Effect of feeding herbal extracts on methanogenesis in ruminants

A study was conducted to identify herbs or herbal extracts having potent methane reducing capacity and determine their optimum level of inclusion in dairy cattle ration. The herbs collected for testing were Acacia concinna pods, Emblica officinalis seeds, Allium sativum bulbs, Zingiber officinale rhizomes, Ferula assafoetida resin, Psidium guajava leaves, Terminalia chebula seeds and Azadirachta indica seed kernels.Two in vitro gas production experiments were carried. The first one was to screen eight herbs, their respective water extracts, water residues, methanol extracts and methanol residues along with control for their potency to reduce methanogenesis and first five ranked extracts were studied at different level. Validation of the results of the second in vitro gas production studies was carried out through an in vitro rumen fermentation experiment (RUSITEC) using complete feed. Compared to that of control all the herbal extracts / residues significantly (P0.05) lowered per cent methane production. Acacia concinna pods methanol residue was able to reduce methane production to a maximum. No alteration was observed in the per cent IVDMD for all the herbal extracts / residues.