Feeding 3-NOP in Irish dairy systems
Hazel Costigan, Laurence Shalloo and Ben Lahart tell us about research at Teagasc Moorepark which shows that the inhibitor 3-NOP can reduce enteric methane emissions by up to 22% in dairy cows.
The majority of the agricultural sector’s total greenhouse gas emissions stem from enteric fermentation, a byproduct of feed digestion within the animal’s rumen. As such, there is an urgent need to develop solutions to reduce enteric methane output.
The inhibitor 3-nitrooxypropanol (3-NOP) has proven to reduce enteric methane output by up to 30% when fed indoors to dairy cows as part of a total mixed ration. However, no work has been conducted with the additive in Irish conditions with dairy cows.
Research at Teagasc Moorepark evaluated 3-NOP when fed to spring calving dairy cows across different scenarios. Results show that feeding 3-NOP to grazing lactating dairy cows after milking twice daily reduced enteric methane by 5%. This reduced output is due to the additive’s rapid metabolism within the rumen.
Slightly greater reductions (-11%) were noted indoors in non-lactating dairy cows when top-dressed onto grass silage twice daily. However, the greatest reductions (-22%) were observed when 3-NOP was mixed through grass silage using a mixer wagon and fed to non-lactating dairy cows, which is comparable to findings in international research. To demonstrate the application of 3-NOP at farm level, approximately 3,500 cows across 18 Teagasc Signpost dairy farms were successfully fed 3-NOP mixed with grass silage in the winter of 2023/2024.
Ultimately, this research can be used to guide policy on the mitigation potential of 3-NOP across different scenarios in the Irish dairy industry. This enables more accurate calculations of enteric methane output from dairy cows when fed 3-NOP and demonstrating its application at commercial farm level.
In any given year, the impact of Teagasc research is a combination of the continuing impact of past research and the new impact of recent research. The most recent publication highlights some of these new impacts achieved in 2023.