Quantitative analysis of ruminal methanogenic microbial populations in beef cattle divergent in phenotypic residual feed intake (RFI) offered contrasting diets

Table 3 Effect of phenotypic RFI and diet on ruminalmethanogen populations ¹

Items	RFI			Diet³			Significance⁴
Items	H	L	SED	HF	LF	SED	RFI	Diet	RxD
Methanogens¹	0.07	0.08	0.010	0.07	0.09	0.010	0.71	0.01	0.08
Methanosphaera stadtmanae ²	0.36	0.37	0.069	0.09	0.64	0.069	0.44	<0.0001	0.68
M smithii ²	0.32	0.25	0.057	0.14	0.43	0.057	0.29	<0.0001	0.33
M ruminantium ²	0.18	0.29	0.089	0.04	0.43	0.089	0.65	<0.0001	0.92

¹Methanogens measured as a proportion of total estimated rumen bacterial 16S rDNA, relative quantification = 2^{-(Ct target-Ct total bacteria).}
²Methanogen spp. measured as a proportion of total estimated rumen methanogen 16S rDNA, relative quantification = 2^{-(Ct target-Ct total methanogens).}
³Diet = HF = high forage (grass silage), LF = Low forage (maize silage (30):concentrate (70)).
⁴Significance values for transformed data. Back transformed means presented for clarity. R = RFI, D = DIET.

ISSN: 2049-1891