New device aims to help asthmatic horses breathe more easily

The new equine respirator (Tim Brouk)

A novel collaboration between Purdue University’s College of Health and Human Sciences and the College of Veterinary Medicine may offer significant relief for horses suffering from asthma—a common respiratory condition often triggered by inhaled particles such as mould spores found in dusty hay.

Equine asthma, like its human counterpart, is frequently linked to allergic sensitisation to airborne irritants. While a range of treatment and management options exist, the most effective strategy remains straightforward: minimise exposure to the particles that trigger the condition. This is typically attempted by soaking or steam-treating hay to reduce airborne dust. However, researchers at Purdue have taken this one step further by developing a wearable device that could filter out harmful particles before they even reach the horse’s airways.

At the heart of this innovation is an equine respirator—a specially designed breathing mask that attaches directly to a horse’s bridle or head collar. The device allows the horse to breathe filtered air through an intake positioned over the bridge of the nose, while exhalation occurs through valves located near the nostrils. Crucially, the design allows horses to eat and drink while wearing the respirator, making it suitable for continuous use in dusty environments like stables or arenas.

The project was born out of a cross-disciplinary partnership. Dr. Jae Hong Park, associate professor of Health Sciences, had been working on developing human respirators, especially for welders working in manufacturing facilities. His research caught the attention of Dr. Laurent Couëtil, a professor of Large Animal Internal Medicine in the College of Veterinary Medicine, who wondered if a similar approach could be adapted for equine use.

Momentum built when Chang Geun Lee, a Ph.D. candidate in Health Sciences with a background in mechanical engineering and industrial design, joined Park’s lab. Lee brought a unique combination of technical skills and practical design experience that proved instrumental in creating a functional and comfortable respirator for horses.

The team, which also includes Laura Murray, RVT and research technologist in the Department of Veterinary Clinical Sciences, spent months designing, prototyping, and refining the respirator. Their efforts have culminated in a practical tool that could significantly improve the quality of life for horses affected by respiratory issues—particularly those regularly exposed to dusty environments.

By combining expertise in health sciences, veterinary medicine, and engineering, this collaboration exemplifies the power of interdisciplinary research to solve real-world problems—and could mark a significant advance in the management of equine asthma.

The research team are now looking to see if the device could be made available for general use.

For more details, see: 

https://vet.purdue.edu/news/asthmatic-horses-can-breathe-easier-thanks-to-purdue-health-and-human-sciences-and-college-of-veterinary-medicine.php

Progress towards understanding the cause of Equine Grass Sickness

Pony with chronic grass sickness (McGorum et al)

 An international team of researchers has identified what they believe to be the probable cause of equine grass
sickness (EGS). Their findings suggest that a neurotoxin, similar in action to snake venom toxins but produced by pasture microbes, is the likely culprit. The work is set to be published in the Equine Veterinary Journal (EVJ) and is currently freely available online. A special editorial in the January 2025 issue of EVJ, authored by Bruce McGorum and colleagues, highlights the study’s findings and their implications. 

This breakthrough has the potential to pave the way for novel treatments and improved diagnostics for this devastating disease.

 

Equine grass sickness (EGS), also known as equine dysautonomia, is a major cause of mortality in horses and ponies in Great Britain, with more than 80% of cases proving fatal. First recognised in Scotland over 100 years ago, EGS remains most prevalent in Great Britain but has been reported in several northern European countries, South America, and very infrequently in North America.

 

EGS damages the autonomic nervous system, which controls involuntary bodily functions, with particularly severe effects on the gastrointestinal tract. Clinical signs range from depression, difficulty eating and swallowing, and weight loss to gastric reflux, abdominal pain, and death. The disease causes rapid degeneration of nerves, leading to paralysis of the gastrointestinal tract and other systemic effects such as muscle weakness, drooping eyelids, excessive salivation, sweating, and muscle tremors.

 

As there is currently no effective treatment for the most severe (acute and sub-acute) forms of the disease, horses are euthanised on humane grounds, typically within 24-48 hours of showing abnormal signs. In contrast, up to 50% of horses with the mild (chronic) form of grass sickness may survive with intensive nursing and supportive care.

Researchers from the Dick Vet Equine Hospital (RDSVS University of Edinburgh), Newcastle University, Istituto Zooprofilattico Sperimentale delle Venezie, and the University of Padova have made significant strides in identifying the neurotoxin responsible for EGS. Using electron microscopy, they examined post-mortem samples from horses with EGS and compared them to control samples. Their findings revealed that 72.2% of neuromuscular junctions (NMJs) in EGS-affected horses displayed abnormal morphology, compared to just 6.9% in controls.

 

These abnormalities are believed to represent a toxin-specific signature for a neurotoxic enzyme known as phospholipase A2. This enzyme disrupts the microscopic sites of communication between nerves and muscles (NMJs), which are crucial for normal muscle function.

 

Ongoing work aims to definitively identify the source of this toxin. Researchers suspect it is produced by a microbe, such as a bacterium or fungus, that thrives on pasture during the cold and dry weather conditions that typically precede outbreaks of EGS.

 

Interestingly, neurotoxic phospholipase A2 enzymes are also found in the venom of many poisonous snakes. While venomous snakes are not implicated in EGS, researchers hope that drugs being developed to treat nerve damage in snakebite victims could help promote nerve regeneration and recovery in horses with grass sickness.

 

Professor Bruce McGorum, R(D)SVS said: “Identifying a probable cause of Equine Grass Sickness represents a significant breakthrough. We hope that this discovery will lead to novel treatments and improved diagnostics for this devastating condition. We are very grateful for the generous support we have received from horse owners, veterinary surgeons, scientists, charities and funding bodies.” 

 

“Further work is underway to determine the source of this neurotoxin; it is likely to be produced by a microbe such as a bacterium or fungus which grows on the horse’s pasture during the cold and dry weather which precedes the disease.” 

 

This discovery represents a significant step forward in understanding equine grass sickness. By pinpointing the probable cause, researchers can now focus on developing effective treatments and preventive strategies. Advances in identifying the toxin’s source and exploring therapeutic interventions for nerve regeneration offer hope for reducing the impact of this devastating disease.

 

For more details, see:

 

McGorum, B., Pirie, R.S., Bano, L., Davey, T., Harris, J. and Montecucco, C. (2025), 

Neurotoxic phospholipase A₂: A proposed cause of equine grass sickness and other animal dysautonomias (multiple system neuropathies). 

Equine Vet J, 57: 11-18.

https://doi.org/10.1111/evj.14442

 

McGorum BC, Davey T, Dosi MCM, Keen JA, Morrison LR, Pirie RS, Shaw DJ, Harris JB.  

Equine grass sickness is associated with major abnormalities in the ultrastructure of skeletal neuromuscular junctions. 

Equine Vet J.  2025; 57(1): 193–202.

https://doi.org/10.1111/evj.14063

The role of equine practice in the downfall of antibiotics

(c) Amaviael Dreamstime.com

 Less than a century ago, Alexander Fleming observed that a mould, Penicillium notatum, inhibited the growth of Staphylococcus bacteria on a petri dish. This discovery paved the way for the development of antibiotics, which
revolutionised medicine in the 20th century.

However, the overuse and misuse of antibiotics have led to a growing problem: antimicrobial resistance (AMR). The "golden age" of antibiotics appears to be waning. In the same way that anthelmintic resistance has become a significant challenge in managing parasites in horses, AMR is now a pressing global issue.

 

The World Health Organization (WHO) has classified AMR as a widespread and serious threat, warning that it "is no longer a prediction for the future; it is happening right now in every region of the world and has the potential to affect anyone, of any age, in any country." While anthelmintic resistance is widely discussed, it is no surprise that bacteria, which reproduce far more rapidly than gastrointestinal parasites, are also developing resistance to substances designed to eliminate them.

 

In 2016, the Review on Antimicrobial Resistance, commissioned by the UK government and chaired by economist Jim O'Neill, predicted that, if current trends continue, antimicrobial resistance  could lead to 10 million deaths annually by 2050, surpassing deaths caused by cancer and other major diseases.

 

Despite that, public interest in the threat of the downfall of antibiotics appears limited, suggests Bruce Bladon, guest editor of the latest virtual issue of the Equine Veterinary Journal (EVJ).  He has chosen 15 of the most pertinent articles on the topic from EVJ and its sister journal, Equine Veterinary Education. His intention is to highlight the significant risk resistance poses and the need to monitor and change equine practice protocols. The virtual collection is free to view here (until 20 January 2025)

 

Three articles: Antimicrobial use and antimicrobial resistance in horses, Antimicrobial resistance in horses, a call to actionand Room for improvement? The use of antimicrobials in equine respiratory disease present the background on current legislation, use and monitoring of antimicrobials in equine practice.

 

Audit of antimicrobial use in eleven equine practices over a five-year period (2014–2018) showed an impressive reduction in antibiotic usage but failed to accommodate the fact that the corporatised practices in the study may have been treating less horses. In addition, the withdrawal of a key antimicrobial from sale during the period had reduced antimicrobial usage figures.

 

Antimicrobial prescribing practice in UK equine veterinary practice and Antimicrobial prescribing and antimicrobial resistance surveillance in equine practice established that potentiated sulphonamides were the most frequently used class of antibiotic in equine practice and that there was a positive adoption of written antimicrobial usage policies. However, both also confirmed that the use of Highest Priority Critically Important Antimicrobials was frequent.

 

Use of antimicrobials licensed for systemic administration in UK equine practice reported the incidence of antibiotic prescription, to 19.5% (95% CI: 19.2%–19.8%) of 322 equids attended by UK veterinary practices in 2018. Category B antimicrobials were prescribed to 1228 equids (1.9%, 95% CI: 1.8%–2.0%). Active racehorses were 1.6 times more likely to receive antibiotics than non-racehorses. 

 

Antibiotic use in first opinion equine practice in the United Kingdom: Serial point prevalence surveys in 17 practicesShowed that Highest Priority Critically Important Antibiotic usage was similar, at 1.6% of consultations, with potentiated sulphonamides and oxytetracycline constituting two thirds of antibiotic prescriptions. 

 

Antibiotic usage in 14 equine practices over a 10-year period (2012–2021) produced volumetric data compatible with the ESVAC and VARSS methodology. It showed that antibiotic usage did decline during the study period, from 60 to 46 mg/kg. A second metric, the Defined Daily Dose Veterinary per year was also reported, which was 1.52 in 2021, down from 1.7 in 2012. 

 

Changing policy to treat foals with Rhodococcus equi pneumonia in the later course of disease decreases antimicrobial usage without increasing mortality rate reported on the treatment only of foals with larger abscesses. The authors documented a reduction in treatment of foals with rhodococcus pneumonia from 82% to 51% and reduction of median course duration from 41 to 23 days, associated with a statistically insignificant increase in all causes of mortality from 1.15% to 1.65%.

 

Standing equine cheek tooth extraction: A multivariate analysis of the effect of antibiotics on the risk of post-operative complications reported there was minimal difference in complication rates associated with antibiotic treatment versus extraction

performed without perioperative antimicrobial prophylaxis.

 

Surgical antimicrobial prophylaxis: Current standards of care reported on the extensive evidence-based guidelines in human surgery, which have been adapted to equine usage. 

 

Post operative synovial sepsis following endoscopic surgery: Increased risk associated with the carpal sheath showed an identical rate of post-operative sepsis following arthroscopy without surgical antimicrobial prophylaxis compared to surgical antimicrobial prophylaxis.

 

Incidence and risk factors for complications associated with equine general anaesthesia for elective magnetic resonance imaging and Antimicrobial prophylaxis is not indicated for horses undergoing general anaesthesia for elective orthopaedic MRI provided contrasting results. This made it difficult to draw a conclusion about the need for peri-anaesthetic antimicrobials.

 

“Ultimately, the issue is reducing antimicrobial resistance, particularly in the human healthcare field,” said Bruce Bladon. “It is acknowledged that surgeon behaviour is a limiting factor in the adoption of appropriate surgical antimicrobial prophylaxis policies. Maybe if a clinician was persuaded that avoiding antibiotic prescription would reduce the incidence of antibiotic resistance, they might be more inclined to withhold prophylactic treatment.

 

“There is a need for a national surveillance programme. If you cannot measure it, you cannot manage it.” 

 

The virtual issue can be found at https://beva.onlinelibrary.wiley.com/doi/toc/10.1001/(ISSN)2042-3306.antibiotics

 and will be free to view until 20 January 2025.

Testing for insulin dysregulation after transportation could lead to a false positive result

(c) Anna Cvetkova Dreamstime.com

Recent research indicates that conducting tests to identify insulin dysregulation (ID) in horses after transportation may lead to false positive results.

The oral sugar test (OST) is commonly used to assess insulin dysregulation, a key component of equine metabolic syndrome (EMS). This test involves taking blood samples at specific intervals before and after administering a dose of sugar, typically in the form of corn syrup. By analysing blood glucose and insulin levels, the OST evaluates how the horse’s body processes a sudden intake of sugar.

 

As this is a time-consuming test, it is often more practical to perform it in a clinic setting. However, recent findings have shown that transportation may influence test outcomes, potentially leading to false positives—where a horse with normal insulin function appears to have ID.

 

Dr. Erica Jacquay and Dr. Amanda Adams from the University of Kentucky, in collaboration with the WALTHAM™ Equine Studies Group, conducted a study to examine the effects of short-term transportation on stress parameters and insulin responses to the OST in horses both with and without ID. The research was recently published in the Equine Veterinary Journal.

 

The study involved seven non-pregnant ID mares and seven non-pregnant non-ID mares, all experienced with transportation. The horses were transported in groups for approximately 1.5 hours to and from their home base by the same driver. An OST (0.15 mL/kg body weight Karo Light Corn Syrup) was conducted 24 hours before and 3 hours after the journey.

 

The findings revealed that both serum and salivary cortisol levels significantly increased due to transportation, with no differences observed between ID and non-ID horses. As expected, the ID mares showed higher insulin responses to the OST on both occasions. 

 

However, in 5 out of 7 non-ID mares, post-travel OST insulin levels surpassed the diagnostic threshold for ID, suggesting that these horses could have been mistakenly diagnosed with insulin dysregulation. Additionally, some ID mares showed post-travel T60 OST insulin levels that were more than double their pre-transportation levels.

 

These results imply that real-world testing conditions, including transportation, may lead to misdiagnoses of insulin dysregulation and inappropriate classification of horses as having EMS.

 

“This research is an important step in improving our understanding of insulin dysregulation and EMS,” said Dr Pat Harris, head of the WALTHAM™ Equine Studies Group which provides the science behind the SPILLERS brand. “The findings show that performing an OST three hours after short-term transportation may result in inaccurate ID status, whether testing a new case or monitoring the status of an ID horse. In addition, special care should be given when transporting horses with ID especially those with a history of hyperinsulinaemia- associated laminitis.

 

“Further studies are needed to determine the best timing of diagnostic testing if transporting horses to a veterinary clinic for OSTs.”

 

For more details, see:

 

Jacquay ET, Harris PA, Adams AA. T

he impact of short-term transportation stress on insulin and oral sugar responses in insulin dysregulated and non-insulin dysregulated horses. 

Equine Vet J. 2024.

https://doi.org/10.1111/evj.14403

Warning of possible adverse effects of SGLT2i on horses.

© Brian Sedgbeer Dreamstime.com

A group of veterinary experts have issued a warning regarding the potential adverse effects of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in horses. In a letter published in the Veterinary Record, Bruce McGorum and clinicians from leading veterinary hospitals like the Royal (Dick) School of Veterinary Studies, Edinburgh, Rossdales Equine Hospital, the University of Liverpool, and the Royal Veterinary College expressed their concerns.

These medications, such as ertugliflozin and canagliflozin, are increasingly used to treat equine metabolic syndrome (EMS), particularly in horses with laminitis that hasn't responded to dietary adjustments. While these drugs have shown promise in reducing serum insulin concentrations, promoting weight loss, and managing laminitis related to hyperinsulinemia, concerns have been raised about significant adverse effects.

 

Minor side effects reported include increased serum triglycerides and liver enzymes, dullness, and increased drinking and urination. However, more serious cases have shown markedly elevated serum triglycerides (above 40 mmol/L), increased liver enzymes (such as GGT, GLDH, LDH), and bile acids, indicating potential liver damage or dysfunction. These biochemical changes were also accompanied by clinical signs such as dullness, loss of appetite, gastric impaction, bilateral laryngeal paralysis, hepatic encephalopathy, and, in some cases, death.

 

Due to these risks, the experts recommend that SGLT2 inhibitors be used only in horses that have not responded to adequate dietary or exercise management, or those with severe laminitis. 

 

Additionally, they advise against using these medications in horses with pre-existing liver disease or hyperlipaemia and emphasize the importance of regular monitoring of diet, liver enzymes, serum triglycerides, and bile acids. Horse owners should be educated about the signs of hyperlipaemia and the potential risks involved in the use of these drugs.

 

Further research is needed to fully understand the risk factors and adverse effects of SGLT2 inhibitors in horses. Until then, their use should be restricted to cases where other treatment options have failed.

For more details, see:

B C McGorum, J A Keen, S McCullagh, CM Marr, C MacKenzie, H Carslake, N Menzies-Gow, Bettina Dunkel, M Hewetson, J Reed, E Knowles.

Potential adverse effects of SGLT2i in horses 

Veterinary Record (2024) vol 195, 253

Seasonal sycamore risk

 The British Equine Veterinary Association (BEVA) is reminding horse owners to keep horses away from sycamore trees as their seeds can cause fatal illness, known as atypical myopathy. 

Seeds (masts or helicopters) from the common sycamore tree (Acer pseudoplatanus) produce a toxin called Hypoglycin A, which can remain present in high concentrations in seedlings. When horses eat these, either by accident or because they are lacking other forage options, some individuals will develop severe and often fatal muscle damage, called atypical myopathy. 

 

Symptoms include muscle soreness, weakness, breathing issues, and dark urine. Immediate veterinary care is crucial, as 75% of affected horses die.

 

“With leaves still on trees now is the time to identify sycamores in the vicinity of your horse’s fields and predict the future risk,” said Lucy Grieve, Veterinary Projects Officer at BEVA “Once the leaves start to turn and then drop it will be much more difficult to spot sycamores.”

 

To prevent atypical myopathy, she advises:

 

·      Identify sycamore trees near fields and anticipate risk before leaves fall.

·      Collect seeds or exclude horses from affected areas using electric fencing or stabling. 

·      provide supplementary forage to prevent seed ingestion.

·      Don’t fell seed-laden trees, as it may worsen contamination.

·      Monitor horses carefully even after they have been moved from affected pasture as disease can occur up to four days after exposure.

 

For further information you can download the Royal Veterinary College’s fact sheet on  Atypical Myopathy: https://www.rvc.ac.uk/Media/Default/Comparative%20Neuromuscular%20Diseases%20Laboratory/Atypical%20Myopathy%20fact%20file%20updated%202022.pdf

 

For further information visit www.beva.org.uk.

Is faecal microbiota transplantation useful for treating diarrhoea in foals?

(c) Rookie72 Dreamstime.com

 Diarrhoea is a common problem in foals under 6 months of age. 

There are many causes, or combination of causes, including infectious, managerial, and environmental factors.  

Foal diarrhoea can lead to dehydration, electrolyte imbalances, and, in severe cases, systemic infections. In such cases, it can become life-threatening.

 

Diarrhoea and Systemic Inflammatory Response Syndrome (SIRS) in foals are interconnected conditions that demand immediate attention. While diarrhoea is a frequent occurrence, it can escalate to SIRS, particularly when associated with severe infections or when significant dehydration and systemic stress occur.

 

A common contributor to diarrhoea in foals is dysbiosis, or a disruption in the normal intestinal microbiota. Could restoring this microbial balance be a potential solution for managing this potentially fatal condition? 

 

Faecal microbiota transplantation (FMT) has been used in adult horses to reduce diarrhoea and improve alpha diversity, a measure of the variety of microbial species within an individual’s gut.

 

A recent study in Australia, published in the Journal of Veterinary Internal Medicine, explored the effects of FMT in foals with diarrhoea and SIRS. The study, led by Jillian Bell, involved clinicians from three equine veterinary hospitals. It included 25 foals under six months of age with diarrhoea and SIRS who were admitted for treatment.

 

In the randomised, placebo-controlled cohort study, 19 foals were enrolled in the FMT group, while 9 were in the control group. The treatment groups received either FMT or an electrolyte solution once daily for three days. Researchers collected faecal samples from the foals on days 0 (D0), D1, D2, D3, and D7 to monitor changes.

 

The FMT solution was prepared 15 minutes prior to treatment. from fresh manure collected from healthy donor horses (previously screened for pathogenic agents). About 300 g of manure was blended with 1 L of warm chlorinated water (95°F) for 30 to 60 seconds, then strained through a wire strainer or gauze into a clean container.

 

The study found that FMT was associated with improvements in some clinical signs and certain clinicopathological parameters. FMT had no significant impact on survival rates (P = 0.3) or the resolution of diarrhoea (P = 0.4). Foals receiving FMT, however, showed a significantly lower heart rate, white blood cell (WBC) count, and packed cell volume (PCV), as well as higher serum chloride concentrations, compared to pretreatment values and the control group. Notably, on Day 3, the WBC count in the FMT group was significantly lower than in the control group (P = 0.04), and heart rate decreased over time in the FMT group.

 

Additionally, although three foals initially in the control group were later transferred to the FMT group, diarrhoea resolved in two of them after FMT treatment.

 

FMT was also associated with a greater diversity in the gut microbiota, with enrichment of beneficial bacteria such as the phylum Verrucomicrobiota, genus Akkermansia, and family Prevotellaceae. Previous studies have shown that Akkermansia is linked to the maintenance of the mucin layer in the intestines and can reduce bowel inflammation in humans. Members of the Prevotellaceae family have been associated with anti-inflammatory effects and improved intestinal health.

 

The authors concluded that FMT appears to be a safe treatment for foals with diarrhoea and can lead to some clinical and microbiota changes that suggest beneficial effects. 

 

However, further research is needed to confirm its impact on survival and long-term outcomes in affected foals.

 

For more details, see: 

 

Bell J,  Raidal SL,  Cuming RS,  Trope G,  Hughes KJ.  

Effects of fecal microbiota transplantation on clinical outcomes and fecal microbiota of foals with diarrhea. 

J Vet Intern Med.  2024; 38(5): 2718-2728.

https://doi.org/10.1111/jvim.17185

Bacterial gut diversity in TB foals improves future racing performance

 The composition of gut bacteria in one-month-old Thoroughbred foals can predict their future
athletic performance, according to a new study from the University of Surrey. Foals with lower bacterial diversity at 28 days old were also found to have a significantly increased risk of respiratory disease later in life.

 Researchers from Surrey's School of Veterinary Medicine and School of Bioscience, led by Professor Chris Proudman, examined the gut bacterial composition of Thoroughbred foals bred for flat racing and its impact on their long-term health and performance.

The three-year cohort study explored the interactions between early-life gut bacterial communities, health outcomes in later life, and athletic performance on the racetrack. The findings were published in Scientific Reports.

 

The study involved analysing 438 faecal samples from 52 foals, tracking their respiratory, gastrointestinal, orthopaedic, and soft-tissue health from birth to three years of age. The researchers also analysed data on race performance, including finishing positions, official ratings, and prize money earnings as measures of athletic performance.

 

Professor Chris Proudman, Professor of Veterinary Clinical Science at the School of Veterinary Medicine at the University of Surrey, said:   "Minimising the risk of disease and injury is important for the welfare of racehorses, and maximising their athletic potential is important for their owners. We have found that gut health, in particular the health of gut bacterial communities very early in life, exerts a profound and enduring impact on racehorse health and performance."

 

The study found a positive association between athletic performance and higher faecal bacterial diversity at one month old. Specifically, a higher abundance of the bacteria Anaeroplasmataceae was linked to a higher official rating, and increased levels of Bacillaceae at 28 days old were associated with better race placings.

 

The researchers concluded that the gut bacterial composition in the first months of life influences the risk of specific diseases and athletic performance up to three years old. Foals with lower bacterial diversity at one month old had a significantly higher risk of developing respiratory disease, which was also associated with a higher relative abundance of the bacteria Pseudomonadaceae.

 

Interestingly, the study revealed that foals treated with antibiotics during their first month of life had significantly lower bacterial diversity at 28 days old compared to those not treated with antibiotics. These foals also earned significantly less prize money and had a higher rate of respiratory disease later in life.

 

Professor Roberto La Ragione, co-investigator from the School of Bioscience at the University of Surrey, commented, "While antibiotics are essential for treating infections and ensuring the long-term health of foals, their use must be carefully managed. Our study demonstrates that antibiotic treatment can disrupt the gut microbiome with long-term consequences for health and performance. The next phase of our research will focus on minimizing this disruption when antibiotics are necessary."

 

Additionally, the researchers found that low gut bacterial diversity in early life is associated with an increased risk of soft-tissue and orthopaedic issues later on. They believe these health impacts are likely related to immunological priming, though the underlying reasons for the observed negative effects on racehorse performance are still not fully understood.

 

Dr. Kirsten Rausing, Chairman of the International Thoroughbred Breeders Federation and study sponsor through her ALBORADA Trust, remarked, "This ground-breaking study has identified the importance of gut health in our very young foals. As breeders, if we can get this right, we will produce foals that will be healthier, and that will grow into more successful racehorses."  

 

Ongoing research aims to develop novel probiotics to enhance foal gut health in early life and to investigate how antibiotics can be used while preserving gut health.

 

The researchers conclude: “For the first time, this study demonstrates a relationship between early-life gut bacterial communities and subsequent athletic performance that has implications for athletes of all species including humans.”

 

 

For more details, see:

 

Early-life gut bacterial community structure predicts disease risk and athletic performance in horses bred for racing

J. Leng, C. Moller-Levet, R. I. Mansergh, R. O’Flaherty, R. Cooke, P. Sells, C. Pinkham,O.  Pynn, C. Smith, Z. Wise, R. Ellis, A. Couto Alves, R. La Ragione and C. Proudman 

Scientific Reports (2024) vol 14, Article number: 17124 

https://doi.org/10.1038/s41598-024-64657-6 

Do endocrine disorders affect anthelmintic performance?

Recent research indicates that insulin dysregulation may affect the performance of anthelmintics
like ivermectin. This suggests that horses with such endocrine disorders might be more prone to parasitic infections.

In a study conducted by Martin Nielsen and colleagues at the University of Kentucky, the response to ivermectin was evaluated in horses with insulin dysregulation (ID), pituitary pars intermedia dysfunction (PPID), or neither condition. 

 

The study population was part of a special herd at the University of Kentucky’s Department of Veterinary Science, which included horses with and without these endocrine disorders. These horses were kept in permanent paddocks without pasture rotation or enhanced hygiene practices and received routine anthelmintic treatments: ivermectin in March or April and July or August, and moxidectin/praziquantel in November.

 

The study focused on senior horses (aged 13 years and over) and those with or without PPID, ID, or both. Out of 47 horses in the research herd, 19 met the criteria for inclusion. These horses, all with positive faecal worm egg counts, were treated with ivermectin at the recommended dose of 200 mcg/kg. Faecal samples were collected before treatment, two weeks post-treatment (for the Faecal Egg Count Reduction Test, or FECRT), and then weekly until worm eggs reappeared in the faeces (Egg Reappearance Period, or ERP).

 

Two laboratory tests were employed to assess the response to ivermectin: the Faecal Egg Count Reduction Test (FECRT) and the Egg Reappearance Period (ERP). For the FECRT, a reduction of at least 99.7% in worm egg counts is considered effective two weeks post-treatment. The ERP for ivermectin is typically 8-10 weeks.

 

The study found no significant differences in the effectiveness of ivermectin between the groups. However, the small sample size may have made it difficult to detect any potential differences. Overall, ivermectin was highly effective, with all horses showing a greater than 99.7% reduction in worm egg counts at the two-week mark. 

 

Nonetheless, the researchers observed that the ERP was shorter in horses with ID and those with both PPID and ID, at six and seven weeks respectively, compared to eight weeks for both the PPID-only and healthy control groups.

 

They suggest that their findings indicate a need for further investigation of the possible influence of endocrine disorders on anthelmintic performance in horses.

 

 

For more details, see:

 

M.K. Nielsen, C.A. Finnerty, N.E. Ripley, A.E. Page, M.E. McClendon, A.A. Adams,

Ivermectin performance in horses diagnosed with equine endocrine disorders,

Veterinary Parasitology, (2024) Vol 328,110182,

https://doi.org/10.1016/j.vetpar.2024.110182

Iron-related inflammatory markers in colic

 

Colic is a major concern for horse owners, with two main types: those treatable with medicine
and those needing surgery. Quickly identifying which cases need surgery is crucial. 

 

In the early stages of inflammation, the liver releases acute phase proteins (APPs) like haptoglobin, fibrinogen, and serum amyloid A. Recent studies propose that blood iron levels could also indicate inflammation severity in colic cases.

 

Paulo Canola and colleagues evaluated serum ferritin, transferrin and iron levels as acute phase inflammatory markers in horses admitted to the hospital with colic. 

 

Ferritin, which stores iron in a non-toxic form, helping to regulate iron levels in the body, is recognized as a positive inflammatory marker, increasing in the acute phase

 

Transferrin, a glycoprotein found in blood plasma that binds to iron and transports it throughout the body, decreases in acute inflammation.

 

The researchers analysed these markers alongside total protein, fibrinogen, ceruloplasmin, albumin, and haptoglobin levels in blood samples from 12 colic surgery cases and 10 healthy horses. They compared healthy horses with colic cases, small and large intestinal obstructions, and survival rates. The work is published in the Journal of Equine Veterinary Science.

 

They found higher transferrin and haptoglobin levels and lower serum iron in colic cases compared to healthy horses. Large intestinal obstruction cases had lower transferrin levels than small intestinal obstruction cases. Fibrinogen levels were higher in horses more likely to die from strangulating lesions.

 

The researchers suggest that the acute phase proteins examined in the study could be used to evaluate the acute inflammatory response in horses with colic requiring surgery. 

 

 

For more details, see: 

 

P.A. Canola, R.F. de Salles, E.R. Daneze, M.F.R. Sobreira, B.E. de Oliveira, M.L. Favero, M.L. Antonioli.

Iron-related markers of inflammation in horses with colic.

Journal of Equine Veterinary Science, (2024) vol 134, 105010,

https://doi.org/10.1016/j.jevs.2024.105010

Investigating cabergoline for treating equine Cushing’s disease

 Cabergoline shows promise as a treatment option for equine Cushing’s disease, according to a recent report.

Cushing’s disease or Pituitary Pars Intermedia Dysfunction (PPID) is a common condition in older horses, resulting from increased activity in the intermediate lobe of the pituitary gland. This excessive activity has been attributed to nerve damage impairing its regulation, with dopamine acting as the crucial neurotransmitter. When dopamine levels are deficient, the pituitary gland becomes overactive, leading to the release of various hormones, such as adrenocorticotropic hormone (ACTH).

 

Clinical manifestations associated with PPID are well-documented and include hypertrichosis, laminitis, polyuria, polydipsia, lethargy, muscle wastage, and delayed wound healing.

 

Dopaminergic agonists, medications that mimic the action of dopamine, function by stimulating dopamine receptors in the pituitary gland. This stimulation results in the inhibition of the release of certain hormones, including ACTH, thereby mitigating clinical signs such as abnormal hair coat, muscle wasting, and laminitis.

 

Pergolide, a dopamine agonist, stands as the primary treatment for managing PPID and is approved for oral administration in equines. However, some horses may exhibit resistance to daily oral dosing. Cabergoline, another dopamine agonist like pergolide, currently is not licenced for use in horses.

 

A recent retrospective study conducted by Tania Sundra of Avon Ridge Equine Veterinary Services in Brigadoon, WA, Australia, along with colleagues, explored the efficacy of intramuscular extended-release cabergoline (ERC) injection in treating PPID. Despite being unlicensed, this treatment modality is increasingly utilized off-label in clinical practice for managing PPID. The study examined clinical records of privately-owned horses with PPID that had undergone intramuscular cabergoline treatment at Avon Ridge Equine Clinic.

 

The study examined the short-term (5–8 days) and longer-term (12 months) clinical and endocrinological responses to two doses of cabergoline: a low dose (0.005mg/kg) extended-release cabergoline (LDERC) and a high dose (0.01mg/kg) extended-release cabergoline (HDERC).

 

Results showed that although both doses of ERC led to a decrease in median ACTH concentration, the levels remained above the seasonal reference range in about half of the treated horses. However, similar responses had been noted in previous studies involving pergolide treatment for PPID.

 

Owners reported clinical improvement in 78.3% and 100% of horses treated with LDERC and HDERC, respectively. 

Common side effects of dopamine agonists, such as decreased appetite, lethargy, gastrointestinal upset, and behavioural changes, were observed. Notably, partial, self-limiting inappetence was reported in 30.0% of LDERC cases and 60% of HDERC cases, with seven horses exhibiting lethargy.

 

In cases of partial anorexia, owners noted that horses preferred long-stem forage (hay or grass) over cereal-based feeds. The clinical and endocrinological responses observed were consistent with previous reports of oral pergolide treatment.

 

The authors suggest that weekly injection of ERC may serve as an effective alternative to pergolide. The 0.005 mg/kg dose appeared to be as effective as the 0.01 mg/kg dose but with a lower risk of inappetence.

 

While cabergoline shows promise as a treatment option for PPID in horses, further research is necessary to fully establish its efficacy, safety profile, and optimal usage protocols.

 

 

For more details, see: 

 

Sundra T, Kelty E, Rossi G and Rendle D (2024) 

Retrospective assessment of the use of extended-release cabergoline in the management of equine pituitary pars intermedia dysfunction. 

Front. Vet. Sci. 11:1332337. 

https://doi.org/10.3389/fvets.2024.1332337