The challenge

It’s generally taken as a given that cattle farming is unequivocally bad for the planet. The Food Climate Research Network has made it clear that livestock production, regardless of the species or rearing method, is a net contributor to global warming.

But the current approach to measuring that contribution is something of a blunt instrument. At present, carbon footprinting of herds relies on quantifying the total greenhouse gas emissions of the entire farm. What we don’t learn from that is whether there are significant differences in the impact of different species, or even individual animals, that could improve each farm’s environmental performance.

What we’re doing

We’ve been working with the world’s oldest agricultural research institute, Rothamsted Research, to more accurately measure the environmental impact of livestock farming.

At Rothamsted’s 63-hectare experimental farm in North Wyke, Devon, a team of researchers, led by Bristol Veterinary School’s Dr Taro Takahashi, have been collecting high resolution data over an extended period using both the standard model of footprinting and a new method that measures the contribution of each animal.

What we found is that the existing approach consistently underestimates the levels of greenhouse gas emissions because it fails to account for the impacts of the worst performers in a herd – cattle that are known to produce disproportionately large amounts of methane.

How it helps

While these findings look initially like bad news for cattle farming, they could drive some very positive actions.

In the short-term, we now have a technique for more accurately recording greenhouse gas emissions and greater accuracy is an important first step to better management.

Longer term, the insights from our new data suggest it may be easier to mitigate emissions from livestock than traditionally thought. The knowledge we’ve gained enables us to get better at selecting the right animals through the right screening methods and increase the value of cattle farming as part of a sustainable food production system. Establishing exactly what those animals and screening methods are is the intended output of the next phase of our work.