Caracterização do padrão de desenvolvimento de gramíneas forrageiras tropicais por meio das características morfogênicas e estruturais

An experiment was carried out with the objective to evaluate growth pattern of tropical forage grass under free growth by using morphogenetic and structural characteristics with the expectation of using this study for forage grass evaluation protocol. The experimental area was established with two cultivars of Panicum maximum Jacq. (Mombaca and Aruana), a hybrid cultivar of P. maximum Jacq. and P. Infestum BRA-7102 (Massai), two cultivars of Brachiaria brizantha (A. Rich.) Stapf (Marandu and Xaraes) and Molasses grass (Melinis minutiflora Beauv.) and jaragua grass (Hyparrhenia rufa (Nees) Stapf.). The grasses were planted in 1.0-m² experimental units with 24 plants arranged in a completely randomized block design with three replications. Growth pattern of the grasses was evaluated through mass development, tiller mortality, development stage and leaf longevity. Development patterns differed significantly among groups of grasses, indicating that the same available resources can be used in different manners by grasses from the same genus and/or species.Um experimento foi conduzido com o objetivo de avaliar o padrão de desenvolvimento de gramíneas forrageiras tropicais em crescimento livre por meio das características morfogênicas e estruturais, com expectativa de uso desse estudo no protocolo de avaliação de gramíneas forrageiras. A área experimental foi estabelecida com dois cultivares de Panicum maximum Jacq. (Mombaça e Aruana), um cultivar híbrido de P. maximum Jacq. e P. infestum BRA-7102 (Massai), dois cultivares de Brachiaria brizantha (A. Rich.) Stapf (Marandu e Xaraés) e com os capins gordura (Melinis minutiflora Beauv.) e jaraguá (Hyparrhenia rufa (Nees) Stapf.). As gramíneas foram plantadas em unidades experimentais de 1,0 m² com 24 plantas arranjadas em delineamento de blocos completos casualizados com três repetições. O padrão de desenvolvimento das gramíneas foi avaliado por meio do desenvolvimento de massa, da mortalidade de perfilhos, do estádio de desenvolvimento e da longevidade foliar. Os padrões de desenvolvimento diferiram significativamente entre os grupos de gramíneas, e isso indica que os mesmos recursos disponíveis podem ser usados de maneira diferente por gramíneas de mesmo gênero e/ou espécie.CNPqFederal University of Vicosa - Departament of Animal Scienc

Características morfogênicas e estruturais do capim-xaraés submetido a alturas de corte

The objective of this work was to evaluate the morphogenetic and structural characteristics of xaraes palisadegrass submitted to three cutting heights (15, 20 and 25 cm) when the sward reached 95% of light interception during regrowth. The experiment was carried out according to a complete randomized block design with three replications. The sward surface height under the cutting condition of 95% of light interception was very homogeneous with values around 30 cm. The increase in cutting height reduced the leaf elongation rate and the number of live leaves but increased stem elongation rate. As the cutting criterion was the same, before the intense competition for light, the variation in the cutting severity had a small influence on the morphogenetic and structural characteristics of this grass. In the summer, due to the better growth conditions, the plants presented a higher tissue renewal, which was characterized by a higher leaf elongation rate, reduced leaf lifespan and leaf senescence rate when compared to the other season of the year. Under intermittent defoliation conditions, the regrowth of xaraes palisadegrass can be interrupted at a sward height of 30 cm (frequency) keeping a residual height of 15 cm.Este trabalho foi realizado com o objetivo de avaliar as características morfogênicas e estruturais do capimxaraés submetido a três alturas de corte (15, 20 e 25 cm) quando atingidos 95% de interceptação de luz durante a rebrotação. O experimento foi conduzido segundo delineamento de blocos completos casualizados com três repetições. A altura do dossel na condição de corte de 95% de interceptação de luz mostrou-se homogênea, com valores próximos a 30 cm. A elevação na altura de corte reduziu a taxa de alongamento de folhas e o número de folhas vivas, mas aumentou a taxa de alongamento de colmos. Como o critério para a realização dos cortes foi o mesmo, antes da competição intensa por luz, a variação na severidade de corte pouco influenciou as características morfogênicas e estruturais dessa gramínea. No verão, devido às melhores condições de crescimento, as plantas apresentaram maior renovação de tecidos, fato caracterizado pela maior taxa de alongamento foliar, pela menor duração de vida da folha e taxa de senescência de folhas comparativamente à outra estação do ano. Em condições de desfolhação intermitente, a rebrotação do capim-xaraés pode ser interrompida aos 30 cm de altura do dossel (frequência) mantendo-se 15 cm de altura de resíduo.CNPqUniversidade Federal de Viçosa - Departamento de Zootecni

NUTRIÇÃO DE RUMINANTES COM USO DO FENO DE CAPIM ELEFANTE AMONIZADO

The objective of this study was to evaluate the chemical and nutritional characteristics of ammonized elephant grass hay with different levels of urea (0.0, 0.5, 1.0, 1.5 e 2.0% of dry matter). The experimental design was completely randomized and the regression coefficients were estimated using the Student's T test (5% significance). The data were also submitted to multivariate analysis using the Gower distance and the UPGMA method of grouping, in addition, they were subjected to principal component analysis. There was a reduction in fibrous fractions with an increase in urea doses, however, there was a linear increase in the contents of digestibility of dry matter (DDM), crude protein, total digestible nutrients (TDN) and ammoniacal nitrogen. It was observed through multivariate analysis that non-fibrous carbohydrates, TDN and DDM were the variables that most contributed to the results observed for the treatment with 2.0% urea. Through the Cluster analysis it was possible to visualize the formation of two groups, the first formed by the use of 2.0% urea, which stood out in the bromatological composition of elephant grass hay and the second group by the other doses of urea, divided into two subgroups.Thus, it is possible to conclude that among the studied doses, the addition of 2.0% urea to the dehydrated elephant grass is recommended, as it beneficially alters the nutritional composition of elephant grass hay, mainly the components of the fibrous fraction.Objetivou-se avaliar as características químicas e nutricionais do feno de capim elefante amonizado com diferentes níveis de ureia (0,0; 0,5; 1,0; 1,5 e 2,0% da matéria seca). O delineamento experimental foi o inteiramente casualizado e a estimativa dos coeficientes de regressão foi feita através do teste T de Student (5% de significância). Os dados também foram submetidos à análise multivariada, utilizando a distância de Gower e o método UPGMA de agrupamento, além disso, foram submetidos à análise de componentes principais. O aumento das doses de ureia não alterou os teores de matéria seca, hemicelulose e material mineral do feno de capim elefante. Houve redução das frações fibrosas com o aumento das doses de ureia, contudo, houve aumento linear dos teores de digestibilidade da matéria seca (DMS), proteína bruta, nutrientes digestíveis totais (NDT) e nitrogênio amoniacal. Observou-se, através da análise multivariada, que os carboidratos não fibrosos, NDT e DMS, foram as variáveis que mais contribuíram com os resultados observados para o tratamento com 2,0% de ureia. Através da análise de Cluster, foi possível visualizar a formação de dois grupos, sendo o primeiro formado pela utilização de 2,0% de ureia, que se destacou na composição bromatológica do feno de capim elefante, e o segundo grupo pelas demais doses de ureia, divididos em dois subgrupos. Em conclusão, entre as doses estudadas, recomenda-se a adição de 2,0% de ureia ao capim elefante desidratado, pois altera beneficamente a composição nutricional do feno de capim elefante, principalmente os componentes da fração fibrosa

Forage mass and structure of piatã grass deferred at different heights and variable periods

The objective of this study was to determine the deferment period and the most adequate initial sward height of Brachiaria brizantha cv. Piatã for deferment in the region of Viçosa, Minas Gerais. For so, the following characteristics were evaluated: masses and bulk density of forage and its morphological components, light interception by the sward, leaf area index, leaf angle, sward and extended tiller height and falling index of the deferred piatã grass. The three deferment periods assessed (65, 85 and 105 days) were randomized to the plots and the three sward heights (20, 30 and 40 cm), randomized in the subplots. The experimental design was of completely randomized blocks, with three replicates, in a subdivided plots arrangement. Masses of forage, green stem and dead tissue were higher in the piatã grass managed with deferment period of 105 days. The mass of green leaf blade was higher in the piatã grass deferred with 20 cm height associated to the deferment period of 85 days, which had, as consequence, greater bulk density of green leaf blade. The interception of light by the sward was greater in the piatã grass kept longer in deferment associated with the higher leaf area index, regardless of its initial height. The heights of the sward and extended tillers were greater in the piatã grass under periods of 85 and 105 days of deferment; however, the falling index was not affected by the factors studied. In the region of Viçosa, Minas Gerais, B. brizantha cv. Piatã fertilized with 75 kg/ha nitrogen and deferred with initial height of 20 cm and for a period of 85 days, from mid April, has adequate productivity and structure for animal production

Morphogenetic and structural characteristics of tillers of guinea grass of different age and grazing severities

The objective of this research was to evaluate the effects of tiller age on morphogenic and structural characteristics of guinea grass cv. Mombaca subjected to intermittent stocking and three stubble heights: 30 cm, 50 cm and 50-30 cm. Stubble heights were assigned to experimental units in a completely randomized block design with three replicates. Grazing was performed when canopy intercepted 95% of light incidence. Leaf appearance rate, leaf elongation rate and number of live leaves per tiller were higher in the summer when compared with the winter. Contrarily, stem elongation rate, phyllochron and leaf lifespan were lower in the summer when compared with the winter. During the summer, young tillers had higher leaf appearance and elongation rates when compared with the older ones. Young and mature tillers had the highest values of live leaves per tiller in the summer. There was no difference between summer and winter for the final length of leaf blade between tillers of the same age, except in mature tillers, which had higher final leaf length during the summer. Senescence rate of leaves was higher in young tillers, followed by mature and old tillers. Age of tiller affects morphogenic and structural characteristics of pasture, showing that young tillers have better growth compared with mature and old tillers

Characterization of silage made from sweet potato vines using corn meal as additive

The objective of this study was to investigate the fermentative and nutritional characteristics of sweet potato (Ipomoea batatas) vine silage using different levels of corn meal as additive. A completely randomized design consisting of seven levels of the additive (0, 5, 10, 15, 20, 25 and 30% corn meal) and four replicates was used, totaling 28 laboratory mini-silos (experimental units). The different levels of additive in sweet potato vine silage exerted quadratic effects on the content of dry matter (DM), crude protein (CP), neutral detergent insoluble protein (NDIP), acid detergent insoluble protein (ADIP), and total carbohydrates. There was an increase in DM content with inclusion of the additive and CP was reduced from 11.23% (no additive) to 9.46% (30% additive) in sweet potato vine silage. NDIP and ADIP content was lower in sweet potato vine silage containing 30% additive (1.15% and 0.70%, respectively). No significant differences in organic matter, ashes, ether extract, neutral detergent fiber, acid detergent fiber, or total digestible nutrients were observed between the different levels of additive. Regarding fermentative parameters, a quadratic effect of sweet potato vine silage containing different additive levels was observed on pH, ammoniacal nitrogen as a percentage of total nitrogen [N-NH3 (%NT)], and losses from gases and effluent. A lower pH was observed at a level of the additive of 15% (3.31) and higher values at levels of 20%, 25% and 30% (3.88, 3.89 and 3.88, respectively). The N-NH3 values (%NT) ranged from 2.84% (no additive) to 3.59% (15% additive), and the lowest loss from gases and effluents was 2.38% DM and 199 kg/t in sweet potato vine silages containing 30% and 10% additive, respectively. Sweet potato vine is a good-quality roughage alternative that can be stored as silage, as along as a water-absorbing additive such as corn meal is used at a level no less than 20%.Objetivou-se investigar as características fermentativas e nutricionais da rama da batata doce (Ipomoea batatas) na forma de silagem utilizando níveis de fubá de milho como aditivo. O delineamento experimental utilizado foi inteiramente casualizado com sete níveis de aditivo (fubá de milho) (0; 5; 10; 15; 20; 25 e 30%) e quatro repetições, totalizando 28 mini silos laboratoriais (unidades experimentais). Efeito quadrático foi observado nos teores de matéria seca (MS), proteína bruta (PB), proteína insolúvel em detergente neutro (PIDN), proteína insolúvel em detergente ácido (PIDA) e carboidratos totais das silagens da rama da batata doce com diferentes níveis de aditivo. Houve aumento no teor de MS com adição do aditivo, e a PB reduziu de 11,23% (zero aditivo) para 9,46% (30% aditivo) nas silagens da rama da batata doce. Os teores da PIDN e PIDA foram menores das silagens da rama da batata com 30% de aditivo (1,15% e 0,70%, respectivamente). Não foi observada diferença significativa nos teores de matéria orgânica, cinzas, extrato etéreo, fibra em detergente ácido, fibra em detergente neutro e nutrientes digestíveis totais nas silagens da rama da batata doce em relação aos níveis de aditivos. Na avaliação dos parâmetros fermentativos, foi observado efeito quadrático no pH, nitrogênio amoniacal, em porcentagem do nitrogênio total [N-NH3 (%NT)], perda por gases e perda por efluentes das silagens da rama da batata doce com diferentes níveis de aditivo. Menor valor de pH foi observado no nível de 15% de aditivo (3,31) e maiores nos níveis 20%, 25% e 30% de aditivo (3,88; 3,89 e 3,88, respectivamente). Os valores de N-NH3 (%NT) variaram de 2,84% (zero aditivo) a 3,59% (15% aditivo), e a menor perda por gases e efluentes foi de 2,38% MS e 199 kg/t nas silagens da rama da batata doce com 30% e 10%de aditivo, respectivamente. A rama da batata doce representa um volumoso alternativo de boa qualidade que pode ser armazenado na forma de silagem, desde que se utilize aditivo absorvente de umidade, como o fubá de milho, em nível não inferior a 20%.Nova Odessa, S