Figure 1.

Methanogenic communities are metabolically active in the first days of life. Rumen fluids of 2‐day‐old and 3‐day‐old calves were sampled and monitored each day for methane production by GC. In addition, genomic DNA was extracted from these samples and archaeal 16S rRNA copy number was quantified. The dark grey bars represent the methane concentration measured for the 2‐day‐old calf and the light grey bars represent the methane concentration measured for the 3‐day‐old calf. The triangle and circle symbols represent the archaeal 16S rRNA copy number for the 2‐day‐old and 3‐day‐old calves, respectively. For each timepoint, at least 3 independent samples were analyzed for methane production and 3 technical repeats were subjected to qRT‐PCR analysis. Mean for each timepoint is plotted ± SEM.