A major study supported by the National Sheep Association (NSA) has found that sheep grazing on moorland in the Yorkshire Dales emit lower levels of both methane and carbon dioxide than those grazing improved grassland lower down in the valley.

The findings come from Forage for CH4nge, an Innovate UK-funded research project supported by the NSA, which brought together farmers and scientists to better understand how forage type, landscape and traditional sheep breeds influence the environmental footprint of upland sheep farming.

The project measured greenhouse gas emissions from native Swaledale ewes and commercial Texel-cross ewes grazing different forage types across the Yorkshire Dales National Park. Results showed that sheep grazing on unimproved moorland forage produced significantly lower methane and carbon dioxide emissions than those grazing improved (treated, seeded and/or fertilised) or herb-rich grassland.

NSA worked alongside project partners including the Game & Wildlife Conservation Trust (GWCT), UK Agri-Tech Centre, Scotland’s Rural College (SRUC), the Yorkshire Agricultural Society and local farmers to ensure the study delivered practical, farmer-focused evidence relevant to the future of upland sheep systems.

The study found that native Swaledale ewes produced less methane overall than Texel-cross ewes, largely due to their smaller body size. When methane emissions were adjusted for liveweight, there was little difference between the two breeds. However, sheep of both breeds produced more methane per day when grazing improved grassland compared to herb-rich grassland or moorland forage.

Native Swaledale ewes also produced less carbon dioxide than crossbred ewes, even after adjusting for weight. For both breeds, carbon dioxide emissions were higher when grazing improved and herb-rich grasslands than when grazing moorland.

The three forage types studied reflected typical upland systems. Improved grassland consisted of fertilised and reseeded ryegrass leys designed to maximise yield. Herb-rich grassland was unimproved pasture that had received no fertiliser or farmyard manure for more than 30 years. Moorland forage comprised unimproved rough grazing including heather, bilberry and other upland shrubs on higher ground.

NSA Project Manager Nicola Noble says: This study provides crucial evidence to help demonstrate the current and future importance of sustainable upland sheep farming. It is great to finally be able to share these results after almost a year and a half’s work on this project.”

A total of 120 sheep, including 60 Swaledales and 60 Texel-crosses, grazed one of the three forage types. Methane and carbon dioxide emissions were measured using mobile Portable Accumulation Chambers (PAC) at a farm near Leyburn, North Yorkshire, with individual sheep monitored for 50 minutes under carefully controlled, low-stress conditions. Liveweight and body condition score were also recorded to support accurate comparisons, before sheep were returned to grazing.

The study also highlights the wider climate value of upland landscapes. Well-aerated moorland and upland grassland soils can act as methane sinks, providing ideal conditions for methanotrophic bacteria to break methane down in the soil.

NSA Policy Manager Micheal Priestley adds: “The sheep sector has committed to reaching net zero by 2040, and reducing methane will be part of that journey, alongside improvements in genetics, nutrition, flock health, efficiency and reduced reliance on fossil fuels. Sheep farmers already play a vital role in managing our uplands, supporting biodiversity and producing highly nutritious food, and this research helps demonstrate how those roles can go hand in hand.”

Lead farmer involved in the work, Adrian Thornton-Berry, says the project shows how native breeds can help deliver environmental benefits while supporting viable farming businesses. “Forage for CH4nge is about showing that farmers are key to a sustainable future for Britain’s uplands. By working with native breeds like the Swaledale, we can farm these sensitive landscapes in a way that protects them for future generations.”