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

   

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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

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  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

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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

Gothenburg Zoo horses remain calm around visitors, study finds

Dennis Björklund CC BY-SA 3.0

  

Visitors to zoos and animal parks often wonder how their presence affects the animals they
come to see. A new study from the University of Gothenburg offers reassuring news for animal keepers and visitors alike: the horses at Gothenburg's Children's Zoo appear comfortable around people, even when surrounded by groups of enthusiastic children.

Animal welfare encompasses both the physical and psychological wellbeing of animals and is a key concern for zoos and other organisations that keep animals in captivity. Understanding how animals respond to visitors is particularly important in facilities involved in conservation and breeding programmes, as stress can negatively affect health and reproduction.

To investigate whether human activity influences the welfare of horses at Slottsskogen, a large city park in Gothenburg, Sweden, researchers from the Department of Biological and Environmental Sciences, University of Gothenburg, monitored the heart rates of eight Gotland russ horses. Heart rate is widely used as an indicator of stress because it rises when animals experience physical exertion or emotional strain.

Lead researcher Isidora Dundjerovic and her colleagues fitted the horses with Polar heart rate monitors and measured their heart rates under three different conditions: while resting, during exercise, and during a playground event in which the horses stood in a paddock next to a children's play area and were petted by visitors while eating hay.

The results showed clear differences between the three situations. The horses' average resting heart rate was 42.5 beats per minute (bpm), while exercise increased it to an average of 85 bpm. During the playground event, however, the average heart rate was only 51 bpm - higher than at rest but far below the level recorded during exercise.

These findings suggest that interaction with visitors was not a significant source of stress for the horses. In fact, despite being surrounded by children and adults, the animals remained relatively calm throughout the event.

The study also provided insight into how the horses reacted to other common features of the urban park environment. During their daily walks, the horses encountered barking dogs, passing cars and other animals. None of these appeared to trigger a measurable stress response.

One exception stood out. During one playground session, an excavator unexpectedly started operating close to the paddock. The horses' heart rates rose sharply, and they quickly moved away from the machine. This reaction indicated that loud mechanical noise was stressful, unlike the presence of visitors or routine park activity.

"Horses have lived alongside humans for thousands of years," says Dundjerovic. "We now know a little more about how they are affected by being in an environment with lots of people, which is important for ensuring their welfare."

The findings are encouraging for the staff responsible for caring for the animals at the Children's Zoo. According to zoologist Linda Thelin, animal welfare is monitored closely through a variety of methods, and physiological studies such as this help identify sources of stress that may not be obvious from behaviour alone.

As zoos continue to balance conservation, education and public engagement, studies like this provide valuable evidence to guide management decisions. For the horses at Gothenburg's Children's Zoo, it appears that friendly human attention is not a problem - but noisy construction equipment is another matter entirely.

 

For more details, see:

Dundjerovic, I., and L. U. Sneddon. 2026.

Heart Rate as an Indicator of Stress in Gotland's Russ Horses.

 Zoo Biology 45: 293-299.

https://doi.org/10.1002/zoo.70052