Ruminal degradation of Panicum grasses in three post-regrowth ages

Bruno Spindola Garcez,Arnaud Azevêdo Alves,Claudiane Morais Dos Santos,Ernando De Oliveira Macedo,Marlúcia Da Silva Bezerra Lacerda,Daniel Louçana Da Costa Araújo

doi:10.1590/1809-6891v21e-55699

Abstract

Abstract The objective was to evaluate the chemical composition and in situ degradation of Maasai, Mombasa and Tanzania grasses belonging to the genus Panicum, at 22, 34 and 46 days after regrowth. The contents of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were determined. For the evaluation of ruminal degradation, 4 g sample were placed in nylon bags and incubated in the rumen of a fistulated animal, for 6, 24 and 72 h. The experiment had a completely randomized design for chemical composition analysis and a split-split plot completely randomized design for in situ degradation, with means compared by Tukey test at 5%. There was an increase in the contents of DM (+ 1.69%) and NDF (+ 5.06%) (P <0.05) of the grasses at the highest cutting ages with reduction in the CP fraction. The potential degradation (PD) of DM, NDF and CP decreased with advancing age of grasses, with an increase in colonization time (0.69 h) and NDF degradation rate (1.14%/h). The increase in the post-regrowth age of the Massai, Mombasa, and Tanzania grasses increases the acid detergent fiber content and reduces the crude protein content, with a negative effect on the degradation of DM, PB and NDF. The management of these cultivars is indicated at 22 and 34 days post-regrowth to obtain forage with better nutritional value.

Highlights

In the current feeding systems of ruminants on pastures, information is needed regarding the nutritional value and their rates of degradation and utilization in the digestive system, in order to balance the availability of energy and nitrogen in the rumen, maximizing microbial efficiency
Panicum maximum CV Mombaça has a high dry matter production, is nutrient-demanding, with good responses when fertilized with nitrogen[5]
There was an average increase of 1.69% in the dry matter (DM) content (P

Summary

Introduction

In the current feeding systems of ruminants on pastures, information is needed regarding the nutritional value and their rates of degradation and utilization in the digestive system, in order to balance the availability of energy and nitrogen in the rumen, maximizing microbial efficiency. The search for tropical grasses with high productivity in dry matter and adequate nutritional value is a challenge for the production of ruminants. In Brazil, Panicum maximum grasses are one of the most important forage groups for ruminant production, as they have good nutritional value; tolerance to high temperatures and shading; adequate responses to more intensive cultural treatments; large production of dry matter; easy to establish, even in periods of water deficit, and possible use in intercropping systems[2, 3]. Tanzania) is an alternative for soil areas with greater fertility, with good resistance to spittlebug and higher production of leaves with adequate nutritional value[15]

Objectives

Methods

Results