Dietary CNO greater than or equal to 2.7%, dry
basis, reduced eCH4
emissions in lactating dairy cows
during habituation to CNO treatment. Reduction in
eCH4
emissions was greater during the first half than
the second half of the day. Increased CNO concentration related to an expedited onset of eCH4
and eCH4
/DMI mitigation, but also of DMI, SCMY, and milk fat
yield reduction. The responses in eCH4
emissions and
DMI were rapid and precipitous with CNO4, but more
delayed and progressive with CNO3.3 and especially
with CNO2.7. Moreover, 2.7% or more of dietary CNO
depressed total-tract NDFD during wk 5 of the experiment.