Table 4. Feasible mitigation options to control the sources of GHG emissions

Emission sources	Mitigation options	Measures	Mechanisms	Reference
Enteric fermentation	Plant bioactive compounds	Tannins	Changing the VFA proportions in ruminal fluid results in a reduction in fermentation	[80]
	Dietary lipids		Increasing fat concentration decreased mean ruminal pH and increased the duration of pH below 6	[81]
	Concentrate inclusion		Increased starch intake reduces ruminal pH, affecting DM and NDF digestibility and favors propionate rather than acetate in the rumen	[82]
	Improving forage quality and management		With lower quality of forage, the fiber contents increase, thus higher CH4 production occurs	[83]
	Processing of low-quality feeds	Reducing herd size	Improving nutritive value of low-quality feeds could increase productivity, thus reducing herd size and concomitant reduction in herd GHG emissions	[31]
		Macro-supplementation (when deficient)	Improve animal performance by supplementing available N for microbial protein synthesis in the rumen and balancing rations for macro and micro nutrients	[31]
Manure management	Dietary manipulation and nutrient balance	Reduced dietary protein	Lower urea-N in urine and TAN results in lower NH3	[84]
	Housing	Biofiltration	High porosity of bio filter media containing a mixture of organic and inorganic media allowed sufficient oxygen transfer for methane oxidation	[85]
		Manure system
	Manure treatment	Anaerobic digestion	Manure composition changes. NPK are transformed from organic forms to inorganic forms, whereas C is transformed to biogas for use as fuel	[86]
	Manure storage	Decreased storage time	When storage time is decreased and manure is applied directly to land, less CH4 occurs after land application of manure	[31]
	Manure application	Timing of application	Application of manure on land before rain can decrease emission spike	[31]
		Soil nutrient balance

Adopted from Hristov et al. [31] with the following criteria: enteric fermentation (effectiveness applicable to all regions), manure management (effectiveness on a minimum of two gases -CH₄, N₂O, NH₃-, applicable to all regions).