With rising environmental awareness, concern has been placed on greenhouse gas (GHC) emission. Amongst various GHCs, methane (CH4) is around 20-30 times more damaging than CO₂ in global warming. Ruminants are major producers of methane, taking up 15-25% of global emission of methane. It is ruminal methanogens that produce methane during rumen fermentation in ruminants, which causes the loss of about 2–12% of gross energy intake of the host.

It is held by many researchers that different types of microflora within the rumen are tightly bound up with different feed efficiencies and production performances of ruminants. Some previous investigations have further inferred that it would be practicable to modulate the rumen microbial community at the early period of rumen development, and early dietary regulations of animal have a greater and more lasting effect than those occurring later in life.

Similarly, it could be possible to reduce methane production of ruminant husbandry in the long term by early manipulations on methanogens in young ruminants. Therefore, it is of great significance to explore the evolution of methanogen colonization as the rumen develops, and seek strategies in shaping the methanogenic community.

Recently, a study performed by scientists from the Institute of Subtropical Agriculture of Chinese Academy of Sciences and the Lethbridge Research Centre (Agriculture and Agri-Food Canada) clarified the changes of ruminal methanogen community during rumen development (from 1 d to 60 d after birth) in Xiangdong black goats (a local breed of goat in Changsha), and how rhubarb supplementation affected the methanogenic community. The study was published in Scientific Reports.

Researchers used RNA isolated from rumen samples instead of DNA since RNA can help to gain insights into real-time activities and metabolic potential of ruminal methanogens. RT-qPCR and 16S rRNA amplicon sequencing both based on RNA were performed to investigate methanogenic population in the rumen of black goats, indicating that Methanobrevibacter, Candidatus Methanomethylophilus, and Methanosphaera were the top three genera across four different fractions.

The discrepancies in the distribution of methanogens across four fractions and various fluctuations in abundances among four fractions according to age were noted, respectively. The addition of rhubarb significantly reduced the abundances of Methanimicrococcus spp. in four fractions on 50 d, but did not alter the methanogen community composition on 60 d.

In summary, this is the first study that uses RNA based samples to investigate the development of the potentially active methanogens in the rumen. It contributes to the knowledge of the development of the rumen methanogen community and relevant modulation, and mitigation of methane production during rumen development.