CAFRE farms lead the way in reducing ammonia emissions from beef and sheep enterprises

Outwintering cattle at the CAFRE Hill Farm Centre, Glenwherry

The College of Agriculture, Food and Rural Enterprise (CAFRE) is at the forefront of sustainable livestock farming, showcasing effective ammonia mitigation strategies at its two demonstration farms in Northern Ireland.

Both the Lowland Beef and Sheep Centre and the Hill Farm Centre are managed as educational platforms for students and farmers, highlighting best practice in beef and sheep production while addressing the growing need for environmental stewardship.

The Beef and Sheep Centre, situated on 130 hectares of grassland, supports around 100 suckler cows and 270 breeding ewes, with all offspring finished on site.

Meanwhile, the Hill Farm, which covers an expansive 960 hectares, is home to another 100 suckler cows and approximately 1,300 breeding ewes. Most of the lambs and all beef cattle from the Hill Farm are finished at the lowland site.

In a proactive effort to tackle agricultural emissions, both sites have been modelled using the National Ammonia Reduction Strategy Evaluation System (NARSES). This allows CAFRE to quantify nitrogen flow and assess the impact of different ammonia mitigation strategies.

Using 2022 data as a baseline, CAFRE has been able to model “what if” scenarios to evaluate how specific changes could benefit each farming enterprise in terms of ammonia output.

Ammonia emission sources for all the beef cattle at CAFRE in 2022.

Ammonia mitigation in action

CAFRE has already implemented a number of key strategies to reduce emissions:

• All slurry is applied using Low Emission Slurry Spreading Equipment (LESSE), reducing emissions by approximately 30%.

• All inorganic fertiliser used is stabilised urea, which lowers emissions by a further 15%.

• Two-thirds of slatted cattle accommodation at the Beef and Sheep Centre are fitted with comfort slat mats, contributing to lower emissions.

LECA being added to the slurry stores at the Hill Farm Centre

• An impermeable cover has been installed on a new above-ground slurry store, while three older stores were treated with Lightweight Expanded Clay Aggregate (LECA) in January 2025.

• At the Hill Farm, 20 suckler cows are outwintered to enhance breeding wader habitats, simultaneously cutting silage demand and reducing slurry storage needs.

• Extended grazing seasons are implemented where feasible, further lowering the environmental footprint.

• Housing, storage, and spreading of manure collectively account for around 70% of total ammonia emissions from cattle enterprises.

CAFRE noted that under an ideal scenario—where all flooring is low-emission and lower-protein diets are optimally matched to livestock needs—emissions could be reduced by an additional 14% beyond the current baseline.

Sheep enterprise insights

Sheep flocks at both farms present a contrast in emissions due to their different housing needs. While the lowland flock is kept outdoors, 80% of the Hill Farm flock is housed for around three months, leading to higher associated ammonia emissions.

Despite already using stabilised urea and outdoor grazing, options for further mitigation are limited due to climate conditions and land availability.

Housing and manure handling for the Hill Farm flock accounts for 43% of total ammonia emissions, but this is deemed necessary given the environmental context.

Summary: a path forward

Cows and calves at the CAFRE Beef and Sheep Centre, Antrim

CAFRE’s ongoing work highlights that meaningful reductions in ammonia emissions from beef and sheep farming can be achieved by implementing a combination of measures such as:

• Using Low Emission Slurry Spreading Equipment (LESSE)

• Applying stabilised urea

• Covering slurry stores

• Extending grazing seasons

These findings are invaluable for informing wider farm practice across Northern Ireland and beyond.

For more information on CAFRE’s initiatives, visit the Business Support section at www.cafre.ac.uk.