HISTORIC England has objected to a plan to modernise a dairy farm, saying cows would destroy the heritage of a scheduled monument overlooked by one of the most important monastic houses in medieval England.

The public body that looks after England’s historic environment has written to the North York Moors National Park Authority to highlight its concerns after tenants on a 193-acre farm at Rievaulx, near Helmsley, on the Duncombe Park Estate said urgent changes were needed to secure the farm’s future.

Holstein Friesian dairy farmers W H Dunn & Sons have lodged a proposal to build a 34m by 49m building for their 130-cow herd, a 18m by 49m milking parlour and a 37m by 9m slurry storage building to help the business grow and also to ensure they meet the demands of the farm’s milk purchaser, Arla Foods.

Documents lodged with the planning authority state the milking herd is currently managed through facilities which are more than 40 years old and in need of replacement, and at the same time there is also a need to increase the size and capacity of the facilities available.

The papers state by introducing a sand-based cubicle system for the cows, incidences of mastitis among the herd would drop significantly from its current system using straw, the price of which has more than doubled in recent years.

Highlighting the health benefits to the herd, the application states: “There is a current agenda by the Government and Defra to significantly reduce antibiotic use in agriculture due to evidence of antibiotic resistance in human medicine and it is a certainty that antibiotics will become less available and less supported.”

The documents state the development would fit in with the existing farm and be sufficiently distanced from the main earthworks to enable the agricultural and heritage interests to share the site.

Countryside charity CPRE North Yorkshire said it was supportive of farms being able to successfully and sympathetically adapt to challenging times both post-pandemic and post-Brexit to enable them to survive and thrive.

It said the development would enable the farm to compete and remain financially viable in dairy markets, but added the large scale of the buildings would have a direct impact on the landscape.

However, Natural England has raised concerns about the farm’s building encroaching onto the scheduled monument, which features especially well-preserved earthworks representing the large number of stone and timber buildings at Newlass monastic grange, a farm established in the 13th Century by the Cistercian monks Rievaulx Abbey.

The grange was independent of the secular manorial system of communal agriculture and servile labour. Its function was to provide food and raw materials for consumption within Rievaulx Abbey and provide surpluses for sale.

A Historic England spokesman said Newlass provides “a very valuable insight into the economy of a major medieval monastery, complimenting the remains of the abbey itself”.

Objecting to the farm development, a Historic England spokesman said: “The effect of cattle entering and exiting the building will be that this intervening space will also become disturbed and puddled, leading to the degrading of any earthworks or buried archaeology.

“The visual impact of the dairy cubicle development will be considerable, altering the current character of the holding from low key to a more industrial feel.”

He said the proposal will lead to “a high level of harm” to the heritage unless it can be mitigated, through modification or relocation.

The spokesman added: “It is our judgement that the proposal represents harm to the significance of the important archaeological deposits, whilst the applicant has not demonstrated that there is any public benefit in the scheme.”