sont la celite, le florisil, l'alumine, le carbonate et le sulfate de calcium. Les sols étudiés sont un sol limoneux-argileux et un sol limoneux-sableux. Nous poursuivons le double but analytique et environnemental d'améliorer les étapes de purification par chromatographie d'adsorption d'extraits en vue de l'analyse de résidus, et de prévoir leur dispersion dans le sol, leur diffusion en direction des nappes et leur exposition à la dégradation microbienne. La méthode suivie passe essentiellement par le tracé de cinétiques et d'isothermes d'adsorption-désorption, et de courbes de mobilité en présence d'eau ; les variations de concentrations des urées dans la phase liquide ont été mesurées par HPLC-UV. Les isothermes ont été modélisées dans les formalismes de Freundlich, Langmuir et Temkin. Les influences sur la mobilité des urées dans des colonnes de sol, de la concentration saline de la phase aqueuse (cacl#2) et de formulants tensio-actifs (polyphénols ethoxyles) ont été évaluées par la même méthodologie. Ces études ont été complétées par l'examen de spectres IR pour caractériser les groupes structuraux de ces molécules engagés dans leur liaison avec les adsorbants. Nous mettons en évidence le rôle privilégié des groupes phenoxy dans l'adsorption sur le florisil ; des effets hydrophobes dus à la substitution des noyaux aromatiques par le chlore pourraient être à l'origine de la rétention du chloroxuron et du chlortoluron sur tous les adsorbants, et la combinaison d'effets stériques dus à la taille du brome, d'effets électroniques et dipolaires dus au groupe methoxy sur la fonction urée pourraient intervenir dans la faible rétention du metobromuron sur tous les adsorbants. Enfin parmi les formulants étudiés, seul le soprophor FL à une concentration supérieure à 0,05 g/l a un effet accélérateur marqué sur la mobilité de l'isoproturon en colonnes de sol.

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39

Sangwan, Jagbinder Singh. "Obtention in vitro de cellules puis de plantes résistantes a certains herbicides chez le datura innoxia mill. Et le nicotania tabacum l". Paris 7, 1988. http://www.theses.fr/1988PA077149.

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La mise au point d'un système pour la sélection in vitro de deux solanacées diploïdes et autogames résistantes a l'atrazine, au chlortoluron et au terbutryne, est décrite. Les effets de ces produits ont été détermines sur des cultures d'organes (explants différencies) et sur des cals (tissus indifférencies). Aucune sélection n'est possible a partir de disques foliaires, entre-nœuds, anthères et cals non chlorophylliens. On procede ensuite au repiquage des tissus sur un milieu organogène. On réalise le micro greffage des apex des tiges ainsi formées sur de jeunes plantes issues de germination. On met en évidence que le caractère de résistance est transmis a certains des embryons produits par les plantes greffées

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40

Troton, Didier. "Modifications de la composition lipidique des thylakoides intervenant au cours de l'adaptation d'euglena gracilis au diuron". Paris 7, 1987. http://www.theses.fr/1987PA077169.

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41

Ke-WeiLin y 林克衛. "Investigation on Hydrogen-rich Syngas Production of Reforming Biofuel Blended with Aqueous Urea Solution". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/w36435.

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博士
國立成功大學
系統及船舶機電工程學系
107
Biofuel and urea are all environment-friendly hydrogen carriers; they can product hydrogen-rich syngas by reforming methods for fuel cell to generate the power or for other applications. There is little literature to discuss the hydrogen-rich syngas production of biofuel blended with aqueous urea solution (AUS) by reforming. In this study, different biofuels reforming including biodiesel, bioethanol, biobutanol, and HVO blend with AUS are investigated by a thermodynamic analysis and experiment. There are four parts in this study; the first part is to discuss the reforming of biodiesel blended with AUS by thermodynamics analysis. The second part is to evaluate the hydrogen production of bioethanol blended with AUS. The main concept is to utilize the AUS to replace pure water and use a thermodynamic analysis to compare the characteristics of steam and autothermal reforming of bioethanol with/without AUS. The third part is the discussion of hydrogen-rich syngas production of biobutanol blended with AUS by a thermodynamic analysis. This part includes steam reforming of biobutanol and autothermal reforming of biobutanol feed using pure steam and AUS. Hydrogen-rich syngas production, carbon formation, and hydrogen production cost are analyzed. The fourth part is the discussion of partial reforming of biodiesel (FAME) and hydrogen vegetable oil (HVO) by experimental and thermodynamic analysis. The thermodynamic analysis is used to evaluate the effect of O2/biodiesel and O2/HVO molar ratios on hydrogen-rich syngas production. The results of first part show that at a reaction temperature of 700 oC, urea/biodiesel ratio=3, and O2/biodiesel ratio=9, the highest reforming efficiency is 83.78%, H2 production 30.43 mol, and CO production 12.68 mol. In terms of bioethanol reforming, the results show that hydrogen-rich syngas production under both steam and autothermal reforming of bioethanol with the blended AUS is higher than that under the pure steam. The best operating condition of autothermal reforming is the H2O/EtOH= 5 and the O2/EtOH= 1.2 at 800 oC, and the reforming efficiency of bioethanol with the blended AUS reaches 93.17%. The results of bioethanol reforming show that hydrogen-rich syngas production with the use of AUS is higher than that without AUS whether steam reforming or autothermal reforming. In the third part, when the AUS/butanol molar ratio is 8, and the O2/butanol molar ratio equals 3, the reforming efficiency reaches up to 81.42%. The results of partial reforming of biodiesel and HVO show that under the best operating conditions at 800 oC and an O2/ biodiesel molar ratio of 10, the concentration of the H2 is 21.96%, and the concentration of the syngas is 45.5%; at an O2/HVO molar ratio of 10, the concentration of the syngas is 45.14% with the reforming efficiency of 62.87%. In the biodiesel experimental results, when the O2/biodiesel molar ratio of 10, the H2 concentration is 18.80%, the CO concentration is 22.87%, and the reforming efficiency is 72.8%. Moreover, for HVO reforming under the air to fuel ratio of 6.30, the H2 concentration is 17.65%; the CO concentration is 17.67%, and the reforming efficiency is 62.87%. Because the composition of HVO is more complex than that of biodiesel, the reforming efficiency for HVO is lower than that for biodiesel.

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42

Chi, Chih-Wei y 紀智偉. "Effect of Urea Concentration on Production of L-Lactic Acid and Chitosan by Culture of Rhizopus oryzae". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/98178033584501145463.

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碩士
大同大學
生物工程學系(所)
94
During L-lactic acid fermentation by culture of Rhizopus oryzae ATCC 9363, the production of biomass and chitosan was affected by the urea concentration. When fermentation was carried out in a 5-L stirred fermenter by adding calcium hydroxide to control the pH at 6.0, biomass increased from 4.35 g/L to 7.25 g/L as urea from 2.5 to 10.0 g/L was used as N-source; meanwhile, the produced chitosan increased from 0.290 g to 0.841 g. The highest yield of L-lactic acid was 101.3 g/L as 5.0 g/L of urea was used. Upon 5.0 g/L of urea as N-source and 120 g/L of glucose as substrate, 8.15 g of biomass and the highest yield of chitosan at 1.362 g were obtained when pH was controlled at 6.0 by adding a mixture of sodium hydroxide and sodium bicarbonate.

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43

Lin, Zi-Yuan y 林子元. "Application of Urea and Plant Growth Regulators on Production of ‘Yu Her Pau’ Litchi (Litchi chinensis Sonn.)". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/3hkybv.

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碩士
國立屏東科技大學
農園生產系所
105
The objective of this study was to investigate the effect of utilizing Urea and Ethephon on the stage of shoot development and flowering management to inhibit the growth of vegetative shoot and flower-thinning of ‘Yu Her Pau’ Litchi, which evaluating the feasibility of Urea and treated different plant growth regulators after the fruit setting stage to prevent fruir dropping. The result indicate there was a significant effect on spraying the Ethephon and 20% Urea for shoot thinning of ‘Yu Her Pau’ Litchi. In 2015 and 2016, the shoot thinning rate of 395 ppm Ethephon were 80% (2015) and 100% (2016), and 20% Urea treatment were 75% (2015) and 95% (2016), respectively. Both Urea and Ethephon treatments had re-shoot phenomenon. It was possible on Urea treatment to increase the nitrogen content and the C / N ratio in the leaves of ‘Yu Her Pau’ Litchi, but no significant effect in the shoot. The flowering rate of spraying Ethephon was the highest (65%), 20% and 10% Urea treatments were 35% and 10%, respectively. However, the litchi flowering was still limited by the environmental temperature. In the flower-thinning experiment, Artificial pruning significantly reduced the amount of male flowers and female flowers on the spikelets, the flowers number were 516.7 and 100.3 flowers, respectively. 10% and 15% urea treatments had the downward trend of flowers number, But there was no significant effect on the rate of female flowers between the treatments. In the fruit yield experiment, The hand-thinning and 10% urea treatment of number of fruit per cluster were significantly higher (5 fruit, and 2.1 fruit, respectively). The urea treatment can significantly increased the nitrogen content in the leaves and shoots of ‘Yu Her Pau’ Litchi. Sprayed different plant growth regulators after 2 weeks of flower blooming. And in the first year experiment, there was no significant different on number of fruit per cluster and yield per plant between untreated, plant growth regulator or the girdling ringing treatments. But the total yield of 5 ppm 2,4,5-TP (2-(2,4,5-Trichlorophenoxy) propanoic acid) treatment had higher trend (24.26 kg) compared with other treatments . In the second year experiment, 5 ppm 2,4-D (2,4-dichlorophenoxyacetic acid) and 2,4,5-TP had significant higher number of fruit per cluster (2.7 and 4.0 fruits, repectively) and significant lower fruit dropping rate, compared with others treatments. For the cluster weight, 2,4,5-TP treatment had significant higher on cluster weight (68.9 g), compared with other treatments. Therefore, after the fruit setting spraying plant growth regulator can improve the serious fruit dropping and increase the production of ‘Yu Her Pau’ Litchi. In conclusion, ‘Yu Her Pau’ Litchi need to cultivate 3 segments of mature shoots before the winter season for benefiting the production next year. During the late-October to mid-November, it needs to control the growth of vegetative shoot strictly. If the vegetative shoot appears during the period, treating 395 ppm Ethephon or 20% Urea before the leaves are not fully unfolded for effective shoot-thinning. Spraying 10% urea solution after flower blooming had the effect of flower thinning. After the flower blooming, treating 5 ppm 2,4-D or 2,4,5-TP can prevent fruit dropping and make ‘Yu Her Pau’ Litchi achieve the purpose of stable production. Keywords: flush- thinning, flower-thinning, carbon, nitrogen, C/N ratio, number of fruit per cluster, yield per plant

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44

BARZAGLI, FRANCESCO. "Innovative methods with low energy consumption for efficient CO2 capture and its re-use as a building block for the synthesis of useful chemicals". Doctoral thesis, 2016. http://hdl.handle.net/2158/1044295.

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The purpose of this research activity has been the development of new and efficient systems for the capture of CO2 from a gas stream in a sustainable way from an energetic, economic and environmental point of view. The chemical absorption by aqueous alkanolamines is considered the most efficient and mature technique for the CO2 capture and separation. Alkanolamines are widely used due to the fast reaction with CO2 and to their solubility in water. In particular aqueous 2-amine ethanol (MEA) has a long story as efficient systems for CO2 separation in ammonia and hydrogen plants, natural gas extraction and gas refinery. Recently, these aqueous sorbents have been also studied for application on CO2 removing from industrial exhaust streams. However, the high operating costs associated to the thermal regeneration of the sorbents because of the particularly high evaporation enthalpy and heat capacity of water, are the major obstacles to extensive application to large scale commercial plants. In addition, the higher is the desorption temperature, the greater are the amine decomposition and evaporation, as well as equipment corrosion, thus increasing the maintenance costs of the CCS process. With the aim of taking advantages of the high efficiency of conventional aqueous alkanolamines yet reducing their disadvantages, we have been pursuing a lab-scale research on alternative absorbent formulations aimed at reducing the energy of the absorbent regeneration and the amine degradation, yet maximising the CO2 capture. With the objective of reducing the energy required by the desorption process, in this thesis has been devised the strategy to avoid water. The replacement of water by organic solvents, or the absence of any solvents, may redirect the reaction of amines with CO2 towards less stable species which, consequently, require lower stripping temperatures at room pressure. The study has been focused on amines which combine high reaction rate with CO2 in a non-aqueous environment, with lower reaction enthalpy (in absolute value) and therefore these absorbents require lower regeneration temperatures compared to those of the aqueous solutions (75-95 °C at room pressure instead of 120-140 °C under pressure). Furthermore, the lower operating temperatures reduce the decomposition rate and the loss of the amines. As additional, not negligible benefit, the absence of water strongly reduces the equipment corrosion and avoids foaming problems. A first stage of this study has been devoted to solutions of alkanolamines in organic solvents. Replacing water with organic solvents may provide significant advantages in regard to the reduced absorbent decomposition and to the energy saving in the regeneration step due to the lower heat capacity (about half), the lower heat of vaporization of organic solvents and the higher boiling temperature compared to water. Furthermore, the use of organic solvents does not require major changes to the equipment which works with aqueous solutions. The sorbents formulated comprised some single or blended alkanolamines and alcohol mixtures containing ethylene glycol. 13C NMR analysis indicates that CO2 is reversibly captured in solution as either monoalkyl carbonate (R-OCO2−) and amine carbamate. Due to the lower stability of monoalkyl carbonates with respect to HCO3− and to the carbamates which are formed in the aqueous solutions, stripping temperatures of 75–90°C at room pressure are sufficient to attain absorption efficiencies greater than 90%. Between different formulation designed, one of the best performing was tested on the pilot plant of the ENEL coal-fired power plant located in Brindisi. Even if the replacement of water by organic solvents may reduce the costs of the stripping process, a lot of energy is wasted by the organic solvent heating from the absorption to the desorption temperatures. Moreover, the solvent, either water or alcohols account for about 70% of the absorbent and therefore requires very large equipments. The avoidance of any solvent, should be a decisive improvement towards the ideal absorbent. Therefore, the study has been focused on amines capable of absorbing CO2 without any dilution provided they are liquid before and after the carbon dioxide uptake. A technique of reversible CO2 capture that does not require absorbent dilution would have beneficial effects over those based on diluted absorbents, in that it avoids the sensible heat and vaporization heat of the solvent that contribute to the overall reboiler duty, as long as the operational conditions and the efficiency of the two techniques were comparable. Further potential benefits would be the reduced mass of the absorbent (water accounts for 70 wt % of the mass of aqueous MEA) and, consequently, an appreciable reduction of the plant size. In this study has been formulated two different classes of solvent-free single-component absorbents based on inexpensive and commercially available amine, in particular some secondary amines and some secondary alkanolamines. CO2 is captured with high efficiency (over 90%) as amine carbamate and amine-carbamic acid. In another part of the study has been devised and developed the use of biphasic sorbents. In such technique, the absorbent solution, after the reaction with CO2, separates into two phases (liquid/liquid or liquid/solid) that comprise the solvent and, separately, the carbonatated species. In this way it is possible to desorb the sole carbonatated phase, preventing the energy wasted by solvent heating. After its thermal regeneration, the absorbent is mixed again with the solvent to get back the starting absorbent solution. This biphasic technique combines the advantages of both organic solvents and solvent–free sorbents previously studied. A first series of experiments, which involves sodium and potassium carbonates and some amines (piperazine and AMP), has been completed with good results. Another series of tests very promising, using alkanolamines in low viscous solvents, is still under development. In these three years, in our laboratory, has been also developed a new concept of CO2 capture technology which combines the CO2 abatement with the production of commercially valuable products. Turning carbon dioxide into useful chemicals in relatively mild conditions circumvent most of the drawbacks of the energy consuming steps of CO2 desorption, absorbent regeneration as well as of CO2 transporting and ultimate disposal. It has been verified the efficient absorption of CO2 by water-ethanol ammonia and by some non-aqueous amines. These experiments were addressed to recover the captured CO2 as solid ammonium carbamate or carbamates of the protonated amines. By heating the solid ammonium carbonate and bicarbonate mixtures or the amine carbamates in a closed reactor, we obtained their conversion into urea and, respectively, 1,3-disubstituted ureas with reasonable yields (30-50%). Urea is the world's most used fertilizer and it is produced in large quantities, while 1,3-disubstituted ureas are valuable products with a wide range of application as intermediates in agrochemical, pharmaceutical, dye chemicals and raw materials of polyurethanes. In addition, it has been studied the chemistry of the CO2 uptake by resorcinol (1,3-dihydroxy benzene) in alkaline aqueous and water/glycerol solutions under different experimental conditions, with the purpose of unveiling the reaction mechanism and maximizing the resorcinol conversion into β-resorcylic acid (2,4-dihydroxybenzoic acid).

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Yeshitela, Teferi Belayneh. "Effect of cultural practices and selected chemicals on flowering and fruit production in some mango (Mangifera indica L.) cultivars". Thesis, 2005. http://hdl.handle.net/2263/23181.

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Although mango (Mangifera indica L.) has been studied for many years, numerous problems still elude researchers. The objectives of the current trials were to study the effects of some cultural practices (fruit thinning, panicle/ bud/ renewal/ post-harvest pruning) and chemicals (Corasil.E, potassium nitrate/urea, paclobutrazol) on various vegetative, floral, yield and quality parameters. The study meant to address problems of both South African and Ethiopian mango growers. The thinning (on ‘Sensation’) and pruning (on ‘Tommy Atkins’ and ‘Keitt’) experiments were conducted for two seasons (2001-2003) at Bavaria Fruit Estate in South Africa. Effects of Paclobutrazol and Potassium nitrate were studied on ‘Tommy Atkins’ during 2002-2003 season at Upper Awash Agro-industry Enterprise in Ethiopia. Complementary effects of paclobutrazol and potassium nitrate on floral induction were studied in growth chamber experiments at the experimental farm of University of Pretoria on ‘Tommy Atkins’ and ‘Keitt’ mango. Where fruit on ‘Sensation’ were thinned to one and two fruit per panicle, a significant increase was obtained for most of the fruit quantitative parameters. The treatments where one fruit and two fruit per panicle were retained and 50% panicles removed, produced a significant increase in size of the fruit, fruit qualitative parameters and fruit retention percentage. Corasil.E produced very small sized fruit with a considerable percentage of “mules” (fruit without seed). Trees subjected to severe thinning intensities showed earlier revival of starch reserves and better vegetative growth. Applications of paclobutrazol (1- (4-chlorophenyl) –4,4-dimethyl-2- (1,2,4- triazol-1-yl) pentan-3-ol) at rates of 5.50 and 8.25 g a.i. per tree, both as a soil drench and spray applications, on ‘Tommy Atkins’ mango were effective in suppressing vegetative growth as compared to the control. Consequently, the trees from these treatments had higher total non-structural carbohydrate in their shoots before flowering which led to higher results of percentages of shoots flowering, number of panicles produced, percentages of hermaphrodite flowers, yield and quality of the fruit. Trees that received panicle pruning (during full bloom) treatment at the point of apical bud attachment, were observed to be induced for synchronized re-flowering and also attained more fruit per panicle. On the other hand, trees on which renewal pruning (early in the season) and post-harvest pruning (especially for early cultivars) treatments were applied, have been observed for the development of an adequate number of productive inflorescences. Post-harvest pruning treatments also resulted in greater vegetative growth on both cultivars. The responses to pruning treatments were greater especially in ‘Tommy Atkins’ than ‘Keitt’. The trend for the interaction of duration and chemicals in Tommy Atkins and Keitt mango cultivars revealed the possible floral induction complementary effect of PBZ after the trees were induced only for 15 days at 10/15 oC temperature. Higher potassium nitrate concentrations especially in combination with urea (5 litre solution of 4% KNO3+0.5 g urea tree-1 and 5 litres of 4% KNO3+1 g urea tree-1 ) produced higher results for most of the flowering and yield parameters in ‘Tommy Atkins’.
Thesis (DPhil (Horticulture))--University of Pretoria, 2006.
Plant Production and Soil Science
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"Optimizing the efficiency of nutrient utilization in dairy cows". Thesis, 2013. http://hdl.handle.net/10388/ETD-2013-03-973.

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A series of experiments were conducted to determine nutritional strategies to improve the efficiency of N utilization in dairy cows when feeding co-products including wheat-based (W-DDGS) and corn-wheat blend distillers grains with solubles (B-DDGS), and dried whey permeate (DWP). In Experiment 1, the objective was to determine the effects of replacing canola meal (CM) as the major protein source with W-DDGS on ruminal fermentation, microbial protein production, omasal nutrient flow, and animal performance. Cows were fed either a standard barley silage-based total mixed ration containing CM as the major protein supplement (0% W-DDGS, control) or diets formulated to contain 10, 15 and 20% W-DDGS (dry matter [DM] basis), with W-DDGS replacing primarily CM. Diets were isonitrogenous (18.9% crude protein [CP]). Inclusion of W-DDGS to the diet did not negatively affect ruminal fermentation, microbial protein production, and omasal nutrient flow. However, there was a 0.7- to 2.4-kg increase in DM intake, and a 1.2- to 1.8-kg increase in milk yield after the addition of W-DDGS in place of CM. In Experiment 2, the objective was to delineate the effects of including either W-DDGS or B-DDGS dried distillers grains with solubles as the major protein source in low or high CP diets fed to dairy cows on ruminal function, microbial protein synthesis, omasal nutrient flows, urea-N recycling, and milk production. The treatment factors were type of distillers co-product (W-DDGS vs. B-DDGS) and dietary CP content (15.2 vs. 17.3%; DM basis). The B-DDGS was produced from a mixture of 15% wheat and 85% corn grain. All diets were formulated to contain 10% W-DDGS or B-DDGS on a DM basis. Feeding up to 10% of dietary DM as B-DDGS or W-DDGS as the major source of protein did not have negative effects on metabolizable protein (MP) supply and milk production in dairy cows. However, reducing dietary CP content from 17.3 to 15.2% decreased milk production. This response was attributed to an insufficient supply of ruminally degradable protein (RDP) that suppressed microbial nonammonia N (NAN) synthesis in the rumen, thus decreasing intestinal MP supply. In Experiment 3, the objective was to determine the effects of replacing barley or corn starch with lactose (as DWP) in diets containing 10% W-DDGS on ruminal function, omasal nutrient flow, and lactation performance. The treatment factors were source of starch (barley vs. corn) and dietary inclusion level of DWP (0 vs. 6%; DM basis) as a partial replacement for starch. Diets were isonitrogenous (18% CP) and contained 3 or 8% total sugar. The starch content of the low sugar diet was 24% compared to 20% for the high sugar diet. Dry matter intake, and milk and milk component yields did not differ with diet. However, partially replacing dietary corn or barley starch with sugar up-regulated ruminal acetate and propionate absorption, and reduced ruminal NH3-N concentration, but had no effect on ruminal pH, microbial protein synthesis, omasal nutrient flow and production in dairy cows. In summary, data presented in this thesis indicate that W-DDGS and B-DDGS can be included as the major source of protein in dairy cow diets without compromising ruminal function, nutrient supply and milk production in dairy cows. Feeding medium to low CP diets, and partial replacement of starch with sugar in diets containing W-DDGS and B-DDGS can improve N utilization efficiency in dairy cows. Additionally, an upregulation of facilitated transport of acetate and propionate across epithelial cells possibly prevents the occurrence of ruminal acidosis when lactose partially replaces starch in cow diets.

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Cherdchim, Banyat. "Actions of lignocellulolytic enzymes on Abies grandis(grand fir) wood for application in biofuel production". Doctoral thesis, 2010. http://hdl.handle.net/11858/00-1735-0000-0006-B138-4.

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Tesis sobre el tema "Urea production"

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