Researchers then looked into whether they were linked to other behaviours, such as grazing and producing milk.
They found the cows that were most fearful of humans spent less time lying down.
This was critical for a cow's welfare as it allowed her to rest and ruminate, researchers said.
The study also found that calmer and more curious cows grazed for longer and researchers concluded this probably contributed to more milk production.
Based on their findings, researchers could suggest which personality test would be the most practical on-farm and this allowed farmers to make tailored plans for managing individual cows.
The study, Toward on-farm measurement of personality traits and their relationships to behaviour and productivity of grazing dairy cattle, was published in Journal of Dairy Science.
It was co-funded by the Ministry of Business Innovation and Employment Strategic Science Investment Fund (SSIF; AgResearch Contract # C10X1702) and New Zealand Dairy Farmers through DairyNZ, Inc. (Hamilton, New Zealand; Contract 2020-1598).
Read the full report here.