Feeding Strategies to Mitigate Enteric Methane Emission from Ruminants in Grassland Systems

Area of Science:

• Agricultural Science
• Environmental Science
• Animal Science

Background:

• Ruminants contribute significantly to global anthropogenic methane emissions (around 30%).
• Enteric methane abatement is crucial for reducing the environmental impact of livestock farming.
• Effective strategies for grazing ruminants are less explored than those for confined animals.

Purpose of the Study:

• To review nutritional enteric methane abatement practices specifically for ruminants under grazing conditions.
• To identify effective grazing management and supplementation strategies for methane reduction.
• To assess the applicability of existing research to real-world grazing systems.

Main Methods:

• A comprehensive literature search identified 1548 relevant research articles.
• Articles were categorized into non-experimental, in vitro, in vivo confined, and in vivo grazing studies.
• Methane abatement strategies for grazing systems were classified into grazing management and supplementation practices.

Main Results:

• Only 9% of reviewed studies focused on grazing conditions.
• Decreasing pre-grazing herbage mass reduced methane emission per product unit.
• Lipid supplementation demonstrated potential for methane reduction in grazing ruminants, though other supplementation and grazing practices yielded mixed results.

Conclusions:

• There is a significant knowledge gap in methane abatement research for grazing ruminants.
• Lipid supplementation appears promising for reducing enteric methane in grazing systems.
• Further research and implementation of tailored grazing and supplementation strategies are essential for sustainable ruminant production.