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Feeding 3-NOP in Irish dairy systems

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.

This article first appeared in Teagasc Research Impact Highlights 2023, read more from the publication here

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.