12 Nov 2020
Team from the Institute of Animal Welfare Science in Vienna examined the effects on the heart rate and behaviour of a group of heifers when interacting with a researcher who spoke to them in a soft voice while stroking their necks.
John Bonner
Job Title
Vets in Austria behind the study explained that when they were being touched, the heifers spent longer than usual with their neck stretched out. Image: © Flying broccoli / Adobe Stock
Austrian vets have shown that dairy cattle find the sound of a gentle human voice relaxing – and can even tell the difference between a live voice and a recording.
The team from the Institute of Animal Welfare Science in Vienna described their study in the journal Frontiers in Psychology1
They examined the effects on the heart rate and behaviour of a group of heifers when interacting with a researcher who spoke to them in a soft voice while stroking their necks.
Lead author Annika Lange explained that when they were being touched, the heifers spent longer than usual with their neck stretched out. This is a posture that is also seen in cows during social grooming by their herd mates. As cattle will actively solicit such attention, neck stretching is interpreted as a sign of enjoyment.
The researchers also recorded the position of the cow’s ears and found that they were usually held low – a position that appears to be linked to a relaxed state.
In contrast, in cattle experiencing an unpleasant stimulus such as pain during dehorning, the ears will be in an upright position with regular flicking movements, she said.
While undergoing these positive interactions with the human researcher, the cow’s heart rate briefly increased, but was then reduced to a lower than normal rate until long after the stimulation phase ended.
The team interpreted this as another sign that the cows were in a positive “low arousal” (that is, calm) state, which was more profound in those cows hearing the live voice than in another group that was just played a recording.
Lange and colleagues were not surprised that cows responded positively to being stroked as the effects of this sort of tactile stimulation has been studied previously in cattle. But “less is known about the effects of vocal stimulation. Despite the possible benefits of applying auditory stimuli in farm environments, research on the effects of gentle vocal interactions on farm animals is scarce”, she said.
Having looked at the behavioural and cardiac effects of these interactions, the team is planning further studies that will look at the physiological effects on levels of immunoglobulin A, cortisol and oxytocin.
This information may have implications for the productivity of dairy herds, as well in improving welfare standards.
Dr Lange said: “Previous studies have shown that a good human-animal relationship can lead to lower cortisol levels, increased weight gain or milk yield and lead to lower heart rates during veterinary procedures.”
Joep Driessen is a 1994 graduate of the Dutch veterinary school in Utrecht and has spent most of his career studying interactions between dairy cattle, and the farmers and vets that look after them.
He congratulated the Vienna team on its good work, saying that the human voice is an underutilised resource in training cattle to cope with the stress of being managed by human keepers.
Dr Driessen said: “Whether it is a live human voice or a recording is matter for academic discussion when you are trying to standardise the experimental process to make the results repeatable. What matters more is that this research provides more evidence that cows can be trained to respond to a human voice, and that they will become more relaxed if you stroke them and handle them gently.”
1. Lange A et al, Bauer L, Futschik A et al (2020). Talking to cows: reactions to different auditory stimuli during gentle human-animal interactions, Front Psychol, https://bit.ly/36c4kV6
