Enteric Methane Production Potential of Non-Leguminous Forages

Abstract

The present study was undertaken to assess the methane production potential of multi-cut nonleguminous forages viz. rye grass and guinea grass harvested through four cuts using in sacco degradation and in vitro gas production (IVGP) procedures. Results revealed that irrespective of cuts, rye grass had higher (P<0.01) rapidly soluble fraction than guinea grass, with a reverse trend (P<0.01) for insoluble but potentially degradable fraction and rumen undegradable fraction (UDF). The rate for the latter was highest (P<0.01) for the younger grasses (I cut) and lowest (P<0.01) for the III cut. The rumen UDF of DM increased (P<0.01) with advancement of cuts. Rye grass had higher (P<0.01) effective rumen degradable protein (ERDP) and lower (P<0.01) rumen undegradable protein (RUDP) than that in guinea grass. The RUDP as % of CP was higher (P<0.01) in guinea grass than that in rye grass. Almost similar trend (P<0.01) was observed in the digestion kinetic parameters for NDF degradability. The IVGP data showed that irrespective of cuts, rye grass produced higher (P<0.01) net gas, lower (P<0.01) methane resulting in higher (P<0.01) partitioning factor. The ME (P<0.01) was higher in rye grass. The young forage from I and II cuts showed higher (P<0.01) net gas production as compared to III and IV cuts. The methane production increased (P<0.01), while digestibility of OM and NDF decreased (P<0.01) with the increase in number of cuts. The availability of ME varied from 6.78 (IV cut) to 8.66 (II cut). Rye grass produced higher (P<0.01) TVFA, acetate, propionate and butyrate than that produced by guinea grass. It was concluded that irrespective of cuts, rye grass had higher nutritional worth with lower methane production as compared to that produced by guinea grass. The methane production increased, while the digestibility decreased with the increase in number of cuts.