Journey To Net Zero Emissions in Dairying
16 May 2025The business C Murchie & Sons is located outside the village of Blackwaterfoot on the island of Arran, and is owned and operated by John Murchie, who farms at Tigheanfroach with his wife and daughter. John has the last dairy farm on the island and produces milk for the local Arran Dairies, primarily for ice-cream and milk sold in vending machines across the island. The farm is home to a modest herd of traditional Holstein cattle and John finishes steers and sells heifers not retained for the main milking herd. The business also takes on wintering sheep over the housed period to manage grass and has a handful of semi-natural habitats and features that also influence overall management.
The farm itself extends to just shy of 50 hectares of permanent land, made up mostly of improved pasture, with isolated pockets of wetland, rush pasture and scrub. The farm is located on the eastern bank of the Black Water, an important watercourse on the island and also has a significant number of intermediate hedges. It takes two cuts of silage annually and grazes the milking herd across a set stocked grazing platform. John also utilises seasonal grazing for youngstock and two nearby businesses. The Arran Dairies processing unit is located in Brodick, some 11 miles from the farm and milk is collected on a daily basis - Arran Dairies has supported John since First Milk withdrew from the island some years ago.
A self-described carbon sceptic at the beginning of his journey, John viewed carbon auditing as a box-ticking exercise but nevertheless came on to complete his first audit in 2021 and since then the farm has completed a further two audits, including the most recent, covering 2024. John originally agreed to carbon audit the farm due to the available funding support from FAS and saw it as an opportunity to benchmark his performance against conventional dairies on the mainland, with potential to make improvements, cut costs and boost productivity. John has also participated in the former Rural Priorities Scheme and a natural capital baselining trial, again, seeing them as opportunities.
Fat And Protein Corrected Milk
The term Fat and Protein Correct (FPC) milk is used to standardise milk production measurements by adjusting for the fat and protein content, which are key components of milk solids. Fat and protein levels are significant because they influence both the economic value of milk and the carbon footprint associated with its production.
By using FPC milk as a metric, comparisons can be made more accurately between farms or production systems, accounting for variations in milk composition rather than just raw volume. This is particularly relevant in carbon auditing, as emissions are often assessed in relation to the quantity and quality of milk produced.
Key Findings
- Actions to improve carbon footprints and to reduce emissions are often different and in competition with one another.
- Improvements happen largely inside the cow, whether that is the quality of milk she is producing or the quality of feed she is digesting.
- Low stocking densities mean increased opportunities to improve grassland utilisation, cropping and scope for carbon sequestration.
Action Summary
Since engaging with Net Zero Arran in 2021 the business has completed three carbon audits, the results of which have been summarised in the charts in this report.
| What has worked? | Rationale |
|---|---|
| Investment in high quality nutrition, including home-grown forage and purchased feed | With a cap on milk production for ice-cream and the vending machines, the farm must focus on quality over litres produced. The improvements to butterfat and protein levels in 2023 were the best across the three audit years and resulted in the lowest carbon footprint for milk (1.63 kg CO2e per kg FPC milk output). |
| Making more use of slurry and dung and more strategic application of inorganic fertilisers and alternatives | Driven in part by the support from the Sustainable Agriculture Capital Grant Scheme and historically high inorganic fertiliser prices, a combination of necessity and precision application meant that the farm was able to cut fertiliser use while maintaining silage production and quality. |
| Maximised the potential of individual cows to facilitate the controlled reduction of the herd | The farm has been able to more-or-less keep total litres around 200,000 litres per annum and to do this while being able to reduce cow numbers and cut methane production in particular. Since the first audit, total emissions have dropped by 113,969 kg CO2e and milk produced dropped by 11,795. |
| What has been actioned | Rationale |
|---|---|
| Participation in the Agri-Environment Climate Scheme (AECS) | The business was a participant of a previous Rural Priorities Scheme but never continued into an AECS. AECS provides an income stream, while promoting nature-friendly farming practices, stipulating sustainable grazing, cutting regimes and the prohibition of inorganic fertiliser use, cutting emissions. |
| Uptake of regenerative principles | Recognising the move towards regenerative agricultural principles within the dairy sector, the business has committed to actions to build soil carbon, protect the water environment and boost biodiversity. Progress will be measured with an agreed methodology and surveys completed to track improvements. |
| Nutrient budgeting | The business is in the process of completing a slurry and nutrient management plan to gauge effective slurry storage and quantify the nutrient value of the slurry on the farm. Better understanding of nutrient availability will help to better inform slurry applications and nutrient uptake. |
| Barriers to change | Rationale |
|---|---|
| Retention of steers and youngstock | Retaining stock that cannot meaningfully contribute to the saleable output of the farm means higher levels of methane produced that contributes to overall emissions. Removal or sale of stock at the earliest possible point limits the emissions calculated on behalf of the business, also freeing up space, labour and other inputs. |
| Grazing platform and opportunities for better grazing | With a set stocked grazing platform, the farm is in all likelihood not utilising its reserves of forage. Low pressure grazing opens up opportunities for weed species to come into the sward. Uptake of rotational grazing could help to improve utilisation, resulting in more milk from forage and less purchased feed required. |
| Fluctuations in milk quality | Litres of milk produced and the quality of that milk can have a huge impact of the carbon footprint of a business. Despite a positive trend towards lower emissions, the carbon footprint has risen in 2024, driven by a reduction in milk solids and less output as a consequence – so many factors are at play with milk quality, some variation, year or year is inevitable. |
Although staggered and not consecutive, the carbon audit results across the three audits show a positive trend of year-on-year reductions in total emissions.
Carbon is complicated and an ever-developing field of study and refinement. But what the results of the audits show is a consistent trend towards lower emissions – aided by the uptake of low carbon farming practices and principles.
FAS Connect
Aimed at promoting knowledge exchange between specialists and farmers, and between farmers themselves, FAS Connect operates across the country, facilitated by consultants and advisors to address the topics and issues impacting farming businesses at sector level and across the industry. The initiative, which is funded by Scottish Government as part of the FAS programme overall is crucial to fostering cooperation and interaction between farmers and is key to many developing their networks and having the confidence to drive forward their businesses.
FAS Connect is run throughout Scotland and covers a wide range of topics, from grassland to arable, livestock and diversification, crofting, carbon and everything in between. For more information and to find out how to get involved, click here: https://www.fas.scot/connect/
Alexander Pirie, SAC Consulting
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