Grayson-Jockey Club Research Foundation project funding announced

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 The Grayson-Jockey Club Research Foundation has approved $1,835,879 to support 13 new
research projects, 13 continuing projects at 16 universities, and three career development awards. This brings Grayson’s total investment since 1940 to more than $45.8 million, funding over 466 projects at 50 universities.

“Grayson remains deeply committed to research that supports every horse, no matter the breed or discipline,” said president Jamie Haydon. “We’re also pleased to expand our career development awards to $30,000, thanks to the generosity of Lucy Hamilton and the Klein Family, and to honor the late Edward Bowen with a dedicated award.”

The 2026 research portfolio spans infectious disease, diagnostics, performance, reproduction, and injury prevention.

Several projects target infectious disease, including Rhodococcus equi, a leading cause of pneumonia in foals. Researchers at Baylor College of Medicine will study how equine lung cells respond to infection to aid vaccine development, while Iowa State University will evaluate hyperimmune plasma as a preventive strategy to reduce disease and antibiotic resistance.

Improved diagnostics are another priority. Louisiana State University is advancing a more sensitive test for nocardioform placentitis, and Texas Tech University is developing rapid field and laboratory tests for contagious equine metritis. At the University of California, Davis, researchers aim to create definitive diagnostic tools for equine neurodegenerative diseases.

Novel therapies are also under investigation. Michigan State University is exploring IFNL3 mRNA as a treatment and vaccine booster for equine herpesvirus-1, while Oregon State University is developing phage therapy for chronic wound infections.

Performance and welfare-focused studies include research at Texas A&M AgriLife on tendon biology to better understand overuse injuries, and at the University of Minnesota on ECG screening to detect cardiac-related poor performance and reduce sudden death in racehorses. The University of Bern will assess a new surgical approach for trigeminal-mediated headshaking.

Metabolic and reproductive health are also addressed, with Cornell University examining the role of bile acids in infertility linked to equine metabolic syndrome.

Finally, two projects at the University of Queensland will investigate gastric health, including acid rebound and the effects of feeding strategies during exercise, with the aim of improving management and reducing gastric disease risk.

Together, the funded projects highlight Grayson’s ongoing commitment to advancing equine health through impactful research.

Details on the new projects are available at the following link:

 grayson-jockeyclub.org/default.asp?section=2&area=Research&menu=2

IVF progress

  

Researchers from the University of Florida Department of Animal Sciences have reported
progress in equine reproduction, demonstrating that frozen-thawed stallion sperm may be more effective for in vitro fertilisation (IVF) than fresh or chilled semen. The findings, published in the journal Reproductive Biology, could have significant implications for the performance horse industry.

In horse breeding, IVF has historically lagged behind its success in other species such as cattle. One major challenge has been the difficulty of achieving proper sperm function outside the body. In particular, stallion sperm require a process known as capacitation before they can penetrate and fertilise an egg. This involves a series of physical and biochemical changes that are highly sensitive to environmental conditions such as temperature and time.

The need for improved IVF techniques is especially relevant in the performance horse sector. Highly valuable mares are often selected for breeding, but not all are able to safely conceive or carry a pregnancy. Certain conditions, including uterine disease, prior foaling injuries, or lameness, may increase the risk associated with pregnancy. Additionally, some mares may be performing at their optimal level and cannot be withdrawn from competition for breeding purposes.

In such cases, producing an embryo via IVF and transferring it into a surrogate mare offers a safer alternative, protecting both the donor mare and the developing foal.

To better understand how to achieve successful fertilisation, the research team investigated how different types of semen - fresh, chilled, and frozen-thawed - respond under capacitating conditions. They also compared various sperm selection methods, including Percoll gradients, Swim-Up techniques, and microfluidic systems*. These approaches were assessed based on key indicators such as sperm motility, acrosome integrity, and biochemical markers like tyrosine phosphorylation.

The results revealed that temperature played a critical role. Incubating sperm at body temperature (38°C) reduced motility, whereas maintaining sperm at ambient temperature allowed optimal capacitation within approximately four hours. At this time point, sperm also showed the highest level of acrosome integrity, an important factor for successful fertilisation.

The research team found that frozen-thawed sperm performed better than fresh or chilled samples in the IVF setting. Although freezing and thawing can place mild stress on sperm cells, this stress appears to trigger changes that promote capacitation. As a result, frozen sperm were able to function effectively with fewer preparatory steps.

Further experiments confirmed fertilisation success through the observation of pro-nuclear formation and early embryo development. Notably, microfluidic sperm selection produced superior results compared to traditional Swim-Up methods, improving sperm quality and fertilisation potential.

Beyond the biological findings, the use of frozen sperm offers practical advantages. Unlike chilled semen, which must be used within a short timeframe, frozen semen can be stored indefinitely and thawed when needed. This flexibility allows veterinarians and breeders to better coordinate the timing of egg collection and fertilisation, making the IVF process more efficient and accessible.

This research represents a significant step forward after more than three decades of limited progress in equine IVF. By identifying conditions that support effective capacitation and demonstrating the advantages of frozen sperm, the study provides a foundation for improving embryo production in horses. For the equine industry, these advances could expand breeding options while prioritising the health and welfare of valuable mares.

 

For more details, see:

Joao D. de Agostini Losano, Jillian E. Guertin, Maura S. McGraw, Lana Katz, Vilceu Bordignon, Justin W. Callaham, Jose H.F. Pontes, Perla Fleury, Marc Maserati, Carly Turner, Bradford W. Daigneault,

Temporal characterization of conditions that promote functional capacitation of stallion sperm,

Reproductive Biology (2026) Vol 26, 2,101201,

https://doi.org/10.1016/j.repbio.2026.101201

 

 

*Percoll gradient centrifugation is a method that separates sperm based on their density. A liquid medium is layered in tubes at different concentrations, and the semen sample is placed on top. When the tube is spun in a centrifuge, sperm cells move through the layers depending on their density and quality. The most viable sperm - those that are motile and structurally normal - tend to settle into a specific layer, while debris, dead sperm, and less functional cells remain elsewhere. This method is widely used because it produces a relatively clean and concentrated sample of high-quality sperm.

Swim-Up technique relies on sperm motility rather than density. In this approach, a semen sample is placed at the bottom of a tube with a layer of culture medium above it. Over time, the most motile sperm actively swim upward into the medium. These sperm are then collected from the top layer. This technique mimics a natural selection process, as only the strongest swimmers are chosen. However, it can result in lower sperm numbers and may not always select for the best overall sperm quality, especially if motility is reduced.

Microfluidic sperm selection systems represent a more modern and precise approach. These systems, such as microfluidic sperm selection, use tiny channels that mimic aspects of the female reproductive tract. Sperm are introduced into a device where they must navigate through narrow pathways and fluid flows. Only sperm with good motility, proper morphology, and functional membranes can successfully pass through the system. This method reduces mechanical stress on the sperm compared to centrifugation and may better preserve their physiological state.

Feeding strategies for horses with severe asthma: effects on behaviour and welfare

    

Equine asthma is a chronic respiratory disease that can be triggered or worsened by inhaling
dust, mould, or other airborne particles commonly found in conventional dry hay. Managing the diet is an essential part of treatment, as feed type can influence not only respiratory health but also time budgets and welfare-related behaviours.

Recent research has compared the effects of feeding steamed hay and alfalfa pellets on horses suffering from severe asthma, shedding light on how different low-dust diets affect feeding behaviour, lung health, and overall well-being.

In a controlled study involving nine severely asthmatic horses, Antoine Symoens  and colleagues at the University of Montreal, Canada evaluated the effects of two low-dust feeding regimes - alfalfa pellets and steamed hay - on feeding duration, activity patterns, and gastric health.

The horses were housed indoors and first fed dry hay to induce a clinical flare-up of asthma. They were then placed on either steamed hay or alfalfa pellets for four weeks, using a crossover design so that each horse experienced both diets. Their behaviour was recorded for 18–22 hours at multiple stages during the trial, and gastroscopies were performed before and after each feeding period to assess gastric ulcers.

Results showed clear differences in eating patterns between the two diets. When fed steamed hay, horses spent a consistent proportion of their day eating - about 48% - both during the first and fourth weeks of feeding. In contrast, when horses were switched to pellets, the time they spent eating dropped significantly by roughly one-third in the first week. Interestingly, horses on the pelleted diet appeared to adapt by breaking up their feeding into shorter, more frequent meals, a pattern described as “fragmented eating.” This adjustment might help maintain some degree of natural foraging behaviour despite the rapid consumption time associated with pellets.

From a welfare perspective, steamed hay appears to preserve a more natural feeding time budget. Horses in the wild spend most of their day grazing, and maintaining this prolonged eating activity is associated with better digestive health and lower risk of behavioural issues such as boredom or stereotypies. Short feeding times, as seen with pelleted diets, can disrupt this pattern, potentially leading to frustration or undesirable behaviours.

However, feeding choices must also consider respiratory benefits. Earlier findings have shown that while steamed hay is much less dusty than untreated hay, it may be less effective than alfalfa pellets at improving lung function in asthmatic horses. Therefore, while steamed hay supports more natural feeding behaviour, pellets may provide a stronger advantage for respiratory management. Importantly, the study found that neither diet had an influence on the occurrence of squamous gastric ulcers, an encouraging finding for owners concerned about ulcer risk.

In practical terms, managing an asthmatic horse’s diet involves balancing multiple factors. Replacing dusty or mouldy hay with low-dust alternatives, such as haylage, steamed hay, or suitably formulated pellets, can help reduce respiratory irritation. For overweight or laminitis-prone horses, haylage may not be ideal due to its higher energy content, making steamed hay a more moderate choice. Combining different low-dust feeds could offer the best compromise, supporting both lung health and natural feeding behaviour.

In conclusion, when feeding horses with severe asthma, steamed hay helps maintain normal feeding time and behaviour, contributing positively to welfare, whereas pelleted diets offer greater respiratory benefits but may shorten eating duration. Selecting or combining these diets thoughtfully allows owners to meet both the physiological and behavioural needs of asthmatic horses.

 

For more details, see:

Antoine Symoens, Mathilde Leclère, Valentine André, Marion Desmarchelier,

Behavioral effects of two diets used for the management of severe equine asthma,

Journal of Veterinary Behavior, (2026) Vol 84, pp34-40,

https://doi.org/10.1016/j.jveb.2025.12.007

Response of horses and donkeys to fireworks in the UK

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Fireworks are widely used in the United Kingdom to mark celebrations such as Bonfire
Night and New Year's Eve. While these displays are enjoyable for many people, they can create significant challenges for animal welfare. Research has long shown that fireworks can cause stress and fear in companion animals such as dogs and cats, but comparatively little attention has been given to their effects on equids. 

A study by Stephanie Gerow and colleagues at the University of Lincoln aimed to address this gap by investigating how fireworks affect horses and donkeys in the UK.

The researchers conducted an anonymous online survey of equid owners aged 18 and over. In total, 1,234 horse owners and 232 donkey owners participated. The survey explored three main areas: how horses and donkeys respond to fireworks, what strategies owners use to reduce their impact, and owners’ opinions about firework use.

Horses are prey animals with a strong instinct for flight when faced with sudden or threatening stimuli. Loud, unpredictable noises such as fireworks can therefore trigger intense fear responses. Owners commonly reported behaviours such as running, kicking, bucking, and rearing. These reactions can be dangerous because frightened horses may attempt to escape from fields or stables, sometimes trying to jump fences or climb over stable doors. In severe cases, horses may injure themselves, other horses, or nearby people. Escaping horses can also pose a serious risk to road users if they enter nearby roads.

In the survey, eight percent of horse owners reported that their horse had suffered an injury associated with fireworks. Importantly, these injuries were usually indirect. They were caused by the horse’s reaction to the noise and lights rather than the fireworks themselves. Tragically, incidents involving fireworks have occasionally resulted in the death of horses after they panic and attempt to escape their environment.

Donkeys, in contrast, appeared to show fewer extreme responses according to owner reports. Only one donkey injury was reported in the survey. Researchers suggested that this difference may be related to the behavioural strategies used by the two species. Horses often respond to fear with a “flight or fight” reaction, which involves rapid movement and increases the risk of injury. Donkeys, however, may be more likely to adopt a “freeze” response when faced with a frightening stimulus. This behaviour may reduce the likelihood of injury, although it does not necessarily mean that donkeys experience less fear.

The survey also found that the type of horse may influence perceived reactions to fireworks. Horses used for hunting or competitive sport were generally reported to be less fearful than other horses. This may reflect differences in training, handling, or regular exposure to noisy environments.

Owners reported using a range of strategies to reduce the effects of fireworks on their animals. Common approaches included stabling horses during firework displays, remaining with the animal to provide reassurance, moving the animal to a different location away from fireworks, and playing music to mask sudden noises. Many owners also emphasised the importance of keeping animals in secure, well-lit environments with minimal hazards that could cause injury if the animal becomes frightened.

Although owners often considered these strategies effective, they are not always able to prevent stress or injury completely. Many of these measures also rely on advance warning of fireworks, which is not always available when displays are organised privately.

Most respondents (77%) supported tighter regulations on fireworks, particularly restrictions on when they can be used and reductions in their maximum noise levels. Overall, the findings highlight fireworks as a potential welfare concern for horses and, to a lesser extent, donkeys. Understanding how equids respond to loud and unpredictable stimuli is therefore an important part of equine management and welfare.

 

For more details, see:

 

Gerow SL, Clegg SR, Cooke AS.

Horse and donkey owners' perspectives on fireworks and their impact on equids in the UK.

Anim Welf. (2026) 35:e11.

https://doi.org/10.1017/awf.2026.10068

How Artificial Intelligence could improve fracture detection in horses

Researchers at the Royal Veterinary College (RVC) are exploring how artificial intelligence (AI) could help veterinarians detect fractures in animals more quickly and accurately. Their work has been shortlisted for the STEM for Britain 2026 award and highlights how technology developed for human medicine can also benefit animal health and welfare.

Fractures are a major concern in Thoroughbred racehorses. These injuries can affect both a horse’s welfare and its racing career, and in severe cases they can be life-threatening. Studies estimate that around 10% of racehorses experience a fracture during training, while bone injuries occur in roughly 1.3 per 1,000 starts in flat racing. Because of this risk, early and accurate detection of bone damage is extremely important.

However, diagnosing fractures is not always straightforward. Veterinarians usually rely on radiographs (X-rays) to assess suspected bone injuries. While X-rays are very useful, identifying fractures on these images can be challenging. Small cracks or subtle changes in bone structure may be difficult to see, and image quality or the angle at which the X-ray is taken can also affect interpretation. As a result, there is growing interest in using technology such as AI to support clinical decision-making.

The RVC research team developed an AI system designed to analyse medical images and identify fractures. The study was led by Associate Professor of Statistics Dr Ruby Chang, with the research carried out by Dr Hanya Ahmed. To train the system, the researchers created a large database of images that included 100 equine fracture cases collected from two UK equine hospitals and from published studies. They also included 70 feline fracture cases and around 4,000 human fracture images from a public database.

The AI system works in three stages. First, it identifies the type of medical image being analysed, such as an X-ray, CT scan, or MRI scan. Next, it determines the angle or projection of the image. Finally, it analyses the image to detect whether a fracture is present and to pinpoint its exact location.

One particularly interesting feature of the study is the use of a technique called transfer learning. In transfer learning, an AI model is first trained on a large dataset (in this case, thousands of human fracture images). The knowledge it gains is then adapted to a smaller dataset from another field; in this case, veterinary medicine. Because there are far fewer veterinary medical images available for training, this approach helps overcome one of the main challenges of developing AI systems for animal healthcare.

Using this method, the AI system was able to detect and locate fractures in horses with accuracy levels between 71% and 84%, despite having a relatively small number of equine images to learn from. The system also achieved very high accuracy when identifying image types and projections, reaching more than 96% accuracy in some stages of the analysis.

The results suggest that AI could become a valuable support tool for veterinarians. By helping identify fractures more quickly and reliably, AI-assisted systems may reduce uncertainty in diagnosis and allow treatment to begin earlier. This could improve recovery outcomes for horses and other animals.

The research team is now expanding the project through collaboration with the Hong Kong Jockey Club. The next goal is to investigate whether AI can detect early bone changes before a fracture occurs. If successful, this could help prevent serious injuries in racehorses and improve welfare within the sport.

Although the current study focuses on horses, the approach could also be adapted for other species such as cats, dogs, and potentially humans. Overall, the research demonstrates how advances in AI and medical imaging could play an increasingly important role in the future of veterinary diagnostics.

 

For more details, see:

Ahmed, Hanya T., Dagmar Berner, Qianni Zhang, Kristien Verheyen, Francisco Llabres-Diaz, Vanessa G. Peter, and Yu-Mei Chang. 2026.

Bridging Species with AI: A Cross-Species Deep Learning Model for Fracture Detection and Beyond

Bioengineering 13, no. 2: 213.

https://doi.org/10.3390/bioengineering13020213

Does starting racehorses early affect their careers? Insights from a German study

 

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When should racehorses begin training and competition? This is a long-standing question in equine science and
welfare. While many horses in other disciplines do not start ridden work until they are around three or four years old, Thoroughbred racehorses are often introduced to training much earlier. A recent study using data from German Thoroughbred racing has explored whether starting training and racing at a young age affects a horse’s racing career.

The research, led by Mailin Hein and colleagues at the University of Veterinary Medicine Hannover in collaboration with Dr Monica Venner from the Equine Clinic Destedt, analysed historical racing data to investigate whether early training leads to shorter or less successful careers. The team used records from the German Racehorse Association, examining the racing histories of 600 Thoroughbred horses.

Racehorses typically begin training at 18–24 months of age and may race as two-year-olds. However, horses do not reach full skeletal maturity until around six to eight years of age, meaning their bones and joints are still developing during early training. Because of this, some experts question whether starting intense work too early could increase injury risk or shorten a horse’s racing career.

The debate is particularly relevant in Germany. German animal welfare legislation generally prohibits training or competing with horses younger than 30 months, although Thoroughbred racing is currently exempt while researchers investigate the welfare implications of early training.

The researchers carried out a retrospective study, meaning they analysed existing records rather than conducting a new experiment. The 600 horses in the dataset were divided into three groups depending on when they began training and racing:

• Early training / early racing – horses that entered training between 16 and 24 months and raced as two-year-olds
• Early training / late racing – horses trained early but did not race until after the age of two
• Late training – horses that began training later, between 25 and 30 months

The researchers compared several indicators of racing success between the groups. These included career length, performance ratings, total number of races, and lifetime earnings.

One interesting finding was that sex influenced career length. Geldings (castrated male horses) tended to have longer racing careers than other horses. This is likely because stallions and mares may retire earlier to enter breeding programmes, while geldings do not have this option. Because of this difference, the researchers looked at geldings as a separate group.

Among geldings, horses that started racing at two years old achieved higher maximum performance ratings than those that first raced at three years of age or later. Importantly, the early-racing group did not show shorter racing careers compared with horses that started racing later.

Overall, the study found no evidence that early training or racing at two years old had a negative effect on career length or performance in the horses analysed.

The findings suggest that, at least in this group of German Thoroughbreds, beginning training and racing at a young age did not appear to reduce racing success or shorten careers. However, the researchers emphasise that the results should be interpreted carefully.

Because the study used historical data, it cannot fully explain why some horses started racing earlier than others. For example, horses that mature physically earlier may naturally be selected to race sooner. Horses with health problems may also leave training early and therefore not appear in racing records.

The researchers suggest that future studies should include veterinary records, training information, and management factors, such as housing conditions and workload. Understanding these factors could help scientists evaluate how a horse’s physical development, health, and mental wellbeing influence its ability to cope with early training.

Ultimately, research like this aims to improve the welfare and management of racehorses, helping trainers and veterinarians make evidence-based decisions about when young horses should begin their athletic careers.

 

For more details, see: 

 

Hein, Mailin, Nina Volkmann, Jeanette Probst, Nicole Kemper, and Monica Venner. 2026.

Thoroughbred Geldings′ Career: Influence of Age at the Start of Training and Racing

Animals 16, no. 4: 576.

https://doi.org/10.3390/ani16040576

Free articles on equine infectious disease and Microbiology in EVJ Special Collection

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The March 2026 issue of Equine Veterinary Journal (EVJ) highlights major advances in equine infectious disease and microbiology, with a Special Collection dedicated to the equine microbiome. The issue, which is free to access for 12 weeks, features 30 research papers spanning a wide range of diseases, body systems, and pathogens. Many of the studies involve international collaboration, reflecting the global importance of managing infectious diseases in horses.

Equine infectious disease remains a key research focus for veterinarians and scientists because of its impact on horse health, welfare, and the equine industry. The special issue identifies three major themes: the importance of national disease surveillance programmes, the need for accurate and definitive diagnoses, and the value of comparing diseases across different animal species to better understand how pathogens behave.

Several studies focus on improvements in diagnostic techniques, particularly for equine fever, equine influenza, and gastrointestinal parasites. These advances aim to support faster detection of disease and enable earlier implementation of biosecurity measures, which can help reduce transmission between horses.

Research into gastrointestinal diseases also features prominently. Studies explore the use of metabolic profiling to detect equine proliferative disease earlier in foals, investigate possible causes of colitis, and emphasise the importance of additional diagnostic testing for chronic hepatitis and liver failure in cases linked to hepacivirus infection. Together, these findings may support earlier intervention and improved disease management.

Antimicrobial resistance is another significant area of concern. One survey found that nearly 40% of hospitalised horses received at least one antimicrobial treatment. Research linked to colic surgery suggests that using antimicrobials for more than 24 hours after surgery is unnecessary for preventing complications, highlighting opportunities to reduce antibiotic use and slow the development of antimicrobial resistance.

Several papers examine diseases affecting multiple body systems. For example, updated guidance on equine botulism emphasises its importance as a differential diagnosis when horses show neurological signs. Other studies investigate multisystem diseases by comparing similar infections in other species, helping researchers better understand how diseases develop and present in horses.

Blood-related infectious diseases are also discussed. Two systematic reviews examine equine trypanosomiasis, focusing on its prevalence, management, and control strategies. Another study introduces a new diagnostic tool for detecting Theileria haneyi, a parasite associated with equine piroplasmosis, and reports the first evidence of its presence in China.

Regionally important diseases are highlighted through research on Hendra virus, which uses government and field data to study how domestic horses may act as bridging hosts for zoonotic pathogens. Another study shows that horses infected with African Horse Sickness virus can develop severe blood clotting disorders that cause significant bleeding. Research also suggests that equine encephalosis virus should be considered when diagnosing African Horse Sickness in regions where both diseases occur.

The issue also examines reproductive health, with one study linking Escherichia coli infection to reduced fertility in Thoroughbred broodmares. Another uses multi-omics technology to study nocardioform placentitis, proposing that the condition be renamed mucoid placentitis due to the variety of bacteria involved.

Respiratory disease research forms a major section, including several studies on strangles. Findings emphasise the importance of screening, quarantine, monitoring, and disease reporting to improve prevention. Additional studies investigate respiratory disease caused by Rhodococcus equi, equine influenza vaccination strategies, and the use of air sampling in stables as a non-invasive surveillance method for equine herpesvirus.

Other research explores infectious skin diseases and rare ulcerative conditions, demonstrating the importance of obtaining accurate diagnoses and comparing disease patterns across species when treatment data in horses is limited.

The Special Focus section also includes a dedicated collection on the equine microbiome, updating earlier research published in 2019. This collection highlights rapid progress in understanding the complex communities of microorganisms that influence equine health.

Overall, the research presented in this EVJ issue aims to improve disease detection, diagnosis, treatment, and prevention. These advances are expected to strengthen equine welfare globally while supporting the livelihoods of communities that depend on horses for work and transport.

The Special Focus Issue is available here:

 https://beva.onlinelibrary.wiley.com/toc/20423306/2026/58/2

Identifying pain in horses faces

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Research led by scientists at Anglia Ruskin University, including its specialist land-based
campus ARU Writtle, has provided new insight into how well humans can recognise pain in horses. The study, published in the academic journal Anthrozoös, highlights important welfare implications and helps explain why recognising equine discomfort can be challenging, particularly for people new to working with horses.

Horses are widely used by humans for sport, leisure, and work. Because they are prey animals, horses have evolved to mask signs of pain or weakness to avoid attracting predators. While this survival strategy helps them in the wild, it can make it harder for humans to detect when a horse is suffering, which may delay treatment and negatively affect welfare.

The research team, which also included collaborators from Bournemouth University and University of São Paulo, investigated how accurately people can recognise pain by studying facial expressions. A total of 100 participants were recruited, including 30 individuals with experience caring for horses and 70 with little or no horse-care experience. Participants were shown 60 photographs: 30 of human faces and 30 of horse faces. They were asked to rate them for signs of pain, emotional intensity (arousal), and whether the expression appeared positive or negative (valence). To provide a benchmark for accuracy, 10 equine behaviour professionals also evaluated the horse images.

The results showed that people were generally better at recognising pain in human faces than in horse faces. However, participants with horse-care experience were significantly more accurate at identifying pain in horses compared to those without experience. The study also found that the number of years spent working with horses improved accuracy, suggesting that recognising equine facial expressions is a skill that develops through observation and practice.

Experienced participants were more likely to recognise subtle indicators of pain, such as changes in ear position, the angle of the eyes, and increased muscle tension around the face. These indicators form part of recognised equine pain assessment methods and are essential for early identification of discomfort.

The research also explored how human psychological traits affect the ability to recognise pain. Participants completed assessments measuring empathy and social anxiety. Interestingly, empathy levels did not appear to influence pain recognition accuracy for either humans or horses. However, social anxiety produced more complex results. People with higher social anxiety were better at recognising pain in human faces but not in horse faces. In fact, these individuals tended to overestimate pain in horses, suggesting that human emotional processing may sometimes interfere with interpreting equine body language.

According to lead researcher Nicola J. Gregory, the study provides the first scientific evidence that humans often struggle to identify pain in horses, but experience significantly improves this ability. Meanwhile, equine behaviour specialist Rosa Verwijs emphasised that horses’ natural tendency to hide pain means problems may only become noticeable when behaviour escalates, which can increase risks to both horse welfare and human safety.

Overall, the findings highlight the importance of education and practical training for anyone working with horses. Improving knowledge of equine facial expressions and behavioural indicators of pain could help owners and professionals identify problems earlier, seek veterinary treatment more quickly, and ultimately improve the welfare of horses in human care.

 

For more detail, see:

Gregory, N. J., Trimmer, M., Dempsey, T., Verwijs, R., Lencioni, G. C., & Moseley, R. L. (2026).

Reading Pain in Horse and Human Faces: The Influence of Horse Experience, Social Anxiety, and Empathy. Anthrozoös, (2026) 39(1), 161–178. https://doi.org/10.1080/08927936.2025.2551433

Pituitary Pars Intermedia Dysfunction (PPID) and the potential role of β-endorphin in diagnosis

Pituitary Pars Intermedia Dysfunction (PPID), commonly known as equine Cushing’s disease, is a common endocrine disorder affecting older horses. The condition is associated with abnormal activity of specialised cells called melanotropes, which are located in the pars intermedia region of the pituitary gland. These cells normally produce several hormones derived from a precursor molecule known as pro-opiomelanocortin (POMC). In horses affected by PPID, melanotropes become overactive, leading to excessive production of several hormones that contribute to the clinical signs observed in the disease.

One of the most important hormones produced by melanotropes is adrenocorticotrophic hormone (ACTH). This hormone stimulates cortisol release from the adrenal glands and is widely used as a diagnostic marker for PPID. Elevated ACTH concentrations in blood samples often support a diagnosis of the disease. However, ACTH may not provide a complete understanding of PPID, as melanotropes also produce other biologically active substances that may influence disease development and clinical signs.

These additional substances include alpha-melanocyte stimulating hormone (α-MSH), corticotropin-like intermediate peptide (CLIP), and β-endorphin. β-endorphin is a peptide hormone composed of 31 amino acids and functions as part of the body’s natural pain and stress regulation system. The amino acid sequence of equine β-endorphin is very similar to that found in humans, differing by only three amino acids. Because β-endorphin is also derived from POMC and secreted by melanotropes, researchers have suggested it may play an important role in the development and progression of PPID.

Traditionally, β-endorphin concentrations in horses have been measured using radioimmunoassay (RIA). However, this technique involves the use of radioactive materials, which presents safety risks and has become less widely available in recent years. In human medicine, enzyme-linked immunosorbent assays (ELISAs) are commonly used as a safer and more accessible alternative for hormone measurement. Researchers have therefore investigated whether commercially available human β-endorphin ELISA tests could be used reliably for equine samples.

A study conducted by Nathalie Fouché and colleagues at the University of Bern, Switzerland, aimed to validate a human β-endorphin ELISA kit for use in horses and to compare β-endorphin concentrations between horses diagnosed with PPID and healthy control horses. Validation of the test involved comparing standard curves generated using both synthetic equine β-endorphin and human β-endorphin. The results demonstrated full parallelism between the curves, indicating the test could accurately measure equine hormone levels.

The researchers also assessed the reliability of the assay by calculating intra-assay and inter-assay variation. These tests measure consistency within a single test plate and between multiple plates. The assay showed acceptable levels of variation, suggesting it is suitable for research use. Additionally, β-endorphin concentrations remained stable in plasma samples over a 24-hour period regardless of centrifugation timing, storage temperature, or storage duration, which supports the practicality of sample handling.

The pilot study compared five horses diagnosed with PPID to twenty healthy aged control horses. The findings revealed significantly higher β-endorphin concentrations in horses with PPID, with median concentrations of 506 pg/mL compared to 35 pg/mL in healthy horses. These results suggest that β-endorphin may be elevated in horses with PPID and could potentially provide additional diagnostic or pathophysiological information alongside ACTH testing.

Overall, this research highlights the possible importance of β-endorphin in understanding PPID and suggests that ELISA-based testing may provide a safer and more accessible method for future investigation. Further studies with larger sample sizes are required to confirm the diagnostic value of β-endorphin in horses with PPID.

For more details, see: 

N. Fouché, J. Howard, V. Gerber, P. Billmann, M. Farinha do Sul, G. Christen, R. Bruckmaier, C. Philipona, N. Besuchet Schmutz, J. Gross,

Pilot study of β-endorphin concentrations in horses with pituitary pars intermedia dysfunction using a newly validated enzyme-linked immunosorbent assay,

Domestic Animal Endocrinology (2026) vol 95,106982

https://doi.org/10.1016/j.domaniend.2025.106982

Gastrointestinal parasites in Slovak horses

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Gastrointestinal parasitism remains a significant health concern in equine populations worldwide. Horses commonly host a wide range of intestinal helminths (parasitic worms), some of which can cause serious disease, reduced performance, and compromised welfare.

In recent years, growing resistance to anthelmintic (deworming) medications has become a major challenge for effective parasite control. This resistance has largely developed due to management practices such as frequent blanket deworming, incorrect dosing, and repeated use of the same drug classes. As a result, current parasite control strategies are shifting toward evidence-based approaches that rely on monitoring infection levels and targeting treatment appropriately.

Slovakia has a well-established horse breeding industry, with over 22,500 horses representing approximately 40 breeds.

To support improved management strategies, recent research conducted by Kuzmina and colleagues aimed to evaluate the distribution and prevalence of gastrointestinal helminths in horses in eastern Slovakia, while also examining management factors that may influence infection levels.

The study involved analysis of 392 faecal samples collected from horses across 24 farms, representing a range of ages, breeds, and management systems. Coprological diagnostic techniques were used to identify parasite eggs. The McMaster method, with a sensitivity of 50 eggs per gram (EPG), was employed to detect nematode infections, while a double-centrifugation sedimentation-flotation method was used to identify tapeworm (Anoplocephala spp.) eggs. Additional information regarding horse age, breed, stocking density, and parasite control practices was collected to allow assessment of risk factors associated with infection.

Results indicated that strongylid nematodes were the most prevalent parasites identified, with 65.6% of horses testing positive. Egg counts ranged widely from 50 to 2800 EPG, demonstrating substantial variation in parasite burdens between individual animals. Notably, approximately 29.8% of horses were responsible for 80% of the total strongylid egg output, supporting previous evidence that parasite burdens are typically unevenly distributed within equine populations. This finding reinforces the principle behind targeted selective treatment, where only horses with higher egg counts are treated to reduce drug resistance and maintain refugia (untreated parasite populations).

Parascaris spp., which primarily affect younger horses, were detected in 4.5% of samples. Tapeworm infections caused by Anoplocephala spp. were relatively uncommon, being detected in only 0.3% of horses, and no additional helminth species were identified. These results confirm that strongylids and Parascaris spp. remain the dominant equine gastrointestinal parasites in Slovakia.

Statistical analysis revealed that horse age and stocking density were significant predictors of strongylid infection levels. Younger horses and animals kept at higher stocking densities were more likely to exhibit higher parasite burdens. In contrast, infection with Parascaris spp. was influenced solely by horse age, with younger horses demonstrating greater susceptibility due to their developing immune systems.

Overall, this study provides valuable insight into the current epidemiology of equine gastrointestinal parasites in Slovakia. The findings highlight the importance of regular faecal egg count monitoring and demonstrate that parasite burdens vary significantly between individuals. Incorporating targeted selective treatment strategies, alongside improved pasture management and reduced stocking density, may help slow the progression of anthelmintic resistance.

 

For more details, see:

Tetiana A. Kuzmina, Alžbeta Königová, Ludmila Burcáková, Yaroslav Syrota, Michal Babják, Marián Várady,

Gastrointestinal parasite occurrence in Slovak horses and factors affecting Strongylidae and Parascaris spp. egg shedding,

Veterinary Parasitology: Regional Studies and Reports,(2025)  Vol 64, 101328,

ISSN 2405-9390,

https://doi.org/10.1016/j.vprsr.2025.101328

Seasonal and breed differences in resting ACTH

Pituitary pars intermedia dysfunction (PPID), commonly referred to as equine Cushing’s
disease, is a common endocrine disorder primarily affecting older equids. Current estimates suggest that approximately 25% of horses and ponies aged 15 years and older may be affected.

The condition arises from degeneration of dopaminergic neurons within the hypothalamus, leading to loss of regulatory control over the pars intermedia region of the pituitary gland. As a result, excessive production of several hormones, including adrenocorticotropic hormone (ACTH), occurs. Although PPID is progressive and currently incurable, early diagnosis and appropriate management can significantly slow disease progression and improve equine welfare.

Clinical signs of PPID are variable and may develop gradually. Common indicators include hypertrichosis (abnormal or excessive hair growth), delayed or incomplete shedding of the winter coat, lethargy, weight loss, and metabolic disturbances. One of the most serious associated complications is laminitis, which can severely compromise quality of life and may become life-threatening. Due to the variable presentation of clinical signs, diagnostic testing is frequently required to support clinical suspicion.

Measurement of baseline plasma ACTH concentration is widely used as a primary diagnostic tool for PPID. However, interpretation of ACTH values is complex, as concentrations are influenced by several factors, particularly seasonal variation. In the Northern Hemisphere, resting ACTH levels typically rise during late summer and early autumn, approximately between August and October. Understanding these physiological fluctuations is essential to avoid misinterpretation of results and potential overdiagnosis.

Breed-related differences in ACTH concentrations have also been documented. An Australian study identified that pony breeds, particularly Shetland ponies, displayed significantly higher ACTH concentrations during autumn when compared with Thoroughbred horses. These findings suggest that species, breed type, and possibly body size may influence endocrine responses and should be considered during diagnostic evaluation.

Further research has expanded understanding of ACTH variation across different equid species. A study conducted by Goodrich and colleagues, involving researchers from Cornell University, the University of California, Davis, and private veterinary practice, investigated baseline ACTH concentrations in donkeys and horse–donkey hybrids across several regions of the United States. The study aimed to provide a more comprehensive understanding of seasonal ACTH variation in healthy equids, as previous research had been limited by small sample sizes and restricted geographic representation.

The study evaluated 19 standard donkeys, 14 miniature donkeys, and 28 hybrids, with animals located in California, Massachusetts, New York, and Texas. Blood samples were collected twice monthly from June to November 2019 and monthly from December 2019 to May 2020. Results demonstrated a clear seasonal rise in ACTH concentrations across all groups, with levels increasing from mid-August and peaking in late September. Mean ACTH concentrations during peak periods reached approximately 109.6 pg/mL in standard donkeys, 134.6 pg/mL in miniature donkeys, and 100.8 pg/mL in hybrids.

Notably, hybrids consistently exhibited lower ACTH concentrations compared to donkeys throughout the year. During the seasonal peak, ACTH levels in hybrids were 23% lower than in standard donkeys and 51% lower than in miniature donkeys. Similar differences persisted during non-peak periods, with hybrids showing reductions of approximately 30% compared to both donkey groups. These findings highlight important species-related differences that may influence diagnostic interpretation.

Overall, research demonstrates that accurate diagnosis of PPID requires careful consideration of seasonal variation, species differences, and breed predisposition alongside clinical assessment. Improved understanding of normal ACTH fluctuations in healthy equids enhances diagnostic accuracy and supports more effective management of this common and welfare-significant endocrine disorder.

 

For more details, see:

Goodrich, Erin L., Sebastián Gonzalo Llanos-Soto, Renata Ivanek, Toby Pinn-Woodcock, Elisha Frye, Amy Wells, Stephen R. Purdy, Emily Berryhill, and Ned J. Place.

Both Season and Equid Type Affect Endogenous Adrenocorticotropic Hormone Concentrations in Healthy Donkeys, Mules and Hinnies in the United States

 Animals (2026) 16, no. 2: 290.

https://doi.org/10.3390/ani160202902