Table 1. Summary of selected methane mitigation studies conducted in Korea

Ingredient	Mitigation strategy	Measuring technique	Methane production	References
Feed approach	Feeding level	In vivo (respiration chamber)	Increase	[42]
	Forage:concentrate ratio	In vivo (LMD, respiration chamber)	Mixed response	[17,39]
	Feed ingredients	In vitro, In vivo (respiration chamber)	Feed ingredients specific	[41,43]
	Forage processing	In vitro	Decrease	[44]
	Feeding system	In vivo (respiration chamber)	Mixed response	[26,29]
	Fat or fatty acids	In vivo (LMD, GreenFeed system)	Decrease	[36,45]
	Crude protein	In vivo (LMD)	Decrease	[46]
Feed additives approach	Halogenated compounds	In vitro	Decrease	[47–49]
	Nitrate	In vitro	Decrease	[50,51]
	Seaweed	In vitro	Mixed response	[37,38,52]
	Direct-fed microbial	In vitro	Mixed response	[53–55]
	Plant extracts	In vitro, In vivo (LMD)	Mixed response	[2,56–60]
	Organic acids	In vitro, In vivo (respiration chamber)	Mixed response	[2,61]
	Minerals (clay, trace)	In vitro, In vivo (GreenFeed system)	Mixed response	[62,63]
	Glycerol	In vitro	Decrease	[64]
	Cordyceps militaris	In vitro	Decrease	[65]
	Spent coffee ground	In vitro	No response	[66]
	Enzyme	In vitro	Mixed response	[67]
	Detoxified sulfur	In vitro	Mixed response	[68]

LMD, laser methane detector.