A four-wheeled robot known as Rover has been successfully tested as a cattle herder in Australia, easily moving a herd from a field to a dairy, researchers say.

The cows, accepting the presence of the robot, were not fazed by it and the herding process was calm and effective, a team from Sydney University said.

University engineers adapted Rover from a robot already being used to monitor fruit and trees on farms, modifying it so it could be put in a field with cows.

"The research is in its very early stages but robotic technologies certainly have the potential to transform dairy farming," Sydney dairy researcher Kendra Kerrisk told the BBC.

Because the robot moved at a slow and steady speed it allowed cows to move at their own natural speed, which is important in avoiding lameness among cattle, she said.

While the Sydney prototype is operated by a human, it's believed future versions could be fully automated, the researchers said, bringing considerable help to dairy farmers.

"When we have discussed this concept with farmers they have been extremely excited and we have had a flurry of calls and emails asking how they can get hold of one," Kerrisk said.