This review analyses methane emissions from dairy farms due to enteric fermentations and use of different feed additives as a strategy to control them. CH4 is a product that forms during the fermentation of food in the rumen of ruminants and on average represents a 7% loss of the energy ingested by the animal. CH4 is also a potent greenhouse gas. Various approaches have been studied in many countries with the aim of reducing methane emissions of digestive origin like the use of biotechnologies to modify the microbial ecosystem. This include selection of rumen micro-organisms through the elimination of protozoans or the inoculation of exogenous bacterial strains, vaccination against methanogenic micro-organisms, etc. or use of new food additives like plant extracts, organic acids, etc. and are theoretically promising paths. Their application is however still not known because trials are being performed mainly in vitro. This article focuses on reducing methanogenesis by adjusting the composition of the feed distributed to animals.
CH4; methanogens; ruminants; energy loss; greenhouse gas; reduction approaches