Table 5. Rumen bacterial abundance at the phylum level in Holstein and Jersey steers with different levels of mineral supplementation

Phylum Holstein Jersey SEM p-value
Con NM HM Con NM HM Breed Treat B × T
Bacteroidetes 74.78 58.82 65.79 69.63 66.21 67.82 3.866 0.6871 0.1106 0.3591
Firmicutes 19.07 36.79 28.08 23.83 26.62 24.66 4.048 0.4277 0.1058 0.2732
Candidatus melainabacteria 1.24 0.40 1.09 1.33 1.54 1.72 0.266 0.0351 0.401 0.2889
Proteobacteria 1.20 0.56 0.97 1.01 1.03 1.25 0.298 0.4969 0.5659 0.5974
Tenericutes 1.19 1.42 1.44 1.60 1.70 1.95 0.398 0.2782 0.7965 0.9654
Spirochaetes 1.13 0.97 1.44 1.35 1.40 1.40 0.271 0.3912 0.6989 0.7138
Fibrobacteres 0.68 0.63 0.68 0.72 0.89 0.56 0.171 0.6841 0.7338 0.5889
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.