Methane gas has a very significant contribution to the increase in greenhouse gases (GHG) globally. The livestock sector, especially ruminants, causes the issue of increasing GHG concentrations. The chapter presents the issue of reducing methane gas production from cattle. Various experiments to reduce methane gas production from ruminants have been carried out and have shown varying results. This series of results of the author\'s research on reducing methane gas production in livestock in beef cattle based on agriculture by-product to animal feed is addressed with this background. Agriculture by-products such as oil palm fronds and rice straw can be used to feed beef cattle in Indonesia. However, agriculture by-product as animal feed can reduce feed efficiency and increase methane gas production due to the high lignin content. Therefore, various alternatives are carried out to optimize the utilization of this plantation waste. One of them is the use of feed additives and methanogenesis inhibitors. The author\'s series of research using feed additives (direct-fed microbial) and various methanogenesis inhibitors (plant bioactive compounds and dietary lipids) were tested to determine their effect on nutrient digestibility and methane gas production in feed based on plantation waste. Experiments were carried out in vitro and in vivo on various types of ruminants. Plant bioactive compounds such as tannins are proven to reduce methane production through their ability to defaunate in the rumen. Tannins may also have direct effect on methanogens and indirectly by reducing fiber digestion. In addition, direct-fed microbial (DFM) feed additives such as Saccharomyces cerevisiae, Bacillus amyloliquifaciens, and Aspergillus oryzae can be used in ruminants to increase livestock productivity. Furthermore, virgin coconut oil as a dietary lipid contains medium-chain fatty acids, mainly lauric acid, which can inhibit the development of ciliates of protozoa and methanogenic bacteria that produce methane in the rumen.
Part of the book: Animal Feed Science and Nutrition