Table 7. Rumen archaeal abundance at the genus level in Holstein and Jersey steers with different levels of mineral supplementation

Methanogen Genera	Holstein			Jersey			SEM	p-value
	Con	NM	HM	Con	NM	HM		Breed	Treat	B × T
Methanobrevibacter	60.88	72.99	57.30	82.04	62.90	58.17	5.843	0.4348	0.1005	0.0651
Methanomassiliicoccus	27.53	15.74	34.57	14.20	33.20	37.75	5.668	0.6271	0.0608	0.0715
Methanosarcina	7.28	7.22	4.80	0.07	0.05	0.00	0.733	< .0001	0.5314	0.5615
Methanobacterium	1.21	1.38	1.10	0.33	0.45	0.45	0.354	0.0348	0.9264	0.9372
Methanosphaera	2.01	2.24	1.68	1.99	1.31	1.31	0.381	0.2366	0.5218	0.5841
Methanimicrococcus	0.67	0.40	0.33	0.61	0.43	0.38	0.172	0.9709	0.2971	0.9475
Methanomicrobium	0.37	0.01	0.20	0.72	1.41	1.87	0.452	0.0373	0.7141	0.5183

Con, only TMR (without mineral supplementation); NM, TMR + NRC recommended concentration of mineral supplementation (Se 0.1 ppm + Zn 30 ppm + Cu 10 ppm)/kg DM; HM, TMR + higher than recommended concentration of mineral supplementation (Se 3.5 ppm + Zn 350 ppm + Cu 28 ppm)/kg DM.
TMR, total mixed rations; NRC, National Research Council; DM, dry matter.