• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 141
  • 37
  • 33
  • 1
  • Tagged with
  • 226
  • 131
  • 83
  • 73
  • 41
  • 28
  • 27
  • 26
  • 23
  • 23
  • 22
  • 21
  • 20
  • 20
  • 19
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

NOx reduction with the use of feedlot biomass as a reburn fuel

Goughnour, Paul Gordon 2006 August 1900 (has links)
Coal fired power plants produce NOx at unacceptable levels. In order to control these emissions without major modifications to the burners, additional fuel called reburn fuel is fired under rich conditions (10-30 % by heat) after the coal burners. Additional air called overfire air (about 20 % of total air) is injected in order to complete combustion. Typically reburn fuel is natural gas (NG). From previous research at TAMU, it was found that firing feedlot biomass (FB) as reburn fuel lowers the NOx emission at significant levels compared to NG. The present research was conducted to determine the optimum operating conditions for the reduction of NOx. Experiments were performed in a small scale 29.3 kW (100,000 BTU/hr) reactor using low ash partially composted FB (LA PC FB) with equivalence ratio ranging from 1 to 1.15. The results of these experiments show that NOx levels can be reduced by as much as 90% - 95 % when firing pure LA PC FB and results are almost independent of. The reburn fuel was injected with normal air and then vitiated air (12.5 % O2); further the angles of reburn injector were set normal to the main gas flow and at 45-degrees upward. For LA PC FB no significant changes were observed; but high ash PC FB revealed better reductions with 45-degrees injector and vitiated air. This new technology has the potential to reduce NOx emissions in coal fired boilers located near cattle feedlots and also relieves the cattle industry of the waste.
42

Water and nitrate movement in poultry litter amended soils

Sanchez, Jaime F. January 2004 (has links)
Thesis (Ph. D.)--University of Florida, 2004. / Title from title page of source document. Document formatted into pages; contains 134 pages. Includes vita. Includes bibliographical references.
43

Evaluation of canola meal derived from Brassica juncea and Brassica napus as an energy source for cattle

2013 December 1900 (has links)
Two trials were carried out to evaluate the effect of inclusion level of canola meal derived from Brassica (B.) napus and B. juncea on cattle performance and nutrient utilization. Trial 1 consisted of backgrounding (54 d) and finishing (153 d) phases. The control diet for the backgounding (BK) phase consisted of 39% barley silage, 30.4% barley grain, 22.8% brome grass hay and 7.8% supplement (DM). Treatments consisted of B. napus or B. juncea at 15 or 30% (DM) inclusion, replacing barley grain. The finishing control diet consisted of 88.3% barley grain, 4.4% barley silage and 7.3% supplement (DM). Treatments consisted of B. napus or B. juncea at 10 or 20% (DM) inclusion, replacing barley grain. During BK, dry matter intake (DMI), average daily gain (ADG), gain: feed (G:F) increased linearly (P < 0.01) as the level of inclusion of B. juncea meal increased. Cattle fed B. napus meal showed a quadratic response (P = 0.05) in DMI and linear increase (P = 0.02) in ADG with increasing inclusion. During finishing, DMI increased linearly (P = 0.05) for cattle fed B. juncea meal while a quadratic response (P = 0.02) was seen with B. napus meal. Feed efficiency and NEg content of the diet (P ≤ 0.02) decreased linearly with increasing inclusion of both meals. Trial 2 evaluated dietary rumen fermentation and total tract digestibility characteristics in a 5 x 5 Latin Square Design. Diets were similar to finishing phase of Trial 1. There was no effect of treatment on rumen pH, however a linear increase in acetate (P ≤ 0.01), ammonia (P < 0.01) and decrease (P < 0.01) in propionate was seen with both meal types. Crude protein and acid detergent fiber digestibility increased (P = 0.03) linearly with increasing inclusion of B. juncea meal. The results indicate that canola meal derived from B. napus and B. juncea is not suitable as a supplemental energy source replacing for barley grain in finishing diets but canola meal from B. juncea can be fed at levels up to 30% of the DM in backgrounding diets if priced appropriately.
44

Movement Restriction Implications on Potential Welfare Slaughter for Texas High Plains Feedlots

Galli, Monica 2011 December 1900 (has links)
Foot and mouth disease (FMD) is regarded as one of the greatest biological threats to the U.S. livestock industry because of its potential to cause catastrophic economic damages and massive livestock depopulation. Current U.S. contingency plans call for "stamping out" of FMD. An integral component of a "stamping out" policy is movement restrictions. The main purpose for movement restrictions is to stop the spread of disease, but they also disrupt the agribusiness sector. Welfare slaughter, the depopulation of healthy quarantined animals, is a possibility if movement restrictions are kept in place for prolonged periods of time. Many studies have analyzed the economic consequences of alternative mitigation strategies, but generally these studies have ignored the costs that might arise because of movement restrictions affecting uninfected premises located within the quarantine zone. Ultimately this study seeks to improve preparedness in the event of a FMD outbreak. It does this by developing information for those formulating plans on the costs associated with movement restrictions regarding quarantined, uninfected large feedlots located in the Texas High Plains Region. To accomplish this objective two strategies were compared: an unrestricted feed strategy, where feed is allowed to be brought onto uninfected premises and finished cattle are sold; and a welfare slaughter strategy, where feed isn't allowed to be brought onto the uninfected premises so animals are depopulated. In addition, seasonal differences in total costs were examined. This study expanded on the High Plains Study conducted by M. Ward, L. Highfield, P. Vongseng, and M. Garner by using their epidemiological data combined with a cost accounting framework to estimate the total cost of each strategy. This study examined direct disease management costs (indemnity payments, feed costs, marketing costs, surveillance costs, cleaning and disinfecting costs, appraisal cost, euthanasia costs, and disposal costs). Overall, the unrestricted feed strategy was less expensive than the welfare slaughter strategy, costing on average $22.6 million compared to $48.5 million, respectively. Disease outbreak timing did impact the overall cost of both strategies. The results suggest the policy makers should strongly consider creating movement policies that address feed supply and finished cattle movement for uninfected large feedlots in prolonged quarantine zones; as such policies appear to reduce outbreak related costs for stakeholder and the U.S. government.
45

Adaptação a dietas de alta energia para bovinos Nelore submetidos previamente à restrição nutricional ou consumo de concentrados e efeitos nas características ruminais /

Pinto, Ana Carolina Janssen January 2017 (has links)
Orientador: Danilo Domingues Millen / Resumo: O objetivo deste estudo foi avaliar o efeito da restrição alimentar prévia ou exposição anterior a ingredientes concentrados sobre o tempo para adaptação à dietas de alto concentrado, sob os parâmetros da fermentação ruminal e o perfil de microrganismos ruminais de bovinos Nelore canulados confinados. Foram utilizados 6 bovinos da raça Nelore, castrados, com peso vivo inicial aproximado de 236 ± 23 kg, 15 meses de idade e canulados no rúmen, os quais foram divididos em dois quadrados latinos 3 x 3. Os tratamentos diferiram somente sobre o tipo de alimentação estabelecida previamente ao período de adaptação: Controle (forragem ad libitum + suplemento mineral); Restrição (forragem restrita a 1,4% do peso vivo + suplemento mineral) e Concentrado (forragem ad libitum + 0,5% do peso vivo de ingredientes concentrados e suplemento mineral). A duração deste estudo foi de 119 dias, sendo compostos por 3 períodos experimentais (33 dias cada período) e dois intervalos de washout (10 dias) entre os períodos 1 e 2, e 2 e 3. Os períodos foram divididos em: 14 dias de pré- adaptação, 6 dias de adaptação 1 (72% de concentrado), 6 dias de adaptação 2 (79% de concentrado) e 7 dias de dieta de terminação (86% de concentrado). O pH ruminal foi monitorado por meio da utilização de data loggers a cada 10 minutos. Foram avaliados a concentração de ácidos graxos de cadeia curta e amônia ruminal; a quantificação relativa das bactérias celulolíticas e utilizadoras de lactato por meio da técnica de PCR... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
46

Effects of hops β-acid extract (Humulus lupulus L.) on cattle performance and fermentation by ruminal microbes

Axman, Justin January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / James S. Drouillard / Hops β-acid extract was fed to 80 heifers (389 ± 23.6 kg initial BW) to assess impact on feedlot performance and ruminal fermentation. Heifers were randomly assigned to individual pens and fed once daily for 147 d. Treatments were a control (no additive); 33 mg monensin (Elanco Animal Health, Greenfield, IN)/kg diet DM; and 10, 25, 50 mg β-acid extract of hops (DSM Nutritional Products, France)/kg diet DM. Ruminal fluid was collected on d 44 and 86 by rumenocentesis for analyses of VFA, lactate, and NH[subscript]3 concentrations. Cattle were harvested at a commercial abattoir on d 147. Hops β-acids decreased propionate (P = 0.01) concentrations and increased caproate (P = 0.05), A:P (P = 0.04), and ammonia concentrations (P = 0.03) compared to monensin. Growth performance of heifers fed β-acid or monensin was not different than that of heifers fed the control diet. Additionally, two in vitro studies were conducted to evaluate effects of hops β-acid extract on starch fermentation by mixed microbial populations from the bovine rumen. In trial 1, 2 treatments were assigned in triplicate to fermentation bottle, fitted with Ankom[superscript]RF1 Gas Production System modules (Ankom[superscript]RF Technology, Macedon, NY) using starch as substrate (Difco Soluble Starch; Dickinson and Company, Sparks, MD) and either 0 or 33 mg hops β-acid extract (10.99% active hops beadlet; DSM Nutritional Products, France)/kg substrate. Gas production was measured over 30 h. Terminal pH, IVDMD, and VFA and lactate were measured after 30 h of fermentation. Gas production increased in response to β-acid (P ≤ 0.05). Terminal pH, IVDMD, VFA, and lactate were unaffected by addition of β-acid extract (P ≤ 0.05). In trial 2, pH, VFA concentrations, and IVDMD were measured at 6-h intervals during a 30-h incubation period using 36 fermentation tubes. There was no effect of hops β-acid on in vitro fermentation (P > 0.05). In conclusion, under the conditions of these experiments, hops β- acid extracts hops had little impact on feedlot performance, though there are indications of an impact on ruminal fermentation.
47

Efeito do uso combinado de monensina sódica e virginiamicina sobre as características da carne de bovinos nelore terminados em confinamento

Luiz, Felipe Pelícia January 2016 (has links)
Orientador: Mário De Beni Arrigoni / Resumo: O objetivo deste estudo foi estudar o efeito do uso combinado de monensina sódica (MON) e virginiamicina (VM) sobre as características da carne fresca (pH, teor de proteína bruta, extrato etéreo, umidade, matéria mineral, perda por cocção e cor), além da avaliação da carne cozida através de painel sensorial e força de cisalhamento. Foram utilizados 72 animais machos não castrados da raça Nelore, com peso vivo médio inicial de 388±31,07 kg, provindos de sistema de recria em pasto. Os animais foram divididos em 4 tratamentos de acordo com associação ou não dos aditivos nas fases de adaptação e terminação: MON (30 mg/kg) na adaptação + terminação; MON (30 mg/kg) + VM (25 mg/kg) na adaptação e VM (25 mg/kg) na terminação; MON (30 mg/kg) + VM (25 mg/kg) na adaptação e VM (25 mg/kg) + MON (30 mg/kg) na terminação e VM (25 mg/kg) na adaptação e MON (30 mg/kg) + VM (25 mg/kg) na terminação, caracterizando assim delineamento em blocos casualizados, com 6 repetições cada tratamento (3 animais por baia, sendo as baias as unidades experimentais). A duração do experimento foi de 90 dias, sendo 19 dias de adaptação, divididos em três períodos (7, 5 e 7 dias) com dietas de 69, e 79% de ingredientes concentrados, respectivamente; e 71 dias de terminação, com dieta contendo 84% de concentrado. Para avaliação da qualidade de carne foram utilizados 24 animais. A associação de MON e VM não apresentou influência pH, composição centesimal, perda por cocção e força de cisalhamento da carne fresca. ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The experiment was designed to evaluate the effect of combined use of monensin (MON) and virginiamycin (VM) on the characteristics of fresh meat (pH, protein, fat content, moisture, ash, cooking water loss and hue), and the evaluation of cooked meat through sensory panel and shear force.Were used 72 bulls Nelore cattle, with average live weight 388 ± 31.07 kg, coming from pasture system. The animals were divided on four treatments according to affix or not of additives on adaptation phases and finishing: MON (30 mg / kg) on adaptation and finishing ; MON (30 mg / kg) + VM (25mg / kg) on the adaptation and VM (25mg / kg) at finishing; MON (30 mg / kg) + VM (25mg / kg) in the adaptation and MV (25 mg / kg) + MON (30 mg / kg) on the finishing and VM (25 mg / kg) in the adaptation and MON (30 mg / kg) + VM (25 mg / kg) on the finishing, characterizing a randomized block design, where each treatment had 6 replicates (3 animals per pen, and they were considered as experimental units bays). The experiment lasted 90 days, 19 days of adaptation, divided into three periods (7, 5 and 7 days) diets of 69, 74 and 79% of concentrated ingredients, respectively; and 71 days finishing, with ration containing 84% concentrate. To evaluate the quality of meat were used 24 animals. The MON and VM association not caused effect on the pH, protein, fat content, moisture, ash, cooking water loss and meat color. The smell and taste of cooked meat also showed no difference in relation to treatment. So ... (Complete abstract click electronic access below) / Mestre
48

Desempenho, metabolismo e emissão de metano de bovinos Nelore em terminação recebendo óleos funcionais em substituição ou combinação com monensina sódica na dieta / Performance, metabolism and methane emission of Nellore finishing cattle receiving diets containing functional oils in replacement or combination with monensin

Lucas Jado Chagas 24 August 2015 (has links)
O surgimento de mercados consumidores cada vez mais exigentes quanto a segurança alimentar é uma realidade crescente. A proibição do uso de antibióticos promotores de crescimento, como a monensina, pela União Europeia é um indicativo disto. Em busca de alternativas aos antibióticos, intensificou-se na última década os trabalhos de pesquisa que visam explorar e desenvolver alternativas economicamente interessantes para a produção animal. Neste sentido, objetivou-se neste trabalho, avaliar o uso de princípios ativos extraídos dos óleos de caju e mamona como moduladores da fermentação ruminal alternativos à monensina sódica. Foram realizados seis experimentos. Um experimento de desempenho, com animais confinados a fim de mensurar o GPD, CMS, eficiência alimentar, características de carcaça. Outro experimento para avaliação de características metabólicas, com a avaliação de CMS, digestibilidade da MS, características da fermentação ruminal, consumo de oxigênio, produção de calor e de metano. Também foi realizado um experimento in vitro para a avaliação da produção de gás e tempo de colonização. Este conjunto de três experimentos foi realizado em uma a base de coprodutos e outra a base de milho moído. A dieta a base de coprodutos foi composta por 5% de bagaço de cana, 50 % de farelo úmido de glutem de milho, 43,5% de casca de soja, 1,5% de núcleo mineral, sendo avaliados os seguintes tratamentos: T1 - Controle, que consistiu em dieta base, sem aditivos; T2 - dieta base com adição de monensina sódica na dose de 25 mg/kg MS; T3 - dieta base com adição de Essential&reg; na dose de 300 mg/kg MS e T4 - dieta base com adição de monensina sódica (25 mg/kg MS) e Essential&reg; (300 mg/kg MS). A dieta a base de milho moído foi constituída de 12% de feno de tyfton, 80 % de milho moído, 4% de farelo de soja, 2,5% de núcleo mineral e 1,5% de uréia e foram avaliados os seguintes tratamentos: T1 - Controle, que consistiu em uma dieta base, sem aditivos; T2 - dieta base com adição de monensina sódica na dose de 30 mg/kg MS; T3 - dieta base com adição de Essential&reg; na dose de 300 mg/kg MS; e T4 - dieta base com adição de Essential&reg; na dose de 500 mg/kg MS. Para o experimento de metabolismo com a dieta a base de milho, foi utilizado bagaço de cana como volumoso e os tratamentos foram os os mesmos aplicados na dieta a base de coprodutos: Os tratamentos foram: T1 - Controle, que consistiu em dieta base, sem aditivos; T2 - dieta base com adição de monensina sódica na dose de 25 mg/kg MS; T3 - dieta base com adição de Essential&reg; na dose de 300 mg/kg MS; e T4 - dieta base com adição de monensina sódica (25 mg/kg MS) e Essential&reg; (300 mg/kg MS). A suplementação com OF melhora o desempenho de bovinos na fase inicial do confinamento em relação ao não uso de aditivos ou ao uso de monensina sódica, porém essa vantagem não se mantêm ao longo do período total de confinamento. Ao contrário do esperado, no presente estudo os aditivos testados não contribuíram para o aumento da eficiência de produção de bovinos em confinamento e para a redução do seu impacto ambiental. / The emergence of increasingly demanding consumer markets as food safety is a growing reality. The ban on antibiotic growth promoters such as monensin, by the European Union is indicative of this. Thus, research looking for alternatives to antibiotics, has been intensified in the last decade, with research works aimed at exploring and developing economically attractive alternative to animal production. In this sense. The aim of this study was to evaluate the use of active ingredients extracted from cashew oils and castor as modulators of ruminal fermentation alternative to monensin. Six experiments were carried out. A performance experiment with animals confined in order to measure the GPD, CMS, feed efficiency, carcass characteristics. Another experiment to evaluate metabolic characteristics with the assessment of CMS, digestibility, ruminal fermentation characteristics, oxygen consumption, heat and methane production. Also an in vitro experiment for evaluation of gas production and colonization time was conducted. This set of three experiments was carried out on two base diets, one with ground corn and other with byproducts. Ground corn basal diet consisted of 12% of tyfton hay, 80% of ground corn, 4% soybean meal, 2.5% mineral mixture and 1.5% urea. The treatments were: T1 - control, which consisted of basal diet, no additives; T2 - basal diet with addition of sodium monensina (30 mg / kg DM); T3 - basal diet added Essential&reg; (300 mg / kg DM); and T4 - basal diet added Essential&reg; (500 mg / kg DM). The bast dosis of functional oils were used in a second trial that used combination of functional oils and monensis. In the second trial was used a byproducts base diet comprised 5% of sugar cane bagasse, 50% of wet corn gluten feed, 43.5% of soybean hulls, 1.5% mineral mixture, being evaluated the following treatments: T1 - control, which consisted of basal diet without additives; T2 - basal diet with addition of sodium monensina (25 mg / kg DM); T3 - basal diet added Essential&reg; (300 mg / kg DM); and T4 - basal diet with addition of sodium monensin (25 mg / kg DM) plus Essential&reg; (300 mg / kg DM). For metabolism experiment with diet from corn was used bagasse as roughage and treatments were: T1 - control, which consisted of basal diet without additives; T2 - basal diet with addition of sodium monensina (25 mg / kg DM); T3 - basal diet added Essential&reg; (300 mg / kg DM); and T4 - basal diet with addition of sodium monensin (25 mg / kg DM) plus Essential&reg; (300 mg / kg DM). Functional oils supplementation improves performance of feedlot cattle during the initial phase with the non-use of additives or the use of monensina only. However , this advantage is not maintained over the total period of feedlot. In study, evaluated additives did not contribute to the increase feedlot cattle performance and to reduce their environmental impact.
49

Ocorrência de Escherichia coli O157:H7 em bovinos abatidos em estabelecimento habilitado à exportação na cidade de Barretos – SP, Brasil

Prata, Camila Barbieri [UNESP] 30 November 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:27:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-11-30Bitstream added on 2014-06-13T18:56:07Z : No. of bitstreams: 1 prata_cb_me_jabo.pdf: 1292020 bytes, checksum: 1886044e5ddc4f62eed48d5f34981c8d (MD5) / Universidade Estadual Paulista (UNESP) / Escherichia coli O157:H7 é uma cepa de importância crescente por estar associada a vários surtos graves de doença em humanos, a maioria derivada do consumo de carne bovina crua ou mal cozida. Os bovinos constituem seu reservatório mais importante, aventando-se a hipótese de que mudanças do regime alimentar em confinamentos atuariam favoravelmente ao aparecimento de cepas shigatoxigênicas. Neste estudo objetivou-se verificar, comparativamente durante o abate, a prevalência desse sorotipo e o comportamento de métodos indicadores como a contagem total de microrganismos viáveis (CTMV) e de contaminação fecal - coliformes totais e E. coli, em amostras de fezes e em carcaças de bovinos terminados a pasto e em confinamento, possibilitando a disponibilização de subsídios necessários aos programas de Análise de Perigos e Pontos Críticos de Controle (APPCC) e de Análise de Risco (RA), empregados na redução do risco de doenças transmitidas por alimentos. Identificados os lotes de acordo com a terminação (dez de cada tipo), desses foram aleatoriamente colhidas e analisadas 100 amostras de suabe retal, 100 amostras de carcaças e 67 amostras de “recortes” da desossa (carne industrial) utilizando-se, para a E. coli O157- H7, técnica automatizada de PCR. À exceção de uma única amostra de recortes (0,37%), as demais, tanto de fezes quanto de carcaças, foram negativas para a cepa pesquisada. Além de contatar-se uma prevalência muito baixa, não se evidenciou diferenças entre os tipos de terminação dos animais. Os resultados dos indicadores - CTMV, de coliformes totais e E. coli, foram considerados aceitáveis em 91%, 85% e 93% das amostras, respectivamente, oferecendo suporte e concordância com a baixa prevalência encontrada. / Escherichia coli O157:H7 is an important strain that has been associated with outbreaks of serious disease in humans, most being derived from consumption of raw or poorly cooked beef. It is likely that cattle are an important reservoir, suggesting the possibility that changes in feedlot diet favor the emergence of shigatoxigenic strains of E. coli. This study is intended to verify, comparatively during bovine slaughter, the occurrence of E. coli O157:H7 associated with the sampling results obtained by means of general indicator methods (total viable count) and fecal contamination indicators (coliforms and E. coli). Samples will be taken from both excreta and carcasses of cattle finished either on pasture or feedlot, allowing the provision of subsidies necessary for Hazard Analysis and Critical Control Points (HACCP) and Risk Analysis (RA) programs and applied in the reduction of the risk of foodborne diseases. After identification of batches according to the type of finishing (feedlot or pasture), samples were randomly collected and analyzed. 100 rectal swabs, 100 samples from carcasses sponging, and 67 samples of sliced meat from the boning room (industrial meat). An automatic PCR technique for detection of E. coli O157:H7 was used. Except for one sample of sliced meat (0.37%), all others, both for excreta and carcasses, were negative for the O157:H7 E. coli strain. There were no significant differences in prevalence between the types of cattle finishing of the animals. The results of the indicators methods (TVC, coliforms and E. coli); were considered acceptable in 91%, 85% and 93% of tested samples, respectively, supporting and in agreement with low prevalence of O157:H7 found.
50

Adaptação a dietas de alta energia para bovinos Nelore submetidos previamente à restrição nutricional ou consumo de concentrados e efeitos nas características ruminais / Adaptation to high energy diets of Nellore cattle previously submitted to either nutritional restriction or intake of concentrate feedstuffs and effects on rumen characteristics

Pinto, Ana Carolina Janssen 20 December 2017 (has links)
Submitted by Ana Carolina Janssen Pinto null (acjpinto@gmail.com) on 2018-02-16T12:43:11Z No. of bitstreams: 1 002-2018-Ana Carolina Janssen Pinto.pdf: 1876951 bytes, checksum: 27350a74dbe91c3eff974936da583047 (MD5) / Approved for entry into archive by Fabio Sampaio Rosas null (fabio@dracena.unesp.br) on 2018-02-16T13:33:21Z (GMT) No. of bitstreams: 1 pinto_acj_me_dra.pdf: 1876951 bytes, checksum: 27350a74dbe91c3eff974936da583047 (MD5) / Made available in DSpace on 2018-02-16T13:33:21Z (GMT). No. of bitstreams: 1 pinto_acj_me_dra.pdf: 1876951 bytes, checksum: 27350a74dbe91c3eff974936da583047 (MD5) Previous issue date: 2017-12-20 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O objetivo deste estudo foi avaliar o efeito da restrição alimentar prévia ou exposição anterior a ingredientes concentrados sobre o tempo para adaptação à dietas de alto concentrado, sob os parâmetros da fermentação ruminal e o perfil de microrganismos ruminais de bovinos Nelore canulados confinados. Foram utilizados 6 bovinos da raça Nelore, castrados, com peso vivo inicial aproximado de 236 ± 23 kg, 15 meses de idade e canulados no rúmen, os quais foram divididos em dois quadrados latinos 3 x 3. Os tratamentos diferiram somente sobre o tipo de alimentação estabelecida previamente ao período de adaptação: Controle (forragem ad libitum + suplemento mineral); Restrição (forragem restrita a 1,4% do peso vivo + suplemento mineral) e Concentrado (forragem ad libitum + 0,5% do peso vivo de ingredientes concentrados e suplemento mineral). A duração deste estudo foi de 119 dias, sendo compostos por 3 períodos experimentais (33 dias cada período) e dois intervalos de washout (10 dias) entre os períodos 1 e 2, e 2 e 3. Os períodos foram divididos em: 14 dias de pré- adaptação, 6 dias de adaptação 1 (72% de concentrado), 6 dias de adaptação 2 (79% de concentrado) e 7 dias de dieta de terminação (86% de concentrado). O pH ruminal foi monitorado por meio da utilização de data loggers a cada 10 minutos. Foram avaliados a concentração de ácidos graxos de cadeia curta e amônia ruminal; a quantificação relativa das bactérias celulolíticas e utilizadoras de lactato por meio da técnica de PCR e a contabilidade total e diferencial de protozoários (0,4,8 e 12 horas após o trato). Os animais restritos, na fase de adaptação, tiveram maior concentração de AGCC (P< 0,01), maior duração de pH abaixo de 6,2 (P<0,01) e menor pH máximo nos dias 15 e 16 (P≤ 0,10) em relação ao tratamento controle. Na fase de terminação, esses animais tiveram menor CMS (P=0,02), maior pH médio e menor área de pH abaixo de 6,2 (P≤0,10) em relação ao tratamento controle. Os animais expostos previamente ao concentrado, na fase de adaptação, tiveram menor concentração de butirato e NH3 ruminal (P≤0,10) em relação ao tratamento controle. Apresentaram também menor quantidade relativa de Fibrobacter succinogenes (P=0,10) e maior CMS (P<0,01) em relação ao controle. Já na fase de terminação o CMS não teve diferença significativa em relação ao tratamento controle. Os animais que passaram por restrição alimentar ou por exposição de concentrado na fase de pré-adaptação apresentam características ruminais semelhantes durante a fase a terminação aos animais em forragem ad libitum. / The objective of this study was to evaluate the effect of diet restriction or prior exposure to concentrate ingredientes prior to the adaption period to high concentrate diet on parameters ruminal fermentation patterns and ruminal microorganisms profile of cannulated Nellore cattle. Six Nelore steers was used, with initial body weight about 350 kg, 20 months and cannulated in the rumen, which will be divided into two Latin squares 3 x 3. The treatments differed only with respect to the type of diets prior to the adaptation period: Control (forage ad libitum + mineral supplement); Restriction (forage restricted to 1.4% of body weight + mineral supplement) and concentrate (forage ad libitum + 0.5% of the body weight of concentrated ingredients + mineral supplement). The study was last 119 days, in which animals was submitted to three experimental periods (33 days each one) and two washout intervals (10 days) between the periods 1 and 2, 2 and 3; each period was divided as follows: 14 days of pre-adaptation, 6 days of adaptation 1 (72% concentrate), 6 days of adaptation 2 (79% concentrate) and 7 days of finishing diet (88% concentrate). The rumen pH and temperature was be monitored through the use of data loggers it was evaluated the rumen production of short chain fatty acids and ammonia concentration; the relative quantification of cellulolytic, amylolytic and lactate bacteria utilizing PCR and total and differential quantification of protozoa. Thus, the hypothesis is to test if Nelore cattle exposed to feed restriction or comsuption of concentrate ingredientes prior to the adaptation period present same rumen fermentation patters and microrganism profile when compared to animals of control treatment in the finish diet. Restricted animals, in the adaptation phase, had a higher concentration of SCFA (P<0.01), a higher duration of pH below 6.2 (P <0.01) and lower maximum pH on days 15 and 16 (P≤ 0.10) in relation to the control treatment. In the finish diet, these animals had lower DMI (P = 0.02), higher mean pH and lower pH area below 6.2 (P≤0.10) in relation to the control treatment. The animals previously exposed to the concentrate in the adaptation diet had a lower concentration of butyrate and ruminal NH3 (P≤0.10) in relation to the control treatment. They also presented lower amount of Fibrobacter succinogenes (P = 0.10) and higher DMI (P <0.01) in relation to the control. In the termination diet the DMI did not affect in relation to the control treatment. Cattle previously submitted to either nutricional restriction or intake of concentrate have similar ruminal characteristics during the finishing diet of the animals in control treatment. / 2016/04262-8

Page generated in 0.0537 seconds