NOP (2.02 vs. 2.36; P = 0.04) compared with CON. No
treatment effects were observed for other VFA. Total
methanogen copy numbers were reduced with feeding
of NOP (0.95 vs. 2.69 × 108/g of rumen digesta; P
= 0.001) compared with CON, but total bacteria and
protozoa copy numbers were not affected by treatment.
A tendency was observed for a positive relationship
between methanogen count number and methane emissions
normalized for DMI (P = 0.08; y = 8.89 + 2.05
× 108x, r2 = 0.16).