Comparison of relative abundance of different microbial populations in low and high CH₄ yield sheep. (A) Relative abundance of microbial domains in low and high CH₄ yield sheep. (B) Relative abundance of methanogenic and nonmethanogenic archaea in low and high CH₄ yield sheep. (C) Relative abundance of classes of CH₄-producing Euryarchaeota in low and high CH₄ yield sheep. (NS) No statistical difference in Wilcoxon rank-sum test in each subgroup.