Reduce emissions from ruminant livestock
Scottish Government, farmers and research institutes should work together to accelerate advances in ruminant livestock selection and breeding; include reducing methane emissions in breeding goals, and encourage uptake of best practice.
Two innovations – effective feed additives and low methane breeding strategies – offer to weaken the link between methane emissions and current levels of production of meat and milk from ruminants.
Cows and sheep produce methane as part of a digestive system which allows them to turn human-inedible grass and by-products into milk, beef and lamb. This digestive system contains a huge diversity of micro-organisms.
Because methane is a much more powerful greenhouse gas than CO2 this accounts for around 3.7MtCO2e of emissions – about half of the total agricultural emissions in Scotland.
Some individual cows and sheep have a population of micro-organisms which produce much less methane than others because they produce less surplus hydrogen for the methane-producing bacteria to use. This is not a difference between breeds but between individual animals. Researchers have now found a reliable and practical way to analyse a sample of rumen microbes from live cattle to predict that animal’s methane performance.262
Much of this difference is passed on to calves and lambs, opening up the possibility of breeding low-methane animals. This is already starting to happen with sheep breeding in New Zealand and with cattle breeding in the Netherlands.
By 2045 a reduction of 50% on current levels is possible through low-methane breeding and widespread adoption of feed additives. There is a possible future for sustainable high welfare, low opportunity cost ruminant livestock systems using grass and by-products to produce human edible protein, while enhancing biodiversity and soil carbon sequestration.
For further information:
- Farming for 1.5: from here to 2045, 2021, https://www.farming1point5.org/reports
Friggens, NL, Hester, et al. (2020) Tree planting in organic soils does not result in net carbon sequestration on decadal timescales. Glob Change Biol.; 26: 5178– 5188. https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15229