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

M.D Rambau,F Fushai,J.J Baloyi

doi:10.4314/sajas.v46i4.8

M.D Rambau, F Fushai + Show 1 more

Open Access

https://doi.org/10.4314/sajas.v46i4.8

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Abstract

The effect of the stage of maturity on the productivity, chemical composition, and ruminal degradability of Napier grass ( Pennisetum purpureum ) leaves under irrigation was studied. Samples were collected at three stages of maturity, at intervals of four weeks starting from the fourth week until the twelfth week (April–July) after sprouting and then harvested to determine biomass. The stages of maturity had significant effects on longest leaf length per plant and plant height, but had no effect on number of leaves per plant and number of tillers. Dry matter (DM) increased significantly with maturity, while crude protein (CP) and fat content decreased significantly, with no significant effect on acid detergent lignin (ADL), ash, acid detergent fibre (ADF) and neutral detergent fibre (NDF). Maturity significantly decreased potassium, copper and sodium, while calcium and zinc increased significantly up to the intermediate stage, then declined toward the late stage of maturity. Maturity did not affect the magnesium, phosphorus, manganese and iron contents of the forage. Ruminal degradability of CP at 48, 72, 96 and 120 incubation hour decreased significantly with maturity, with no effect on all other incubation times for DM and CP. Maturity significantly decreased the soluble fraction (a) of DM, with no significant effect on other fractions of DM and CP. Effective degradability (%) of DM and CP decreased with maturity when the rate of passage increased from 2% to 8%. Napier forage should be harvested before maturity to retain its high nutrient content, and the degradability of DM and CP. Keywords: mineral composition, in sacco, dry matter, crude protein disappearance

Highlights

There is increasing demand for ruminant animal products owing to the growing population and improved livelihoods (Dastagiri, 2004)
Sci. vol 46 determining the productivity, chemical composition and ruminal degradability of Dry matter (DM) and crude protein (CP) of Napier grass harvested at three stages of maturity
The longest leaf length per plant, plant height, number of leaves per plant and number of tillers increased with maturity of the grass

Summary

Introduction

There is increasing demand for ruminant animal products owing to the growing population and improved livelihoods (Dastagiri, 2004). Pasture and fodder remain the cheapest forms of animal feed. Napier grass (Pennisetum purpureum), known as Elephant grass, has been the most promising high-yielding fodder, giving DM yields that surpass most other tropical grasses (Ansah et al, 2010). It originates from sub-Saharan tropical Africa (Clayton et al, 2013) and has been introduced in most tropical and subtropical regions worldwide as forage. Sci. vol 46 determining the productivity, chemical composition and ruminal degradability of DM and CP of Napier grass harvested at three stages of maturity

Materials and Methods

Results

Discussion

Conclusion