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Scientific reports2018; 8(1); 14680; doi: 10.1038/s41598-018-32993-z

Facial expression and oxytocin as possible markers of positive emotions in horses.

Abstract: Behavioural and physiological markers of discrete positive emotions remain little investigated in animals. To characterise new markers in horses, we used tactile stimulations to induce emotional situation of contrasting valence. In the Gentle grooming group (G, N = 13) horses were gently groomed during 11 sessions on the body areas they appreciated the most. Horses in the Standard grooming group (S, N = 14) were groomed using a fixed procedure, reported to induce avoidance reactions in some horses. At session 11, G horses expressed significantly more contact-seeking behaviours than S horses, which expressed significantly more avoidance behaviours. This result suggests positive emotions in G horses and negative emotions in S horses. Blood cortisol, oxytocin, heart rate and heart rate variability never differed between before and after the grooming session. However, after the 11 sessions, basal oxytocin levels were lower in the G than in the S group. This difference was unexpected, but supports studies showing that a low level of basal oxytocin could be a marker of better well-being. Analyses of facial expressions during grooming revealed significant differences between groups. These expressions appear to be more sensitive than behavioural indicators because they alone enabled differentiating emotions according to the group when horses were re-exposed to neutral grooming one year after the treatment.
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Publication Date: 2018-10-02 PubMed ID: 30279565PubMed Central: PMC6168541DOI: 10.1038/s41598-018-32993-zGoogle Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research investigates how certain behaviours and physiological markers can indicate positive emotions in horses. The study found that horses receiving their preferred form of grooming exhibited more signs of positive emotions and lower basal oxytocin levels, which contradicts previous research but indicates better well-being.

Research Methodology

  • The researchers conducted an experiment with two groups of horses. The “Gentle grooming group (G)” comprised 13 horses that were groomed gently in the areas they seemed to appreciate most across 11 sessions. Meanwhile, 14 horses in the “Standard grooming group (S)” were groomed using a fixed method known to cause avoidance reactions in some horses.
  • Various physiological factors, such as blood cortisol, oxytocin levels, heart rate and heart rate variability, were monitored before and after each grooming session in both groups.
  • The researchers also carefully evaluated the horses’ behaviours during grooming, looking for signs of either contact-seeking (indicating positive emotions) or avoidance (indicating negative emotions).

Key Findings

  • At the end of the 11 sessions, horses in the G group conducted significantly more contact-seeking behaviours than those in the S group, who showed more avoidance behaviours. This suggests that G horses were experiencing positive emotions while S horses were experiencing negative emotions.
  • Surprisingly, the basal (basic) levels of oxytocin in the G group were lower than in the S group after the 11 sessions. While this seems contradictory to common physiological understanding, it falls in line with studies indicating low levels of basal oxytocin as a marker of better overall well-being.
  • Facial expressions were found to be a sensitive and reliable indicator of the horses’ emotional state. Particularly, facial cues allowed researchers to differentiate between experiences of positive and negative emotions even when both groups were subject to neutral grooming one year post-experiment.

Significance of the Research

This research adds to our understanding of animal emotions, particularly in horses. It highlights how simple changes in grooming method can significantly affect a horse’s emotional state. Additionally, it suggests the potential validity of low basal oxytocin levels as an indicator of better emotional well-being in horses, challenging previous understanding. Finally, it underscores the sensitivity and importance of facial cues as indicators of emotion in animals.

Cite This Article

APA
Lansade L, Nowak R, Lainé AL, Leterrier C, Bonneau C, Parias C, Bertin A. (2018). Facial expression and oxytocin as possible markers of positive emotions in horses. Sci Rep, 8(1), 14680. https://doi.org/10.1038/s41598-018-32993-z

Publication

Scientific reports
ISSN: 2045-2322
NlmUniqueID: 101563288
Country: England
Language: English
Volume: 8
Issue: 1
Pages: 14680
PII: 14680

Researcher Affiliations

Lansade, Léa
  • PRC, INRA, CNRS, IFCE, University Tours, 37380, Nouzilly, France. lea.lansade@inra.fr.
Nowak, Raymond
  • PRC, INRA, CNRS, IFCE, University Tours, 37380, Nouzilly, France.
Lainé, Anne-Lyse
  • PRC, INRA, CNRS, IFCE, University Tours, 37380, Nouzilly, France.
Leterrier, Christine
  • PRC, INRA, CNRS, IFCE, University Tours, 37380, Nouzilly, France.
Bonneau, Coralie
  • PRC, INRA, CNRS, IFCE, University Tours, 37380, Nouzilly, France.
Parias, Céline
  • PRC, INRA, CNRS, IFCE, University Tours, 37380, Nouzilly, France.
Bertin, Aline
  • PRC, INRA, CNRS, IFCE, University Tours, 37380, Nouzilly, France.

MeSH Terms

  • Animals
  • Emotions
  • Horses / physiology
  • Oxytocin / blood

Conflict of Interest Statement

The authors declare no competing interests.

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