Opinion: Cuts in livestock emissions must be properly recorded

The 30% methane reduction pledge made at the COP26 climate change conference in Glasgow in 2021 is still alive and kicking, and the UK cannot deliver on this goal without agriculture contributing to the challenge.

The focus on methane has been implemented to protect the world from a reduced ability to curb the high use of fossil fuels, which are at the core of climate change.

Novel interventions – including feed additives and genetics – that determine the profile of the rumen biome and act directly on rumen function to reduce enteric methane emissions have the potential to scale back emissions.

See also: How livestock producers can cut their carbon footprint

However, at present, the official inventory system is blind to their impact. The inventory must be upgraded to factor in the value of new, validated science and genetic interventions.

The mismatch between new science and agreed carbon accounting standards is a barrier to progress.

Health gains

Animal health interventions, which often generate a positive cost benefit, are different. Health gains improve physical production and are therefore captured by the current inventory.

As we stand today, progress on animal health provides an immediate route to recorded emission reductions that count at both farm and international level.

We know that reducing the prevalence of key endemic diseases – such as sheep scab and bovine viral diarrhoea – will provide immediate production gains on farms, while also reducing the carbon cost of ruminant production. 

However, there is a significant range of other conditions that determine total emissions from the national flock and herd.

All conditions that limit growth rates or food conversion efficiency directly influence emissions from ruminants, while conditions that reduce the productive life of breeding stock – resulting in premature or involuntary culling – also place a heavy emissions burden on breeding systems.

Efficiency priorities

Parasitic diseases, reproductive failure, lameness, respiratory disease, Johne’s disease and the iceberg diseases of sheep are all industry production efficiency priorities that also determine the rates of emissions from the sector.

Ruminant Health & Welfare’s report – Acting on methane – turns the spotlight on production diseases that define greenhouse gas emission levels.

It maps out some of the quantifiable production constraints caused by poor animal health, estimating that a 10% reduction in greenhouse gas emissions from livestock is feasible through achieving a high-health status across the national herd and flock, with further reductions possible through changes to breeding and feeding systems.

More recent studies have shown that gastrointestinal parasites in lambs lead to a minimum 10% increase in greenhouse gas emissions, while liver fluke infection adds an extra 19 days to the time to slaughter in cattle, adding 2% to the greenhouse gas footprint of those cattle.

Johne’s disease is estimated to increase greenhouse gas emissions by 25% per litre of milk produced, and by 40% per kg of beef produced.

Improving health

Improving ruminant health is therefore an immediate mitigation measure farmers can focus on to reduce the emissions of livestock.

Quantifying this is important at both farm and national level, and accurate carbon accounting systems are a vital baseline and management tool for low-carbon food production.

Yet, a year on from the headlines of COP26 there has been little progress in validating a range of recognised tools to manage emissions levels from ruminants, or to develop assured monitoring and recording systems that are fit for purpose.

Without even modest investment from government, the 2030 methane emission reduction targets look increasingly unattainable.