Livestock is one of the longest sources of methane emission with 80 – 115 million tons produced per year, equivalent to 15 – 20% of total anthropogenic methane (IPCC, 2001).
Ruminants are major contributors to biogenic methane formation. It has been estimated that preventing methane formation from ruminants would stabilized atmospheric methane concentrations and improve animal performance (Johnson and Johnson, 1995). The global cattle population is responsible for 73% of methane emissions of all livestock and methane produced during ruminal fermentation represents a loss of 2-15% of gross energy intake and may also known as a great contributor to global warming which is a primary environmental concern world wide (moss et al., 2000).
Recent studies have shown that plant secondary metabolites such as tannin, essential oils and Saponin at lower concentration could be used to manipulate rumen fermentation favorably.
Plant bioactive (PB) or plant secondary compounds are chemicals synthesized in plants but are not involves in the primary biochemical processes of plant growth but acts as a protective agents against predators.
Plant extracts from spices and medicinal plants with high concentrations of secondary compounds such as tannin and saponin are good candidates for reducing ruminal methanogenesis (Teferedegne, 2000).
Therefore altering dietary formulation can have great impacts on environmental performance from dairy operations.
Many studies have reported that feeding forages containing tannin decreases ruminal protein degradation (Min et al., 2003) and also have the potential to reduce enteric CH4 emissions (Carulla et al., 2005; Animut et al., 2008).
It was also reported that saponins or saponin-like substances had the potential to suppress the methane emission, reduces protozoa counts and change fermentation patterns (Hristov et al., 1999). At appropriate dose tannin and saponin decreases methane production and increases the efficiency of microbial protein synthesis (Min et al., 2003).
Therefore this experiment is planned to ascertain the effect of plants extracts such as tannin and saponin from different species and their effect on methane are other in vitro fermentation parameter.