Thesis (PhD(Agric) (Agronomy))--University of Stellenbosch, 2005. / The response of perennial ryegrass and white clover, grown under controlled conditions, to fertiliser N rates applied under variable soil temperature (6, 12 and 18 °C), soil water potential (-10, -20, -25 and -35 kPa) and seasonal growing (June/July and October/November) conditions as well as field conditions, were evaluated. Primary- (PDM), residual- (RDM) and total dry matter (TDM) production (g pot-1) were recorded over the first- and second regrowth cycles as well as the accumulative DM production over the two regrowth cycles, respectively. Leaf N content (%) was recorded at the end of first and second regrowth cycles. Tiller/stolon numbers and root dry mass (g pot-1) were recorded at the end of the second regrowth cycle. Soil ammonium-N and nitrate-N (mg kg-1) content was monitored after fertiliser N application. Decreasing soil temperatures resulted in decreased TDM production in both crops. Only perennial ryegrass was influenced by fertiliser N rate, with a general increase in dry matter production as fertiliser N rate was increased. Ryegrass TDM production did not differ between the 100 and 150 kg N ha-1 rates but were both higher (P=0.05) if compared to the 0 and 50 kg N ha-1 treatments. Soil nitrate levels 31 days after application of 150 kg N ha–1 were still sufficient to stimulate ryegrass RDM production. The 173.8% increase in ryegrass TDM production measured at 6 °C where 150 kg N ha-1 was applied compared to the 0 kg N ha-1 treatment illustrated the ability of ryegrass to respond to fertiliser N at low soil temperatures. Soil water potential of -20 kPa resulted in higher ryegrass PDM and TDM production compared to the -25 and -35 kPa levels. White clover PDM and TDM production were however not influenced by soil water potential or fertiliser N rate. Ryegrass TDM production increased (P=0.05) as fertiliser N rates were increased. The most favourable soil water level for both ryegrass and clover root development was found to be -35 kPa. Perennial ryegrass and white clover PDM, RDM and TDM production were higher during the October/November season compared to the June/July season. Increased fertiliser N rates resulted in increased (P=0.05) ryegrass PDM and TDM production. White clover dry matter production was not influenced by fertiliser N rates. In the field study the effect of 0, 50, 100 and 150 kg N ha-1 applied as a single application either in autumn, early winter, late winter, early spring or late spring on pasture dry matter production, clover content and selected quality parameters of a perennial ryegrass-white clover pasture were investigated. Soil nitrogen dynamics in the 0-100, 200-300 and 400-500 mm soil layers were studied for 49 days following fertiliser N application. The effect of 50 kg N ha-1 on soil N dynamics was generally the same as found at the 0 kg N ha-1 applications and may therefore be regarded as a low risk treatment. The application of 150 kg N ha-1 especially in autumn and early winter showed a tendency to exceed the absorption capacity of the pasture and thereby expose fertiliser N to possible leaching and contamination of natural resources. Increased fertiliser N rate resulted in a general increase in pasture dry matter production with the highest yields recorded where N was applied in early and late spring and the lowest in early winter. The application of 150 kg N ha-1 in early and late spring resulted in the highest TDM production, however, the 50 kg N ha-1 resulted in a more efficient conversion of N applied to additional DM produced. In contrast to DM production, the clover percentage generally decreased as fertiliser N rate was increased. The effect of season of application was inconsistent. Annual trends show that the clover percentage eventually recovered to the same levels as the 0 kg N ha-1 treatments. Due to the above minimum levels recorded for most mineral and quality parameters tested it is envisaged that treatment combinations as used in this study will not be at any disadvantage to pasture and animal productivity. The study has shown that the use of fertiliser N to boost perennial ryegrass-white clover productivity and thereby minimising the negative effect of the winter gap on fodder flow management during the cool season in the Western Cape Province, may be an important management tool. Except for late spring applications, all seasons of application reduced the negative impact of the winter gap on fodder availability. It is concluded that regression lines as summarised in Tables 7.2 and 8.2 show great potential to be instrumental in developing regression models, accurately predicting the effect of fertiliser N rate on pasture performance. Other factors to be considered includes the productivity of the pasture, initial clover content, expected clover content at the end of the first regrowth cycle after fertiliser N application and the quantity of additional fodder required. Additional requirements will be to maintain and 150 kg N ha-1) in winter, as the N uptake capacity of the pasture could be exceeded and thereby increasing the risk of N leaching, resulting in environmental pollution. The N response efficiency of the pasture is also the lowest at the 150 kg N ha-1 rates, thereby reducing the profitability of these treatments.

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.

Typescript (photocopy) / Digitized by Kansas Correctional Industries

Abstract can be viewed in PDF document. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1994.

Call number: LD2668 .T4 1954 H4 / Master of Science

Les assemblages d'espèces colonisatrices des déjections constituent des systèmes d'étude intéressants de par la nature de la ressource exploitée et de par le rôle qu'ils exercent dans les écosystèmes pâturés. Une grande diversité d'espèces d'insectes, principalement des diptères et des coléoptères, colonisent les bouses et contribuent à leur disparition, permettant un apport en nutriments au pâturage. Comprendre le lien entre ces différentes espèces et les fonctions écologiques réalisées représente donc un enjeu afin de préserver ce système et d'en assurer son bon fonctionnement. Certaines molécules administrées comme endectocides au bétail, comme l'ivermectine, impactent la structure de la communauté coprophile par leurs effets toxiques sur certains groupes comme les Sepsidae. Bien que leurs effets se soient montrés significatifs sur l'émergence des insectes coprophiles, la disparition des bouses ne s'en est pas trouvée affectée. Il convient alors de rester prudent sur les effets à long terme de ce type de molécules, même si à court terme les effets ne paraissent pas pertinents. La première semaine est essentielle à la bonne dégradation des bouses par l'action d'une première vague de colonisation par les insectes coprophages, tandis qu'en seconde semaine la colonisation par les prédateurs en réduit la vitesse. L'ensemble de la communauté coprophile ne permet donc pas d'accélérer le processus de recyclage des bouses. Une augmentation des effectifs de bousiers accélère la disparition des bouses et indirectement favorise la minéralisation de la litière dans le sol. Toutes les espèces ne contribuent pas équitablement au fonctionnement du système. Les plus gros fouisseurs enterrent des quantités plus importantes de matière fécale, facilitant ainsi les échanges de nutriments entre le sol et la déjection. D'importantes pistes restent à développer concernant les facteurs influençant la colonisation et les interactions entre les organismes afin de pouvoir utiliser les bousiers comme bioindicateurs pour en mesurer les services rendus. / Assemblages of species colonizing droppings constitute interesting systems for study due to the nature of the resource they exploit and the role they exert in the grazed ecosystems. A wide diversity of insects, mainly flies and beetles, colonize dung pats and contribute to their disappearance allowing a contribution in nutrients to the pasture. Understanding the relationship between these species and the ecological functions they perform represents therefore a stake to maintain this system and ensure its proper functioning. Some molecules administered as endectocides to livestock, such as ivermectin, impact the coprophile community structure by their toxic effects on certain taxonomic groups such as Sepsidae. Although their effects are significant on the emergence of coprophilous insects, dung disappearance was not affected. It is then advisable to remain careful on the long-term effects of this type of chemicals, even if the short-term effects are not relevant. The first week of colonization by the wave of coprophagous insects appear essential for complete dung degradation while the second week of colonization by predators reduced the speed of degradation. Therefore the whole coprophilous community does not accelerate the process of recycling dung. An increase of the numbers of dung beetles accelerates the disappearance of dung pats and the loss of litter in the soil. However, all species do not contribute in the same manner to the functioning of the system. The largest tunnelers bury larger amounts of fecal matter and thus they facilitate exchange of nutrients between soil and dung. Important trails remain to be developed concerning the factors influencing colonization and the interactions between organisms before to be able to use dung beetles as bioindicators and to measure their services.

New farming needs and innovations have, over time, led to changes in land use. Arable fields have been turned into pastures and semi-natural pastures into arable fields. Due to the ecological value of continually grazed semi-natural pastures in Sweden the aim of this study is to find out how former arable fields that are permanently grazed differ from semi-natural pastures. In this study I selected appropriate semi-natural pastures from a national monitoring program on seminatural- pastures and meadows. Plots continuously grazed were compared with grazed plots on former arable fields. Pair-wise differences in the Ellenberg indicator values Light (L), Soil moisture (F), soil pH (R) and soil nitrogen (N), vertical coverage of trees, bushes and vegetation, species richness and species composition were tested. Except for species composition there were only small differences between former arable fields that are permanently grazed and semi-natural pastures. That means former arable fields can with time and grazing gain many of the values continuously grazed semi-natural pastures have.

A produção animal em regiões tropicais tem sido feita basicamente por pastagens devido ao baixo custo de alimentação proporcionado pela alta resposta das forrageiras tropicais ao clima. Quando não há limitação de água, radiação solar e temperatura, a produtividade dessas culturas é grande e fica limitada apenas pelo sistema de manejo. Quando o manejo é feito na maneira correta produtividades vegetal e animal são altas e limitadas apenas pelos fatores climáticos. Dentre eles o único em que é possível uma modificação significativa é o déficit hídrico, que pode ser eliminado por meio da irrigação. A estimativa de demanda de irrigação pode ser feita com o auxílio de dados climáticos, com os quais se calcula o consumo de água das plantas, denominado evapotranspiração da cultura. Com essa e outras variáveis meteorológicas é possível a realização do balanço hídrico da cultura. Este trabalho tem por objetivo estimar e comparar os valores da deficiência hídrica para forrageiras tropicais obtidos por meio do balanço hídrico com diversas probabilidades de ocorrência. Para isso foram coletados dados meteorológicos de 156 estações que foram espacializados por meio do software QGis, e com isso foram identificadas áreas que não atendem os critérios para o pleno desenvolvimento de forrageiras tropicais, recomendadas por COOPER E TAINTON (1968), PEDREIRA et al. (2015), GOMES (1994) e RODRIGUES e RODRIGUES (1988). Houve localidades em que não há deficiência, por excesso ou por disponibilidade ideal (região Sul, litoral do Nordeste, região Norte).As localidades em que o déficit hídrico é tolerável, mas que apresentam boa resposta à irrigação situam-se na faixa que se estende difusamente pelo leste do País, entre os estados da região Nordeste até o norte do Paraná e as localidades prioritárias à irrigação situam-se numa faixa que vai do Nordeste brasileiro até a divisa leste do MT e MS.Utilizando o conceito de Zonas Agroclimáticas Homogêneas foram escolhidos 27 locais, com o objetivo de calcular o balanço hídrico de cultura, a partir do qual se obteve o déficit hídrico. Com o método de Kimball foram encontrados os valores de ocorrência de déficit hídrico para as probabilidades de ocorrência (p) de 50%, 75%, 80%, 85%, 90% e 95%. A partir desse estudo foi possível concluir que a deficiência hídrica de pastagens tropicais variou de 9 mm.decêndio-1 (Rio Branco - AC) a 64,4mm.decêndio-1 (Conceição do Araguaia- PA) e o balanço hídrico de cultura feito com probabilidades de 75% a 95% apresentou resultados de deficiência hídrica muito superiores aos do balanço hídrico de cultura convencional (p=50%). / The livestock farming in tropical regions has been made primarily of pasture due to the low cost of feeding provided by the high response of tropical forages to climate. When there is no water limitation, solar radiation and temperature, the productivity of these crops is large and is limited only by the management system, if the management is done in the correct plant productivity and animals are so high and limited only by climatic factors, among them unique in that it is possible modification is a significant water stress, which can be removed by irrigation; The estimated demand for irrigation can be made with the assistance of weather data, with which to calculate the water consumption of plants, known as evapotranspiration, with this and other meteorological variables it is possible to hold the water balance of the culture; This study aims to estimate and compare the water deficiency values for tropical forages obtained by the water balance with different probabilities, for that were collected meteorological data from 156 stations that were spatialized through the QGIS software, and it identified areas that do not meet the criteria for the full development of tropical forages recommended by COOPER AND TAINTON (1968), PEDREIRA et al. (2015), GOMES (1994) and RODRIGUES and RODRIGUES (1988). And so it was concluded that there were places where there is no water deficiency, because there is excessive rainfall or optimal availability (South, Northeast coast, Northern regions), the locations where the water deficit is tolerable, but having good response to irrigation are in the range extending diffusely to the east side of the Country, between the states of the Northeast region to the north of Paraná and the priority locations to irrigation are in a range that goes from Northeast Brazil to the east boundary of MT and MS. The concept of homogeneous agro-climatic zones was used to choose a number of 27 counties, in order to calculate the crop water balance. With the Kimball methodology, it was found the water deficit occurrence for the values for the probabilities (p) of 50%, 75%, 80%, 85%, 90% and 95%. It was concluded that the crop water deficit for tropical pastures varied from 9 mm.decendial-1 (Rio Branco - AC) to 64.4 mm. decendial-1 (Conceição do Araguaia - PA) and the crop water balance made with probabilities rangingfrom75% to 95% had water stress results higher them the conventional crop water balance (p = 50%).

O presente trabalho teve o objetivo geral de estudar as respostas produtivas de capins do gênero Cynodon em resposta a estratégias de corte. O experimento foi conduzido no campus da ESALQ em Piracicaba, SP. Foram avaliados três cultivares, Tifton 85 e Jiggs (estabelecidos vegetativamente) e Vaquero (propagado por sementes) submetidos a três intervalos de corte, 14, 28 e 42 dias. O delineamento experimental foi completamente casualizado com arranjo fatorial completo. Foram medidas a produção de forragem, composição morfológica da forragem produzida, o índice de área foliar (IAF), a interceptação luminosa (IL) e altura do dossel. Foi feito também um estudo de análise de crescimento. Os cultivares Jiggs (22,6 Mg MS ha-1) e Tifton 85 (21,8 Mg MS ha-1) apresentaram os maiores acúmulos de forragem total na média das frequências de 28 e 42 dias de rebrotação. Na frequência de 14 dias de rebrotação, não houve diferença para o acúmulo total de forragem entre os cultivares com média de 13,3 Mg MS ha-1. A proporção de folhas, em média, foi maior nas frequências de 14 (69,6%) e 28 (55,2%) dias de colheita no verão. No inverno a proporção de folhas foi de 57,6% e 59,8% para as frequências de 14 e 28 dias de corte, respectivamente. Tifton 85 e Vaquero apresentaram maior porcentagem de folhas no verão, com médias de 63,3% e 56,0%, respectivamente. No inverno o Tifton 85 apresentou maior porcentagem de folha, com média de 63%. As frequências de 14 e 28 dias resultaram em maiores porcentagens de folha. O Jiggs apresentou maior porcentagem de colmo (46,7%) no verão e no inverno (40,0%). A frequência de 42 dias de corte no verão resultou em maior porcentagem de colmo (51,2%) e maior IAF no pré-corte (4,8). No inverno, a porcentagem de colmo (43,9%) e o IAF pré-corte (3,9) também foram maiores sob a frequência de 42 dias de colheita. A altura pré-corte no verão foi maior na frequência de 42 dias com média de 32,7 cm e o cultivar Jiggs foi o que apresentou maior altura pré-corte com média de 26, 5 cm nessa estação. A frequência de 28 dias de colheita no verão resultou em IL de 93,4%. A frequência de 42 dias de colheita gerou maior taxa de crescimento de cultura, TCC (30,9 g MS m-2 dia-1) no verão. Maior taxa de crescimento relativo, TCR, ocorreu nas frequências de 28 (0,26 g g1dia1) e 42 dias (0,32 g g1dia1) também no verão. No inverno, maior TCR foi medida na frequência de 28 dias (0,21 g g-1 dia-1). Maiores razão de área foliar, RAF, e razão de peso foliar, RPF, ocorreram na frequência de 28 dias no verão. Jiggs e Tifton 85 são os cultivares mais recomendados para produção de forragem e a frequência de desfolhação a cada 28 dias é a que garante melhor produção quando o objetivo é produzir massa de forragem com uma proporção maior de folhas. / The objectives in this study were to investigate the productive responses of Cynodon grasses to a range of defoliation strategies. The field trial was conducted at ESALQ-USP in Piracicaba, SP, Brazil. Three commercial Cynodon cultivars (Tifton 85 and Jiggs, vegetatively propagated; and Vaquero, a seeded type) were mechanically harvested every 14, 28, and 42 days under a completely randomized design in a complete factorial arrangement with four replicates. Responses measured included forage accumulation (yield), plant-part composition in the accumulated forage, leaf area index (LAI), sward light interception (LI), and sward height. A classical growth analysis study was also carried in the same field plots. Jiggs (22.6 Mg DM ha-1) and Tifton 85 (21.8 Mg DM ha-1) were the highest yielding materials under the 28- and 42-d schedules. Under the 14-d frequency, total forage accumulation did not differ among cultivars, averaging 13.3 Mg DM ha-1. On average, leaf percentage in the accumulated forage was higher in plots clipped every 14 (69.6%) and 28 (55.2%) days. In the cool-dry season, with irrigation, leaf percentage in the harvested forage was 57.6 and 59.8% in plots harvested every 14 and 28 days, respectively. Tifton 85 and Vaquero forage had more percent leaves in the warm-rainy season (63.3 and 56 %, respectively). In the cool season, Tifton 85 forage was leafier, at 63%. The 14- and the 28-d harvest schedules resulted in leafier forage. Jiggs forage had more % stem both in the warm (46.7) and in the cool (40) seasons. The 42-d harvest schedule resulted in highest stem percentage (51.2%) but also higher LAI (4.8) at harvest during the warm season. In the cool season, stem percentage (43.9%) and LAI at harvest (3.9) were also highest in plots clipped every 42 days. Sward height at harvest during the warm season was greater in plots clipped every 42 days, averaging 32.7 cm, with Jiggs being the tallest grass in the warm season, on average (26.5 cm). The 28-d schedule resulted in mean sward LI of 93.4 % on average. Crop growth rate (CGR) was highest (30.9 g DM m-2 d-1) under the 42-d frequency in the warm season. Higher warm-season relative growth rates (RGR) were registered under the 28- and the 42-d schedule (0.26 and 0.32 g g-1d-1, respectively). In the cool season, the highest RGR (021 g g-1 d-1) was measured under the 28-d schedule. The highest leaf area ratio (LAR) and leaf weight ratio (LWR) were measured in the 28-d treatment during the warm-season. Jiggs and Tifton 85 are recommended for their high yield potential under a 28-d harvest schedule, which ensures the production of leafy forage.

Na natureza, durante milhares de anos de convivência, gramíneas forrageiras e herbívoros passaram por um processo de co-evolução desenvolvendo múltiplas estratégias de sobrevivência e de adaptação. Práticas de manejo que interferem na forma como a forragem é disponibilizada aos animais (estrutura do dossel forrageiro) podem causar mudanças dos padrões de procura e ingestão de forragem e interferir com o desempenho animal. Nesse contexto, o objetivo deste estudo foi avaliar a estrutura do dossel forrageiro e a taxa de consumo de forragem em pastos de capim-elefante cv. Napier (Pennisetum purpureum Schum.) submetidos a estratégias de pastejo rotativo. O experimento foi conduzido em área da Escola Superior de Agricultura \"Luiz de Queiroz\", Piracicaba, SP, de janeiro de 2011 a abril de 2012. Os tratamentos corresponderam a combinações entre duas condições pós- (alturas pós-pastejo de 35 e 45 cm) e duas condições pré-pastejo (95% e máxima interceptação de luz pelo dossel forrageiro - IL), alocados às unidades experimentais (piquetes de 870 m²) segundo arranjo fatorial 2x2 e delineamento de blocos completos casualizados, com quatro repetições. Foram avaliadas em pré- e em pós-pastejo as seguintes variáveis-resposta: distribuição vertical dos componentes morfológicos da massa de forragem dos pastos, taxa de bocados, massa do bocado, taxa de consumo e valor nutritivo da forragem consumida (composição morfológica e bromatológica de amostras de extrusa).A estrutura do dossel influenciou fortemente a massa do bocado, a taxa de bocados e a taxa de consumo independente de tratamento e época do ano. Em pré-pastejo, apesar de a massa do bocado ter sido maior nos pastos manejados com a meta ILMáx, não houve diferença em taxa de consumo entre as metas de IL avaliadas, resultado da maior taxa de bocados registrada nos pastos manejados com a meta IL95%. Em pós-pastejo a taxa de consumo também não variou entre as metas de IL avaliadas, sendo observados ajustes na taxa de bocados como forma decompensar as variações em massa do bocado. As metas de altura pós-pastejo modificaram a composição morfológica e bromatológica da forragem consumida, as quais variaram também em função da época do ano. De maneira geral, pastos manejados com a meta IL95% e altura pós-pastejo de 45 cm resultaram em maior porcentagem de folhas na extrusa, o que conferiu melhor taxa de consumo e valor nutritivo da forragem consumida pelos animais em pastejo. / In nature, during thousands of year of co-existence, forage grasses and herbivores underwent a co-evolution process that resulted in multiple survival strategies and adaptations. Management practices that interfere with the way forage is presented to animals (sward structure) may cause changes in patterns of search and consumption of herbage, affecting animal performance. The objective of this experiment was to evaluate sward structure and rate of herbage intake of rotationally stocked elephant grass (Pennisetum purpureumSchum., cv. Napier). The experiment was carried out at Escola Superior de Agricultura \"Luiz de Queiroz\", Piracicaba, SP, Brazil, from January 2011 to April 2012. Treatments corresponded to combinations between two post- (post-grazing heights of 35 and 45 cm) and two pre-grazing swards conditions (95% and maximum canopy light interception - LI), and were allocated to experimental units (870 m2 paddocks) according to a 2x2 factorial arrangement in a complete randomised block design, with four replications. The following response variables were evaluated in both pre- and post-grazing conditions: vertical distribution of morphological components of sward herbage mass, bite rate, bite mass, rate of intake and nutritive value of the consumed herbage (morphological and chemical composition of extrusa samples). Sward structure strongly influenced bite mass, bite rate and rate of intake regardless of treatment and season of the year. At pre-grazing, in spite of the larger bite mass on swards managed with the pre-grazing target LIMax, there was no difference in rate of intake between LI targets, consequence of the higher bite rate recorded on swards managed with the pre-grazing target LI95%. At post-grazing, there was no difference in rate of intake between LI targets, with variations in bite rate used to compensate variations in bite mass. Post-grazing targets altered the morphological and chemical composition of the consumed herbage, which also varied with season of the year. Overall, swards managed with the pre-grazing target LI95% and the 45 cm post-grazing height resulted in larger percentage of leaves in the extrusa, favouring higher rates of intake and nutritive value of the herbage consumed.