The aim of the current study was to evaluate the efficacy of herbal plant oils on methane reduction and as rumen fermentation modulators in different diets by using in vitro gas production technique. Garlic (Allium sativum, GO), Eucalyptus (Eucalyptus globules, EuO) and Neem (Azadirachta indica, NO) oils were tested for their inhibitory action on methane production on HFD, MFD and LFD. Methane was done by Gas Chromatography and it has been shown that supplementation of all three oils, GO reduces the maximum (55.06%) methane emission in LFD as compared to that of control. Digestibility of dry matter also decreased due to GO supplementation, which may affect the production of volatile acid production.
