Researchers have found that calculating individual livestock greenhouse gas emission figures and then aggregating the information can reduce standardised output levels compared to applying average herd emission scores. This method also identifies the more efficient animals for future breeding programmes.

A way of carbon footprinting pasture-based cattle systems by assessing the impact of individual animals has been developed by scientists from Rothamsted Research and the University of Bristol. Using data collected at the North Wyke Farm Platform (NWFP) in Devon, the study recorded the environmental impact of each animal separately, before calculating the overall burden of a farm.

The ability to identify “green” cattle within a herd – cattle that produce lower emissions per kilogram of liveweight gain – promises more sustainable farming, they report in the study published in the Journal of Cleaner Production.

In fact, the averaging method may actually underestimate the level of GHG emissions, as it fails to account for poorly performing animals which are known to produce disproportionally large amounts of methane through enteric fermentation.

 “Short-term, many carbon footprint estimates currently available are probably too low, which is clearly bad news for the industry,” notes Taro Takahashi, research scientist at North Wyke. “But long-term, this also means that mitigation of greenhouse gas emissions originating from ruminants could be easier than traditionally thought—if we are able to select the right animals through the right screening methods. This is precisely what we are trying to achieve at North Wyke.”

Professor Michael Lee, Head of North Wyke adds: “At Rothamsted, not only do we aim to advance knowledge on how to minimise negative impacts of agricultural production, as exemplified by the current paper, but also on how to optimise the positive contribution grazing livestock can bring to us as part of a well-designed food supply chain.

“Such aspects include the effective use of land unsuitable for growing crops; production of higher quality protein and more bioavailable micronutrients; improved animal welfare; prosperous rural communities and flood prevention. They all make up the bigger picture when looking for a sustainable future for food production.”