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Dry matter, crude protein and starch degradation characteristics of one corn (Pioneer 39P78) and four barley grain varieties (CDC Bold, CDC Dolly, Harrington and Valier) were evaluated in two in situ nylon bag trials. Trial 1 compared ground and rolled treatments of Harrington barley and Pioneer 39P78 corn, whereas Trial 2 evaluated ground and rolled treatments of the four barley varieties. Rumen degradability characteristics were compared with analytical results from thermal- and synchrotron-source FTIRM. Infrared absorbance spectra were collected from corn and four barley varieties using thermal-source FTIRM on the mid-IR beamline at the Canadian Light Source, Ltd. (Saskatoon, SK). Synchrotron-source FTIRM spectral data was collected for corn, Harrington barley and Valier barley on the U2B mid-IR beamline at NSLS-BNL (Upton, NY). CHO:Amide I peak area ratios were compared to the in situ rumen degradation results to determine if FTIRM spectral data could be related to the rate and extent of rumen degradation, and if thermal- and synchrotron-source FTIRM yielded different results. A grain x processing method interaction (P<0.01) was observed in both in situ trials where grinding produced a greater increase in the rate and extent of rumen degradation for Harrington barley than it did for corn (Trial 1) along with a greater increase in the rate and extent of rumen degradation for CDC Bold and CDC Dolly than for Harrington and Valier (Trial 2). Among barley varieties, increasing rate and extent of rumen degradation (CDC Bold>CDC Dolly>Harrington>Valier) corresponded to increasing starch:protein ratio as estimated by chemical analysis. This relationship was reversed for corn and Harrington barley where corn had a higher starch:protein ratio yet slower rumen degradation kinetics. For both thermal- and synchrotron-source FTIRM, CHO:amide I peak area ratios were greater (P<0.05) for corn than for Harrington barley. Comparison of CHO:amide I peak area ratios of barley varieties measured with thermal-source FTIR showed that varieties with higher (P<0.05) CHO:Amide I peak area ratios generally had higher rate and extent of rumen degradation. This indicates that starch:protein ratio estimated with FTIRM may be an indicator of rumen degradability characteristics when comparing varieties of the same grain, but not for different species of grains.

Dry matter, crude protein and starch degradation characteristics of one corn (Pioneer 39P78) and four barley grain varieties (CDC Bold, CDC Dolly, Harrington and Valier) were evaluated in two in situ nylon bag trials. Trial 1 compared ground and rolled treatments of Harrington barley and Pioneer 39P78 corn, whereas Trial 2 evaluated ground and rolled treatments of the four barley varieties. Rumen degradability characteristics were compared with analytical results from thermal- and synchrotron-source FTIRM. Infrared absorbance spectra were collected from corn and four barley varieties using thermal-source FTIRM on the mid-IR beamline at the Canadian Light Source, Ltd. (Saskatoon, SK). Synchrotron-source FTIRM spectral data was collected for corn, Harrington barley and Valier barley on the U2B mid-IR beamline at NSLS-BNL (Upton, NY). CHO:Amide I peak area ratios were compared to the in situ rumen degradation results to determine if FTIRM spectral data could be related to the rate and extent of rumen degradation, and if thermal- and synchrotron-source FTIRM yielded different results. A grain x processing method interaction (P<0.01) was observed in both in situ trials where grinding produced a greater increase in the rate and extent of rumen degradation for Harrington barley than it did for corn (Trial 1) along with a greater increase in the rate and extent of rumen degradation for CDC Bold and CDC Dolly than for Harrington and Valier (Trial 2). Among barley varieties, increasing rate and extent of rumen degradation (CDC Bold>CDC Dolly>Harrington>Valier) corresponded to increasing starch:protein ratio as estimated by chemical analysis. This relationship was reversed for corn and Harrington barley where corn had a higher starch:protein ratio yet slower rumen degradation kinetics. For both thermal- and synchrotron-source FTIRM, CHO:amide I peak area ratios were greater (P<0.05) for corn than for Harrington barley. Comparison of CHO:amide I peak area ratios of barley varieties measured with thermal-source FTIR showed that varieties with higher (P<0.05) CHO:Amide I peak area ratios generally had higher rate and extent of rumen degradation. This indicates that starch:protein ratio estimated with FTIRM may be an indicator of rumen degradability characteristics when comparing varieties of the same grain, but not for different species of grains.

The overall objective of this study was to evaluate the effects of feeding hulless barley and supplementing a xylanase enzyme on production performance and nutrient utilization of lactating dairy cows. In study 1, we evaluated production performance, milk fatty acid composition, and nutrient digestibility in high-producing dairy cows consuming diets containing corn and hulless barley in different proportions as the grain source. We hypothesized that a plausible reduction in production performance would be explained by an altered rumen function, which would be reflected in a reduction of the proportion of de novo fatty acids in milk fat. The inclusion of hulless barley grain as the energy source in diets for lactating dairy cows resulted in similar production performance and nutrient utilization as corn grain. We concluded that hulless barley is as good as corn grain as an energy source and increasing NDF concentration in hulless barley-based diet is not necessary. In study 2, we evaluated production performance, nutrient digestibility, and milk fatty acid composition of high-producing dairy cows consuming diets containing hulled or hulless barley as the grain source. We hypothesized that rumen function is altered when cows are fed low-forage diets containing barley grains, and this altered rumen function would be reflected in lower production performance and a reduction of fatty acids synthesis in the mammary gland. Contrary to our expectations, feeding hulled barley or hulless barely based diets with different forage to concentrate ratios to lactating dairy cows resulted in similar production performance and nutrient utilization. We concluded that both hulled or hulless barley grains are good energy sources for sustaining high milk production and there is no need to increase NDF concentration in diet when using barley grain as the grain source. In study 3, we evaluated the effects of supplementing a xylanase enzyme on production performance and nutrient digestibility of lactating dairy cows fed diets containing corn or sorghum silage as the forage source. We hypothesized that supplementing a xylanase enzyme product in diets containing corn or sorghum silage increases NDF digestibility, and production performance of lactating dairy cows would also be improved due to enhanced fiber digestion. Supplementation of xylanase for 19 d did not affect cow performance and nutrient utilization. Supplementation of xylanase may require a longer period of time to show any response in production performance and nutrient digestibility. We concluded that supplementing xylanase to cows fed corn or sorghum silage-based diets did not improve fiber digestion. But for feeding hulled or hulless barley grains to lactating dairy cows, increased NDF concentration in diets is not necessary and hulless barley is good as corn grain for feeding lactating dairy cows as the grain source. / Ph. D. / The overall objective of this study was to evaluate the effects of feeding hulless barley and supplementing a xylanase enzyme on production performance and nutrient utilization of lactating dairy cows. Barley starch is fermented faster than corn starch and can possibly reduce ruminal pH. Reduced ruminal pH can compromise cow production performance and cause some health problems. In study 1, we evaluated production performance, milk fatty acid composition, and nutrient digestibility in high-producing dairy cows consuming diets containing corn or hulless barley as the grain source. We hypothesized that a plausible reduction in production performance and milk fat percentage would be reduced by feeding hulless barley as the grain source in the diet. According to our results, the inclusion of hulless barley grain as the energy source in diets for lactating dairy cows resulted in similar production performance and nutrient utilization as corn grain. We concluded that hulless barley is as good as corn grain as an energy source and increasing fiber concentration in hulless barley-based diet is not necessary. In study 2, we evaluated production performance, nutrient digestibility, and milk fatty acid composition of high-producing dairy cows consuming diets containing hulled or hulless barley as the grain source. We hypothesized that rumen function is altered when cows are fed low-forage diets containing barley grains, and this altered rumen function would be reflected in lower production performance and a reduction of milk fat percentage. Contrary to our expectations, we did not observe any differences in cow production performance among all treatments. We concluded that both hulled or hulless barley grains are good energy sources for sustaining high milk production and there is no need to increase fiber concentration in diet when using barley grain as the grain source. In study 3, we evaluated the effects of supplementing a xylanase enzyme on production performance and nutrient digestibility of lactating dairy cows fed diets containing corn or sorghum silage as the forage source. We hypothesized that supplementing a xylanase enzyme product in diets containing corn or sorghum silage increases fiber digestibility, and production performance of lactating dairy cows would also be improved due to enhanced fiber digestion. Supplementation of xylanase for 19 d did not affect cow production performance and nutrient digestion. The effects of supplementation xylanase may require a longer period time to detect. We concluded that supplementing xylanase to cows fed corn or sorghum silage-based diets did not improve fiber digestion. For feeding hulled or hulless barley grains to lactating dairy cows, increased fiber concentration in diets is not necessary and hulless barley is good as corn grain for feeding lactating dairy cows as the grain source.

Este trabalho foi desenvolvido com a finalidade de testar alterações nas metodologias in vitro de produção de gases (diferentes proporções de inóculo) e incorporação de 32P (velocidade de centrifugação, número de lavagens e diferentes tipos de inóculos) para adequá-las às condições climáticas e às especificidades da microbiota dos ruminantes mantidos no clima tropical brasileiro. Além dessas técnicas utilizadas, foram feitas determinações de análise bromatológica com posterior análise de nutrientes digestíveis totais, degradabilidade ruminal in situ e digestibilidade in vitro a partir da técnica dos dois estágios. Os substratos testados foram divididos em, fibrosos (feno de alfafa e capim colonião), concentrados (milho grão e farelo de soja) e fermentado (silagem de milho). O delineamento experimental utilizado foi inteiramente casualizado, todos os substratos foram avaliados para cada uma das variáveis com pelo menos três repetições no tempo. Cada variável foi comparada por análise de variância considerando a hipótese de nulidade dentro dos substratos. As correlações entre as metodologias foram testadas quando biologicamente significantes e compatíveis. A técnica de incorporação in vitro de 32P, obteve resultados satisfatórios (P<0,05) em relação à velocidade de centrifugação e número de lavagens. Os diferentes tipos de inóculos testados (100% fase líquida do rúmen, 50% fase líquida e 50% fase sólida) não apresentaram diferença significativa (P>0,05). As diferentes proporções do inóculo testado na técnica in vitro de produção de gases (A contendo 100% de fase líquida e 0% de fase sólida; inóculo B, 75% de fase líquida e 25% de fase sólida; inóculo C, 67% de fase líquida e 33% de fase sólida; inóculo D, 50% de fase líquida e 50% de fase sólida) apresentaram diferença significativa (P<0,01); os fatores analisados permitiram a interpretação de que usando o inóculo com maior porcentagem de fase sólida, o processo fermentativo foi mais parecido ao potencial de produção de gases. Para a técnica in vitro de incorporação de 32P sugere-se usar uma velocidade de centrifugação de 39.907g, 4 lavagens e um inóculo com apenas a fase líquida do conteúdo ruminal. É sugerido que para a técnica in vitro de produção de gases pode ser usado um inóculo contendo 50% de fase sólida e 50% de fase líquida do conteúdo ruminal. / This study was developed to test the adaptations in in vitro methodologies of gas production (different proportion of solid phase in the inoculum) and 32P incorporation technique (centrifugation speed, number of washings and different kinds of inoculum) to adequate them to the climate condition and to the microbiota specifications of the ruminants kept in the Brazilian tropical climate. Besides these techniques, bromatological analysis determinations were made with further total digestible nutrients and also, in situ rumen degradability and in vitro digestibility from the two-stage technique. The tested substrata were divided in fibrous (Panicum grass and Lucerne hay), concentrated (soybean meal and corn grain) and fermented (corn silage). The experimental design was completely randomized, where all the substrata were evaluated for each of the variables with at least three repetitions. Each variable was compared for analysis of variance considering the hypothesis, within substrata. The correlations between methodologies were tested when biologically significant and compatible. The 32P in vitro incorporation technique obtained satisfactory results (P<0,05) in relation to the centrifugation speed and the number of washings. The two different kinds of tested inocula (100% rumen liquid phase, and 50% both liquid and solid phase) showed no significant difference (P>0,05). The different inoculum proportion tested for in vitro gas production (inoculum A containing 100% liquid phase and 0% solid phase; inoculum B, 75% liquid phase and 25% solid phase; inoculum C, 67% liquid phase and 33% solid phase; and inoculum D, 50% both liquid and solid phases) showed significant difference; the analyzed factors allowed the interpretation that using the inoculum with higher solid phase percentage, the fermentation process was more similar to the gas production potential. In the in vitro 32P incorporation technique it is suggested to use a centrifugation speed of 39,907g, 4 washings and an inoculum with only liquid phase from the rumen. It is suggested that for the in vitro gas production technique can be used an inoculum containing 50% of solid phase and 50% of liquid phase.

Com o avanço da maturidade fisiológica, ocorre enchimento dos grãos, aumento do teor de matéria seca (MS) e assim mudanças na composição bromatológica da planta de milho. Desta forma é importante o estudo do tamanho de corte da forragem que preserve as características da planta fresca, permitindo adequada fermentação da massa e consequentemente a produção de uma silagem de qualidade. O objetivo deste estudo foi avaliar o processo de produção de silagens de milho planta inteira, com foco em avaliar o impacto sobre a fermentação e o pós-abertura de silagens produzidas à partir de híbridos distintos, colhidos em diferentes estágios de maturação e processados mecanicamente sob gradiente de tamanho de corte. E definir a melhor estratégia de configuração de tamanho de corte para a colheita em diferentes estágios de maturação. A ensilagem da cultura de milho foi realizada em silos experimentais com capacidade de 20 L, os híbridos foram colhidos com a colhedora JF AT 1600 (sem processador de grãos). Os tratamentos foram constituídos por teores de matéria seca das plantas (300 e 370 g/kg de MS), diferentes híbridos (LG 6030, LG 6036 e AG1051) e três tamanhos teóricos de corte (TTC) de acordo com a regulagem da colhedora (3, 5 e 7 mm), sendo utilizadas quatro repetições por tratamento e armazenadas por 90 dias. Foram avaliados: composição química-bromatológica, ácido lático, pH, microbiologia, perda de matéria seca (PMS), estabilidade aeróbia (EA), kernel processing score (KPS), características físicas das partículas e dos grãos, degradabilidade in situ da MS, FDN e Amido, e amido degradável. Houve interação entre híbrido, maturidade e TTC e esses fatores tiveram efeito sobre o valor nutritivo, características físicas, estabilidade aeróbia, degradabilidade in situ da MS, FDN e amido das silagens de milho neste estudo. Os teores de MS e amido da silagem aumentaram com o avanço da maturidade e como efeito deste aumento, as concentrações de FDN e FDA diminuíram. Os tratamentos com 300 g/kg de MS apresentaram maiores contagens de leveduras, maiores PMS e menor EA. As silagens de milho colhidas a um TTC menor (3 mm), como esperado, tiveram menos partículas maiores que 19 mm, mais partículas entre 1.18 - 8 mm, e um menor TMP comparado com as silagens de milho colhidas com 5 e 7mm. A degradabilidade in situ de MS, FDN e Amido foi afetada principalmente pelo tipo de híbrido e maturidade. O desaparecimento da MS foi maior para os híbridos AG 1051 e LG 6036, de FDN foi maior para o híbrido LG 6036 e do amido foi maior para o híbrido AG 1051. O desaparecimento da MS, FDN e Amido foi maior quando foi incubada amostras com teor de MS de 300 g/kg de MS do que para silagem de milho com 370 g/kg MS. Reduzir o TTC (de 7 mm para 5 ou 3 mm), é eficaz quando a planta é colhida com 300 g/kg de MS mas não é efetivo com 370 g/kg de MS. No entanto o melhor resultado para colheita em maturidade mais avançada foi potencializado pelo uso do híbrido AG 1051 caracterizado pela empresa responsável como macio e pelo LG 6036 caracterizado pela empresa responsável como duro. Contudo se o milho passar de 370 g/kg de MS e utilizar colhedora acoplada ao trator sem processador de grãos, reduzir TTC não irá melhorar o processamento dos grãos. A colheita com 300 g/kg de MS foi mais eficiente com redução do TTC para 3 ou 5 mm e para o híbrido LG 6030 e a colheita com 370 g/kg de MS independente do TTC foi mais eficiente para os híbridos AG 1051 e LG 6036. O TTC e a maturidade na colheita constituem estratégias efetivas em refinar as recomendações para ensilagem de híbridos de milho diferentes. / With the advent of physiological maturity, grain growth, increased dry matter content (DM) and assimilation in the bromatology of the corn plant. In this way it is important to study the cut of weight to preserve the characteristics of the fresh plant, allowing the fermentation of the mass and, consequently, the production of a quality silage. The objective of this study was to evaluate the whole plant of corn silage production process, with a focus to evaluating the impact of the fermentation and the aerobic stability of silages produced from different hybrids harvested at different stages of maturation and mechanically processed under gradient of length of cut. And define the best strategy of setting the cut size for harvest at different stages of maturation. Corn silage ensiling was performed in experimental silos with a capacity of 20 L, the hybrids were harvested with the JF AT 1600 harvester (without grain processor). The treatments were constituted by dry matter contents of the plants (300 and 370 g/kg DM), different hybrids (LG 6030, LG 6036 and AG1051) and three theoretical lengths of cut (TLOC) according to the harvester adjustment (3, 5 and 7 mm), using four replicates per treatment and stored for 90 days. The following parameters were evaluated: chemical composition, lactic acid, pH, microbiology, dry matter loss (DML), aerobic stability (EA), kernel processing score (KPS), particle and grain physical characteristics, in situ DM degradability, NDF and Starch, and degradable starch. There was interaction between hybrid, maturity and TLOC, and these factors had effect on the nutritive value, physical characteristics, aerobic stability, in situ degradability of DM, NDF and corn silage starch in this study. The content of DM and starch of the silage increased with the advancement of maturity and as a result of this increase, the concentrations of NDF and ADF decreased. Treatments with 300 g/kg DM showed higher yeast counts, higher DML and lower EA. Maize silages harvested at a lower TLOC (3 mm), as expected, had fewer particles larger than 19 mm, more particles between 1.18 - 8 mm, and lower TMP compared to maize silages harvested at 5 and 7 mm. The in situ degradability of DM, NDF and Starch was mainly affected by hybrid type and maturity. The disappearance of MS was higher for the AG 1051 and LG 6036 hybrids, where as the NDF disappearance was higher for the LG 6036 hybrid and the starch was higher for the AG 1051 hybrid. The disappearance of DM, NDF and Starch was higher when samples were incubated with DM content of 300 g/kg DM than for corn silage at 370 g/kg MS. Reducing TLOC (from 7 mm to 5 or 3 mm) is effective when the plant is harvested at 300 g/kg DM but is not effective at 370 g/kg DM. However the best result for harvesting in more advanced maturity was potentialized by the use of hybrid AG 1051 characterized by the company responsible as soft and by the LG 6036 characterized by the company responsible as hard. However, if maize exceeds 370 g/kg DM and uses harvester coupled to the tractor without a grain processor, reducing TLOC will not improve grain processing. Harvesting with 300 g/kg DM was more efficient with TLOC reduction for 3 or 5 mm and for the LG 6030 hybrid, and harvesting with 370 g/kg DM independent of TLOC was more efficient for hybrids AG 1051 and LG 6036. TLOC and maturity at harvest constitute effective strategies to better fine tuning ensiling recommendations for different corn hybrids.

Regardless of the type of diet used, the search for increased digestion of nutrients has been the target of most research worldwide. The objective of this thesis was to evaluate the effects of the inclusion of essential oils, enzymes, ionophores and combinations of additives in animal performance, ruminal health and apparent digestibility in Nellore cattle fed with high concentrate diets. The study was composed of two performance experiments and two of metabolism In Chapter 1 of this thesis 2 experiments were conducted to evaluate the performance responses of finishing feedlot cattle receiving diets containing essential oils and exogenous enzymes. The treatments in each experiment consisted of (dry matter basis): MON - sodium monensin (26 mg/kg); BEO - a blend of essential oils (90 mg/kg); BEO+MON - a blend of essential oils plus monensin (90 mg/kg + 26 mg/kg, respectively); BEO+AM - a blend of essential oils plus exogenous &#945;-amylase (90 mg/kg + 560 mg/kg, respectively); and BEO+AM+PRO - a blend of essential oils plus exogenous &#945;-amylase and exogenous protease (90 mg/kg + 560 mg/kg + 840, mg/kg respectively). Exp. 1 consisted of a 93-d finishing period using 300 Nellore bulls in a randomized complete block design. Compared with MON, the combination of BEO+AM resulted in greater dry matter intake, greater average daily gain, 12 kg heavier hot carcass weight, although feed efficiency was not significantly different between BEO+AM and MON. BEO+MON and BEO did not improve performance when compared to MON. In Exp. 2, five ruminally cannulated Nellore steers were used to evaluate intake, apparent total tract digestibility of nutrients, and ruminal parameters in a 5 × 5 Latin Square design. Intakes of all nutrients measured, except for EE were greater in animals fed BEO+AM when compared with MON, with no differences on total tract nutrient digestibilities between these two treatments. Feeding BEO increased the total tract digestibility of CP compared to MON. In summary, diets containing the BEO used herein enhanced dry matter intake of growing-finishing feedlot cattle compared with a basal diet containing MON without impair feed efficiency. A synergism between BEO and AM was detected, resulting in increased carcass production. This study evaluated the growth performance and digestion responses of finishing feedlot beef cattle fed high-concentrate diets containing 82.5% flint corn (DM basis) ground to medium (1.66 mm; MG) or coarse particle sizes (2.12 mm; CG), added with monensin (26 mg/kg; DM basis; MON) or a blend of essential oils + exogenous &#945;-amylase (90 mg/kg + 560 mg/kg commercial product, respectively, DM basis; BEO+AM). In Exp. 1, 256 Nellore bulls were blocked by initial body weight (360 &#177; 12 kg), assigned to 48 pens and pens within blocks were randomly assigned, in a 2 × 2 factorial arrangement, to treatments during 99 d. Feed additive effect was detected for DMI, which was greater for bulls fed BEO+AM vs. MON. The HCW was 11 kg heavier for bulls fed BEO+AM vs. MON in diets containing CG, but not MG particle size. In Exp. 2, four ruminally cannulated Nellore steers were offered the same treatments of Exp. 1, in a 4 × 4 Latin Square design, to evaluate intake, apparent total tract digestibility of diets and ruminal fermentation parameters. Effect of corn particle size was detected for intake of DM, CP, NDF, NFC, starch and TDN which were greater for steers fed CG than steers fed MG corn. Feed additive affected (P = 0.02) ruminal NH3-N concentration, which was less for steers fed BEO+AM compared to MON. In summary, reducing flint corn particle size from 2.12 to 1.66 mm in finishing diets failed to improve cattle growth performance, digestibility of most nutrients and ruminal fermentation characteristics. A blend of essential oils associated with exogenous &#945;-amylase resulted in the heavier carcass weights compared to monensin supplementation when included in diets containing coarse ground corn. / Independente do tipo de dieta utilizada, a busca por aumento da digestão dos nutrientes tem sido alvo da maior parte das pesquisas realizadas no mundo. O objetivo dessa tese foi avaliar os efeitos da inclusão de óleos essenciais, enzimas, ionóforos e combinações de aditivos na performance animal, saúde ruminal e digestibilidade aparente em bovinos de corte da raça Nelore confinados alimentados com dietas de terminação com alto concentrado. O estudo foi composto por dois experimentos de desempenho e dois de metabolismo. No Capítulo 1 dessa tese 2 experimentos foram conduzidos para avaliar o desempenho de bovinos terminados em confinamento recebendo dietas que continham óleos essências e enzimas exógenas. Os tratamentos em cada experimento consistiram em: MON (monensina sódica, 26 mg/Kg); BEO (blend de óleos essenciais - 90 mg/kg); BEO+MON; BEO+AM (blend de óleos essenciais mais &#945;-amilase - 90 mg/kg + 560 mg/kg, respectivamente) e BEO+AM+PRO (óleos essenciais mais &#945;-amilase mais protease (90 mg/kg + 560 mg/kg + 840 mg/kg, respectivamente). No Exp. 1 foram utilizados 300 animais Nelore distribuídos aleatoriamente em 60 baias. Comparado com MON, a combinação BEO+AM resultou em maior CMS, maior GPD e proporcionou 12 kg a mais de carcaça, sem alterar a eficiência alimentar. BEO+MON e BEO não proporcionaram melhora no desempenho, quando comparada com MON. No Exp. 2, 5 animais canulados no rúmen foram usados para avaliar, CMS, digestibilidade aparente dos nutrientes e parâmetros ruminais em um quadrado latino 5 x 5. BEO aumentou a digestibilidade no trato total da PB comparada com MON. Os consumos de todos nutrientes, com exceção de EE foram maiores para animais alimentados com BEO+AM, quando comparados com MON, sem diferenças na digestibilidade no trato total. Em resumo, BEO aumenta o CMS de animais confinados em relação a MON, sem alterar a eficiência alimentar. Um sinergismo entre BEO e AM foi observado, resultando em aumento da produção de carcaça. No Capítulo 2, avaliou-se o desempenho e respostas metabólicas de animais confinados recebendo dietas com alto teor de milho (82.5% da MS), processado em moído (1,66 mm; MG) e moído grosso (2,12 mm; CG), combinado com monensina (monensina sódica, 26 mg/Kg; MON) ou com blend de óleos essenciais mais &#945;-amilase (90 mg/kg + 560 mg/kg, respectivamente; BEO+MON). No Exp. 1, 256 animais Nelore foram blocados em 48 baias, as quais foram distribuídas aleatoriamente a um arranjo fatorial 2 x 2 nos tratamentos por 99 dias. Animais alimentados com BEO+MON apresentaram maior CMS do que animais alimentados com MON. Foi observada interação entre processamento e aditivo para PCQ, na qual animal alimentados com BEO+MON e CG obtiveram 11 kg a mais. No Exp. 2, quatro animais canulados no rúmen foram assimilados as mesmos tratamentos do Exp. 1, em um quadrado latino 4 x 4. Efeito de processamento foi detectado no consumo de MS, PB, FDN, CNF, amido e NDT, os quais foram maiores para animais alimentados com milho CG do que MG. Efeito de aditivo foi observado na concentração de NH3-N ruminal, a qual foi menor para animais alimentados com BEO+AM comparado a animais que receberam MON. Em suma, reduzir o tamanho de partícula de 2,12 mm para 1,66 mm não melhorou o desempenho e os parâmetros de fermentação ruminal. A suplementação com BEO+AM resulta em maior produção de carcaça comparada com monensina, quando incluída em dietas com milho moído grosseiramente.

Made available in DSpace on 2014-06-11T19:32:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-07Bitstream added on 2014-06-13T18:44:44Z : No. of bitstreams: 1 rodrigues_mmfc_dr_botfmvz.pdf: 187134 bytes, checksum: 41a810da060eba822861f2da21c00b4d (MD5) / Esta pesquisa avaliou os efeitos dos processamentos ensilagem, extrusão e secagem do milho e de sorgo sem tanino e com tanino sobre a composição química e a cinética de digestão ruminal da matéria seca e da proteína bruta. O delineamento experimental foi o inteiramente casualizado, com arranjo fatorial de tratamentos 3 X 3, sendo três tipos de grãos (milho, sorgo sem tanino e sorgo com tanino) e três processamentos (seco, ensilado e extrusado). Para a avaliação da composição química e do tanino e para o experimento de degradabilidade utilizou-se delineamento em blocos casualizados, em um esquema fatorial 3 x 3 x 3, sendo três tipos de grãos (milho, sorgo com tanino e sorgo sem tanino), três formas de processamentos (moído seco, ensilagem e extrusão) e três blocos (animais) com a técnica de degradação ruminal in situ. Os valores encontrados para os teores de proteína bruta estiveram entre 8,7 e 10,7% para o milho e entre 9,9 e 11,1% para o sorgo. Os teores de extrato etéreo sofreram modificações com o processamento nos três tipos de grãos, onde se constatou redução significativa com a secagem, a ensilagem e a extrusão em relação ao material úmido nos três grãos. Para os teores de fenóis, tanino total e tanino condensado houve efeito de híbrido, de processamento e da interação entre eles. O sorgo com tanino apresentou teores mais elevados de fenóis, tanino total e tanino condensado do que o sorgo sem tanino. Embora a composição do milho e dos dois híbridos de sorgo tenha sido similar a interação desses ingredientes no ambiente ruminal associada a presença do tanino, proporcionou diferenças na degradabilidade da matéria seca. Conclui-se que o sorgo sem tanino deve ser ensilado ou extrusado, enquanto o sorgo com tanino deve ser extrusado por melhorar a degradabilidade e a disponibilidade de nutrientes no rúmen. / This research evaluated the effects of the high moisture silage processing, extrusion and drying of corn and of sorghum with and without tannin on the chemical composition and dry matter degradability ruminal. The assay design was entirely randomized arranged in a factorial (3x3), with three types of grains (corn, sorghum without tannin and sorghum with tannin) and three types of processing (dry, high moisture silage and extruded). Tannin chemical evaluation and the degradability were evaluated in a blocks randomized design. The treatments were arranged in a factorial (3x3x3), with three types of grains (corn, sorghum with tannin and sorghum without tannin), three forms of processing (dry, high moisture silage and extrusion) and three animals. Degradation ruminal in situ technique was used. The values crude protein ranged between 8,7 and 10,7% for corn and between 9,9 and 11,1% for sorghum. The ethereal extract values of the three types of grains changed with the processing. Significant reduction was verified, in the three grains, with drying, high moisture silage and extrusion correlated to the moisture material. Phenol values, total tannin and condensed tannin was affected by the hybrid, processing and by the interaction among them. Sorghum with tannin showed elevated phenol values, total tannin and condensed tannin than sorghum without tannin. Although the composition of corn and the two hybrid of sorghum it has been similar, the interaction of those ingredients in the ruminal ambient associated with the presence of tannin provided differences in dry matter degradability. It is ended that sorghum without tannin should be ensiled or extruded, while sorghum with tannin should be extruded for improving degradability and readiness of dry matter in the rumen.

Este trabalho foi desenvolvido com a finalidade de testar alterações nas metodologias in vitro de produção de gases (diferentes proporções de inóculo) e incorporação de 32P (velocidade de centrifugação, número de lavagens e diferentes tipos de inóculos) para adequá-las às condições climáticas e às especificidades da microbiota dos ruminantes mantidos no clima tropical brasileiro. Além dessas técnicas utilizadas, foram feitas determinações de análise bromatológica com posterior análise de nutrientes digestíveis totais, degradabilidade ruminal in situ e digestibilidade in vitro a partir da técnica dos dois estágios. Os substratos testados foram divididos em, fibrosos (feno de alfafa e capim colonião), concentrados (milho grão e farelo de soja) e fermentado (silagem de milho). O delineamento experimental utilizado foi inteiramente casualizado, todos os substratos foram avaliados para cada uma das variáveis com pelo menos três repetições no tempo. Cada variável foi comparada por análise de variância considerando a hipótese de nulidade dentro dos substratos. As correlações entre as metodologias foram testadas quando biologicamente significantes e compatíveis. A técnica de incorporação in vitro de 32P, obteve resultados satisfatórios (P<0,05) em relação à velocidade de centrifugação e número de lavagens. Os diferentes tipos de inóculos testados (100% fase líquida do rúmen, 50% fase líquida e 50% fase sólida) não apresentaram diferença significativa (P>0,05). As diferentes proporções do inóculo testado na técnica in vitro de produção de gases (A contendo 100% de fase líquida e 0% de fase sólida; inóculo B, 75% de fase líquida e 25% de fase sólida; inóculo C, 67% de fase líquida e 33% de fase sólida; inóculo D, 50% de fase líquida e 50% de fase sólida) apresentaram diferença significativa (P<0,01); os fatores analisados permitiram a interpretação de que usando o inóculo com maior porcentagem de fase sólida, o processo fermentativo foi mais parecido ao potencial de produção de gases. Para a técnica in vitro de incorporação de 32P sugere-se usar uma velocidade de centrifugação de 39.907g, 4 lavagens e um inóculo com apenas a fase líquida do conteúdo ruminal. É sugerido que para a técnica in vitro de produção de gases pode ser usado um inóculo contendo 50% de fase sólida e 50% de fase líquida do conteúdo ruminal. / This study was developed to test the adaptations in in vitro methodologies of gas production (different proportion of solid phase in the inoculum) and 32P incorporation technique (centrifugation speed, number of washings and different kinds of inoculum) to adequate them to the climate condition and to the microbiota specifications of the ruminants kept in the Brazilian tropical climate. Besides these techniques, bromatological analysis determinations were made with further total digestible nutrients and also, in situ rumen degradability and in vitro digestibility from the two-stage technique. The tested substrata were divided in fibrous (Panicum grass and Lucerne hay), concentrated (soybean meal and corn grain) and fermented (corn silage). The experimental design was completely randomized, where all the substrata were evaluated for each of the variables with at least three repetitions. Each variable was compared for analysis of variance considering the hypothesis, within substrata. The correlations between methodologies were tested when biologically significant and compatible. The 32P in vitro incorporation technique obtained satisfactory results (P<0,05) in relation to the centrifugation speed and the number of washings. The two different kinds of tested inocula (100% rumen liquid phase, and 50% both liquid and solid phase) showed no significant difference (P>0,05). The different inoculum proportion tested for in vitro gas production (inoculum A containing 100% liquid phase and 0% solid phase; inoculum B, 75% liquid phase and 25% solid phase; inoculum C, 67% liquid phase and 33% solid phase; and inoculum D, 50% both liquid and solid phases) showed significant difference; the analyzed factors allowed the interpretation that using the inoculum with higher solid phase percentage, the fermentation process was more similar to the gas production potential. In the in vitro 32P incorporation technique it is suggested to use a centrifugation speed of 39,907g, 4 washings and an inoculum with only liquid phase from the rumen. It is suggested that for the in vitro gas production technique can be used an inoculum containing 50% of solid phase and 50% of liquid phase.

O objetivo foi avaliar o efeito de teores de proteína bruta (PB) (14,5 vs 16%) e da fonte nitrogenada na dieta de vacas leiteiras em lactação sobre o consumo e digestibilidade da matéria seca (MS) e nutrientes, fermentação ruminal, produção e composição do leite e balanço de energia, utilizando cana-de-açúcar como volumoso. Foram utilizadas 12 vacas Holandesas com média de 235 dias em lactação, agrupadas em três quadrados latinos 4x4 contemporâneos, com período experimental de 21 dias, sendo 14 para adaptação às dietas e os 7 últimos para coletas. As vacas foram alimentadas &quot;ad libitum\' com rações isoenergéticas, com duas fontes nitrogenadas principais (farelo de soja e uréia) e dois teores de PB (14,5 e 16,0 %) na dieta: A) 16% PB e farelo de soja (FS) como fonte nitrogenada, com 65% de PDR; B) 14,5% PB e uréia (U) como fonte nitrogenada, com 70% de PDR; C) 16% PB U e 70% de PDR; D) 14,5% PB FS e 65% de PDR na MS. As amostras de leite para análise da composição foram coletadas do 14º ao 17º dia de cada período. As amostras de líquido ruminal foram coletadas com a utilização de sonda esofágica, três horas após a alimentação matinal. A digestibilidade foi determinada por meio de indicador interno FDAi. Não houve efeito das dietas sobre o consumo de MS (Kg/dia), de energia líquida de lactação (Mcal/dia), coeficiente de digestibilidade em porcentagem e consumo em porcentagem do peso vivo. Houve interação entre fonte nitrogenada e teor de PB da dieta sobre o pH e relação acetato propionato. Houve tendência (P=0,052) da fonte nitrogenada para PB (kg/dia), na qual as dietas com farelo de soja apresentaram maior valor, quando comparada as dietas com ureia. A gordura do leite foi maior (4,06%) nas dietas com fonte nitrogenada ureia , em relação a fonte nitrogenada FS com (3,5%). / The objective was to evaluate the effect of crude protein (CP) (14.5 vs. 16%) of the nitrogen source in the diet of lactating dairy cows on intake and digestibility of dry matter (DM) and nutrients, rumen fermentation, production and milk composition, energy balance, using sugar cane as forrage. We used 12 Holstein cows averaging 235 days in milk, grouped in three 4x4 contemporary Latin squares, with experimental period of 21 days, 14 for diet adaptation and 7 for sample collections. The cows were fed with diets isoenergetic \"ad libitum\", with two major nitrogen sources (soybean meal and urea) and two CP levels (14.5 and 16.0%) in diet: A) 16% CP soybean meal (SBM) as a nitrogen source, with 65% RDP; B) 14.5% CP and urea (U) as a nitrogen source, with 70% RDP; C) 16% CP U and 70% RDP; D) 14.5% CP and 65% FS RDP in DM. The milk samples for composition analysis were collected from the 14th to the 17th day of each period. The rumen fluid samples were collected using an esophageal tube , three hours after the morning feeding. The digestibility was determined by means of an internal indicator iADF. There was no effect of diets on the DM intake (kg / day), net energy for lactation (Mcal / day), percentage of digestibility and intake in percentage of body weight. There was interaction between nitrogen source and content of CP on pH and the acetate propionate ratio. There was a trend (P = 0.052) of source of nitrogen for CP (kg / day) in which diets with soybean meal had a higher value when compared with urea diets. Milk fat was higher (4.06%) in diets with urea nitrogen source, the source nitrogen compared with soybeans meal (3.5%).