Correlation between chemical composition, kinetics of fermentation and methane production of eight pasture grasses

Abstract

Eight different grasses collected from pastures of the Kermanshah province (Kermanshah, Iran), at mid-vegetative stage were used to study the relationships between their chemical compositions, kinetic parameters of in vitro gas production and rumen methane production. There was a positive correlation (r = 0.62, p < 0.05) between crude protein (CP) content of grasses and total gas production (A) at 96h incubation. Negative correlations were also observed between acid detergent fiber (ADF) content and total gas production (r = -0.60, p < 0.05). Amongst the nutrients, neutral detergent fiber (NDF) and ADF were positively correlated with methane concentration, (r = 0.75 and 0.77, p < 0.01). The methane reduction potential (MRP) was negative for Trachyspermum copticum indicating higher methane production than the control hay for this grass. The MRP of Chamaemelum nobile was more than 25%, indicating plants that reduce methane production more than 20 percent methane in comparison with control actually have ingredients to reduce methane.