Experienced horses can exert a steadying influence in a paddock, researchers have found.
The findings of the study in Denmark, reported in the journal Applied Animal Behaviour Science, support the belief of many horse owners, that placing “old hands” with younger animals can help shape their behaviour.
Researchers in the Department of Animal Science at Aarhus University devised two experiments to investigate what it means to young horses to be exposed to a frightening situation when one of them is already familiar with the scenario.
How animals in groups interact when it comes to either increasing or decreasing fear is relatively unexplored, despite its importance in relation to animal and human safety.
“What we wanted to investigate in our study was whether a so-called demonstrator horse – a horse which has already been habituated to a ‘frightening object’ – can have a calming effect on the other herd members’ reactions when exposed to the same object,” said associate professor and project leader Janne Winther Christensen.
The first experiment included 32 Danish Warmblood horses of the same age divided into eight groups of four horses each.
The socially highest-ranking horse from each group, determined through feeding tests, was used as the demonstrator.
Half the demonstrators were habituated to a sudden appearance of stimulus (a big, multi-coloured umbrella being unfolded) while fed in a test arena. The other half of the demonstrator horses were not habituated.
The same test arena was used when testing the horses. The four horses in each group were fed from individual troughs placed in a semicircle in order to be able to register the horses’ reactions and positions when the umbrella unfolded.
The study team monitored the horses’ behavioural reactions (scored on a scale from 0-4) and the time it took them to resume eating behaviour after the presentation of the umbrella.
The results showed that the strength of the young horses’ behavioural reaction was reduced in the groups including a habituated demonstrator. However, the latency to resume eating and the horses’ heart rates were unaffected.
In the second experiment, the researchers conducted the same set-up as in Experiment 1, but this time with 32 Icelandic horses and with adult horses as demonstrators.
The aim of the second experiment was to investigate the effect of the presence of an adult demonstrator in groups of four, including three 2-year-old horses in each group.
The results showed that the young horses, grouped with a habituated adult demonstrator, displayed fewer severe behavioural reactions, shorter latency to resume eating and a tendency to a lower heart rate compared to young horses in groups with a non-habituated demonstrator.
“Both experiments have shown that a single habituated demonstrator horse can attenuate fear reactions in smaller groups of young horses,” explains Janne Winther Christensen.
“Thus, it seems that a certain level of social transmission takes place, meaning that an experienced horse plays an important role in the regulation of fear reactions in groups of horses.”
The results also showed that there was a stronger fear-reducing effect of the habituated adult demonstrators in the second experiment compared to the first experiment, in which young horses were the demonstrators.
As there were several varying factors between the two test rounds, including breed, time of year and feeding, it is not possible for the researchers to make a direct comparison.
“Further studies will be required before we can finally conclude whether adult horses have a greater influence as demonstrators than young horses.
“However, from our study, it seems that it is possible to attenuate fear reactions in groups of young horses by means of a single habituated demonstrator,” Christensen says.
“This knowledge has huge potential regarding practical management within horse keeping, as fear reactions in horses cause many accidents every year in relation to human handling of horses.
The study was funded by The Independent Research Fund Denmark, Technology and Production.
Reporting: Linda Søndergaard Sørensen
Attenuation of fear through social transmission in groups of same and differently aged horses.
Maria Vilain Rørvang and Janne Winther Christensen.
Applied Animal Behaviour Science, Volume 209, December 2018, Pages 41-46 https://doi.org/10.1016/j.applanim.2018.10.003