Variability in fermentability and methane production in lucerne (Medicago sativa)

Summary

Methane is the dominant agricultural greenhouse gas in Australia, the majority of which arises from enteric fermentation in ruminant domestic livestock. Lucerne is the most widely grown and important forage legume in Australia. Lucerne hay production in Australia is estimated alone to be worth over $ 280m pa and supports dairy, beef, sheep and horse production, as well as a growing export market.
Lucerne is widely used as a benchmark species to other forages or diets for their potential to mitigate methane (CH4). However, there are only very limited data available as to the effect of lucerne genotypes on CH4 production. Practical tools for graziers to reduce methane emissions from extensive livestock production systems are extremely limited and few practical and cost-effective options for significant and persistent abatement have been developed. Evaluation of the amount and distribution of genetic diversity among accessions can enhance the genetic exploitation of lucerne by plant breeders. Increased knowledge and understanding of the potential of lucerne to decrease ruminal methanogenesis will ultimately assist producers in their ability to reduce greenhouse gas emissions, improve animal production and importantly improve farm profit.
In this project, an in vitro rumen batch culture study was completed to compare the effect of Lucerne genotypes and the effect of physiological maturity on CH4 production.
Results to date suggest there is significant genetic variation in the chemical composition of lucerne. The implications demonstrate the potential to achieve a significant reduction in energy loses from the livestock industry.​