Made available in DSpace on 2016-04-28T14:59:43Z (GMT). No. of bitstreams: 1 2004--Milene Malta Souza.pdf: 295926 bytes, checksum: b539a3252226c536b4d26b1fc5640a95 (MD5) Previous issue date: 2004-08-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / It was carried out an experiment at the Santa M?nica Experimental Farm, a subdivision of the Embrapa Dairy Cattle Research Center, which is located at the Juparan?, district of Valen?a city; Rio de Janeiro State, Brazil. The objective of this study was to evaluate the composition, structure and quality of the elephantgrass managed in a rotationally grazing system. The residue of the grazing was 70 cm of height. Three cycles of grazing had been analyzed; each cycle corresponded by 3 days of pasture with 30 days of rest. In the 1st cycle was evaluated the average of foliar area of main, aerial and basal tillers. In 2nd and 3rd cycle the same data had been evaluated, had been the concern in substituting the lost tillers during grazing. There were had differences between three cycles of pasture (P < 0,05). During 1st cycle, was observed higher rate of foliar area 93,97c (cm2.tiller-1) because main tillers had presented greater area of leaves in expansion, and expanded, already the tillering of aerial and basal tillers presented minor foliar area because apical meristem still was preserved of grazing. At the 2nd cycle, the rate of foliar area reduced (73,35b) because grazing resulted the intake of leaves in expansion and consequently the elimination of apical meristem promoted the aerial and basal tillering. After 3rd cycle, the main tillers, by being with apical meristem decapitated speeds up the aerial tillering and basal and tillers with apical preserved meristem blossom. However, leaves in expansion and expanded of main tillers presented minor or almost none foliar area, totalizing lesser average of total foliar area (28,82a). The production of dry-matter of leaves in expansion (26,1b) and expanded (26,7c) in the 1st cycle of pasture of fellow tillers to the main tillers had been increase by higher pluviosity and protection of apical meristem. In 2nd cycle, leaves in expansion (18,3a) and expended leaves (18,4a) were consumed by grazing thus apical meristem, causing lesser production of dry-matter. Leaves that were not consumed by pasture came into senescence and tiller stocked energy to emit aerial and basal tillers to the 3rd cycle of pasture, resulting raise in of dry-matter production in expansion leaves (19,1a) and expended leaves (22,6b). Data are been reforced by the rate of colm+sheath, that exhibited arger average for dry-matter production at 3rd cycle of grazing (23,0b), followed by 1st cycle (14,9a) and 2nd one (13,7a). / Em trabalho realizado no Campo Experimental de Santa M?nica da Embrapa Gado de Leite, localizado no distrito de Bar?o de Juparan?, munic?pio de Valen?a / RJ, o objetivo foi avaliar a composi??o, estrutura e qualidade do capim-elefante sob pastejo rotativo. Tr?s ciclos de pastejo foram analisados, cada ciclo correspondeu a 3 dias de pastejo com 30 dias de descanso. No 1? ciclo avaliou-se a ?rea foliar m?dia de perfilhos principais, a?reos e basais. No 2? e 3? ciclo os mesmos dados foram avaliados, sendo que houve a preocupa??o em substituir os perfilhos perdidos durante o pastejo. Houve diferen?a entre os tr?s ciclos de pastejo (P < 0,05). Durante o 1? ciclo, observou-se maior m?dia de ?rea foliar 93,97c (cm2.perfilho-1) porque os perfilhos principais apresentaram maior ?rea de folhas em expans?o e expandidas, j? o perfilhamento a?reo e basal apresentou menor ?rea foliar porque o meristema apical ainda estava preservado do pastejo. No 2? ciclo, a m?dia de ?rea foliar diminuiu (73,35b) devido ao pastejo provocar o consumo das folhas em expans?o e consequentemente a elimina??o do meristema apical promove o perfilhamento a?reo e basal. Ap?s o 3? pastejo, os perfilhos principais, por estarem com o meristema apical decapitado aceleram o perfilhamento a?reo e basal e os perfilhos com meristema apical ainda preservado florescem, por isto, as folhas em expans?o e expandidas de perfilhos principais apresentam menor ou quase nenhuma ?rea foliar, totalizando menor m?dia de ?rea foliar total (28,82a). No 1? ciclo de pastejo a produ??o de mat?ria-seca de folhas em expans?o (26,1b) e expandida (26,7c) de perfilhos semelhantes aos perfilhos principais aumentou devido a maior pluviosidade e prote??o do meristema apical. No 2? ciclo, as folhas em expans?o (18,3a) e expandidas (18,4a) foram consumidas pelo pastejo assim como o meristema apical, ocasionando menor produ??o de mat?ria-seca. As folhas que n?o foram consumidas pelo pastejo entraram em senesc?ncia e o perfilho armazenou energia para a emiss?o de perfilhos a?reos e basais para o 3? ciclo de pastejo, o que provocou aumento da produ??o de mat?ria-seca de folhas em expans?o (19,1a) e expandidas (22,6b). Esses dados s?o refor?ados pela rela??o de colmo+bainha, que apresentou maior m?dia da produ??o de mat?ria-seca no 3? ciclo de pastejo (23,0b), seguido do 1? ciclo (14,9a) e 2? ciclo (13,7a).