Strategies Used to Reduce Methane Emissions from Ruminants: Controversies and Issues

Abstract

Methanogenesis plays a crucial role in the digestive process of ruminant animals. During this process, methanogenic archaea produce methane as a byproduct of their metabolism. However, the production of methane by ruminants is also a significant contributor to greenhouse gas emissions. Methane is a potent greenhouse gas that has a 28-fold greater global warming potential than carbon dioxide. Around 15% of all anthropogenic greenhouse gas emissions are generated by livestock. Therefore, reducing methane emissions from ruminant livestock is an important goal for reducing the environmental impact of agriculture. There is a variety of strategies that can be used to reduce methane emissions, including dietary modifications, genetic selection, microbiome manipulation, and feed additives, such as plant secondary metabolites, methane inhibitors, lipids, essential oils, and algae. The main and important objective of this paper is to critically discuss the current strategies proposed to reduce methane emissions from livestock. Though many strategies, such as chemical intervention, have remarkably reduced methane emissions from ruminants, their usage remains unappealing because of health and safety concerns as well as consumer decisions. Hence, genetic animal selection and biological feed additives, such as probiotics and secondary plant metabolites, have emerged as promising techniques for mitigating enteric methane emissions. These strategies are highly promising, but more intensive research is needed to validate these approaches and assess their effectiveness in reducing methane production by ruminants.

The Effect of Saponite Clay on Ruminal Fermentation Parameters during In Vitro Studies

“…The digestion process in ruminants produces gases as a byproduct of metabolism. The limitation of gas emissions and, in particular, CH 4 production is highly desirable [ 4 ]. However, reducing CH 4 emissions can negatively affect the efficiency of feed use efficiency [ 59 , 60 , 61 ].…”

“…Furthermore, the latest report published in April 2023 by the Intergovernmental Panel on Climate Change reported that agriculture accounts for 22% of global greenhouse gas emissions, rendering the agricultural sector one of the leading contributors to global warming [ 2 , 3 ]. Different strategies, such as dietary modification, genetic selection, microbiome manipulation, and feed additives, such as plant secondary metabolites, CH 4 inhibitors, lipids, essential oils, and algae, are used to reduce the enteric emissions of gases like CH 4 or carbon dioxide during the production of food products [ 4 ]. The general importance of minerals in the body is known and indisputable.…”

Alternative Approaches to Feeding Small Ruminants and Their Potential Benefits

“…Methanogenesis has been playing a significant role in digestion, producing methane as a byproduct of metabolism in ruminant animals, and this process has been a significant contributor to greenhouse gas emissions [ 52 ]. Various mitigation strategies have been developed to reduce methane (CH 4 ) emissions, including dietary modifications involving lipids, essential oils, and algae [ 53 , 54 ].…”

“…However, factors such as the physiological stage of the animal, the composition of the basal diet’s lipids and other nutrients, and the fatty acid profile of the supplemental oil can influence the maximum oil inclusion in ruminant diets. High lipid concentrations (>6% DM) in feed can reduce feed and fiber digestibility, potentially increasing OM [ 52 ].…”

β-Dicarbonyls Facilitate Engineered Microbial Bromoform Biosynthesis

“…Methane, a potent greenhouse gas with 28× the global warming potential of CO 2 , is a critical target for reduction given this compound's high global warming potential. , Agricultural production of ruminant livestock is responsible for 24% of global methane emissions. − Methane has a short atmospheric lifetime (8.6 years), so effective mitigation strategies could have a large impact in a relatively short period of time. Consequently, the agricultural sector faces an urgent challenge to reduce ruminant methane emissions, especially with an anticipated 80% increase in demand for beef by 2050 .…”