908 resultados para BOVINOS


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The use of digesters has become an important alternative for the proper disposal of organic agricultural wastes, serving as a solution to some environmental and health problems. Furthermore, the process of digestion provides commercially valuable by products such as biogas and bio fertilizer. The generation of biogas from agricultural waste, and its use in power generation systems has aroused great interest in rural areas because it enables supply in whole or in large part the energy demand of ownership by reducing production costs. The advent of technology has brought new forms of energy conversion of biogas, as the use of micro turbines specifies to be fuelled with biogas derived from the decomposition of organic matter in digesters, since it has a low level of methane in its composition, and high degree of impurities such as hydrogen sulphide, which are harmful to equipment and reduce the calorific value of biogas. The use of micro turbines behind other advantages like low emissions, great fuel flexibility and low maintenance. This paper presents an analysis of the feasibility of using biogas generated from cattle manure in micro turbines to generate electricity. Behind also an assessment of the energy potential that each animal has on various uses of biogas, and forms of energy recovery from the exhaust gases of the micro turbine. Also conducts an evaluation of the energy savings that the use of biogas aggregates properties.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Genética e Melhoramento Animal - FCAV

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Pós-graduação em Ciência e Tecnologia Animal - FEIS

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Pós-graduação em Genética e Melhoramento Animal - FCAV

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This study evaluated the effect of daily chromium supplementation at growing doses on serum Cr levels in cattle. Sixty Nellore heifers 2 to 5 years old were randomly assigned to one of four groups (15 heifers/group) fed non-fertilized Brachiaria decumbens pasture. In the control group (Gc), the heifers received a mineral mixture without Cr. In the other groups, heifers received 0.59, 1.19 or 2.38 mg Cr+3/animal/day, groups G8,5, G17 and G34, respectively. Blood samples were collected on days 0, 30 and 60. Serum concentration of chromium was determined by graphite furnace atomic absorption spectrophotometer. The chromium source used was the chromium yeast. The results do not support any significant difference (p>0.05) among serum chromium levels of heifers in groups Gc, G8,5, G17 and G34 at a same observation day. Only effect of supplementation time was detected in group G34. In this group there was significant increase (p<0,05) in the concentration serum chromium 60 days after the beginning of the experiment. Concluded Cr yeast can be used as the source of this mineral element for animals and supplementation with 2.38 mg/ cattle/day was the dose that most increased the serum concentration of Cr in Nellore cattle during the experimental period.

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Despite the efforts made to improve the production of bovine embryos in vitro, their efficiency is still low, since only 30-40% of developed blastocysts are obtained from oocytes after in vitro maturation (IVM), fertilization and cultured embryos. Assisted reproductive technologies have a limiting impact due a lack of oocytes capable to fertilization.The comprehension of mechanism involved in oocyte maturation are crucial to establish a culture system that allows a larger number production of good quality embryos. The study of the early stages of oocyte and follicle development in vivo is important for a better understanding of the molecular pathways that regulate oogenesis, folliculogenesis and oocyte maturation. Thus the physiological biochemical and molecular mechanisms involved in maturation may contribute to the increased efficiency of in vitro embryo production. Therefore, the aim of this literature review is to understand the basic mechanisms that underlie oocyte maturation in cattle, since oocyte and follicle cells in vivo formation to its use in the in vitro environment.

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The aim of this work was draw an endemic level of reproductive losses and determine positivity for four infectious agents related to reproductive problems in dairy cattle on a property in São Carlos city. Blood serum samples were collected of 142 breeding animals more than two years old, from which 21.1% showed history of abortions or stillbirths in at least one pregnancy. Immunofluorescent antibody technique, tamponated acidified antigen test, serum neutralization technique and microscopic agglutination test, were used for detection of antibody anti-Neospora caninum, anti- Brucella abortus, anti-Bovine Herpesvirus Type-1 (BoHV-1) and anti-Leptospira spp , respectively. The serological tests carried out showed that 28.9% of the animals had titers greater than or equal to 100 of anti-Neospora caninum. Viral neutralization tests demonstrated that 26.8% of the animals had titers greater or equal to 256 for antibody anti-BoHV-1.Only 7.7% of the animals studied had titers equal to or greater than 100 in the microscopic agglutination test for Leptospira spp. There weren’t observed positive reactions to the tamponated acidified antigen test for diagnosis of bovine brucellosis. The study suggests the presence of BoHV-1, N. caninum and Leptospira spp in contact with dairy cattle property and could be involved in the occurrence of abortions and stillbirths in cattle. Reproductive losses are endemic and implies a possible behavior of chronic infections caused by these microorganisms.