Características agronômicas e qualitativas de híbridos de milho e valor nutritivo das silagens avaliadas em ovinos

• Autor(a) principal: Soriani Filho, José Luis
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/1692
• topic: Silagem de milho; Consumo; Valor nutricional; Altura de corte; Ovinos; Digestabilidade; Composição química; Brasil.; Corn silage; Consumption; Nutritional value; Cutting height; Sheep; Digestibility; Chemical composition; Brazil.; Ciências Agrárias; Zootecnia

There were evaluated the morphological parameters, production and chemical composition of five corn hybrids for silage at three cutting heights. With these hybrids and two others it was evaluated levels of consumption and silages digestibility in sheep. The hybrids were: AS 32, AG 9090, CD 308, 747 and DKB P 30F87, harvested at three cutting heights (15, 35 and 55 cm) and the Hybrid A 2555 and BX 981, which were only used for analysis of consumption and digestibility. The experimental design was a randomized block with split plot with three replications to evaluate the productivity and chemical composition, levels of consumption and digestibility were evaluated in two Latin squares, a 4x4 one and a 3x3 one. The milk line was used as an visible indicator of the harvest point, which occurred at the stage of ½ ?ilk line, or about 34% of DM. Agronomic characteristics showed differences among hybrids, but the total production of forage, grain and cob had no difference. There was no interaction among hybrid and cutting height for production and chemical composition of the leaf blade. There was an interaction of hybrid and cutting height for the fraction stem + sheath, both in production and the CP, ADF, ADL and ratio LDA: NDF. The proportion of fractions: stem + sheath, leaf lamina, bracts, cob and panicle showed differences between hybrids, only the fraction of grain did not differ, as to the heights all the fractions obtained differences with the exception of the leaf blade. With the increase of the cutting height there was a decreased in the stem fraction and an increased in the proportion of grains, but this did not differ (P>0.05) between the altitudes of 35 and 55 cm. Forage production was lower by increasing the cut height, with no difference (P>0.05) between the heights of 35 and 55 cm. The content of the forage showed an increasing when it was raised the cut height. In general the chemical composition differed (P<0.05) for height of 15 to 35 cm and 55 cm. In the evaluation of consumption and digestibility of the experiment I (4x4 Latin square) did not differ (P>0.05) both the consumption and digestibility of the hybrids. Correlations were higher in digestibility and consumption among the variables, but showed negative correlations to the DMD and CPI variables, OMD, NDFI and CPI; NDFD, DMI, OMI and CPI. The experiment II (3x3 Latin square) was different (P<0.05) in CP intake, and the hybrid A 2555 had the lowest consumption (0.41% BW). For NDF digestibility there was no difference (P<0.05) among treatments, where the hybrid BX 981 stood out with 68.05%, while the DKB 747 presented 54.6%. For the experiment I, there was no difference (P>0.05) among hybrids for digestibility coefficient, the choice of hybrids for silage can be made by productivity, even if the hybrids examined showed differences in the proportions of morphological fractions and not differ in productivity. In the second experiment, thehybrid showed better BX 981 CP intake and increased digestibility.