A newly published research article in PLOS One suggests that simply allowing a horse to see, hear and smell a calm companion may help reduce signs of short-term stress during restraint.
Researchers found that horses restrained in stocks while socially isolated showed higher heart rate, respiratory rate and eye temperature, along with more facial expressions associated with stress, than when a familiar companion horse was positioned nearby without physical contact.
The research article, published on 20 April 2026, investigated whether “social noncontact enrichment” could provide a buffering effect during a routine but potentially aversive management procedure. The researchers used 11 Pantaneiro horses in a crossover design, comparing two scenarios: restraint in stocks with social isolation, and restraint in stocks with a familiar conspecific standing at a distance of approximately 3 metres, allowing visual, auditory and olfactory communication.
Across the 24-minute restraint period, horses in the socially enriched setting generally appeared calmer. Heart rate was lower in the final five-minute interval, respiratory rate was lower at key timepoints, and eye temperature remained more stable. The horses also showed fewer facial expressions linked with stress, including nostril dilation, inner brow raiser, upper eyelid raiser, increased eye white, and repeated ear movements.
The researchers used both physiological measures and EquiFACS, a facial action coding system developed specifically for horses, to assess responses. Together, these measures suggested that restraint in stocks can trigger an emotional state associated with high arousal and negative valence, even in habituated horses. However, the presence of a calm companion appeared to reduce that response.
The authors say the findings support the idea of “social buffering”, where the presence of another horse helps an individual cope better with a stressful situation. Importantly, this was achieved without direct physical contact, suggesting that sensory contact alone may be enough to make a meaningful difference.
Although the study was small, involving 11 horses of one locally adapted breed, it adds to growing evidence that management and handling procedures may be made less stressful through relatively simple welfare-focused changes.
For vets, handlers and yard managers, the message is practical: if a horse has to undergo restraint for a procedure, the presence of a suitable companion nearby may help reduce stress and improve cooperation.
Click here to read the extensive open-access article and see all the diagrams and research tables.
