Deepa, K.Senthilkumar, S.Kalpana, K.Senthilkumar, R.P.Muralidharan, T.Suganya, T.Sasikumar, P.Sureshkumar, R.TANUVAS2017-09-042017-09-042016-042278-3687http://krishikosh.egranth.ac.in/handle/1/5810030296Sulphur hexafluoride (SF6) is the most common tracer gas used to estimate CH4 production from the ruminants. This technique relies on a constant release of SF6 from a bolus administered into the rumen of an animal. Gas samples are collected from around the nose and mouth of the animal via a harness and evacuated canister and these samples are then analysed using a gas chromatograph. The release rate of SF6 from the bolus and the ratio of SF6 to CH4 in the breath sample are used to calculate the CH4 emission from each animal. This method of estimating CH4 emissions has the advantage that individual grazing animals can be measured, as well as groups of animals simultaneously. It is also a relatively cheap method for measuring CH4 emissions, although the cost of purchasing a gas chromatograph capable of measuring SF6 in parts per trillion is considerable.en-USVeterinary ScienceAnimal NutritionArticle