Increasing the inclusion rate of 3-nitrooxypropanol and dietary grain content reduces methane yield in feedlot cattle fed steam-flaked wheat and barley-based diet

Directly inhibiting methyl-coenzyme M reductase, a key enzyme in the methanogenesis pathway, with a methanogenic inhibitor like 3-nitroxypropanol (3-NOP) is effective in reducing enteric CH₄ in ruminants (Almeida et al., 2023). No studies have examined the effects of 3-NOP on CH₄ emissions in Angus steers while increasing the grain content in a feedlot diet. Thus, the aim of our study was to examine how the combination of 3-NOP level and grain content in the diet affects enteric CH₄ emissions in feedlot steers fed steam-flaked wheat and barley-based rations, with the hypothesis that CH₄ emissions would decrease with increasing levels of 3-NOP and dietary grain content.