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Search Results: 1 - 10 of 285093 matches for " Mello Alexandre Carneiro Le?o de "
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Respostas morfológicas do capim-Tanzania (Panicum maximum Jacq. cv. Tanzania-1) irrigado à intensidade de desfolha sob lota??o rotacionada
Mello, Alexandre Carneiro Leo de;Pedreira, Carlos Guilherme Silveira;
Revista Brasileira de Zootecnia , 2004, DOI: 10.1590/S1516-35982004000200003
Abstract: the objective of this research was to quantify morphological responses of tanzania grass (panicum maximum jacq. cv. tanzania-1) under three grazing intensities in an irrigated, rotationally stocked setting. treatments consisted of three grazing intensities represented by three post-graze forage masses (t1=1,000; t2=2,500, and t3=4,000 kg green dry mass/ha), in a randomized complete block design with four replications. during the grazing season (eight 36-d cycles; three days of grazing followed by 33 days rest), the following measurements were taken: mean sward height, leaf area index (lai), light interception (li), mean leaf angles, all measured on four occasions (1, 11, 22, and 33 days after grazing) of each rest period. partial correlation analysis indicated the existence of correlation between height and li, as well as between lai and li. as the grazing season progressed from spring-summer to autumn-winter, mean lai declined. mean critical lai (95% li) was 3.6 (t1), 4.0 (t2), and 4.5 (t3) and was always reached around the 22nd day after grazing. over the season, hard grazing (lower residual mass) altered the sward structure causing shifts in plant architecture, as shown by reduced leaf angles (more horizontal), as plants begun to intercept more light per unit of leaf area. critical lai values suggest that relatively short rest periods may be advantageous for tanzania grass pastures managed intensively under rotational stocking and irrigation.
Fotossíntese e taxa diária de produ??o de forragem em pastagens de capim-tanzania sob lota??o intermitente
Braga, Gustavo José;Mello, Alexandre Carneiro Leo de;Pedreira, Carlos Guilherme Silveira;Medeiros, Henrique Rocha de;
Pesquisa Agropecuária Brasileira , 2009, DOI: 10.1590/S0100-204X2009000100012
Abstract: the objective of this study was to evaluate the effects of grazing intensity on forage accumulation rate and on net leaf photosynthesis of tanzania guinea grass (panicum maximum jacq.) pastures under rotational stocking. the experiment was carried out from november 1999 to october 2000, in a randomized complete block experimental design, with four replications. treatments were three levels of residual green forage biomass (1,000, 2,500, and 4,000 kg ha -1) in grazing cycles of 36 days (33 days of rest and 3 days of grazing). forage accumulation rate was not affected by grazing intensities, and it was highest in the first 11 days of regrowth during the periods of the highest temperatures. net leaf photosynthesis was not affected by grazing intensity (mean 23.2 μmol m -2 s -1 co2) and increased during regrowth with the highest values between the 11th and the 22nd days of rest, depending on the season of the year. net leaf photosynthesis was correlated with sward structure changes, during leaf development. the use of fixed rest periods avoided alterations of forage accumulation rate caused by grazing intensity.
Repetibilidade de variáveis produtivas e qualitativas da forragem e da excreta bovina em pastagem de braquiária
Teixeira, Vicente Imbroisi;Dubeux Jr., José Carlos Batista;Mello, Alexandre Carneiro Leo de;Lira Jr., Mário de Andrade;Lira, Mario de Andrade;Saraiva, Felipe Martins;
Pesquisa Agropecuária Brasileira , 2011, DOI: 10.1590/S0100-204X2011000600012
Abstract: the objective of this work was to determine the repeatability and the number of the required evaluations to obtain determination coefficient greater than 90% in the productive and qualitative variables of forage and cattle excreta on a signal grass (urochloa decumbens) pasture. the utilized variables were: fecal production, feces mineral composition, herbage mineral composition around dung pads, feces biometry, herbage mass and herbage rejection around dung pads, urinary volume, and urine chemical composition. a fixed rotational stocking was used, with three days of occupation and 32 or 67 days of resting period, during the rainy and dry seasons, respectively. repeatability analyzes were obtained with the software genes, using the principal component method based on the covariance. the repeatability coefficients (r) had high estimates, and the r2 were equal to or greater than 90%, except for herbage mass at 20-40 cm, for the difference between pre-and post-grazing herbage height of herbage grown on dung pad, and for nitrogen concentration in the urine for the treatment with 3,2 animal units per hectare (r<0.50). for r2 above 90%, the number of evaluations required would be 11, 9, and 9, for the variables forage, feces, and urine, respectively.
Caracteriza??o e Sele??o de Clones de Capim-Elefante (Pennisetum purpureum Schum.) na Zona da Mata de Pernambuco
Mello, Alexandre Carneiro Leo de;Lira, Mário de Andrade;Dubeux Júnior, José Carlos Batista;Santos, Mércia Virgínia Ferreira dos;Freitas, Erinaldo Viana de;
Revista Brasileira de Zootecnia , 2002, DOI: 10.1590/S1516-35982002000100004
Abstract: this work aimed to characterize an elephantgrass collection (pennisetum purpureum schum.) comprising 71 clones and selecting the best ones to be tested later under grazing conditions. it was carried out at cedro experimental station - ipa, located in vitória de santo ant?o, forest zone of pernambuco state. the period of evaluation included both the raining and the dry season. each clone was represented by a non-replicated plot of 10 m2. according to linear correlation analysis, the more productive clones also showed highest plant height and highest growing point height, greatest stem diameter, highest stem/leaf ratio, highest basal and total tiller numbers and greatest leaf lenght. the same characteristics above were also positively correlated with the leaf blade yield, except stem/leaf ratio. there was a high correlation coefficient (r = 0.9517) between dry matter yield and leaf blade yield. the selection of clones to be tested under grazing conditions was based on the materials that showed the highest leaf blade yield. these materials were: mineir?o/ipeaco, hexaplóide, mole de volta grande, king grass, 591-76 or cameroon, ce 5 ad, gigante de pinda, ce 4 ad, elefante da col?mbia and vrukwona
Caracteriza o e Sele o de Clones de Capim-Elefante (Pennisetum purpureum Schum.) na Zona da Mata de Pernambuco
Mello Alexandre Carneiro Leo de,Lira Mário de Andrade,Dubeux Júnior José Carlos Batista,Santos Mércia Virgínia Ferreira dos
Revista Brasileira de Zootecnia , 2002,
Abstract: O estudo visou caracterizar uma cole o de 71 clones de capim-elefante e selecionar os mais promissores para serem testados sob pastejo. A caracteriza o foi realizada na Esta o Experimental do Cedro/IPA, no município de Vitória de Sto. Ant o/PE, nas esta es chuvosa e seca. Cada clone foi representado por parcelas n o repetidas de 10 m2. Segundo análise de correla o linear, os clones mais produtivos em rela o à MS, também apresentaram maiores alturas de planta e de meristemas apicais, diametros de colmo, rela es colmo/folha (C/F), números de perfilhos basais e total e comprimentos de folha. Excetuando-se a rela o C/F, as mesmas características também correlacionaram-se positivamente com a produ o de lamina foliar (LF). Foi observada uma correla o linear positiva e altamente significativa (r = 0,9517) entre as produ es de MS e de LF. Baseando-se nos materiais que apresentaram as maiores produ es de LF/área, foram selecionados 10 clones: Mineir o/IPEACO, Hexaplóide, Mole de Volta Grande, King Grass, 591-76 ou Cameroon, CE 5 A.D., Gigante de Pinda, CE 4 A.D., Elefante da Col mbia e Vrukwona
Rela??o entre características morfológicas e produtivas de clones de palma-forrageira
Silva, Nalígia Gomes de Miranda e;Lira, Mario de Andrade;Santos, Mércia Virginia Ferreira dos;Dubeux Júnior, José Carlos Batista;Mello, Alexandre Carneiro Leo de;Silva, Maria da Concei??o;
Revista Brasileira de Zootecnia , 2010, DOI: 10.1590/S1516-35982010001100011
Abstract: this research evaluated the relationship among the morphological and productive characteristics of clones of cactus forage for identification of those that directly contribute to the production. it was evaluated 50 clones of cactus forage planted five years ago and submitted to the first cut two years before the evaluation. characteristics of the plant and of the cladode were evaluated and data were analyzed by descriptive characteristics, pearson correlation and by path analysis of the explanatory independent variables on the dry matter production in t/ha/2 years (main dependent variable). production varied among clones and it was the highest in clones 8, 782 e 418 whose dry matter production was of 40.8; 18.1 and 12.1 tms/ha/2 years, respectively. there was a low correlation among almost all the explanatory variables and the production considered main variable, so, association of characteristics was needed. characteristic height associated with plant width explained better the potential of dry matter production in t/ha/2 years because they presented a high correlation with production (r = 0.71) and the highest direct effect (0.69). indirect and non destructive selection for production have to be based on higher and larger plants.
Ensaios preliminares sobre autofecunda??o e cruzamentos no melhoramento do capim-elefante
Silva, Maria da Concei??o;Santos, Mércia Virginia Ferreira dos;Lira, Mário de Andrade;Mello, Alexandre Carneiro Leo de;Freitas, Erinaldo Viana de;Santos, Ramilton Jader Menezes;Ferreira, Rinaldo Luiz Caraciolo;
Revista Brasileira de Zootecnia , 2008, DOI: 10.1590/S1516-35982008000300004
Abstract: the objectives of this work were to evaluate the self-pollination as a tool in the elephantgrass (pennisetum purpureum) breeding and to compare progenies of pennisetum purpureum origined from different breeding strategies: self-pollination, intraspecific crossbreeds, and interspecific crossbreeds with pennisetum glaucum. the experimental treatments were represented by the three fecundation forms: intraspecific crossbreed, interspecific crossbreed and self-pollination. a total of ten families originated from intraspecific crossbreed resulting in 160 progenies; two families originated from interspecific crossbreed resulting in 38 progenies, and two families originated from self-pollination resulting in 40 progenies, was evaluated. the evaluated traits were dry matter production (kg/tussock), dry matter concentration (%), plant height (m), number of basal tillers (n./tussock) and survival index (%), in two evaluations and non-replicated plots. the intraspecific crossbreed, interspecific crossbreed and self-pollination presented average dry matter production of 0.47, 0.78, and 0.46 kg of dm/tussock, at first evaluation and 0.14, 0.23, and 0.22 kg of dm/ tussock, at second evaluation, respectively. this indicates the necessity of plot replication to separate the environmental effect from the genetic effect. the interspecific crossbreed showed potential to generate progenies with satisfactory dry matter concentration which is more appropriated for ensiling. the treatments showed potential to release variability of traits evaluated through vegetative propagation, however, the low survival index of self-pollinated progenies reduces the probability of obtaining pure lines of elephantgrass.
Caracteriza??o da caatinga e da dieta de novilhos fistulados, na época chuvosa, no semiárido de Pernambuco
Santana, Daniel Fernando Ydoyaga;Lira, Mario de Andrade;Santos, Mércia Virginia Ferreira dos;Ferreira, Marcelo de Andrade;Silva, Maria José de Araújo;Marques, Kleyton Alcantara;Mello, Alexandre Carneiro Leo de;Santos, Djalma Cordeiro dos;
Revista Brasileira de Zootecnia , 2011, DOI: 10.1590/S1516-35982011000100010
Abstract: the experiment was carried out to characterize a manipulated caatinga and to estimate the botanical composition and quality of diet for fistulated steers. the experiment was carried out during the rainy season from march to july, 2003. caatinga was browsed by 24 guzerá and 12 girolando breed heifers and by two esophageal fistulated steers. in caatinga, it was identified 24 families, 38 genus, and 41 species in the two studied strata (out of them, ten species were found in the diets of the animals). forage mass of herbaceous and shrubby-tree components ranged, respectively, from 6,454 and 3,495 kg dm/ha in the beginning of the experiment to 782 and 378 kg dm/ha in the end. in the shrubby-tree and in the herbaceous strata, species grouped as "other species" showed higher absolute frequency. the shrubby-tree stratum is formed mainly by legumes whereas the herbaceous stratum is formed mainly by the "other species" group. grass presence in the diet ranged from 55% in the beginning to 41.8% at the end of the experimental period. "mororó" legume and the buffel grass had high absolute frequencies, showing an expressive presence in the vegetation. leaves of mororó and non-identified grass prevailed in the diet. significant portion of forage crude protein is unavailable because it is linked to acid detergent fiber.
Consumo de matéria seca e desempenho de novilhas das ra?as Girolando e Guzerá sob suplementa??o na caatinga, na época chuvosa, em Pernambuco, Brasil
Santana, Daniel Fernando Ydoyaga;Lira, Mario de Andrade;Santos, Mércia Virginia Ferreira dos;Ferreira, Marcelo de Andrade;Santos, Djalma Cordeiro dos;Mello, Alexandre Carneiro Leo de;Dubeux Júnior, José Carlos Batista;Araujo, Gherman Garcia Leal de;
Revista Brasileira de Zootecnia , 2010, DOI: 10.1590/S1516-35982010001000007
Abstract: to estimate dry matter intake and to evaluate variation on live weight of heifers, an experiment was conducted from march to july 2003, with the following supplementation strategies: no supplementation (control), cottonseed cake (1 kg); spineless cactus (10 kg); spineless cactus + 0.5 kg of cottonseed cake (5 kg). dry matter intake of native pasture was not affected by supplementation, but it affected total dry matter intake. intake of total dry matter (dm) differed among breeds with values of 5.44 and 6.75 kg/day, respectively for guzerat and girolando breeds. for animal fed cottonseed cake supplementation, total dm intake was higher than in the control group (no supplementation), however, it was similar for those under spineless cactus and cottonseed cake + spinelles cactus supplementation. daily average body weight gain (517 and 434 g/animal, respectively, for girolando and guzerat groups) did not differ among breeds neither was affected by breed ? supplementation interaction. however, among strategies of suplementation, values were significantly different and they were 412, 620, 371 and 498 g/animal/day, respectively, for control and cottonseed cake suplementation group; spineless cactus; cottonseed cake + spineless cactus. in pernambuco semiarid, 1 kg of cottonseed cake supplementation improved daily average weight gain, regardless to breed of the animal during the rainy season.
Genótipos de capim-elefante sob pastejo no período de seca na Zona da Mata de Pernambuco: fatores relacionados à eficiência de pastejo
Cunha, Márcio Vieira da;Santos, Mércia Virginia Ferreira dos;Lira, Mário de Andrade;Mello, Alexandre Carneiro Leo de;Freitas, Erinaldo Viana de;Apolinário, Valéria Xavier de Oliveira;
Revista Brasileira de Zootecnia , 2007, DOI: 10.1590/S1516-35982007000200004
Abstract: the experiment was carried out to evaluate factors related to the grazing efficiency of five pennisetum sp. genotypes (ce 08 a.d., venezuela, hv-241, elephant b and hexaplóide) during the dry period in the forest zone of pernambuco. genotypes were managed under rotational stocking (44 days of resting and four days of grazing period). it was used a split-plot arrangement in a complete randomized block design (genotypes represented the plots; grazing cycles, the subplots). six replications were used to determine pre-grazing total leaf blade mass and green and senescent leaf blade mass. four replications were used for leaf blade accumulation and grazing efficiency and, for these variables, it was used a complete randomized blocks design. the ce 08 a.d. and elephant b presented greater pre-graze total leaf blade mass, green leaf blade, green leaf blade accumulation, and grazing efficiency, with averages of 1,374 kg dm/ha, 737 kg dm/ha, 654 kg dm/ha/44 days and 80% of the green leaf blade accumulation, respectively. the highest grazing efficiency (100% of the green leaf blade accumulation) occurred at the hv-241 pastures. this high grazing efficiency was associated to the low green leaf blade accumulation (155 kg of ms/ha/44 days). the lowest grazing efficiency was observed for the hexaplóide (59% of the green leaf blade accumulation), possibly due to high losses under grazing (30% of the pre-grazing total leaf blade mass). the green leaf blade mass decreased mostly until the second grazing day, while the losses of total leaf blade were higher in the second and third grazing days. the genotypes ce 08 a.d. and elephant b presented potential to be used under rotational stocking, in the pernambuco forest zone.
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