Effect of Irrigation and Annual Seasons on the Chemical Composition and Digestibility of Grasses Under Grazing

C.A.B Alencar,A.C Cóser,F.F Cunha,C.E Martins,R.A Oliveira

doi:10.13083/1414-3984.v22n04a05

Abstract

The aim of the study was to evaluate the chemical composition and in vitro dry matter digestibility (IVDMD) of six grasses subjected to different irrigation depths and seasons. The experiment was conducted in a completely randomized arrangement with two replications in a split-split plot design. The treatments included plots with six grasses (Xaraes, Mombaca, Tanzania, Pioneiro, Marandu and Estrela), six irrigation depths for the split-plots (0%, 18%, 45%, 77%, 100% and 120% of the reference value provided by the tensiometer), and two seasons as the split-split plots (autumn/ winter and spring/summer). A line source sprinkler system was used for application of the irrigation depths. Crude protein (CP), neutral detergent fiber (NDF) and IVDMD were evaluated and obtained in accordance with literature. The factors studied affect the CP. However in the autumn/winter season the grasses presented differences in the NDF content, where Estrela presented the largest and Pioneiro the smallest NDF contents. The season and irrigation depths did not affect the NDF. Estrela grass presented the smallest IDVMD and the autumn/winter season resulted in greater digestibility for the grasses Xaraes, Mombaca and Tanzania only. The irrigation depths had an effect on some combinations of grasses and seasons.

Highlights

Animal performance is directly linked to the consumption and quality of dry forage matter because it determines the amount of nutrients that must be ingested by animals to meet their demands for maintenance and production (LIMA et al, 2001; CUNHA et al, 2010)
In irrigated areas the nutritional value of forage throughout the year is different compared to nonirrigated pastures
The concept of nutritional value refers to the chemical composition of the forage and digestibility (GERDES et al, 2000)

Summary

Introduction

Animal performance is directly linked to the consumption and quality of dry forage matter because it determines the amount of nutrients that must be ingested by animals to meet their demands for maintenance and production (LIMA et al, 2001; CUNHA et al, 2010). Forage plant utilization efficiency by animals is dependent on several factors such as the quality and quantity of forage available in the pasture and genetic potential of the animal. When forage availability and potential of the animal are not limiting factors, forage quality is defined by production per animal and is directly linked to the intake and availability of nutrients contained in it (REIS et al, 1992). Supplementation of water by irrigation can alter the chemical composition and nutritional quality of these plants. The concept of nutritional value refers to the chemical composition of the forage and digestibility (GERDES et al, 2000)

Objectives

Methods

Results