Dairy farmers often describe themselves as "tied to the tails of their cows". What they mean is they get little time off as they have to milk their cows at least twice-a-day.

Generally speaking, and depending on the stage of the lactation, cows yield more milk in response to being milked more often. That is why some farmers milk their cows three times-a-day. Indeed robotic milking systems will automatically milk higher-yielding cows four times-a-day.

Despite the proven advantages of regular milking, some dairy farmers are adopting the practice of once-a-day (OAD) milking. One such farmer is Rory Christie who farm a coastal strip near the village of Port William, in the South Machars of Wigtownshire in a limited farming company, Dourie Farming Co., with his brother Gregor.

Gregor is in charge of a recently modernised pig enterprise, where the progeny from 200 sows are finished, while Robin runs the dairy herd that exploits the unique climate created by the Gulf Stream as it crosses the 1,000 hectares of grass that the brothers farm.

The aim is to produce milk from that grass without any concentrated feed, and that is now being achieved by milking 1300 Jersey cross Friesian cows OAD on an outdoor, New Zealand system. The hybrid vigour of cross-bred cows makes them aggressive grazers and more fertile, as well as giving them better feet.

The herd calves between February and April so that their milk production is matched to the grass growing season, and is divided into groups of 300 that are grazed on a paddock system. Milk from the farm is sold to Lactalis in Stranraer to be made into Seriously Strong and Galloway Cheddar. The company pays a premium for milk with higher milk solids, particularly protein, that yields more cheese.

To maximise the amount of milk from forage, cows need a daily intake of 17kg of grass dry matter (DM). To achieve that, Rory monitors grass DM in the same way a conventional dairy farmer monitors the ingredients of his feed wagon. That involves measuring the grass in every paddock each week with an ATV-trailed D-Dax grass meter imported from New Zealand.

The information gathered is downloaded to a PC, which quantifies the DM available on the farm. That way he can understand the daily growth rate of the grass, enabling him to budget the herd's feed. The computer programme allows him to select appropriate paddocks to graze the 300-cow groups.

To avoid poaching (trampling the grass into mud) during the winter months the herd is brought into an unroofed, concreted cubicle yard, although cows are calved under cover in straw-bedded pens.

The cows are milked through a 44-point rotary parlour that was installed in 2005 and originally designed for 500,but it had become too small as the herd expanded. Milking that number twice-a-day led to a high rate of staff churn as they were starting work at 3am and not getting finished until 9pm. If there was a breakdown they could themselves finishing the milking the day after they started. So although the system was profitable Rory decided it was unsustainable from a worker's point of view - the staff were not enjoying their day.

Then in 2015 the milk price began to crash before finally bottoming out at 16.5ppl. The collapsing price of milk prompted Rory to undertake a LEAN analysis of his business . This is the industrial business analysis technique developed by Toyota and used to find and remove waste (cost) from the system. The LEAN assessment led to a plan to move to OAD milking.

Rory had expected the milk yields to drop by 15 per cent, but the reality was they fell by 30 per cent to a low of 2,700 litres per cow a year. There were also fertility issues in the first couple of years with the barren rate rising to 15 per cent, although Rory believes this was created by management decisions not OAD milking.

On the plus side the cows are now very healthy, the barren rate has dropped to 9.6 per cent, milk solids have improved, while yields have risen from a low of 2,700 litres to 3,000 litres and are continuing to rise as a result of selective culling. In 2015, 16, and 17 the cows received no concentrated feed, although some had to be fed this summer as a result of a shortage of grass caused by the drought.

More importantly, the staff are much happier as they now start work at 6am at this time of year and are home by 1pm.