Farm buildings were not an option for U.K. tenant farmers Tom Foot and Neil Grigg so they opted for a mobile milking setup. Moving the parlour each day means they can reduce their environmental footprint with no need to collect and store effluent and wash down water and no expensive concrete infrastructure. Nick Fone reports.

rospect Farming in Dorset, where the 840 cows not only run outside all year round but are also milked outside through mobile parlours, were profiled four years ago.

In that short time quite a bit has changed with partners Tom Foot and Neil Grigg upping output by moving from hired-in 14-28 milking bails to a pair of their own home-built 20-a-side portable parlours.

“When we first took on the ground in Dorset in 2011 it was a completely bare farm with just a few scrappy buildings that weren’t suitable for milking in,” Foot says.

“The tenancy doesn’t provide any capital compensation so we didn’t want to start investing in buildings. We looked at our options and decided we could get by initially by hiring in some Hosier temporary milking bails. Although they were very time-consuming to move and manual to operate, they proved the concept would work.”

As cow numbers grew from 300 in that first season to 720 three years later, it was clear there was a desperate need for extra parlour capacity. But rather than just being able to order an off-the-shelf package, the options were limited for mobile parlours with the output potential to deal with serious numbers of cows. With a bit of a leaning towards wielding a grinder and getting creative with a MIG welder, Foot decided the simplest solution would be to design and build his own tractor-towable rigs.

“Obviously the key criteria was that we could get more cows through any new milking set-up but they also needed to be designed for the job and critically easy to move.

“We couldn’t afford to spend a day taking down and then setting up a parlour – it had to take less than an hour to shift from field to field. But we wanted to keep it simple with existing milking gear that you’d find in any normal static parlour. For that reason alone I knew we needed to stick with the same layout you’d find on any dairy farm.

“I went and measured a friend’s 20-40 herringbone and with the help of local engineering firm – MJ Fry – we came up with some drawings.”

The construction process wasn’t straightforward and by the nature of the job happened on a fairly ad-hoc basis with a meeting every morning at the workshop to decide how things were going to take shape.

It started out with a pair of chassis rails that would form the backbone of the whole rig, forming the support for the cow stands and the sides of the pit. Two eight-stud axles were chopped in half and modified so they could be coupled back together using top-link style turnbuckles for transport but with the parlour in its working position are removed to make for free access up and down the pit. (Cranked axles would have ground out too easily.)

The checker-plate steel platforms down each side are supported by box-section cross-members which also carry the framework for the breast-bars and roof.

A total of 12 hydraulic jack legs along the length of the rig stabilise the platforms and level the parlour on even ground. Each operated by individual spool-valves, they all run off a single ring-main circuit with oil provided by a flow and return service from the tractor that is used to move the parlours.

At the back is a full-width set of shallow steps the cows climb to enter the parlour. Running on skids, they skim along the surface for field moves. Up front a pair of folding steps flank the drawbar to provide the exit route for the cows and hinge upwards with the aid of assistor springs when the rig is on the move.

Each parlour is 4.3 metres wide so gateways on the main ring-fenced grazing block have all been widened to accommodate the oversize rigs. It’s a bit of a faff but the corrugated plastic roof panels can be removed and the cow platforms split in half to bring it down to a 3m transport width should it ever have to go on the road.

“The basic structure of the parlour is very straightforward – it just took reels and reels of MIG wire and buckets full of Tek screws to get it right,” Foot says.

“The more-technical challenge was in getting all the parlour kit installed. I sourced second-hand clusters, cups and drop-down washers but splashed out on new Fullwood pulsators and pulsation boxes.”

Much of what was originally flexible hose has now been replaced with longer-lasting stainless steel pipework.

Three 30-year-old Fullwood vacuum pumps were obtained for £700 ($NZ1360). They’re housed in the plant trailer that is parked up alongside the parlours in the field and also accommodates a generator, milk pumps, compressors, and hot water heater. The trailer is an old twist-lock HGV drag converted by trailer specialist Merrick Loggin. A shipping container protects most of the equipment from the elements with a gantry at the rear to carry a Cool Energy milk chiller.

It’s piped directly into an 18,000-litre milk tanker body that cost £4500 ($NZ8750) and can hold milk at a steady temperature for over 24 hours without further refrigeration. The tank is mounted on a six-wheel-drive ex-army DAF eight-wheeler. Bought for just £12,000 ($NZ23,350) 350hp truck is registered as an agricultural vehicle and delivers the herd’s milk to Ashley Chase cheese plant each day.

Capable of handling around 120 cows and hour, the set-up worked well from the start with very few modifications required and so in 2013 Foot started work on a second identical rig. The two now run alongside each other comfortably dealing with 800 cows in a four-hour shift.

Until this spring the herd was averaging 15-20-litres/day per cow but a switch from once- to twice-a-day milking has seen that climb to 20-25-litres.

“The key to what we’re doing is simplicity. There’s nothing special about what we’re doing – it’s just that our parlours have wheels and move from field to field each day,” Foot says.

“People come and visit us to see what we’re doing on a regular basis and a number have been inspired to go away and build their own mobile parlour which we take as a compliment. We’ve also had people asking us to build rigs for them and we’re just starting on our first one. Alongside that we’ve just started selling our own cheese under the ‘Open Air Dairy’ banner so we’re getting even more interest in what we’re doing.”


At the Open Air Dairy the cows are moved on to fresh grass every day and the mobile parlours move with them. Operating entirely on rented ground which has historically been run under an arable cropping regime, there is a distinct lack of drinking troughs or water mains.

Given each of the 36 paddocks would require at least two tanks, installing them and the associated plumbing would be prohibitively expensive as tenants. Instead the inventive pair came up with the idea of a mobile drinker set-up that can be moved with the parlours.

Trailer maker Merrick Loggin was enlisted to build a simple low-loader to carry two 2500-litre troughs. A 63mm plastic above-ground main was then run around the perimeter of the land with tees to enable the rig to be connected wherever required.

Until this point the cows had each been given £9/head ($NZ17.50) mineral boluses and magnesium flakes had been dropped into the troughs to avoid any problems with deficiencies. However with the arrival of the mobile drinkers, Foot could see an opportunity to do away with the labour-heavy business of bolusing animals.

“The new trough set-up gave me the idea that we could move to a mineral dosing system that would provide exactly what the cows needed.

“It has become increasingly critical as our grazing leys have matured and the clover has established itself. It’s a great source of protein but can cause issues with bloat. Simply adding oil to each trough wasn’t enough and in our worst week we lost 15 cows – that’s a huge cost.

“I approached a company called Liquid Mineral Services because they offered a special oil additive system to deal with bloat. Between us we came up with a plan for an automatic system that would also inject exactly the right amount of vitamins and minerals according to the requirements of the season.”

The set-up uses flow meters to monitor water being consumed by the cows and alters the quantity of liquid supplements being pumped into the troughs accordingly. Consequently on a rainy day when water intakes are lower, the concentration of minerals is increased to ensure the cows still receive the correct dose.

Liquid Mineral Services come in on a fortnightly basis to check on the cows’ mineral status through milk and blood samples and tweak the dosing computer accordingly. In addition once a season liver biopses are used to double check this. On average the cost works out at 5-10p per head per day. Foot estimates each rig cost about £2500 ($NZ4850) to build plus another £1000 ($NZ1950) for the dosing system powered by batteries and solar panels.


Prospect Farming near Dorchester, Dorset

  • Farmed area: 396ha plus separate 182ha young stock/beef unit in Devon
  • Cropping: 270ha grazing platform, 40ha triticale/stubble turnips, 101ha rotational arable and hill-ground
  • Soils: predominantly chalk downland
  • Livestock: 840 NZ Friesian crossbreds, 350 heifers, 150 Longhorn X steers, 40 Red Devon beef cows plus 50 Friesian and 15 Longhorn bulls
  • Machinery
  • Tractors – 2 x JD 6930s, 6430 and 6420
  • Forage wagon – Strautmann Super Vitesse
  • Parlours – 2 x home-built 20-40 swing-over herringbones
  • Milk tanker – 350hp DAF 8×6 ex-MOD hook-loader
  • Staff: Tom Foot and Neil Grigg plus six other full-timers