Half a century ago, no-one would have looked twice at the handful of red, white and roan pedigree shorthorn cattle grazing on the hillside by the road from Kettlewell to Starbotton in the upper Wharfe valley.

In the days of the "house cow" and when small Dales holdings were farmed the traditional way, Northern Dairy Shorthorns, as the breed was known, were everywhere. This is the only breed of cattle that is native to Yorkshire's limestone dales going back several hundred years and at one time an entire family might have lived on a dozen cows and their milk and beef.

In the intervening years they have vanished, not just from these hillsides, but everywhere. In 1978, Dales Shorthorns were added to the critical list of the Rare Breeds Survival Trust (RSBT) as extinction threatened. Ask any livestock farmer why, and the answer is: the breed was not commercial.

As the two industries developed separately, specialist beef cattle have evolved that can put more beef on much quicker. Yields from specialist dairy cows could more than double the 10 litres a day from the Dales Shorthorn.

These genetically-modified breeds are more productive. But subtract from the value of their impressive output the input costs – housing them, the vets' bills for disease and difficulties with calving, plus the rocketing costs of special feed – and the balance sheet looks less certain.

Today, the Northern Dairy Shorthorns is worth another look. They are hardy, docile, dual-purpose, produce both milk and beef, mainly off grass, and cost less to rear. Add into the mix the swelling demand for ethical, local and sustainable produce, and the financial case for keeping them again seems persuasive. This at least is the outline of the argument put forward by Les Woodcock. He is backing it with his own money since he is the owner of the 10-strong Starbotton herd which is unique in having the only live working Northern Dairy Shorthorn bull in existence.

Les doesn't think he can make the breed's revival happen by himself – he is a smallholder keeping them as a sideline. His belief, however, is that someday soon a commercial suckler beef and/or milk producer, especially one in the Yorkshire Dales, will take things forward as an experiment and reap the benefits.

"My personal view is that the pedigree Northern Dairy Shorthorn – or Dales Shorthorn breed as we now prefer to call them to avoid confusion with the UK Dairy Shorthorn – only has a future if we can demonstrate a commercial future," says Les.

"The economics are much more favourable now. They mostly live on a low input diet of rough grassland and wildflowers and mineral lick. The cost of fattening beef off cereal, or producing milk from high-protein concentrates, has more than doubled in the last 18 months.

"Yes, they may only produce half as much milk as cows from black-and-white herds, but it's better quality. Their beef, because of their grass-fed diet, tastes much better. They cost half the price and they will live to be 20. The Dales Shorthorn will out-winter, hence there are low labour costs, and no vets' bills – at least I've had none, yet. Many older farmers in the Dales who remember these shorthorns all say the same."

Les's life in the dale seems almost a self-conscious step back into the past. He also keeps a couple of dozen pedigree Dalesbred ewes, and his land came with two laithes, or old stone barns, one of which he has been restoring. It's at least 200 years old, maybe more. Step through the door and you are inside a Dales world that existed from time immemorial. The essentials are still in place, including the timber stalls where the animals were once tethered for months on end in winter.

It's called Tug Gill Laithe after Tug Gill which cascades down from the fell a few yards away. Restoration of the laithe and preservation of the gill's woodland has been assisted by 80 per cent grants from the Pennine Dales division of English Nature's Environmentally Sensitive Area (ESA) scheme.

A sort of umbilical cord used to stretch between a laithe and a farmer's house in the nearby village, where a farmer's home would often bear the same name as his laithe. Les maintains that proximity, living alone, a short walk away in Starbotton in a rented cottage built in 1655.

Here he keeps his souvenir collection of memorabilia, gathered from e-bay, of Northern Dairy Shorthorn Herd pedigree registration books from the Forties and Fifties. The books list entries for his present farming family neighbours, the Listers of Kettlewell and the Closes of Starbotton, two generations ago. The Close family farm, lies across the road from Les's 30 acres and its present incumbent, commercial farmer Richard Close, who specialises in rearing black and white heifers for the dairy industry, has been very helpful. Richard's son Matthew keeps an eye on Les's stock when he's away.

Les, originally from Heckmondwike in West Yorkshire, is the second son of a coal miner. After Batley Grammar School he became one of the brighter stars in the scientific firmament. Aged 33 he became Professor of Physical Chemistry at Amsterdam University. He came back to Yorkshire in 1982, preferring the open spaces of Upper Nidderdale to crowded north Holland.

Once settled on a smallholding at Thornthwaite, he looked round for a suitable job. Bradford University promptly made him Professor of Chemical Engineering Science where he stayed for 17 years. He retired from teaching at 55 and, for eight years now, he is Professor of Chemical Thermodynamics at Manchester University, where he commutes in an average two days a week. He is also senior research associate at the United States Air Force's research laboratory and Distinguished Visiting Professor at the National University of Singapore. When he's not living the life of a Dales farmer of a century ago, he may be at an Air Force base in Dayton, Ohio where his work suggests something more akin to science fiction. One air force assignment involves futuristic bombers that could be the size of a bat with nuclear capability. He's also an expert on predicting advanced materials for radar-reflecting surfaces, the sort used by Stealth bombers.

Just over 10 years ago, Les made science history. He completed a chemistry calculation after 22 years of working at it. In 1975, he set out to discover the most stable crystal structure of atomic spheres and in 1997 he had the answer – a face-centred cubic, and all its properties. Four years ago he came to Starbotton and read an article about Brian Bellas, who farms at Crediton in Devon, and owns a few Dales Shorthorns. "It captured my imagination and I got in touch," says Les. "He was over-the-moon that I was calling him from the Yorkshire Dales where his rare cattle belonged. I bought three in 2004. At that time, the total population of pure Dales Shorthorn females was six. Now it's 16."

There were no bulls, but the RBSTrust had collected and preserved the semen from eight, the last survivor having died in the 1970s. Five of Les's cows are in calf now and he has a bull calf which he will keep for breeding.

He also has a three-acre laithe in Swaledale, and a couple of cows have free grazing on Ingleborough, courtesy of English Nature, due to their being native beef breed animals. The working bull will have to leave before his daughters get much older. At 750 kilograms already, the bull is still growing and could make up to £1,000 for beef at current high prices.

Les's neighbour, Richard Close did take one of his maiden heifers, Millie, who was in calf, with the idea of putting her with a black-and-white commercial dairy herd.

"Richard would have done more to save the breed in three weeks, than the RSBT in 30 years if the experiment had been successful," says Les. It only meant moving her home to a field across the road. Unfortunately, the calf was stillborn and Millie's milk dried up. She had spent her life with the same group and the switch may have proved too stressful. Her new arrangement violated the "Three Rs rule" which are said to be the essential constants needed to maintain a happy cow – Residence, Rations and Relatives: only change one at a time.

Les is undaunted. "I get a buzz out of looking after the Shorthorns, seeing them grow and thrive. Pure Shorthorn beef takes 2-3 years on grass. We still hope a commercial dairy farmer out there will be prepared to take Millie on, she's due to calve in two months time, and demonstrate that she can add high quality milk to any black-and-white herd and make it more efficient.

"In a diverse farming economy, free from political interference and financial subsidy, there should be a niche in the market for Dales Shorthorns. Commercial farmers might see me as a bit of an eccentric, finding it hard to understand why anyone would be keeping cattle for recreation."

Anyone interested in Les's Dales Shorthorn enterprise, email leswoodcock@ hotmail.com