Strategies to Mitigate Enteric Methane Emissions in Ruminants: A Review

Abstract

Methane is the main greenhouse gas (GHG) emitted by ruminants. Mitigation strategies are required to alleviate this negative environmental impact while maintaining productivity and ruminants’ health. To date, numerous methane mitigation strategies have been investigated, reported and suggested by scientists to the livestock industry. In this review, the authors will focus on the commonly practiced and available techniques expanding the knowledge of the reader on the advances of methane mitigation strategies with a focus on the recent literature. Furthermore, the authors will attempt to discuss the drawbacks of the strategies in terms of animal health and performance reduction as well as the concept of feed and energy loss, adding an economic perspective to methane emission mitigation which is in the farmers’ direct interest. As a whole, many factors are effective in reducing undesired methane production, but this is definitely a complex challenge. Conclusively, further research is required to offer effective and efficient methane production mitigation solutions in ruminants worldwide, thus positively contributing to climate change.

Methane emission, intake, digestibility, performance and blood metabolites in sheep supplemented with cupuassu and tucuma cake in the eastern Amazon

“…The addition of fat to the diet increases energy content and, more recently, has been studied for CH 4 mitigation due to the toxic effects on methanogenic ruminal microorganisms, increased carbon capture, and hydrogen sequestration for biohydrogenation ( 58 – 60 ). Fat causes a decrease in the population of methanogenic ruminal protozoa and an increase in biohydrogenation, serving as a sink for metabolic hydrogen and reducing its availability for the formation of CH 4 ( 5 , 61 , 62 ). However, the effectiveness of this inclusion in CH 4 reduction varies depending on the fatty acid profile of the ingredient, which makes studies with unconventional ingredients even more important ( 5 , 63 ).…”

Production of 17 strains of edible mushroom grown on corn stover and its effect on the chemical composition and ruminal in vitro digestibility of the residual substrate

“…Since enteric methane emissions are directly related to the amount and type of feed consumed, the increase in forage digestibility also has a direct effect on ruminant greenhouse gas emissions. Fermentation of fibrous feeds results in higher methane production and lower energy supply than concentrated feeds [ 29 ].…”

Management of Enteric Methane Emissions in Ruminants Using Feed Additives: A Review

“…The economic gains are immediate, and the climate benefits are more mid- and long-term. One must not forget that climate change exerts a negative feedback loop in livestock production (e.g., Palangi et al [ 19 ], and Lackner et al [ 5 ]), so reducing methane emissions is in the best interests of those who produce meat and milk with ruminant animals. It is also possible to claim carbon credits for enteric methane reduction.…”

“…However, further experiments are needed to establish the effects of yeast in mitigating CH 4 production in ruminants as responses may vary depending on yeast dosage, basal diets and forage/concentrate ratio. At this point, the reader is also referred to Palangi et al [ 19 ].…”

“…Hence, actions to minimize enteric CH 4 production and emission from ruminants not only limit the emission of GHG, but can also enhance production performance of the operations. Over the past few years, review papers and meta-analyses have been published on how different mitigation strategies influence CH 4 production in ruminants, e.g., Eckard et al [ 10 ], Cottle et al [ 11 ], Hristov et al [ 12 ], Broucek [ 13 ], Jeyanathan et al [ 14 ], Yáñez-Ruiz et al [ 15 ], McCauley et al [ 16 ], Min et al [ 17 ], Cardoso-Gutierrez et al [ 18 ], and Palangi et al [ 19 ]. Diet modification can be a good strategy for methane mitigation in ruminants.…”