Grain processing and texture in the ensiling of corn hybrids / Processamento e textura de grÃos na ensilagem de hÃbridos de milho

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Corn silage is the conserved roughage most utilized by the stockmen in the period of poor production of pastures or by those who adopt the confinement of the animals the whole of the year. That is justified on account of the excellent nutritive value, a factor closely associated with the amount of grains in the ensiled mass. This work was conducted with the purpose of evaluating the interaction between digestibility, corn grain texture in silages of different commercial hybrids. For the study of that interaction, two experiments started in 2006 were conducted, with the planting of the hybrids for silage production till 2007, with the evaluation performed in laboratory and on animals. In the first experiment, it was aimed to evaluate the interaction of grain texture x particle size of the silages on the bromatologic characteristics, digestibility and consumption. For evaluation of in vivo digestibility and nutrient consumption, ten sheep housed in metabolism cages, allotted into a randomized block design with three replicates in time were utilized. The treatments consisted of five commercial hybrids, ensiled with two particle sizes (2 and 11 mm), in a 5 X 2 factorial. In the second experiment, the influence of grain texture on the in vitro digestibility of dry matter (DIVMS) and the bromatologic composition of the silages of the corn hybrids was determined. A completely randomized design with five treatments and eight replicates was utilized. The treatments were constituted of hybrids BM-3061, BM-2202, BRS-3150, BRS-3003 and AG-1051. it was found, with the accomplishment of the first experiment, that the interaction grain texture x particle size was not significant to the digestibility of the hybrids. For particle size, singly, the best values of digestibility were found for the largest particles, pointing out that the reduction of particle size increased passage rate, so that the shortest time of retention in the rumen caused reduction of the digestibility values for the 2 mm size. A difference for nutrient consumption was observed only for non-fiber carbohydrates (CNF) and that can be related to the fact that hybrid BM-3061, which presented the highest contents of DM and lowest contents of NDF, a variable linked closely to consumption. The second experiment enabled to conclude that grain texture has an influence on the DIVMS of the silages evaluated, and the hybrids which present grains of the dent type show the best values of DIVMS. That finding is related to the fact that in the grains of the dent type, starch granules are larger and more scattered and possess a poorer interaction with protein bodies responsible for limited digestibility. Thus, that characteristic of the grains comes to be a variable of vital importance in choosing of hybrids to ensile, since they have a direct relationship with digestibility.

ASSUNTO(S)

balanÃo de nitrogÃnio nutrientes digestÃveis totais produÃÃo hÃbridos zootecnia zea mays endosperma

ACESSO AO ARTIGO

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