What riding school horses' faces reveal about their experience

  

© Igordabari  Dreamstime.com

   

Horse owners are often taught to watch for obvious signs of discomfort, such as pinned ears, tail swishing, bucking or resistance under saddle. But what if a horse's face could reveal more subtle clues about how it is coping long before those more obvious behaviours appear?

New research from the University of Guelph suggests that tiny changes in facial expression may provide valuable insights into how lesson horses experience their work and interactions with riders.

 As part of her PhD research in Equine Exercise Physiology, Aveil Oberhammer used the Equine Facial Action Coding System (EquiFACS) to study the facial expressions of 35 riding school horses before, during and after both beginner and advanced hunter/jumper lessons. Unlike the Horse Grimace Scale, which was developed specifically to identify pain, EquiFACS is a comprehensive system that records individual facial muscle movements without assigning them an emotional meaning. Researchers can then investigate what those movements may indicate in different situations, from learning and communication to stress and welfare.

The study examined short video clips taken at five stages of a typical lesson: before tacking up, after saddling, after bridling, immediately after riding and following untacking. A certified EquiFACS observer analysed each clip, recording facial action units including eye movements, ear position, nostril shape and oral behaviours such as chewing and lip movements.

Some facial expressions are surprisingly difficult to interpret. Chewing, for example, has traditionally been viewed as a sign of relaxation, yet growing evidence suggests it may instead function as a self-soothing behaviour that helps horses regulate their emotional state. Similarly, nostril dilation may reflect physical exertion, heightened attention or anticipation depending on the circumstances.

"You need to be very observant," Oberhammer explained. "Doing it live is much harder than analysing video. Sometimes you're trying to determine whether a tiny lip movement is upwards or backwards because that changes the facial action score."

One of the study's key questions challenged a common assumption within riding schools: that beginner riders are easier for horses because the physical demands are generally lower. The findings suggest the reality is more complex.

Overall, rider ability alone had surprisingly little effect on the horses' facial expressions. However, certain groups of horses responded differently. Less experienced lesson horses, particularly those with fewer than three years in a lesson programme, were more likely to display facial movements such as nostril lifting, nostril dilation and tongue movements when working with beginner riders. Mares also showed more facial activity than geldings and exhibited more eye blinks, nostril movements and lip parting with novice riders.

These findings may reflect the additional mental effort required to interpret inconsistent rider cues. Horses constantly attempt to understand what their riders are asking, and unclear timing or conflicting signals may increase their cognitive workload.

"We know that horses learn from trial and error," said Oberhammer. "If they don't associate a certain cue with a positive outcome, they might just do nothing."

The research also highlighted how facial expressions changed throughout the lesson itself. Horses were most expressive before preparation began, showing a variety of movements around the eyes, nostrils and mouth. Overall facial activity declined after saddling and became even more subdued once bridled. Following the ride, oral behaviours such as chewing became more common again, suggesting horses may communicate differently once tack and riding pressures are removed.

The authors conclude that the greatest changes in facial expression were linked not to rider ability but to different stages of the lesson, potentially reflecting anticipation before work and recovery or relief afterwards.

As equitation science continues to reshape understanding of horse behaviour and welfare, subtle facial expressions are emerging as another valuable tool for looking "behind the bridle". While they should never be interpreted in isolation, careful observation of these quiet signals could help riders, coaches and instructors better understand how horses experience their work, refine communication and support more horse-centred training and management practices.

 

For more details, see:

Aveil Oberhammer, Caleigh Copelin, Lais Rabel, Katrina Merkies

Behind the bridle: Understanding facial expressions in lesson horses before and after riding.

Applied Animal Behaviour Science,(2026) Vol 300,106982,

https://doi.org/10.1016/j.applanim.2026.106982

 

Interested in learning more about subtle behavioural cues, learning theory, and how horses communicate? Discover how the latest research in equine behaviour can help you better understand your horse and build stronger partnerships through informed, welfare-focused training.
Register for Equine Guelph’s 12-week accredited, online course Equine Behaviour, offered in partnership with School of Continuing Studies through the University of Guelph.  Go to:

https://courses.scs.uoguelph.ca/search/publicCourseSearchDetails.do?method=load&courseId=17912

 

 

AI camera system could give breeders early warning of foaling

  

© Janian Mcmillan Dreamstime.com

For most mares, foaling is a straightforward process that ends with the arrival of a healthy foal. However, when
complications occur, they can escalate rapidly. Problems such as an abnormal foetal presentation can quickly become life-threatening for both mare and foal, making rapid veterinary intervention essential. Having experienced staff on hand at the right moment can mean the difference between a successful birth and a tragic outcome.

 

The challenge is knowing exactly when that moment will arrive. Mares often show remarkably few obvious signs that foaling is imminent, forcing stud farms to maintain overnight watches throughout the breeding season. On large commercial studs, this means dedicated staff monitoring mares around the clock, while owners with just one or two mares frequently endure several sleepless nights waiting for labour to begin.

 

A reliable system capable of predicting foaling before labour starts would therefore be invaluable, improving welfare while reducing both labour demands and the risk of missing a difficult birth.

 

Researchers from the School of Veterinary Medicine at Kitasato University in Japan, working with engineers from Noritsu Precision Co., Ltd., have now tested a fully non-contact monitoring system that combines thermal imaging with artificial intelligence to predict the onset of foaling under commercial breeding conditions.

 

The study involved 115 pregnant Thoroughbred mares on 13 breeding farms in Hokkaido during the 2024 foaling season. Each mare was housed individually in a foaling box overnight between 3 p.m. and 7 a.m. and turned out during the day. A camera unit, combining a thermal infrared camera with a conventional visible-light camera, was mounted on the stall wall so the mare always remained within view.

 

Unlike wearable sensors or invasive monitoring systems, the camera required no contact with the mare. Instead, artificial intelligence analysed images every five minutes, measuring locomotor activity and body surface temperature from the thermal images while simultaneously identifying posture changes and tail-raising behaviour from the visible-light footage.

 

The researchers discovered that mares exhibit two distinct phases before giving birth. The earliest indicators appeared around 70 to 90 minutes before foaling, when both movement and body surface temperature relative to the surrounding environment increased significantly. More obvious behavioural changes, including frequent posture adjustments and repeated tail raising, occurred much closer to delivery, typically within the final 25 to 45 minutes 

These sequential changes allowed the researchers to develop a prediction model that reflected the natural progression towards labour. Using only the early indicators of movement and temperature, the system correctly detected impending foaling in 80% of mares, providing an average warning time of just over three hours 

 

When the later behavioural signs were incorporated into the model, predictive accuracy increased dramatically. The complete system correctly predicted foaling in 94.8% of mares, with an average alert approximately 89 minutes before delivery, providing staff with sufficient time to prepare for the birth or summon veterinary assistance if necessary.

 

The findings suggest that combining thermal imaging with AI-based behavioural analysis could offer breeders a practical, reliable and welfare-friendly method of monitoring mares during the foaling season. Because the system operates entirely without physical contact, it avoids the limitations of wearable devices while remaining suitable for routine use on commercial breeding farms.

 

While further studies will be needed to evaluate its performance in different breeds and management systems, the technology represents a promising step towards smarter foaling surveillance. For breeders, earlier warning of impending birth could reduce overnight monitoring, improve staff efficiency and, most importantly, increase the chances of providing timely assistance when mare and foal need it most.

  

For more details, see:

 

Nabenishi, Hisashi, Nagisa Taki, Shoji Nishibayashi, and Tomoyuki Ishii.

Noninvasive Two-Phase Foaling Prediction in Thoroughbred Mares Using Thermal Imaging and AI-Based Behavioral Analysis

Animals (2026) 16, no. 14: 2221.

https://doi.org/10.3390/ani16142221

Effects of prophylactic antimicrobial duration for colic surgery

  

© Maria Itina Dreamstime.com

Colic surgery remains one of the most challenging procedures performed in equine practice. Even with major
advances in anaesthesia, surgical techniques and postoperative care, it continues to carry significant risks. Horses requiring surgery are often already critically ill, the procedures can be lengthy, and opening the intestine inevitably increases the risk of bacterial contamination. To minimise the chance of postoperative infection, surgeons routinely administer prophylactic antibiotics, known as surgical antimicrobial prophylaxis (SAP).

However, the widespread use of antibiotics raises another important concern: antimicrobial resistance. The more frequently antibiotics are used, and the longer they are administered, the greater the selective pressure encouraging bacteria to develop resistance. Antibiotics can also disrupt the normal community of beneficial microorganisms living within the horse's digestive tract – the gut microbiome – which plays an important role in digestion, immunity and overall health.

In human medicine, evidence has shown that extending antibiotic prophylaxis beyond 24 hours after abdominal surgery offers little additional benefit and may even be harmful. Current human guidelines therefore recommend limiting SAP to less than 24 hours whenever possible. Whether the same approach could safely be adopted in equine colic surgery has remained uncertain.

To investigate, researchers led by Louise L. Southwood at the Department of Clinical Studies, New Bolton Center, University of Pennsylvania, together with colleagues from the Children's Hospital of Philadelphia, carried out a prospective randomised clinical trial comparing 24 hours and 72 hours of antibiotic prophylaxis following colic surgery.

The study enrolled 140 horses recovering from colic surgery, with 71 receiving potassium penicillin and gentamicin for 24 hours and 69 receiving the same treatment for 72 hours. The researchers monitored the horses for postoperative complications, including surgical wound infections and gastrointestinal problems. They also examined how the different treatment durations affected the horses' gut microbiome and "resistome" - the collection of antimicrobial resistance genes carried by the bacteria living in the intestine.

To analyse these changes, faecal samples from a subset of 49 horses were collected when they entered hospital and again before discharge. Using advanced DNA sequencing techniques, the team identified both the bacterial species present and the antibiotic resistance genes they carried.

The clinical results were reassuring. There were no significant differences between the two treatment groups in any measured postoperative complication. Rates of incisional infection were almost identical, occurring in around 16–17% of horses regardless of whether antibiotics had been given for one day or three. Gastrointestinal complications were also similar.

The microbiological findings told a different story.

Simply being hospitalised and undergoing surgery significantly altered the composition of the horses' intestinal microbiome. Overall bacterial diversity declined during hospitalisation, while genes associated with resistance to the antibiotics used during treatment became more common. These changes were considerably more pronounced in horses that received antibiotics for 72 hours.

In particular, the longer treatment group showed significantly higher levels of beta-lactam resistance genes, including TEM beta-lactamases, by the time they left hospital. These genes enable bacteria to resist an important class of antibiotics, raising concerns that prolonged treatment may increase selective pressure for antimicrobial resistance without providing additional clinical benefit.

The researchers conclude that limiting surgical antimicrobial prophylaxis to 24 hours appears to be the preferable strategy for horses undergoing colic surgery. It provided postoperative outcomes comparable to a 72-hour course while causing less disruption to the gut microbiome and resulting in fewer increases in antimicrobial resistance genes.

The authors note several limitations, including the study being conducted at a single hospital, relatively small numbers for detecting rare complications, and the fact that clinicians were aware of which treatment each horse received. Nevertheless, the findings provide encouraging evidence that shorter antibiotic courses may safely reduce antimicrobial use in equine practice while helping to preserve both the gut microbiome and the long-term effectiveness of these vital medicines.

For more details, see:

Southwood, L. L., Long, A., Perez, J., Daniel, S., Bittinger, K., Aitken, M., & Redding, L.

Effect of surgical antimicrobial prophylaxis duration for colic surgery on complications and resistome. 

Equine veterinary journal, (2026) 58(2), 390–403.

https://doi.org/10.1002/evj.70137

New technology helps unravel the mare's role in building the foal microbiome

  

 The first few weeks of a foal's life are a critical period for the development of its gut microbiome - the complex community of microorganisms that supports digestion, immunity and overall health. Researchers are now taking a closer look at where those microbes come from, and a new DNA sequencing technique could accelerate progress.

 

Scientists from the Horse Microbiome Research Group at the University of Surrey have demonstrated that Oxford Nanopore sequencing offers a rapid and affordable way of profiling bacterial communities in horses. Led by Dr Joy Leng and published in the Journal of Medical Microbiology, the study provides the technological foundation for the Alborada Well Foal 2 project, which is investigating how mares help establish the microbiome of their newborn foals.

 

The research follows on from the original Alborada Well Foal Study, which showed that the composition of the gut microbiome during early life may influence the future health and athletic performance of Thoroughbred racehorses. One particularly important finding was that foals treated with antibiotics during their first four weeks of life were more likely to experience poorer health and performance later on, highlighting how easily the developing microbiome can be disrupted.

 

The new project aims to answer two important questions. Firstly, how do mares pass beneficial bacteria to their foals? Secondly, if antibiotics are essential during early life, can their impact on the developing gut microbiome be reduced?

 

To find out, researchers will collect faecal, milk, saliva and skin samples from mares before and after foaling, together with faecal samples from their foals during the first 60 days of life. By comparing the bacterial communities found at these different sites, they hope to identify the main sources of the microbes that first colonise the foal's gut.

 

The study will also develop a laboratory model of the foal gut microbiome to investigate how different antibiotic treatments alter bacterial populations. This will allow potential protective strategies, including prebiotics, probiotics and postbiotics, to be evaluated before they are used in the field.

 

A key feature of the project is the use of Oxford Nanopore long-read sequencing. Unlike conventional short-read sequencing, which analyses DNA as thousands of small fragments that must later be reconstructed using sophisticated computing, long-read sequencing reads much longer stretches of DNA directly as they pass through microscopic nanopores. The portable MinION Mk1D device can be operated within a standard laboratory, while user-friendly analysis software makes the technology far more accessible than traditional sequencing platforms.

 

To evaluate the approach, the researchers analysed bacterial DNA from faeces, saliva, milk and skin samples collected from Thoroughbred mares and foals during a pilot study. The technique successfully identified distinct bacterial communities at each anatomical site, with results closely matching those reported previously using conventional sequencing.

 

Perhaps most impressively, complete microbiome profiles were generated within just three days at a cost of around £30 per sample, substantially reducing both the time and expense involved.

 

Although this was a relatively small pilot study, it demonstrates that Oxford Nanopore sequencing can provide reliable, rapid and cost-effective microbiome analysis across a range of equine tissues. As the Alborada Well Foal 2 project continues, the technology is expected to provide valuable insights into how mares seed their foals with beneficial microbes and may ultimately help identify practical ways of protecting the developing microbiome when antibiotic treatment is unavoidable.

 

For more details, see:

 

Leng, J., Tait, C., Alsubaie, B., Van Vliet, A. H. M., Sells, P., La Ragione, R. M., & Proudman, C. (2026).

Rapid bacterial community profiling of equine faecal, skin, milk and saliva samples using Oxford Nanopore long-read 16S rRNA amplicon sequencing. 

Journal of medical microbiology, 75(7), 002176.

https://doi.org/10.1099/jmm.0.002176

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.

Study challenges assumptions about “knee chips” in Thoroughbred yearlings

© Slowmotiongli  Dreamstime.com

  

The discovery of carpal osteochondral fragments (COF), commonly known as “knee chips,” on
pre-sale radiographs has long been viewed as a red flag in the Thoroughbred industry. Horses showing these lesions are often discounted at auction because buyers assume they will be less likely to succeed on the racetrack. However, new research suggests that this long-held belief may not be as straightforward as previously thought.

A study published in the Equine Veterinary Journal by researchers at the University of Kentucky's Maxwell H. Gluck Equine Research Center is the first to directly compare sales and racing outcomes of Thoroughbred yearlings with COF against a matched population of radiographically clean horses. The findings indicate that while the presence of COF can negatively affect both sales and racing performance, arthroscopic surgery may help mitigate some of those disadvantages.

“The idea came from seeing a large number of these cases get significantly marked down in price, just because people assume a chip means the horse won’t perform,” said Bruno Menarim, one of the study’s senior authors. “That was possibly true in the ’80s and part of the ’90s, but not with current arthroscopic surgery approaches.”

Researchers reviewed clinical records from Hagyard Equine Medical Institute between 2015 and 2018 and identified 46 Thoroughbred yearlings with dorsal osteochondral fragments of the radial or intermediate carpal bones. Twenty-six horses underwent arthroscopic removal of the fragments before sale, while 20 were managed conservatively. A control group of 138 sire- and year-matched siblings without radiographic abnormalities was also assembled.

The team then tracked sales and racing records up to June 2023, examining variables including sale price, career earnings, average earnings per start, number of starts, seasons raced, highest speed figure achieved and the highest class of race reached.

Overall, the presence of COF was associated with lower sale prices and reduced lifetime earnings, regardless of treatment. Horses in both the surgical and non-surgical groups also recorded fewer starts and raced for fewer seasons than their unaffected counterparts.

However, important differences emerged when treatment was considered. Horses whose fragments were removed arthroscopically were significantly more likely to achieve a racing career than those managed conservatively. Statistical analysis showed surgically treated horses had more than six times the odds of making it to the racetrack compared with untreated horses.

Perhaps more importantly from a commercial perspective, surgically treated horses were not significantly different from the control group in either sale price or total earnings. In contrast, untreated horses were heavily penalised at auction and earned significantly less during their racing careers.

“In other words, the gap between a surgically treated horse and a clean horse was not statistically significant,” Menarim explained. “The gap between an untreated horse and a clean horse was.”

The researchers also noted that the average difference in sale price between treated and untreated horses was nearly $2,000 - roughly equivalent to the cost of the surgery itself.

The study’s authors caution that the relatively small sample size and single-centre design limit the broader applicability of the findings. Nevertheless, the results suggest that while a history of COF can affect buyer perception, arthroscopic removal may preserve both sales appeal and future athletic potential.

For consignors and owners faced with a yearling diagnosed with a knee chip, the research offers reassurance that the lesion itself need not be career-defining - particularly when modern surgical treatment is employed.

For more details, see:

 

Daria C Debald, Victoria L Stanton, Cole B Sandow, Dwayne H Rodgerson, Michael A Spirito, Robert J Hunt, Bruno C Menarim.

Racing and sales performance in Thoroughbred yearlings after carpal osteochondral fragment removal.

Equine Vet J. 2026;58(3):682–691

https://doi.org/10.1111/evj.14532