Fig. 3

Effects of breed, sex, diet, and age on the richness (a, b), evenness (c, d), and abundance (e, f) of rumen bacteria and archaea. The 16S rRNA gene copy numbers per milliliter of rumen sample were log10-transformed before statistical analysis. Values within each factor that do not have a common superscript are significantly different (P < 0.05) according to the Kruskal-Wallis rank sum test. The correlations between age and other indices were calculated using the Spearman’s rank correlation (ρ = correlation coefficient)