O teste alérgico intradérmico (TID) é uma importante ferramenta no diagnóstico dos alérgenos implicados nas reações de hipersensibilidade mediada por IgE. O objetivo deste estudo foi avaliar o TID em eqüinos não alérgicos com extratos alergênicos de Cynodon dactylon, Lolium multiflorum, Paspalum notatum, Culex sp. e Aedes aegipty, e três concentrações de histamina, em dois volumes diferentes, e baseado nos resultados, verificar a acurácia do TID em eqüinos alérgicos. Foram realizados TID em 17 eqüinos não alérgicos com três concentrações de cada extrato (1:2000v/w, 1:4000v/w e 1:8000v/w) e três concentrações de histamina (0,1mg/ml, 0,05mg/ml e 0,025mg/ml), em dois volumes (0,1 e 0,05ml). Baseado nos resultados obtidos, foram realizados TID em seis eqüinos alérgicos utilizando os extratos na concentração de 1:2000v/w, a histamina na concentração de 0,025mg/ml, em um volume de 0,05ml. Nos eqüinos não alérgicos, nenhuma das três concentrações dos extratos testados nos dois volumes mostrou-se irritativa. Concentrações maiores de histamina provocaram halos maiores e levemente mais túrgidos, e quanto maior o volume injetado, maiores as reações Os TID realizados em eqüinos alérgicos mostraram confiabilidade dos resultados por evidenciar hipersensibilidade individual e não provocar reações irritativas. Em conclusão, as diferentes concentrações dos estratos testados em eqüinos não alérgicos não provocaram reações falso positivas (irritantes). O volume de 0,05ml é mais recomendado para realização dos TID pois as aplicações com 0,1ml produziram reações maiores, prejudicando a sensibilidade do teste. A concentração de 0,025mg/ml da solução de histamina provocou a formação de halos menores, permitindo maior acurácia do cut off no TID. Os extratos alergênicos testados em equinos alérgicos não provoraram reações em todos os animais, o que poderia ser considerado uma reação irritativa. Os equinos alérgicos apresentaram reações positivas diferentes, de acordo com a hipersensibilidade individual, demonstrando sensibilização alérgica verdadeira. / The intradermal test (IDT) is an important tool in the diagnosis of allergens involved in IgE-mediated hypersensitivity reactions. The aim of this study was to evaluate the IDT in nonallergic horses with allergenic extracts of Cynodon dactylon, Lolium multiflorum, Paspalum notatum, Culex sp. and Aedes aegypti, and three histamine concentrations, in two different volumes, and based on the results, verify the accuracy of IDT in allergic horses. IDT was performed on 17 nonallergic horses with three concentrations of each extract (1:2000v/w, 1:4000v/h and 18000v/w) and three histamine concentrations (0,1mg/ml, 0,05mg/ml and 0,025mg/ml) in two volumes (0,1 and 0,05ml). Based on the results obtained, IDT was performed in six allergic horses using extracts at the concentration of 1:2000v/w, histamine at a concentration of 0.025mg/ml, in a volume of 0,05ml. In nonallergic horses, none of the three concentrations of the extracts tested in the two volumes were irritant. Larger concentrations of histamine provoked larger and slightly more turgid wheals, and the larger the volume injected, the greater the reactions The IDT performed in allergic horses showed reliability of the results because they demonstrated individual hypersensitivity and did not provoke irritative reactions. In conclusion, the different concentrations of extracts tested in nonallergic horses did not provoke false positive (irritant) reactions. The volume of 0,05ml is more recommended for execution of IDT because the applications with 0,1ml produced larger reactions, impairing the sensitivity of the test. The concentration of 0,025mg/ml of the histamine solution caused the formation of smaller wheals, allowing a better accuracy of the cut off in the IDT. The allergenic extracts tested in allergic horses did not provoke reactions in all the animals, what could be considered an irritative reaction. Allergic horses presented different positive reactions, according to individual hypersensitivity, demonstrating true allergic sensitization.

A produção de forragem é fortemente influenciada pelo número e tamanho de perfilhos. Estes, variam em função das condições climáticas, edáficas e de espécie forrageira, razão pela qual seu estudo e conhecimento são fundamentais para a elevação da produtividade animal em pastagens. O presente ensaio foi conduzido no Departamento de Produção Animal da ESALQ/USP, em Piracicaba (SP), entre 18/08/98 e 08/03/99, com o objetivo de avaliar os padrões demográficos de perfilhamento e o acúmulo de forragem em pastagens de Cynodon spp.. Os tratamentos foram constituídos pela combinação de três cultivares de Cynodon spp. (Tifton-85, Florakirk e Coastcross) e quatro alturas de pasto (5, 10, 15 e 20 cm), mantidas por pastejo de ovinos em regime de lotação contínua e taxa de lotação variável. O delineamento experimental utilizado foi o de blocos completos casualizados em arranjo de parcelas subdivididas com quatro repetições. As parcelas corresponderam aos cultivares1 e as subparcelas às alturas de pasto. Foram analisadas as variáveis taxa de natalidade, taxa de mortalidade, densidade populacional de perfilhos, taxa de acúmulo de forragem e produção de matéria seca. O cultivar Tifton-85 apresentou as maiores densidades populacionais, menores taxas de mortalidade e maior sobrevivência de perfilhos por geração. A menor altura de pasto (5 cm) promoveu as maiores densidades populacionais, maiores taxas de mortalidade e menor sobrevivência de perfilhos por geração. As taxas e o acúmulo de forragem durante o período experimental foram semelhantes em todos os tratamentos. O período de coleta de dados (tempo) influenciou os resultados de todas as variáveis analisadas, sendo que a ocorrência de verânico em novembro/98 promoveu fortes efeitos sobre as mesmas. As taxas de mortalidade foram determinantes básicos das diferenças em densidades populacionais de perfilhos observadas para cultivares e/ou alturas de pasto. A observação de florescimento foi marcante para os cultivares Coastcross e Florakirk durante as estações de final de inverno e primavera, respectivamente. Tifton-85 demonstrou ser mais tolerante a pastejos mais intensos que os demais cultivares. Pastejo intenso (5 cm) após um período de alta mortalidade de perfilhos promoveu queda acentuada nas densidades populacionais durante o período subsequente. / Herbage dry matter production from pastures is strongly influenced by tiller number and tiller size in plant communities. These factors vary according to climatic and edaphic conditions as well as grass species, highlighting the need for understanding the way they relate to each other in order to increase animal productivity on pastures. The present experiment was carried out at the Animal Production Department, ESALQ/USP, Piracicaba-SP, from 18/08/98 until 08/03/99, aiming at evaluating the demographic patterns of tillering and herbage accumulation in Cynodon spp. swards. Treatments comprised all combinations between three Cynodon spp. cultivars (Tifton-85, Florakirk and Coastcross) and four sward estate conditions (5, 10, 15 and 20 sward surface height – SSH) generated by sheep under continuous stocking and variable stocking rate. The experimental design used was a complete randomised block, with treatments arranged in split-plot and replicated four times. Grass cultivars were assigned to plots and SSH to sub-plots. Pasture responses evaluated were: tiller natality and mortality rates, tiller population densities, herbage accumulation rates and dry matter production. Tifton-85 presented the highest values for tiller population densities, the smallest tiller mortality and the highest tiller survival rates. Herbage accumulation rates as well as dry matter production did not differ among treatments throughout the experimental period. There was a time effect on all variables studied and a dry spell in November/98 caused a decrease in tiller population and herbage accumulation rates. Tiller mortality rates were important determinants of the differences observed in tiller population densities for cultivars and/or SSH. Reproductive growth was a feature for Coastcross and Florakirk during late winter and spring, respectively. Tifton-85 presented a higher tolerance to hard grazing than Coastcross and Florakirk. Hard grazing (5cm) after a period of high mortality rate caused a strong reduction in tiller population densities.

O baixo custo, grande aptidão produtiva e fácil cultivo das plantas forrageiras são razões para que os pastos sejam a base da bovinocultura no Brasil, e que diversas forrageiras estejam entre as culturas mais amplamente distribuídas no país. A grande extensão territorial ocupada, no entanto faz com que as áreas pastoris estejam sujeitas a condições diversas de clima e ambiente, dificultando a estimação de sua produtividade para fins de planejamento. O sucesso dos empreendimentos agropecuários depende, cada vez mais, do desenvolvimento de ferramentas que racionalizem as intervenções gerenciais no processo produtivo, possibilitando estimar o desempenho, minimizar riscos e facilitando o planejamento do empreendimento agropecuária. Modelos matemáticos que possibilitem estimar o acúmulo de matéria seca e sua distribuição estacional são atualmente uma das grandes lacunas da zootecnia brasileira. Os objetivos deste trabalho foram modelar e implementar uma estrutura de banco de dados para experimentos de crescimento de plantas forrageiras, identificar e quantificar o efeito de atributos condicionantes do acúmulo de forragens nas condições do Brasil central e desenvolver modelos estimadores do acúmulo de forragem potencial com base em parâmetros climáticos. Foram usados seis conjuntos de dados, dois para Cynodon com cinco cultivares em dois anos em um mesmo local, um para Panicum, com cinco cultivares, em um ano e um local, e três para Brachiaria, com seis cultivares, em três anos em dois locais diferentes. Uma estrutura de banco de dados foi modelada e implementada de forma a permitir a inserção do atual conjunto de dados, e a inserção futura de novos dados. Com o banco de dados populado foram realizadas consultas de forma a se obter listagens ordenadas das taxas médias de acúmulo de forragem (TMA) e das variáveis climáticas como temperatura média (Tmed), máxima (Tmax) e mínima (Tmin), radiação global incidente (Rad) e dias julianos (DJ) para cada período de crescimento. Foram realizadas regressões lineares simples e múltiplas usando as variáveis climáticas como regressoras e taxa média diária de acúmulo como variável resposta. As análises evidenciaram alta correlação entre as variáveis climáticas no conjunto de dados analisados, ficando entre 0,81 para Tmin e Rad e 0.98 para Tmed e Tmin. Termos quadráticos para as variáveis regressoras não foram significativos (P>0,05). Dentre os modelos estudados, o simples com Tmin como variável independente se destacou apresentando os melhores valores para o coeficiente de determinação (R2), critério de informação de Akaike (AIC) e critério de informação Bayesiano (BIC) para os diferentes cultivares. Com isso, optou-se por modelos simples com a Tmin como variável preditora. Inicialmente foram gerados modelos para cada gênero, agregando os diversos cultivares. Testes de coincidência demonstraram diferença de parâmetros entre cultivares. Novos modelos foram gerados para cada cultivar individualmente, e desta vez os teste de coincidência permitiram agrupar os cultivares em B1 para Marandu, Basilisk e Arapoty (TA=-94.92+8.19Tmin); B2 para Capiporã e Xaraés (TA=-128.07+10.66Tmin); C1 para Tifton 85 e Estrela (TA=- 84.69+9.06Tmin); C2 para Coastcross, Florico e Florona (TA=-67.01+7.97Tmin); P1 para Atlas e Mombaça (TA=-55.22+6.36Tmin) e P2 para Tanzânia e Tobiatã (TA=- 29.15+5.93Tmin). / Low production costs, yield potential, and ease of cultivation are three major reasons why tropical forages are the backbone of livestock production systems in Brazil. It also explains why pasture species are among the most widely grown crops in the country. The large land area of the country, make for contrasting environments, which, in turn, make it difficult for the establishment of standard management practices, as well as for the prediction of pasture productivity for planning purposes of the forage-livestock enterprise. The success of the agricultural enterprise depends increasingly on the development of tools that can support management decisions, allowing for the estimation of pasture performance, minimizing risks and facilitating planning. The lack of strong, proven mathematical models developed to estimate the forage accumulation and seasonal yield distribution are some of the shortcomings of the Brazilian pasture-bases livestock industry. The objectives of this study were to develop and implement a database on major tropical forage species, compiled from published studies, organize the datasets in standard formats, identify and quantify the constraints and major attributes related with forage accumulation in central Brazil conditions, and to propose models for estimating potential forage accumulation based on climatic variables. Five datasets were used, two on Cynodon spp. with five genotypes, grown over two years at the same location, one on Panicum spp. using five genotypes grown in one year at one location, and two on Brachiaria spp. using five genotypes grown at two locations over three years. A database structure was modeled and implemented to allow for the insertion of future data points. Whit the database completed, queries were simulated in order to check for output listings on mean herbage accumulation rates (HAR), as well as climatological variables such as low (Tmin), mean (Tmean) and high (Tmax) temperatures, incoming radiation (Rad), and day of the year (DOY), for each regrowth period. Simple and multiple regression models were tested using the climatological data as independent variables and mean herbage accumulation rate as the dependent variable, after correlation analysis showed high association between accumulation and the independent variables tested (from 0.81 for Tmin and Rad to 0.98 for Tmed and Tmin). No quadratic coefficients were significant in the regression models. The Tmin model showed the highest R2 and the best values for both the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC) across genotypes. Thus, simple models based on Tmin were selected and initially, models were generated for groups of genotypes (genera), where concidence tests showed differences among genotypes within groups. For this reason, new models were generated for each genotype individually, which resulted in the following grouping: B1 for Marandu, Basilisk and Arapoty (HAR = - 94.92 + 8.19 Tmin), B2 for Capiporã and Xaraés (HAR = -128.07 + 10.66 Tmin), C1 for Tifton 85 and stargrass (HAR = - 84.69 + 9.06 Tmin), C2 for Coastcross, Florico and Florona (HAR = - 67.01 + 7.97 Tmin), P1 for Mombaça and Atlas (HAR = - 55.22 + 6.36 Tmin), and P2 for Tanzania and Tobiatã (HAR = - 29.15 + 5.93 Tmin).

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In Brazil, most soils used in the livestock presents some fertility limitations. One of the alternatives to improve the soils quality is the introduction of perennial species, including grassy and associated legumes and correction of the soil that it will hold the cultures forage crop. There s a lack of Information and researches on soil quality improvement using perennial forages. Therefore, the objective of this work was to evaluate different systems of forage cultures constituted by Pennisetum americanum, Arachis pintoi and Stylosanthes guianensis associated with Cynodon dactylon and both isolated species, with and without mineral fertilizer, and evaluations of the attributes of a Ultisols. In both treatments, Cynodon dactylon received 100 kg of nitrogen during a year. The crops of forage samples were accomplished at every 28 days, making botanical separation and drying the same. After the weighting to calculate the dry matter per area (ha) the samples were crushed for analyses of fiber of neutral detergent (FDN), fiber of acid detergent (FDA), rude protein (PB), calcium (Ca), magnesium (Mg), phosphorus (P) and potassium (K). The samples collecting were taken during January, March, April and October of 2007. The best results of nutritional values were found in the legumes and in the consortium, being with inferior quality the grassy ones. The dry matter present a great variation among the cuts and the forage systems. After the winter the Stylosanthes portions were lost, due to the frosts that happened during this period. This confirms that it not has an adaptation on our conditions of winter. After a year of implantation of the experiment was collected soil to analysis: density of the soil (DS), microporosity (Mip) and macroporosity (Map) porosity and total porosity of the soil (PT) and size of aggregates. In the chemical part, were analyzed total nitrogen (NT), total organic carbon (COT) and phosphorus (P) and potassium (K). DS presented variation between the treatments and the appraised layers, since 1,40 to 1,62 Mg m-3. In Mip and PT didn't present significant differences between the treatments and layers, but Map presented significant differences. In the aggregate size there was significant differences, and the geometric medium diameter (DMG) it varied from 1,41 to 3,21 mm. In the soil chemical attributes both maintained similarities, in other words, larger concentration in the first layer (0 to 5 cm). But some treatments standing out in larger concentration in the first layer, however maintain similarities in the deep layers, unless the potassium (K), that has a distribution more constantly in the evaluated layers. / No Brasil, a maioria dos solos utilizados para pecuária apresenta algumas limitações de fertilidade. Uma das alternativas para melhorar as condições desses solos é a introdução de espécies perenes, incluindo gramíneas e leguminosas consorciadas e correção do solo que comportará as culturas forrageiras. Informações e pesquisas sobre melhorias de solos com uso de espécies forrageiras perenes são escassas. Nesse sentido, o objetivo deste trabalho foi avaliar diferentes sistemas de culturas forrageiras constituídas de milheto, amendoim forrageiro e estilosantes consorciados com tifton 85 e ambas as espécies isoladas, com e sem adubação mineral, e avaliações dos atributos de um Argissolo vermelho. Em ambas as parcelas adubadas e não adubadas, o tifton 85 recebeu 100 kg de nitrogênio ano-1. As colheitas de amostras de forragem eram realizadas a cada 28 dias, realizando-se separação botânica e secagem da mesma. Feita a pesagem para calcular matéria seca (MS) por área (ha) realizava-se a moagem das amostras para análises de fibra de detergente neutro (FDN), fibra de detergente ácido (FDA), proteína bruta (PB), cálcio (Ca), magnésio (Mg), fósforo (P) e potássio (K). Realizaram-se coletas nos meses de janeiro, março, abril e outubro de 2007. Os melhores resultados de valores de PB, FDA e FDN, foram encontrados nas leguminosas e no consórcio, ficando com qualidade inferior o tifton 85 + 100 kg ha-1 de N. Quanto à produção de MS, variou muito entre os cortes e os sistemas forrageiros. Após o inverno as parcelas de estilosantes foram perdidas, devido às geadas que ocorreram no período de inverno. Isso confirma que o mesmo não tolera frio e não se adapta a nossas condições de inverno. Após um ano de implantação do experimento realizou-se coletas para análise dos atributos do solo, sendo: densidade do solo (DS), micro (Mip) e macro (Map) porosidade e porosidade total do solo (PT) e tamanho de agregados. Na parte química, analisou-se nitrogênio total (NT), carbono orgânico total (COT) e teores de fósforo (P) e potássio (K). A DS apresentou variação entre os tratamentos e as camadas avaliadas, desde 1,40 a 1,62 Mg m-3. Na Mip e PT não apresentou diferenças significativas entre os tratamentos e camadas, mas o Map apresentou diferenças significativas. Nos tamanhos dos agregados houve diferenças significativas, sendo que o diâmetro médio geométrico (DMG) variou de 1,41 a 3,21 mm. Nos atributos químicos do solo, como NT, COT, P e K ambos mantiveram semelhanças, ou seja, maior concentração na primeira camada (0 a 5 cm). Mas alguns tratamentos se destacaram em maior concentração na primeira camada, mantendo semelhanças nas camadas mais profundas, exceto o K que teve uma distribuição mais uniforme nas camadas avaliadas.

O presente experimento foi conduzido no Departamento de Produção Animal da ESALQ/USP, em Piracicaba (SP), entre 15/12/98 e 04/07/99. Os tratamentos foram constituídos pelas combinações entre três cultivares de Cynodon spp. (Tifton-85, Florakirk e Coastcross) e quatro alturas de pasto (5, 10, 15 e 20 cm) mantidas por pastejo de ovinos em regime de lotação contínua e taxa de lotação variável. O delineamento experimental utilizado foi o de blocos completos casualizados em arranjo de parcelas subdivididas com quatro repetições. As parcelas corresponderam aos cultivares e as subparcelas (unidades experimentais) às alturas de pasto. Foram analisadas as seguintes variáveis: biomassa na área total, densidade populacional de perfilhos, massa por perfilho, massa de folha por perfilho e área foliar por perfilho. A partir dessas medições foram realizados cálculos de índice de área foliar do pasto (IAF), volume por perfilho, relação folha:haste por perfilho e relação área foliar:volume por perfilho (R). O mecanismo de compensação tamanho/densidade populacional de perfilhos operou em pastagens de Cynodon spp.. No entanto, as inclinações das retas foram consistentemente maiores que a proposição teórica de 3/2. Perfilhos individuais de Cynodon spp. apresentaram um padrão de crescimento isométrico e parecem agruparse em clones para assegurar estratégia competitiva e otimização de IAF. Pastos mantidos a 5 cm durante o outono apresentaram densidades populacionais reduzidas, indicando um padrão de tolerância ao pastejo dependente da época do ano. Tifton-85 e Coastcross apresentaram uma capacidade de aumento em biomassa que pode ir além da altura de 20 cm, enquanto que para o cultivar Florakirk essa capacidade situou-se em torno de 20 cm. O estádio reprodutivo das plantas interferiu de forma significativa nos processos de competição intra-específica e dinâmica populacional de perfilhos. / The experiment was conducted at the Department of Animal Production, ESALQ/USP, Piracicaba (SP), from 15/12/98 until 04/07/99. Treatments were combinations of three Cynodon spp. cultivars (Tifton-85, Florakirk and Coastcross) and four sward surface heights (SSH) (5, 10, 15 and 20 cm) maintained by sheep under continuous stocking and variable stocking rate. A complete randomised block design was used, with treatments arranged in split-plot and replicated four times. Grass cultivars were assigned to plots and SSH to sub-plots. Pastures responses evaluated were: total biomass above ground level, tiller population density, tiller weight, leaf mass and leaf area per tiller. From these measurements calculations of sward leaf area index (LAI), tiller volume, tiller leaf:stem ratio and tiller leaf area:volume ratio (R) were derived. A tiller size/population density mechanism operated in Cynodon spp. However, a slope steeper than the theoretical expectation of 3/2 was observed. Individual tillers presented an isometric pattern of growth and seemed to demonstrate a clonal integration among tillers in order to enhance competitive ability and optimise LAI. Swards maintained at 5 cm during autumn presented reduced tiller population densities, indicating a pattern of grazing tolerance dependent of time of the year. Tifton-85 and Coastcross pastures showed a capacity to increase total biomass that could go beyond 20 cm, while Florakirk stabilised around that SSH. Reproductive development of plants interfered with the processes related to intra-specific competition and tiller population dynamics.

O presente trabalho teve como objetivo avaliar o efeito do emurchecimento da forragem associado ou não ao uso do aditivo bacteriano-enzimático na ensilagem do capim Tifton 85 (Cynodon spp.). Foi realizada avaliação de perdas nos painéis das silagens experimentais, assim como da composição bromatológica e do tamanho de partículas das mesmas. Ocorreram observações periódicas de comportamento ingestivo, consistência ruminal, consumo voluntário, parâmetros de fermentação ruminal, digestibilidade dos nutrientes, taxa de passagem de sólidos e líquidos ruminais em novilhos que receberam rações contendo 80% desses volumosos na base seca. Foram utilizados sete novilhos da raça Nelore, distribuídos ao acaso em um experimento do tipo quadrado latino 7 x 7. Os tratamentos avaliados foram resultantes da combinação de 3 concentrações de matéria seca (MS) na silagem do capim Tifton 85 (25, 45 e 65%) associadas (CA) ou não (SA) ao aditivo bacteriano-enzimático. Um tratamento adicional contendo 55% MS sem aditivo também foi avaliado. O aditivo utilizado foi o produto comercial SIL–ALL®, contendo cepas de Streptococcus faecium, Lactobacillus plantarum, Pediococcus acidilactici e as enzimas hemicelulase, celulase e amilase, aplicadas na dosagem de 250 g de SIL–ALL® diluídas em 50 litros de água por tonelada de forragem, imediatamente antes da ensilagem. A técnica de emurchecimento possibilitou elevar o teor de matéria seca mas, da mesma maneira que a adição do inoculante bacteriano-enzimático, provocou alterações pouco pronunciadas na composição química da silagem. Nas silagens SA o aumento da concentração de MS foi acompanhado de elevação no teor de FDN resultando em redução do teor de carboidratos não fibrosos (CNF). A fração protéica B3 nas silagens apresentou tendência de aumento com a elevação na concentração de MS, em função da progressiva elevação da fração N insolúvel no FDN, simultaneamente à redução N insolúvel no FDA. A avaliação dos silos após abertura, indicou aumento de perdas com a elevação da concentração de MS que, entretanto, podem ter sido decorrentes de uma menor taxa de utilização dos fardos contendo silagens com menor umidade. Tanto a consistência ruminal, avaliada como o tempo de ascensão do pêndulo no interior do rúmen (1194 seg.), como os parâmetros de cinética de passagem de sólidos (3,09% hora -1 ) e de líquidos (4,37% hora -1 ) foram similares para os tratamentos avaliados. O comportamento ingestivo dos animais não foi alterado com a elevação da concentração de MS da silagem, sendo observados tempos (minutos dia -1 ) e taxas (min kg MS –1 ) de ingestão de MS (324; 47), ruminação (518; 75) e mastigação (841; 123), respectivamente. O consumo diário de MS das rações, pelos animais, foi semelhante para os tratamentos avaliados, resultando em média de 6,95 kg equivalente a 1,88% do peso corpóreo. As concentrações molares (mM) individuais e totais (140,29) dos ácidos graxos voláteis, a relação acetato:propionato (4,2:1), concentração de nitrogênio amoniacal (6,31 mg dL -1 ) e o pH (6,76), do fluido ruminal, não foram alterados pelos tratamentos estudados. As digestibilidades da matéria orgânica (71,5%), proteína bruta (69,1%), FDN (71,3%), FDA (64,9%) e hemicelulose (83,3%) não foram, em geral, fortemente influenciadas pela concentração de MS da silagem do capim Tifton 85, aditivadas ou não. No entanto, a digestibilidade da MS (71,0%) apresentou um comportamento quadrático (P<0,05), com ligeira elevação ao redor de 45% de concentração de MS, nas silagens. Diante destas observações, pode-se concluir que o emurchecimento da forragem e o uso de aditivo bacteriano-enzimático não resultaram em alterações expressivas nos parâmetros ruminais, digestivos e no comportamento ingestivo dos animais. / The present trial aimed to study the effects of forage wilting associated or not with a bacterial-enzymatic inoculant on ensiling Tifton 85 grass. Front panel of experimental silos (325 kg square wrapped bales) were daily scored for fungi development and weekly sampled for chemical composition analysis and particle chop length measurements. In a randomized 7 x 7 Latin square design, seven ruminal cannulated growing beef steers were assigned to diets (treatments) containing 80% silage. Periodically chewing behavior, feed intake, ruminal mat consistency, ruminal fermentation parameters, nutrient digestibility and ruminal rate of passage of solids and liquids phases were evaluated. Treatments combined 3 planned dry matter (DM) concentrations (25, 45 and 65%) of Tifton 85 grass silage associated (CA) or not (SA) with the bacterial-enzymatic (BE) inoculant source. An additional treatment containing wilted silage (55% DM) without (BE) was also studied. SIL-ALL®, the BE source used, was sprayed onto chopped forage just before silage packing at a rate of 250g diluted in 50L of deionized water per ton of wet forage. The commercial BE showed the following composition: Streptococus faecium, Lactobacillus plantarum, Pediococcus acidilactici plus hemicellulase, cellulase and starch degrading enzymes. The wilting of forage allowed to increase the DM concentration of silages, however, as well as BE addition, it was not effective to promote major changes on chemical composition of silages. On SA silages, higher NDF levels were observed as the DM level of the wilted silage increased, which resulted in lower non-fiber carbohydrate (NFC) fraction. The B3 protein fraction (NDIN minus ADIN) showed an increase as the DM concentration of wilted silage was raised, probably as result of an opposite trend between neutral detergent insoluble nitrogen (NDIN) and acid detergent insoluble nitrogen (ADIN) across DM levels. Silage losses, measured as both, fungi scored at bale front panel and percentage of spoiled silage, indicated higher levels associated with increased DM concentration. It might be explained by the lower bale unloading rate observed during the feeding trial, mainly in higher DM wilted silages. Both, ruminal mat consistency, measured as time required to weight ascension into the rumen (1194 sec.) as well as ruminal kinetics, evaluated as passage rate of solid (3.09% hour -1 ) and liquid (4.37% hour -1 ) phases were similar for all treatments. Animal ingestive behavior measured as total time (minutes day -1 ) and rate (minutes DM kg -1 ) was not changed across silages DM concentration, averaging DM eating (324; 47), DM ruminating (518; 75) and DM chewing (841; 123), respectively. Residual daily time was spent with drinking and idling activities. The DM intakes observed among experimental diets, containing wilted silages, were not statistically different and averaged 6.95 kg day -1 or 1.88% as body weight basis. Individual and total (140.29) molar concentration (mM) of volatile fatty acids (VFA), acetate:propionate ratio (4,2:1), ammonia-N (6.31 mg dL -1 ) and average daily pH (6.76) of ruminal fluid were similar across silages diets. Nutrient digestibilities were, also, not significantly affected by the increased DM concentration in wilted silages or by the BE inoculation, as follows: organic matter (71.5%), crude protein (69.1%), NDF (71.3%), ADF (64.9%) and hemicellulose (83.3%). DM digestibilities, however, performed a quadratic pattern (P<0.05), with a slight increase at 45% DM concentration in silages. According to the results it may be concluded that neither the increase of DM concentration of grass silages nor the addition of bacterial-enzymatic inoculant changed animal ingestive behavior or improved ruminal and digestive parameters analyzed.

Resumo: O objetivo deste trabalho foi avaliar respostas do capim-tifton 85 a doses de nitrogênio (N) associadas a doses e fontes de boro (B). Em casa de vegetação, conduziu-se um experimento fatorial 3 ' 3 ' 3 {três doses de N (0, 100 e 200 mg kg-1), três doses de B (0, 1,3 e 2,6 mg kg-1) e três fontes de B [colemanita fundida ao termofosfato (CF), colemanita em mistura com termofosfato (CM) e ácido bórico (H3BO3)]} em delineamento inteiramente ao acaso. As plantas cresceram em vasos preenchidos com amostra de um Latossolo Vermelho distrófico. Elas foram avaliadas em três ciclos de crescimento. O N foi aplicado no início de cada ciclo e o B apenas antes do plantio. A aplicação de N aumentou a massa seca da parte aérea e o número de perfilhos do capim nos três ciclos. A aplicação de B, isolada ou associada à de N, não teve influência nesses atributos, embora o solo tivesse baixo teor de B disponível. O suprimento de N aumentou também os teores de carboidratos de reserva na raiz da planta nos dois ciclos em que foram avaliados (primeiro e terceiro). O suprimento de B aumentou o teor desses carboidratos na base do caule no primeiro ciclo. Os fornecimentos de N e B aumentaram seus respectivos teores na parte aérea do capim no três ciclos, exceto no caso do teor de B no terceiro ciclo. Todas as fontes de B aumentaram o teor de B disponível no solo, mas a CM e o H3BO3 aumentaram mais do que a CF. O efeito mais evidente da aplicação conjunta de N e B ocorreu no acúmulo de B na parte aérea da planta, aumentando mais com a combinação das duas aplicações. O teor inicial de B no solo (0,15 mg dm-3) foi suficiente para atender as necessidades do capim-tifton 85 nos três ciclos de crescimento. / Abstract: The objective of this work was to evaluate responses of Tifton 85 bermudagrass to nitrogen (N) rates associated with boron (B) rates and sources. In greenhouse, it was carried out a factorial experiment 3 ' 3 ' 3 {three N rates (0, 100 and 200 mg kg-1), three B rates (0, 1.3 and 2.6 mg kg-1) and three B sources [colemanite fused to termophosphate (CF), colemanite in mixture with termophosphate (CM) and boric acid (H3BO3)]} in complete randomized design. The plants grew in pots filled with sample of a Typic Haplustox. They were evaluated during three growth cycles. The N was applied at the beginning of each cycle and the B just before the planting. The N application increased both top dry mass and tiller number of the grass in the three cycles. The B application, isolated or associated with N application, did not have influence on these attributes, though the soil had low available B content. The N supply increased reserve carbohydrates contents in plant root in the two cycles in which they were evaluated (first and third). The B supply increased the content of these carbohydrates in the stem base in the first cycle. The N and B furnishings increased their respective contents in top grass in the three cycles, except in the case of the B content in the third cycle. All the sources increased the available B content in soil, but CM and H3BO3 increased more than CF. The most evident effect of the N and B applications together occurred in the B accumulation in top plant, increasing more with the combination of the two applications. The initial B content in soil (0.15 mg dm-3) was enough to attend necessities of Tifton 85 bermudagrass in the three growth cycles. / Orientador: Edson Luiz Mendes Coutinho / Coorientador: Edemo João Fernandes / Banca: Mara Cristina Pessôa da Cruz / Banca: Cassio Hamilton Abreu Junior / Banca: Takashi Muraoka / Banca: Renato de Mello Prado / Doutor

Low temperature injury is among the greatest challenges facing golf courses with ultradwarf bermudagrass (UDB) (Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy) putting greens in Virginia. This research focused on the impact of turf covers, fungicide programming, core aeration, and trinexapac-ethyl (TE) on UDB cold tolerance, winter quality, and cold de-acclimation (CD). Our results indicate that the use of turf covers significantly increased UDB canopy and soil temperatures when air temperatures were below -3.9°C. Air gaps under covers and the use of double turf covers increased soil and canopy temperatures compared to single covers alone in some instances, but results were inconsistent. Late fall and early winter fungicide applications of chlorothalonil and azoxystrobin improved UDB quality throughout winter dormancy and spring green up. The addition of a pigmented phosphonate significantly improved winter and spring UDB quality. The addition of acibenzolar-S-methyl to fungicide programs did not improve winter UDB quality or spring green up. Summer core aeration programs were evaluated for their impact on spring green up, turfgrass quality, surface firmness, and moisture retention. Spring UDB green up was improved incrementally as surface disruption increased. Treatments with 20%, 15%, and 10% surface disruption produced higher color vs treatments with lower surface disruption. Surface firmness and volumetric water content of UDB were impacted by construction method but were not significantly impacted by core aeration programs. Field research revealed that 'fall only' and 'fall and winter' TE applications improved UDB quality but only 'fall and winter' delayed UDB premature CD in early spring when UDB can be susceptible to low temperature injury. Growth chamber studies evaluated the impact of TE on UDB cold tolerance to -9.4°C x time duration. Regression analysis predicted a 50% mortality exposure point for UDB under TE treatments of 9.84 hours at -9.4°C (r2=0.836) compared to 11.38 hours at -9.4°C (r2=0.671) for non-treated UDB during cold acclimation. Winter and spring scenarios resulted in delayed CD under TE but no differences in cold tolerance when exposed to -9.4°C. Together, these results increase our understanding of the impact of management practices on UDB winter quality, CD, and low temperature injury. / Doctor of Philosophy / Ultradwarf bermudagrass putting greens are commonly found on golf courses in warm climates. These grasses thrive in heat and humidity but are susceptible to injury or death when exposed to cold temperatures. This research is focused on evaluating management practices that may impact bermudagrass' susceptibility to injury from cold temperature exposure. The cultural practices evaluated include turf covers, fungicide programming, core aeration, and the use of plant growth regulators to manipulate the turfgrasses own self defense mechanisms. Our results show that the use of turf covers significantly increased putting green canopy and soil temperatures when air temperatures were below -3.9°C. Air gaps under covers and the use of double turf covers increased soil and canopy temperatures compared to single covers alone in some instances, but results were inconsistent. Late fall and early winter fungicide applications of commonly-used fungicides improved putting green quality throughout winter dormancy and spring green up. The addition of a green-pigmented phosphonate fungicide significantly improved winter and spring putting green quality. The addition of a plant defense activator, acibenzolar-S-methyl to fungicide programs did not improve winter quality or spring green up. Summer core aeration programs were evaluated for their impact on spring green up, turfgrass quality, surface firmness, and moisture retention. Spring green up was improved incrementally as surface disruption increased. Treatments with 20%, 15%, and 10% surface disruption produced higher color vs treatments with lower surface disruption. Surface firmness and soil moisture content of the putting greens were impacted by construction method but were not significantly impacted by core aeration programs. Field research revealed that 'fall only' and 'fall and winter' plant growth regulator applications improved ultradwarf bermudagrass quality but only 'fall and winter' delayed premature green-up in early spring when the turfgrass can be susceptible to low temperature injury. Growth chamber studies revealed that plants treated with the growth regulator, trinexapac-ethyl were more sensitive to low-temperature exposure than non-treated plants. Together, these results increase our understanding of the impact of management practices on UDB winter quality, CD, and low temperature injury.

Goosegrass [Eleusine indica (L.) Gaertn.] and smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.] are problematic weeds in bermudagrass and creeping bentgrass turf. Increased incidences of herbicide resistant weed populations and severe use restrictions on formerly available herbicides have increased need for selective, postemergence control options for these weeds in creeping bentgrass and bermudagrass turf. This weed management exigency has led turf managers to utilize less effective, more expensive, and more injurious options to manage goosegrass and smooth crabgrass. Although potentially injurious, topramezone can control these weeds, especially goosegrass, at low doses. Low-dose topramezone may also improve bermudagrass and creeping bentgrass response. An initial investigation of three 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibiting herbicides in different turf types showed that Kentucky bluegrass, perennial ryegrass, and tall fescue were highly tolerant to topramezone, while creeping bentgrass and bermudagrass could tolerate topramezone doses that may control grassy weeds. Further investigation suggested that frequent, low-dose topramezone applications or metribuzin admixtures could enhance weed control and may conserve turfgrass quality. A novel mixture of topramezone at 3.7 g ae ha-1 and metribuzin at 210 g ai ha-1 controlled goosegrass effectively and reduced bermudagrass foliar bleaching associated with topramezone 10-fold compared to higher doses of topramezone alone in 19 field and 2 greenhouse trials. In an attempt to further enhance bermudagrass tolerance to topramezone, post-treatment irrigation was applied at various timings. When bermudagrass turf was irrigated with 0.25-cm water at 15 or 30 minutes after herbicide treatment, bermudagrass injury was reduced to acceptable levels when following low-dose topramezone plus metribuzin but not when following high-dose topramezone alone. Goosegrass control was reduced significantly by post-treatment irrigation in all cases, while irrigation reduced goosegrass control by low-dose topramezone plus metribuzin to below-commercially-acceptable levels. Novel, low-dose, frequent application programs containing topramezone or siduron were developed for season-long crabgrass or goosegrass control on creeping bentgrass greens. Greens-height creeping bentgrass quality was preserved following five biweekly treatments of siduron at rates between 3,400 to 13,500 g ai ha-1 and topramezone at 3.1 g ha-1. Siduron programs controlled smooth crabgrass and suppressed goosegrass while topramezone programs controlled goosegrass and suppressed smooth crabgrass. In laboratory and controlled-environment experiments, goosegrass absorbed three times more 14C than bermudagrass within 48 hours of 14C-topramezone treatment. Bermudagrass also metabolized topramezone twice as fast as goosegrass. Metribuzin admixture reduced absorption by 25% in both species. When herbicides were placed exclusively on soil, foliage, or soil plus foliage, topramezone controlled goosegrass only when applied to foliage and phytotoxicity of both bermudagrass and goosegrass was greater from topramezone than from metribuzin. Metribuzin was shown to reduce 21-d cumulative clipping weight and tiller production of both species while topramezone caused foliar discoloration to newly emerging leaves and shoots with only marginal clipping weight reduction. These data suggest that selectivity between bermudagrass and goosegrass is largely due to differential absorption and metabolism that reduces bermudagrass exposure to topramezone. Post-treatment irrigation likely reduces topramezone rate load with a concomitant effect on plant phytotoxicity of both species. Metribuzin admixture decreases white discoloration of bermudagrass by decreased topramezone absorption rate and eliminating new foliar growth that is more susceptible to discoloration by topramezone. / Doctor of Philosophy / Goosegrass and smooth crabgrass are problematic weeds in bermudagrass and creeping bentgrass turf. Increased incidences of herbicide resistant weed populations and severe use restrictions on formerly available herbicides have increased need for selective, postemergence control options for these weeds in creeping bentgrass and bermudagrass turf. Although potentially injurious, topramezone (Pylex™) can control these weeds, especially goosegrass, at low doses. Low-dose Pylex™ may also improve bermudagrass and creeping bentgrass response. An initial investigation evaluating tembotrione (Laudis®), Pylex™, and mesotrione (Tenacity®) in different turfgrass species showed that Kentucky bluegrass, perennial ryegrass, and tall fescue were highly tolerant to Pylex™ at rates ranging from 0.75 to 2.25 fl. oz./A, while creeping bentgrass and bermudagrass were low to moderately tolerant to Pylex™. Further investigation suggested that frequent, low-dose (less than 0.25 fl. oz./A) Pylex™ applications or metribuzin (Sencor®) admixtures could enhance weed control and may conserve turfgrass quality. A novel mixture of Pylex™ at 0.15 fl. oz./A and Sencor® at 4 oz. wt./A controlled goosegrass effectively and reduced bermudagrass injury to near acceptable levels and significantly less than Pylex™ applied alone at 0.25 fl. oz/A. In an attempt to further enhance bermudagrass tolerance to Pylex™, post-treatment irrigation was applied at different timings. When bermudagrass turf was irrigated at 15 or 30 minutes after herbicide treatment, bermudagrass injury was reduced to acceptable levels when following Pylex™ at 0.25 fl. oz./A plus Sencor® at 4 oz but not when following Pylex™ applied alone at 0.5 fl. oz./A. Goosegrass control was reduced significantly by post-treatment irrigation in all cases, while irrigation reduced goosegrass control by low-dose Pylex™ plus Sencor® to below-commercially-acceptable levels. Novel, low-dose, frequent application programs containing Pylex™ or siduron (Tupersan®) were developed for season-long crabgrass or goosegrass control in creeping bentgrass greens. Greens-height creeping bentgrass quality was preserved following five biweekly treatments of Tupersan® at rates between 6 and 24 lb./A and Pylex™ at 0.125 fl. oz./A. Tupersan® programs controlled smooth crabgrass and suppressed goosegrass while Pylex™ programs controlled goosegrass and suppressed smooth crabgrass. The data from these studies indicate that utilizing low-dose Pylex™ in combination with Sencor® can impart acceptable bermudagrass safety while also controlling goosegrass effectively. For creeping bentgrass greens, the low-dose, frequent application of Tupersan® is the safest legal option for golf course superintendents to control smooth crabgrass effectively, while having some ability to suppress goosegrass.

Grasses of the genera Brachiaria and Cynodon are some of the most important pasture introductions in Brazil. Convert HD 364 brachiariagrass, a new Brachiaria hybrid, was released as an option for a broad range of environmental conditions, high nutritive value and forage production. Forage-based livestock systems are complex and interactions among animals, plants, and the environment exist at several levels of complexity, which can be evaluated using computer modeling. Herbage accumulation, crude protein (CP), neutral detergent fiber (NDF), in vitro organic matter digestibility (IVOMD), plant-part composition, leaf photosynthesis, leaf area index (LAI), and light interception (LI) were evaluated as affected by two harvest frequency (28 and 42-days), irrigated and rainfed in a clipping study from April 2011 to April 2013, contrasting Convert HD 364® brachiariagrass (Brachiaria hybrid CIAT 36061), Marandu palisadegrass {Brachiaria brizantha (Hochst. ex A. Rich.) R. D. Webster [syn. Urochloa brizantha (A. Rich.) Stapf]; CIAT 6297}, and Tifton 85 bermudagrass (Cynodon spp.). The experimental design for both the irrigated and the rainfed trials was a randomized complete block with four replications. Convert HD 364 had similar or higher annual herbage accumulation, seasonal yield and herbage accumulation rate than Marandu and Tifton 85, (15% more herbage accumulation than Marandu and 12% more than Tifton 85 when irrigated and when harvested at shorter regrowth intervals). Convert HD 364 had good seasonal distribution of total annual herbage produced and accumulates about 30% of the total herbage mass during the cool season in Piracicaba, similar to Marandu. Tifton 85 produced around 20% of its average annual yield during dry season. Tifton 85 forage had higher CP concentration than the other two grasses when harvested at shorter intervals and when irrigated. The NDF concentration in Convert HD 364 was lower than in the other grasses regardless of irrigation treatment, harvest frequency, and season of the year, resulting in high IVOMD (more than 650 g kg-1), similar to that of Marandu. Regard to CROPGRO calibration, in general the model performance was good for the three grasses. Leaf and stem weight simulations were improved, due to increase partitioning to stem for low harvest frequencies. The LAI and LI were well performed by the model, showing increase for lower harvest frequency, with exception to Tifton 85. Under rainfed conditions, the simulations using the Penman-Monteith-FAO 56 method gave more realistic water stress responses than using the Priestley and Taylor method. Calibration results suggest that the CROPGRO - Perennial Forage Model can be used to adequately simulate growth of Marandu, Convert HD 364, and Tifton 85 under irrigated and rainfed conditions, being able to simulate different harvest frequency managements. / As gramíneas do gênero Brachiaria e Cynodon são algumas das pastagens cultivadas introduzidas no Brasil de maior importância. Convert HD 364, um novo híbrido de Brachiaria, foi lançado como uma opção para uso numa ampla gama de condições ambientais, com alto valor nutritivo e produção de forragem. Sistemas pecuários em pastagens são complexos e as interações entre os animais, as plantas e o meio ambiente existem em vários níveis de complexidade, que podem ser avaliados utilizando modelagem computacional. Acúmulo de forragem, proteína bruta (PB), fibra em detergente neutro (FDN), digestibilidade in vitro da matéria orgânica (DIVMO), a composição morfológica da planta, fotossíntese foliar, índice de área foliar (IAF) e interceptação luminosa (IL) foram avaliados em resposta à duas frequências de colheita (28 e 42 dias), irrigada e não irrigada, em um estudo com parcelas colhidas mecanicamente a partir de abril de 2011 até abril de 2013, contrastando os capins Convert HD 364® (Brachiaria híbrida CIAT 36061), Marandu {Brachiaria brizantha (Hochst. ex A. Rich.) RD Webster [syn. Urochloa brizantha (A. Rich.) Stapf]; CIAT 6297} e Tifton 85 (Cynodon spp.). O delineamento experimental utilizado tanto para o irrigado quanto para o não irrigado foi de blocos casualizados, com quatro repetições. Convert HD 364 teve acúmulo de forragem anual, produção sazonal de forragem e taxa de acúmulo de forragem semelhante ou superior ao Marandu e Tifton 85, (acúmulo de forragem 15% maior do que Marandu e 12% maior do que o Tifton 85, quando irrigado e colhido em intervalos de rebrotação mais curtos). Convert HD 364 teve boa distribuição sazonal de forragem total do ano, produzindo cerca de 30% da massa total de forragem durante a estação fria, em Piracicaba, semelhante ao Marandu. Tifton 85 produziu cerca de 20% do seu rendimento médio anual durante a estação fria. Tifton 85 teve PB maior do que as outras duas gramíneas, quando colhidas em intervalos mais curtos e quando irrigadas. A concentração de FDN em Convert HD 364 foi menor do que nas outras gramíneas, independentemente da irrigação, da frequência de colheita e das estações do ano, resultando em alta DIVMO (mais de 650 g kg-1), semelhante à do capim Marandu. Em relação à calibração do CROPGRO, em geral, o desempenho do modelo foi bom para as três gramíneas. Simulações de massa de folha e colmo foram melhoradas para os capins, devido ao aumento na partição de assimilados direcionados para colmo em condição de baixa freqüência de colheita. O IAF e IL foram bem simulados pelo modelo, mostrando aumento com a diminuição da freqüência de colheita, com exceção do Tifton 85. Em condição não irrigada, as simulações utilizando o método de Penman -Monteith - FAO 56 deram respostas mais realistas de estresse hídrico do que usando o método de Priestley e Taylor. Os resultados da calibração sugerem que o modelo CROPGRO - forragem perene pode ser usado para simular adequadamente o crescimento de Marandu, Convert HD 364 e Tifton 85 sob condições irrigadas e não irrigada, sendo capaz de simular diferentes manejos de frequência de desfolhação.