Cows prefer 'live' chat with a human rather than listening to a pre-recorded voice.
They 'like stroking in combination with gentle talking', experiments have shown.
Cow stress is known to trigger a chemical reaction that can lead to drier meat.
Farmers should converse with a cow face-to-face if they want them to unwind in the run up to being slaughtered, according to a new study.
Austrian researchers found cows were more relaxed when spoken to directly by a human, compared with when they were played voice recordings over a loudspeaker.
The experts observed signs of relaxation when cows were spoken to in-person, such as heart rate variability and the positions of their necks.
Feeling stress can stop cows from producing milk and make their meat tough, dry and flavourless, according to farmers.
It's already known voices can reduce stress for cattle, but busy farmers could spend more time with cows in-person, as opposed to playing them pre-recorded audio.
'Cattle like stroking in combination with gentle talking,' said Annika Lange of the University of Veterinary Medicine in Vienna, Austria.
'In scientific contexts, a recording of a human voice speaking gently could be used to relax the animals, because it can be difficult to repeat the same phrases in the same way during experiments.
'Interactions may be less positive when they become artificial.'
The quality of the animal-human relationship and the welfare of animals can be improved by gentle interactions such as stroking and talking, the team claim.
The perception of different stimuli during these interactions likely plays a role in their 'emotional experience', but studies into this so far have been scarce.
The experts therefore worked with a herd of 28 cattle, comparing the benefits of either stroking the animals while playing a recording of an experimenter's voice ('playback'), or stroking while speaking to the animals directly ('live').
In both conditions, similar phrases with positive content were spoken calmly, using long, low-pitched vowels.
All tests were video recorded and analysed for cow behaviours, while the effects on the cows’ cardiac parameters were also assessed.
After monitoring the animals' responses during the experiments, they found 'live' talking was the best mood enhancer for their bovine friends.
Heart rate variability (HRV) was higher when cattle were spoken to directly, indicating they were enjoying themselves.
HRV determines time between each beat and how it varies, and a greater HRV at rest is generally an indicator of better wellbeing.
Also, heart rates were lower after face-to-face chats compared to voice recordings, again suggesting the animals were more relaxed.
The team also observed some behavioural characteristics that were indicators of relaxation.
'When relaxed and enjoying the interaction, the animals will often stretch out their necks as they do when they groom each other,' said Lange.
'Additionally, it is thought that ear positions may indicate mood – hanging ears and low ear positions appear to be linked to relaxation.'
Lange and her team concluded the use of recorded auditory stimuli to promote positive states for cows 'is possible, but not necessarily preferable'.
The experiment included only one herd and one playback recording, the team admitted.
Lange has therefore called for further research to see if results are also valid for different herds and situations, such as with cows that are more fearful of humans.
This will help in further studies on the improvement of cattle-human relationships, which is an important aspect of animal welfare.
Cattle stress triggers a fight-or-flight reaction that produces a chemical response, which itself causes the animals' muscles to tense.
Whooping and hollering, aggressive animals like dogs, travel and cattle prods are all sources of cattle stress.
The research has been published in Frontiers in Psychology.
In September 2020, scientists reported the creation of the first gene-edited livestock that can produce sperm with the traits of donor animals, allowing them to act as 'surrogate sires'.
The breakthrough could result in 'elite' offspring that are bigger, healthier and meatier, helping to meet the food demands of a growing global population.
The technique was developed by researchers from Washington State University and Edinburgh University's Roslin Institute, which is famous for creating the world's first cloned mammal, Dolly the Sheep.
It involves breeding sterile male animals and then transplanting stem cells from donor animals into their testes, causing them to produce sperm that only carries the genetic material of the selected donor.
Project leader Professor Jon Oatley said the new technique could improve the efficiency of food production - or even save species from extinction.
'With this technology, we can get better dissemination of desirable traits and improve the efficiency of food production,' said Professor Oatley.
'This can have a major impact on addressing food insecurity around the world.
'If we can tackle this genetically, then that means less water, less feed and fewer antibiotics we have to put into the animals.'
The study was detailed in the journal Proceedings of the National Academy of Sciences.