W7 Methane mitigation by feed supplements
Authors: John Newbold, Carol-Anne Duthie, Andrew Moxey and Steven Thomson
Ref: RESAS/005/21 – W7
The Report is available in the supporting documents of this publication.
This summary draws on Duthie et al's (2022) report to Defra on Methane Inhibiting Livestock Feed Supplements: Review of Net Impacts, Barriers to Success and Consumer Acceptance.
The potential of feed supplements to reduce emissions intensity by inhibiting enteric methane production from ruminant livestock has attracted considerable attention. A variety of potential supplements have been investigated, varying in their origins and composition. For example, 3-nitrooxypropanol (3-NOP), Essential Oils, Probiotics, Nitrate, and Seaweed.
Widespread adoption of such methane inhibitors will be dependent upon their availability, efficacy, and acceptance by farmers. However, none currently have the necessary regulatory approval, supply-chain infrastructure and appropriate incentives in place for widespread commercial release and adoption.
One (Agolin Ruminant, an existing but rebranded essential oils product) is currently available in the UK – but its regulatory approval does not as yet relate explicitly to its potential for reducing enteric methane.
One other (Bovaer 10, a branded 3-NOP product) is authorised for use to reduce methane emissions from dairy cows in the EU, but is not yet authorised in the UK.
Reported emission reductions vary widely from c.5% to over 50%, reflecting challenges in measurement but also variation across different supplements and farming systems.
Practical difficulties in ensuring individual animals receive correct daily dosages are likely to result in lower emission savings than those achieved under experimental conditions. Inclusion of supplements in pre-mixed concentrate-based feed rations may be feasible for some farming systems, but alternative delivery mechanisms (e.g., boluses, feed blocks/tubs/licks) may be required for (especially) forage-based systems.
Most feed supplements designed to reduce methane have little or no beneficial effect on animal performance (and therefore farm revenue). Some may have negative effects on perceived product quality (e.g., taste). Regulation, direct payment and/or subsidy (as well as advice and training) will be required to incentivise adoption.
Cost data are scarce but suggest £0.02 to £0.20 per animal per day. For comparison, typical daily feed costs for dairy cows are currently about £4.00 and for finishing beef cattle the currently range from £2.80 - £4.00 depending on the intensity of finishing system.
Further research is needed into efficacy, to establish robust verification of emission savings to inform both on-farm and policy decisions, and to counter general scepticism about the accuracy and consistency with which farming's net emissions are portrayed.
Technical, market and regulatory developments in this field are rapidly evolving and hence briefing notes would benefit from regular (e.g., quarterly) updates.
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