Horses recognise predators by sight alone, even when they appear only on a screen

Experimental setup.  © Z. Benderlioglu CC BY 4.0

Domestic horses can distinguish between a potential predator and a harmless animal using
visual information alone, according to new research from The Ohio State University. The findings suggest that horses are capable of rapidly assessing danger without relying on sound, scent or previous experience, while also revealing that they may conceal signs of stress despite experiencing significant physiological arousal.

As prey animals, horses have evolved sophisticated mechanisms for detecting threats. Previous research has shown that they respond to predators through increased vigilance, flight behaviour and elevated stress levels. However, most studies have examined combinations of visual, auditory and olfactory cues. The latest study is among the first to isolate vision alone, demonstrating that horses can identify a predator even when it is presented as a silent video image.

The researchers studied 18 horses of varying ages and both sexes housed at The Ohio State
University Equine Center. Each horse watched a series of 20-second silent video clips projected onto a screen while wearing a heart rate monitor and being filmed for behavioural analysis.

The control footage showed grazing wombats, a species unfamiliar to the horses but posing no threat. This was followed by clips of wolves, also unfamiliar to the horses, displaying either affiliative behaviours such as grooming or aggressive interactions.

Despite the absence of sound, movement towards the horses or any scent cues, the animals reacted very differently to the two species. Heart rates remained close to baseline while the horses watched the wombats, but increased significantly whenever wolves appeared on the screen. Surprisingly, there was no difference in the horses' responses to wolves that were fighting compared with those calmly grooming one another, suggesting that the horses identified the animals themselves as potential predators rather than responding to the behaviour they were displaying.

Lead author Zeynep Benderlioglu explained that the findings indicate horses engage in rapid cognitive assessment rather than immediately entering a classic fight-or-flight response. Although their heart rates increased markedly, they showed few obvious behavioural signs of anxiety.

Unlike a startled horse that might snort, toss its head or attempt to flee, these horses largely maintained a calm outward appearance while internally experiencing heightened alertness. This disconnect has important implications for both equine welfare and rider safety, as handlers may assume a horse is relaxed when it is actually processing a potential threat.

The study also found differences between individual horses. Male horses exhibited stronger heart rate responses to the wolf videos than females, despite having similar resting heart rates. Horses occupying higher social positions within the herd also showed greater physiological responses. The researchers suggest that dominant horses may play a key role in monitoring danger because other members of the herd often rely on them when making collective decisions about safety.

Age also influenced behaviour, with older horses showing lower levels of fearfulness and social dependency than younger animals.

The team also investigated how the horses viewed the videos. Previous research has suggested horses often use their left eye when assessing threats because the right side of the brain is specialised for processing danger. However, the horses in this study showed almost no preference for left-eye viewing while watching the wolves. Instead, they displayed no clear lateralised gaze, while the harmless wombats were viewed predominantly using binocular vision, suggesting exploratory rather than defensive processing.

The researchers believe this unexpected finding highlights the complexity of equine cognition. Rather than reacting automatically, the horses appeared to evaluate the visual information before deciding that no immediate action was necessary.

Overall, the study demonstrates that horses possess a sophisticated ability to recognise unfamiliar predators using vision alone while masking their internal state. The findings provide new insight into how horses perceive potential threats and underline the importance of recognising that a horse may be experiencing significant stress even when it appears outwardly calm.

For more details, see:

Hofacker R, Sebunia N, Pihlblad J, Benderlioglu Z (2026)

Recognition of unfamiliar predators in domestic horses through only visual predator cues. PLoS One 21(7): e0349298.

 https://doi.org/10.1371/journal.pone.0349298

Inside the Horse – An Equine Anatomy Exhibition. August 2026

  

Discover how your horse really works at "Inside the Horse", an immersive equine anatomy exhibition from Horses
Inside Out. 

 

Designed for everyone from curious horse owners to experienced professionals, this exhibition offers the chance to explore one of the UK's most extensive equine anatomy collections.

 

See real skeletons, anatomical specimens and interactive displays, while learning about bones, joints and biomechanics, muscles, tendons, ligaments and fascia, the digestive system and gut health, common injuries and diseases, and teeth, ageing, growth and development.

 

Public open days: 14–16 August and 21–23 August 2026

 

Whether you're passionate about horse welfare, performance or simply want to understand horses better, this exhibition offers an insight into the horse from the inside out.

 

For a 10% DISCOUNT use the code AX10

 

To book, and for more details, go to:

 

https://www.horsesinsideout.com/inside-the-horse

Equine anaesthesia becomes safer, but risks remain higher than in people and dogs

   

© KellyVandellen Dreamstime.com

General anaesthesia in horses has become significantly safer over the past two decades,
according to the latest findings from the Confidential Enquiry into Perioperative Equine Fatalities (CEPEF4). The large international study shows that advances in anaesthetic techniques, monitoring and recovery management have reduced the number of horses dying after anaesthesia, although the risks remain substantially higher than those seen in both human and small animal medicine.

Approximately every 10 years, the CEPEF project brings together veterinary hospitals around the world to assess the safety of equine general anaesthesia and identify factors that influence patient outcomes. The fourth phase of the study (CEPEF4) analysed 47,396 general anaesthetic procedures performed at 93 veterinary centres across 28 countries between November 2020 and June 2023, making it the largest and most comprehensive assessment of equine anaesthesia undertaken to date.

Researchers followed every horse for seven days after anaesthesia, recording whether the animal survived, was euthanased or died, while also analysing 249 different patient, surgical and anaesthetic variables.

The overall mortality rate associated with general anaesthesia was 1.2%, representing a substantial improvement compared with the 1.9% reported in the previous major enquiry (CEPEF2) in 2002. Horses undergoing procedures unrelated to colic had an even lower mortality rate of 0.6%, compared with 0.9% previously. Among horses requiring emergency surgery for colic, where patients are already critically ill, mortality fell from 7.8% to 4.2%.

Despite this encouraging progress, horses remain one of the highest-risk domestic species to anaesthetise. In comparison, modern human anaesthesia carries an anaesthesia-related mortality estimated at around one death in 100,000 to 200,000 anaesthetics (approximately 0.001% or lower) in healthy patients. In dogs, reported anaesthetic mortality is typically around 0.05–0.2% in healthy animals, increasing in those that are seriously ill. Even with recent improvements, healthy horses therefore continue to face a considerably greater risk.

The study highlights the recovery period as the most dangerous stage of anaesthesia. Unlike people or dogs, horses are large prey animals whose instinct is to stand as quickly as possible when they regain consciousness. This natural behaviour can result in panic, falls and catastrophic injuries while they are still uncoordinated.

Among otherwise healthy horses undergoing non-colic procedures, fractures sustained during recovery accounted for more than one-third (35.7%) of all deaths. Abdominal complications were responsible for 18.1%, while central nervous system disorders accounted for 13.2%.

The researchers also identified several factors associated with increased risk. Pregnant mares, geriatric horses, animals in poor body condition, patients with more severe underlying disease, urgent procedures and anaesthetics lasting either less than one hour or more than two hours all carried greater odds of death.

Importantly, the study also identified clinical practices associated with improved survival. Horses whose anaesthesia included invasive blood pressure monitoring, end-tidal carbon dioxide measurement, arterial blood gas analysis and continuous body temperature monitoring experienced significantly lower odds of death. Adequate pain relief, including combinations of opioid drugs with non-steroidal anti-inflammatory medications before anaesthesia, together with the administration of alpha-2 agonist sedatives immediately before recovery, were also associated with improved outcomes.

The findings provide valuable evidence that continued investment in monitoring equipment, careful anaesthetic management and recovery protocols is improving safety for equine patients. They also offer practical guidance to veterinarians when planning anaesthesia for higher-risk horses and help owners make informed decisions about treatment.

Although healthy horses can still die following routine anaesthesia, the steady decline in mortality over successive CEPEF studies demonstrates how advances in veterinary medicine continue to make equine anaesthesia safer. Researchers believe the extensive CEPEF4 database will continue to generate new insights that could further reduce risks in the years ahead, particularly during the critical recovery period where the greatest opportunities for improvement remain.

 

For more details, see:

Miguel Gozalo-Marcilla, José I. Redondo, Regula Bettschart-Wolfensberger, Luis Domenech, Javier Doménech, G Mark Johnston, Polly M. Taylor.

The Confidential Enquiry into Perioperative Equine Fatalities: phase 4 (CEPEF4) – a worldwide observational, prospective, multicentre cohort study in 2025.

Veterinary Anaesthesia and Analgesia (2025) Vol 52,  (5), p 525-538.

https://doi.org/10.1016/j.vaa.2025.06.005

Horses Inside Out Poster submission deadline approaching

   

There's still time to submit your scientific poster for the Horses Inside Out Conference 2027, but the deadline is fast approaching.

This year's poster theme is Welfare and Wellness, with 16 posters selected for display at the conference on 20–21 February 2027 at the Holywell Conference Centre, Loughborough.

Students, lecturers, researchers, industry professionals, companies and anyone with relevant research are welcome to submit. Posters may present the author’s own research or a literature review on the chosen subject, and work previously presented at other conferences is also eligible.

Throughout the conference, poster authors will have the opportunity to discuss their work with delegates, and six selected authors will also give short oral presentations during the weekend.

A prize will be awarded for the Best Scientific Poster.

Poster submission deadline: 31 July 2026

 For more details, see:

https://www.hioconference.com/science 

 

Case reports suggest oral cabergoline may offer alternative treatment for challenging equine PPID cases

© Hikersmurf Dreamstime.com

  The Equine Cushing's and Insulin Resistance Group Inc. (ECIR Group) has announced the publication of a new retrospective case report by Eleanor M. Kellon, VMD, examining the use of oral cabergoline as a treatment option for horses with equine pituitary pars intermedia dysfunction (PPID) that failed to respond to conventional therapy. 

PPID, commonly known as equine Cushing's disease, is most often managed with oral pergolide, which has become the standard treatment due to its high success rate in controlling clinical signs and hormone levels. However, a subset of horses either fails to respond adequately to pergolide or develops unacceptable behavioural or gastrointestinal side effects, leaving veterinarians and owners with limited therapeutic alternatives.

Until now, the primary alternative has been injectable sustained-release cabergoline. There is little published information on other oral treatment options.

Dr. Kellon's report, published in the Open Veterinary Journal, reviews the outcomes of five horses owned by ECIR Group members that were treated with daily oral cabergoline under the supervision of their attending veterinarians 

"All horses were confirmed PPID by Cornell University Vet Diagnostic Laboratory criteria, and were considered failures of mainline therapy due to inability to control ACTH and clinical signs," Dr. Kellon said. "Based on the success in a 2022 study*, members of the ECIR Group, under the direct care of their personal veterinarians, decided to try oral cabergoline as an alternative to pergolide or injectable cabergoline." 

The horses represented particularly challenging cases. All had previously failed to respond adequately to treatment with oral pergolide. Four of the five had also been treated with injectable sustained-release cabergoline, but this had been unsuccessful because of severe injection-site reactions, gastrointestinal side effects, or both. All of the horses had either longstanding PPID or rapidly progressive disease.

Despite the severity of these cases, the retrospective review found encouraging responses following the introduction of oral cabergoline. No changes were made to diet, concurrent medications, or overall management, allowing the observed improvements to be attributed to the change in therapy.

Although limited to a small number of horses, the findings suggest that daily oral cabergoline may provide a well-tolerated and effective alternative for PPID patients that cannot be successfully managed with pergolide or injectable cabergoline.

Dr. Kellon emphasised that these preliminary observations warrant further investigation. She believes additional research is needed to better understand the pharmacodynamics and pharmacokinetics of oral cabergoline in horses, establish its side-effect profile, and determine effective dosing strategies, particularly in horses with less severe disease.

While larger prospective studies will be necessary to confirm these findings, the report provides early evidence that oral cabergoline could expand treatment options for veterinarians managing some of the most difficult cases of equine PPID.

 

For more details, see:

Eleanor M. Kellon. 

Oral cabergoline for the management of equine pituitary pars intermedia dysfunction: Five cases.

Open Vet. J.. 2026; 16(6): 3818-3825.

https://doi.org/10.5455/OVJ.2026.v16.i6.52

 

*Godoy, A.F. and De La Fuentes, C.I. 

Cabergoline monotherapy in a Chilean creole horse with pituitary pars intermedia dysfunction (Cushing’s disease): a case report. 

Clin. Res. AnimSci. (2022) 2(3), 1–4

 

Shire Horse Society launches genetic study to safeguard the breed’s future

  

The Shire Horse Society is set to embark on a major scientific project in 2026 aimed at helping
secure the future of one of Britain’s most iconic native horse breeds.

Originating in England, particularly across the Midlands and Fenland regions, the Shire horse is renowned as a powerful draught breed with a history stretching back to the great horses of medieval England. Following the decline of heavy cavalry, Shires became indispensable to British agriculture and industry, ploughing heavy clay soils and hauling wagons, barges and brewery drays. The breed became a cornerstone of the Industrial Revolution, serving farms, mills and breweries throughout the country.

Today, however, the breed faces significant challenges. The Shire horse is currently classified as “At Risk” by the Rare Breeds Survival Trust, with official UK figures indicating a breeding population of fewer than 1,000 mares.

To help protect the breed’s future, the Shire Horse Society will work with genetics specialists at Nottingham Trent University’s Medical Technologies Innovation Facility (MTIF) to undertake a comprehensive genomic analysis of the UK Shire horse population. The project will be led by Dr Adam Varney, Senior Research Fellow at MTIF, alongside Dr Andy Dell, who has already worked closely with the Society on genetic management initiatives.

The study aims to provide a detailed understanding of the breed’s genetic makeup and evaluate the effectiveness of current pedigree-based breeding programmes. By examining the breed at a genomic level, researchers hope to identify both current and potential future genetic issues, enabling breeders to make more informed decisions and helping to ensure that future generations of Shires remain healthy, diverse and fit for purpose.

The Society has already adopted the SPARKS (Single Population and Records Keeping System) breeding support programme, which helps manage genetic diversity and reduce the risk of inbreeding. SPARKS calculates the relatedness of horses within the stud book and provides guidance on suitable mare and stallion pairings. While the system has proven valuable, genomic analysis offers a far more detailed picture of genetic diversity and health.

Managing inbreeding is particularly important in rare breeds, as loss of genetic diversity can lead to increased infertility, higher foal mortality, a greater risk of inherited disorders and reduced disease resistance. By combining pedigree information with modern genomic science, the Society hopes to strengthen long-term breeding strategies.

Similar genomic projects have already been successfully completed by the Eriskay Pony Society and the Cleveland Bay Horse Society, while the Suffolk Horse Society has recently begun its own programme.

Funded entirely through a generous legacy donation, the project is open to all owners of pure-bred Shire horses registered in the UK Shire Horse Society Stud Book. Mares, stallions and geldings of all ages are eligible to participate.

Collecting samples will be straightforward, requiring only a small hair sample. Testing kits, together with instructions, will be distributed directly to owners, who can either collect the samples themselves or ask their veterinarian to assist. Samples must be returned to the Society by 30 August 2026.

Once received, the DNA will be extracted and analysed by the NTU research team. Importantly, while samples identify individual horses during collection, all data will be anonymised before analysis. The project is designed to assess the breed as a whole, rather than individual animals.

The Shire Horse Society hopes that widespread participation will provide the most complete genetic picture possible. The findings are expected to play a vital role in shaping future breeding plans and ensuring that this historic British breed can thrive for generations to come.