The in vitro gas production technique was used to evaluate effect of different plant powder combinations on rumen fermentation parameters and methane production. Neem (Azadiracta indica); Mehndi (Lawsonia inermis) and Eucalyptus (Eucalyptus globulus) plant parts were used for the preparation of different combinations (1:1) i.e Mehndi + Neem (T1), Neem + Eucalyptus (T2), Mehndi + Eucalyptus (T3) and Neem+ Mehndi + Eucalyptus (T4). The different combinations (20 mg) were incubated with in vitro substrate (200 mg, 50R:50C) and 30ml buffered rumen fluid for 24 h. Results show that methane production, protozoa population were reduced significantly on addition of T3. T3 also increase DDM (mg), propionate concentration and partition factor on incubation with wheat straw based diet. Among the all treatments, T4 reduced pH and protozoa population significantly. The present results demonstrate that plants powder combination is a promising feed additive in wheat straw based diet. They have the potential to modulate the methane production, dry matter digestibility, propionate concentration and microbial biomass synthesis
