More than 40 mega-dairies exist across the UK, the largest of them housing 2,600 cows. The number of farms keeping cattle indoors year-round has more than doubled over the past decade, increasing the volume of slurry that must be stored and managed, while existing infrastructure is failing to keep pace.
Meanwhile, UK organic dairy cow numbers fell by 6% between 2023 and 2024, continuing a decline since 2019. In 2024, organic dairy accounted for just 1.5% of cow numbers in the June consensus.
The current system, weighted towards farms with hundreds or even thousands of cows and billed as ‘more efficient’ and ‘lower carbon’, is driving increased pollution and exposure to the impacts of climate change. “[…] we cannot measure the health of the dairy sector by output alone,” said Gemma Lane, Land Use Policy Manager at The Wildlife Trusts.
Analysis of recent Environment Agency figures by The Wildlife Trusts calculated that dairy activity was responsible for 71% of serious agricultural pollution incidents in England alone – damaging rivers, contributing to algal blooms, reducing oxygen levels and harming wildlife.
However, unlike intensive pig and poultry units, large dairy and beef farms are not subject to the same government monitoring, meaning their size and environmental impacts are left largely unchecked.
Less dirty way of doing dairy
The Doing Dairy Differently report, published this week by the Wildlife Trusts, warns of the growing pressure these larger farms are placing on the land, water and wider environment on which farms, people and wildlife depend.
Indeed, milk production for the 2025/26 season is forecast to rise above 13 billion litres (up 5% on the previous year). Over the last decade, average milk yield per cow has increased by 9%, reaching 8,169 litres per cow per year.
At the same time, the number of dairy producers is falling: dairy producer numbers fell 14% between 2019 and 2023, from 8,720 to 7,500, with a further 190 producers leaving in the past year. As of October 2025, the total dairy herd stood at 2.51million cattle; the average conventional herd size has increased from 134 cows in 2005 to 226 in 2025.
As one member of the peer-to-peer platform Farming Forum UK noted during an online discussion about yields and consolidation: “Farmer near me milking 5000+ cows across multiple sites, all housed, tarmac farming, 12,000 litre plus av. yield. Would have taken 100 dairy farms to produce that a generation or two ago. ’tis progress, apparently.”
Indeed, the milk gains are often presented as efficiency improvements, but they also mean greater pressure on land, feed, slurry storage and water quality, argued Lane. Consolidation is concentrating production into fewer businesses, increasing the scale of local nutrient, slurry and feed pressures where herd expansion is not matched by land, infrastructure or regulation, she explained.
The Bureau of Investigative Journalism recently found the number of intensive units where animals are kept permanently indoors has more than doubled in the past 10 years. Within this has been the rise of ‘megadairies’, which house more than 700 cattle.
Supermarkets milk profits at producers’ expense
The authors of the new report argue that the barrier to a more sustainable dairy sector is not a lack of good practice, but a “supermarket profits-led system” that too often rewards volume over resilience, pushes risk back onto farmers, and fails to account for the damage caused by pollution, imported feed and declining natural resources.
The Wildlife Trusts called for stronger regulation and investment to help prevent pollution – including the permitting of very large, housed units and farms with little or no grazing, while helping farmers invest in slurry storage and other pollution-prevention infrastructure.
Permitting of intensive dairy and beef farms is being considered by the Government but concrete plans are yet to emerge. The National Farmers Union has raised concerns about the cost of permitting and is pushing back against extending the environmental permitting regime to cattle.
Environmental permitting is a regulatory process that sets minimum standards for operations that aim to reduce pollution and potential risk in terms of air, water and land. These cover nutrition, housing systems, slurry management and the control of and monitoring of emissions.
Both the pig and poultry sectors are required to obtain environmental permits; for poultry this is required for above 40,000 places and for pigs this applies to numbers over 2,000 places over 30kgs for production and 750 places for sows.
The government’s plans to extend permits come on the back of intensive scrutiny of pollution from large, intensive farms. The UK Government’s Water White Paper, published in January, called for a ‘once in a generation’ plan to reform the water system. And it was within this paper that the government renewed its ambition to extend permitting to the cattle sectors, which refers to both dairy and ‘intensive beef’.
The Wildlife Trusts not only pointed the finger at the lack of regulation of large farms, the group also recommended a new maximum sustainable output (MSO) approach – which looks at the level of production a farm can sustain profitably. This suggests that lower-input, nature-friendly systems can improve returns, reduce environmental pressures and build resilience to economic and climate shocks, the Trusts said.
The analysis also showed that well-managed grazing and healthy soils, alongside suitable slurry management, can reduce pollution risks and reliance on costly inputs such as artificial fertiliser and concentrated feed.
Lane called for better advice and support for farmers and greater support for nature-friendly dairy – “supporting organic and regenerative dairy farms through government agri-environment schemes and fairer supply chains so that farmers are rewarded for the environmental benefits they deliver”.
But last week, England’s £233m pot of funding under the second stage of the Sustainable Farming Incentive ran out in just six hours. This left thousands of farmers who were planning to improve the sustainability of their farms out in the cold with no cash.
Soil Association Policy Director, Brendan Costelloe, called the situation a shambles: “When we’re facing a nature and climate crisis, it really is disheartening that so many farmers who wanted support to do something about it have been locked out, and this has implications for food security and the environment.”
In Scotland, where there is more government support and guided action plans to increase organic land coverage, organic farming has doubled the volume growth reported for non-organic (6% versus 3%). “With the right funding, advice and supply-chain support to embed nature into farming practices, more farmers can reduce pollution risks, restore local wildlife and build profitable, sustainable businesses fit for the future,” explained Lane.
Funding nature-friendly farming
Demands for more funding are now likely to intensify. Campaigners and experts warned of the consequences of leaving farmers disengaged on more sustainable approaches to production. Climate change, bringing extremes of weather, continues to bite hard, and nature-friendly approaches are needed more than ever to provide resilience and security.
“For months, UK dairy farms produced below a normal summer, and by August the scale of the impact was regularly worse than anything seen in 18 years,” said Tom Cantillon, a senior analyst at the ECIU, a think tank focused on energy and climate. “The missing £83 million from farmers’ pockets has gone in a year when many were already milking at a loss,” he added.
Analysis by ECIU this month also showed UK dairy farmers delivered over four days’ less milk than would be expected this summer from May to August – enough for more than a billion school milk cartons – as the UK recorded its hottest summer since records began.
“The costs don’t stop now that the rain has come,” Cantillon said. “A second bad year for grass has pushed farmers into their winter forage early, with feed prices to follow. Farmers need help to build resilience – shade, trees, water – but summers like this will keep getting worse until we cut emissions to net-zero and bring the climate back into balance.”
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