In situ degradability of corn stover and elephant-grass harvested at four stages of maturity

Abstract

Among tropical forages, corn silage is largely used by farmers trying to explore the maximum genetic potential from the animals. However, other tropical forages, such as elephant-grass (Pennisetum purpureum), are more productive and therefore cheaper to use than corn silage. Our objective was to compare the in situ degradability of elephant-grass with that from corn hybrids, all harvested at four stages of maturity. The experimental design followed a randomized block design with nested subplots. Two corn hybrids: AG5011, ZN8392 were harvested with 25, 30, 35, and 40% dry matter (DM) in the whole plant, and separated in stem + leaf sheath + leaf blade (stover), and cobs. Elephant-grass was harvested with 30, 40, 50 and 60 days after a leveling cut. Dried and ground samples were incubated in nylon bags inside the rumen for 0, 6, 12, 24, 48 and 72 h to estimate the kinetics of ruminal DM and neutral detergent fiber (NDF) degradation. The advance of maturity increased the NDF and acid detergent fiber (ADF) content in elephant-grass, and reduced its DM degradability. However, maturity had little or no effect on fiber content and DM degradability of corn stover. Elephant-grass had a higher NDF degradability than corn stover, and there was no effect of maturity on NDF degradability of either elephant-grass or corn stover. Fiber degradability of elephantgrass was not worse than that of corn stover, and therefore the choice of forage should be made on economical analysis rather than assuming an intrinsic low production potential for elephant-grass based diets. Key words: Pennisetum purpureum, corn silage, digestibility, rumen, tropical grass DEGRADABILIDADE IN SITU DE HÍBRIDOS DE MILHO E DE CAPIM-ELEFANTE COLHIDOS EM QUATRO ESTÁDIOS DE MATURIDADE

Determining Nutritive Value of Cereal Crop Residues and Lentil (<i>Lens esculanta</i>) Straw for Ruminants

“…The values obtained for the DM b fraction and c for CS in this study are similar to those reported in Silva et al (2008) but results from the two studies differ in that the a fraction is lower in the current study than in [10]. Further, [10] pointed out that the high value for the a fraction of CS in their study could be explained by the lower NDF content across four stage of maturity tested.…”

“…Further, [10] pointed out that the high value for the a fraction of CS in their study could be explained by the lower NDF content across four stage of maturity tested.…”

Productivity, chemical composition and ruminal degradability of irrigated Napier grass leaves harvested at three stages of maturity

“…The decline in DM and CP rumen degradability with plant maturity has been reported widely (Aufrère et al, 2003;Yu et al, 2004;Rodrigues et al, 2004;Silva et al, 2008;Belachew et al, 2013;Ribeiro Junior et al, 2014). This reduction in disappearance could be explained by the decrease in protein content and increase in ADL content of grass with maturity.…”

Cinética de degradação in situ das silagens de capim Andropogon gayanus produzidas em três idades de corte

“…Reduction of DM degradability with increasing regrowth age has been reported for several tropical forages (Coblentz et al, 1998;Aguiar et al, 1999;Rodrigues et al, 2004;Silva et al, 2008). This reduction of DM degradability with grass maturity is explained by the increase in stem/leaf ratio and reduction of stem nutritional quality (Nelson andMoser, 1994, Wilson andHatfield, 1997).…”

“…It is well known that vegetative pastures have better nutritional quality than mature pastures, but they also have lower dry matter (DM) yield and high moisture content which may result in secondary fermentation, production of silage effluents and spoilage of the silage (McDonald et al, 1991). At more advanced maturity, DM yield is higher and DM content (30 to 35% DM) of the pasture can be more favorable for silage production, but the high cell wall and lignin content can limit intake and nutritional value of the forage (Van Soest, 1994). Therefore, it was our aim to compare the in situ rumen degradability characteristics of A. gayanus grass silage, harvested at three stages of maturity.…”