Estimates of kinetic degradability parameters and passage of materials originated from intercropping of brachiaria grass and corn and soybean crops

Tadeu Silva De Oliveira,Fernando De Paula Leonel,Ricardo Augusto Mendonça Vieira,José Carlos Pereira,Marcelo Teixeira Rodrigues

doi:10.1590/s1516-35982011001200038

Tadeu Silva De Oliveira, Fernando De Paula Leonel + Show 3 more

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https://doi.org/10.1590/s1516-35982011001200038

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Abstract

The study was conducted to determine the kinetic parameters of in situ DM and NDF and the passage of particles of forages produced from the intercropping of brachiaria grass with corn and soybean crops. Three experiments were performed, as follows: Experiment 1 - Brachiaria grass intercropped with corn at different plant ages; Experiment 2 - Cultivation of brachiaria grass intercropped with corn set in different sowing arrangements; and Experiment 3 - Intercropping of brachiaria grass and soybean. Passage kinetic of particles was determined by the recovery of markers in feces. In order to obtain the ruminal degradation of DM and NDF, nylon bags were used at zero time, 3, 6, 9, 12, 24, 48, 72, 96, 120 and 144 hours. The particles' passage kinetic of corn with brachiaria grass silage and brachiaria grass silage presented 3%/h and 2.3%/h, respectively; and for soybean and brachiaria grass silage, it was 1.8%/h, which can be explained in part by the mixture of materials ensiled. The materials originated from the intercropping caused rumen fill. Degradation rates were lower when compared with literature data. The brachiaria grass silage obtained from corn and/or soybean crop-pasture integrated system is a feed with low nutritive value due to its low NDF degradation rate and low passage rate, causing rumen fill and, thus, possibly resulting in low intake and poor animal performance.

Highlights

The feeds’ capacity of supplying nutrients to animals is a characteristic intrinsic of the feedstuff itself, which depends on the degradation extension and the rate of passage through the gastrointestinal tract, which determine, on the one hand, the quality of the substrate that may be absorbed in digestion and, on the other hand, condition the amount of feed that can be ingested by the animal.In Brazil, pasture constitutes the basis of the feed of the ruminants and, generally, it is characterized by its high fiber content, which is very important, since its components are related to digestibility, rumen fermentation and energy value of the feed – factors that are directly connected to animal productivity
Passage rates varied for silages, with values of 3%/hour for the silage of corn with brachiaria grass (SCB); 2.3%/hour for the silage of brachiaria grass (BG); and 1.8%/hour for the silage of soybean with brachiaria grass (SSB) (Table 1)
For SSB, the passage rate was 1.8%, a value that can be considered low if compared with the 5.5%/hour found by Rigueira (2007) for the silage of soybean in exclusive cultivation

Summary

Introduction

In Brazil, pasture constitutes the basis of the feed of the ruminants and, generally, it is characterized by its high fiber content, which is very important, since its components are related to digestibility, rumen fermentation and energy value of the feed – factors that are directly connected to animal productivity. There are studies presenting results in which the crop-livestock integration system generates improvement of the nutritional value of the forage and digestibility. Results from other studies proved that, in this system, there is increase in lignin and silica content in shadowed plants (Castro et al, 1999); and others indicate that the dry matter (DM) digestibility of forage decreases with reduction of light intensity (Masuda, 1977; Castro et al, 1999)

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