Lely unveils new Voyager robotic fencer for automated grazing control

A robotic grazing control system for dairy cows has been developed by Lely.

The Dutch company already has Astronaut milking robots and Discovery robotic muck-scrapers in its armoury. The Voyager is the latest machine to join this high-tech line-up.

Essentially an automated strip grazing system, it utilises two robots to move an electrified fence-line at a pace that ensures that the sward is completely grazed.

Lely says that this ‘frontal grazing’ approach maximises grass utilisation because the movement of the fence can be set slow enough that cows consume all the forage on a given area before any more becomes available.

This means that ungrazed areas are not poached or contaminated by manure.


A study conducted by Dutch research organisation – the Animal Science Group – showed that an automated frontal grazing approach increased grassland utilisation by 12% when compared with four day rotational system.

This increase apparently translates into a saving in feed costs of 0.68p/litre or a potential increase in milk yield of 90-litres per cow from the same grazed area.

The study also found that milk production is more consistent when using an automated grazing system because a constant amount of forage is available at all times

Lely Voyager Diamgarm


Each robot runs along an electric fence-line at the side of each paddock. Sensors monitor the angle of the wire relative to the direction of travel and steering the robot accordingly.

Electric motors drive left and right pairs of wheels and use a ‘skid-steer’ technique to alter the robot’s course.

Power for these motors and the electric fencing unit is supplied by a solar panel on each robot.

The fence-line can stretch to 200m and Lely recommends at least 1m is available per cow.

‘Spider-wheels’ set at intervals along the line ensure that the wire is maintained at an even height across all contours.

A tensioner reel within one of the robots keeps the wire taught at all times and allows the two units to move closer or further apart as the follow uneven, angled boundaries.

The two robots communicate with each other via a Bluetooth wireless connection and can be programmed to drive the cows back to the parlour for milking at set times throughout the day.

Having been tested in Northern Ireland last year, the Voyager system will be available in limited number this year at a price of about £15,000.

Robot-controlled grazing 

  • reduces forage waste

  • increases cows’ harvesting efficiency by 12%

  • saves labour

  • avoids fluctuations in milk production and composition

  • lower feed costs (can save 0.68p/litre)

  • higher milk production from pasture (up to 90-litres extra per cow)

  • costs approx. £15,000