Nutritional quality of ensiled gamba grass (Andropogon gayanus) fortified with graded levels of Centro (Centrosema pascourum)

Abstract

The study was conducted with the field grown gamba grass (Andropogon gayanus) and Centro (Centrosema pascourum) to examine the nutritional quality of gamba grass ensiled with graded levels of Centrosema pascourum. The forages were harvested separately chopped into 2-3cm length manually and mixed thoroughly as follows: (100:0, 90:10, 80:20,70:30, 60:40, 50:50 and 40:60% of Andropogon gayanus: Centrosema pascourum, respectively) and designated as T1 , T2 , T3 , T4 , T5 , T6 and T7 respectively. The treatments were ensiled in a laboratory using bottle silos in triplicates per treatments and kept for 30 days fermentation period. The silages were evaluated for quality characteristics, proximate composition, fibre fractions, volatile fatty acids composition and ammonia nitrogen concentration (NH3 -N) using standard procedure. The results obtained showed that the silages were adequately fermented with pleasant and fruity odour, greenish-yellow colour, firm and dry texture. The pH, ether extract (EE), nitrogen free extract (NFE), organic matter (OM) and Ash contents of the silages were similar across the treatments (P<0.05). However, the crude protein (CP) contents of silages (9.44-14.88%), varied significantly (P<0.05) across the treatments. The crude fibre (CF), cellulose, hemicellulose and fibre fractions (neutral detergent fibre (NDF) and acid detergent fibre (ADF) of the silages differed significantly (P<0.05) except for acid detergent lignin (ADL) which was similar across the treatments. Other parameters such as volatile fatty acids (VFAs), NH3 concentration, temperature (°C) and dry matter (DM) moisture content (MC) differed significantly across the board. The results of this study indicated that ensiled Andropogon gayanus with Centrosema pascourum at varied levels of inclusion improved physico chemical properties of the silages. The inclusion of Centrosema pascourum legume forage also improved the crude protein (CP) contents of ensiled gamba grass significantly. Thus, the study recommends the use of 60% Andropogon gayanus and 40% Centrosema pascourum, which is practicable and obtainable.