Cows use individualised calls to communicate with each other, a study that identified particular types of mother-offspring contact calls in cattle has showed.
"The research shows for the first time that mother-offspring cattle 'calls' are individualised - each calf and cow have a characteristic and exclusive call of their own," said Monica Padilla de la Torre, who lead the research at University of Nottingham in Britain.
"Acoustic analysis also reveals that certain information is conveyed within the calf calls - age but not gender," she added.
The researchers spent 10 months studying the ways cows communicate with their calves, carefully examining acoustic indicators of identity and age.
They studied two herds of free-range cattle on a farm in Nottinghamshire. Recordings were made using highly sensitive equipment.
The researchers identified two distinct maternal 'calls'. When cows were close to their calves, they communicated with them using low frequency calls.
When they were separated - out of visual contact - their calls were louder and at a much higher frequency.
Calves called out to their mothers when they wanted to start suckling. And all three types of calls were individualised - it was possible to identify each cow and calf using its calls.
"Our results provide an excellent foundation for investigating vocal indicators of cattle welfare," said Alan McElligott from Queen Mary University of London.