Tuesday, December 27, 2022

Does early castration affect foals’ development?

Male horses are generally castrated to make them easier to manage. Traditionally equine castration (or gelding) has been carried out at the yearling stage (c6-18 months of age). The procedure may be delayed in the hope that doing so will allow the colt to grow more.


A recent study at the National Research Institute for Agriculture, Food and Environment, France, assessed theimpact of very early castration of foals on their morphological and behavioural development.


Juliette Cognie and co-workers compared the effect of early castration at 3 days of age and traditional castration at about 18 months.


The study used 22 male Welsh ponies from an experimental herd and included foals born in three consecutive years. A report is published in the Equine Veterinary Journal.


Eleven ponies were castrated as neonates (ie within three days of birth) and 11 as yearlings /18 months of age. All were castrated using a primary closure technique under general anaesthesia. 


The researchers report that no mare rejected her foal after surgery, and neither did any foal show any behavioural problems – such as refusing to suck - after recovery from the anaesthetic.


The research team followed the ponies’ progress until they were three years old.  They recorded weight and body size measurements - initially monthly until 8 months of age, then less frequently. Behavioural assessments were carried out when the ponies reached one- and three-years of age.


Overall, the researchers found no significant differences in temperament or physical development between horses castrated as neonates and those castrated as yearlings.


They conclude “early castration at 3 days does not interfere with morphological or behavioural development.”



For more details, see:



Early castration in foals: Consequences on physical and behavioural development.

Juliette Cognie, Sandrine Freret, Lea Lansade, Celine Parias Philippe Barriere Amandine Gesbert Fabrice Reigner Stefan Deleuze

Equine Veterinary Journal (2022)



Monday, December 26, 2022

Could analysing saliva help detect Equine Gastric Ulcers?

(c) Dahlskoge Dreamstime.com
Gastric ulcers are widespread in horses – studies have found ulcers in around 60% of sport
horses, and in up to 90% of Thoroughbred racehorses in training. 

Many non-specific signs have been attributed to gastric ulcers. Weight loss, reduced appetite, poor physical condition, dullness, colic, diarrhoea, poor performance and altered behaviour have all been blamed on gastric ulceration. Even so, adult horses with gastric ulcers often show no signs. 


Full assessment and a definitive diagnosis rely on the use of a gastroscope, which although relatively straightforward, is expensive.


In horses showing signs that might be due to gastric ulceration, a simple method of differentiating those with or without ulcers would be very useful.


Analysing saliva has proved useful – for example in behavioural studies where cortisol is measured as an indication of stress, and in assessment of tapeworm infection.


Could analysis of saliva provide a way of differentiating horses with gastric ulcers from normal horses??


In research conducted at the Large Animal Teaching Hospital at the University of Copenhagen the potential use of a panel of salivary biomarkers to detect Equine Gastric Ulcer Syndrome (EGUS) was evaluated.


Alberto Muñoz-Prieto and colleagues enrolled 147 horses in the study. They measured 23 salivary biomarkers and compared the values found in horses with EGUS, with those from healthy animals and from horses showing signs like EGUS but with no ulcers seen on gastroscopic examination. 


The research team found that 17 biomarkers were increased in saliva from horses with EGUS compared to healthy animals. Three of those biomarkers, uric acid (UA), triglycerides (Trig), and calcium (Ca), showed a modest but statistically significant difference between horses with EGUS and horses showing signs suggestive of EGUS but with no ulceration on endoscopy.


A full report of the work is published in Animals. 


The authors suggest that “These analytes could have potential use as biomarkers in horses with EGUS. For example, an ADA value within the range of healthy horses in our study could indicate that the horse is not likely to have EGUS at gastroscopy.” (ADA - adenosine deaminase – has been found to be higher in saliva of horses with gastric ulceration)


“In addition, higher values of UA, Trig, and Ca in a horse with clinical signs of EGUS would indicate a high probability of having EGUS at gastroscopy” they add. 


“These assays have the advantages of being non-invasive and also easy to measure because most of them are commercially available and are often included in the routine biochemistry profiles in clinical pathology laboratories.” 


“Further research using a larger population of horses will be needed to confirm these findings and the potential practical application of these salivary analytes in the diagnosis and treatment monitoring of EGUS.”


For more details, see:


Evaluation of a Comprehensive Profile of Salivary Analytes for the Diagnosis of the Equine Gastric Ulcer Syndrome. 

A Muñoz-Prieto; JJ Cerón; CP Rubio; MD Contreras-Aguilar; L Pardo-Marín; I Ayala-de la Peña; M Martín-Cuervo; I-M Holm Henriksen; JJ Arense-Gonzalo; F Tecles; S Hansen. 

Animals 2022, 12, 3261.


Wednesday, December 21, 2022

Free webinar to update on Horse-Human Interaction research

(c) Photojogtom Dreamstime.com
A free webinar on the work of the Horse-Human Interaction Lab at Texas Tech University will
take place on
 January 4, 2023 at 7:00pm (ET)

Christine Rudd, a PhD candidate in the lab, will talk about her research into Equine-Assisted Services (EAS)volunteers and the relationship between volunteer education, session safety, and horse welfare. 

She’ll also describe some of her research investigating EAS horses’ experiences in some common activities and their implications for future research and equine wellbeing. 

For more details, go to:


Antibiotic use in equine practices in the UK

(c) Monika Wisniewska Dreamstime.com
Equine vets are not doing enough to limit the development of antimicrobial resistance, according to a recent study.

Antimicrobial resistance poses a significant and growing threat to human and animal health. Once antimicrobial resistance develops, it can result in treatment failure in veterinary patients and risks transferring resistant bacteria to people.


The study, by Sarah Allen and colleagues, set out to monitor antimicrobial use in equids in the UK. It was conducted as part of the VetCompass programme at the Royal Veterinary College (RVC) and was funded by the Veterinary Medicines Directorate.


The researchers used anonymised electronic health record data from 64,322 horses, ponies and donkeys in the year 2018, supplied by 39 veterinary practices. They analysed both the prescription data and clinical notes documented within these records.


Their findings highlighted that in 2018, approximately 20% of equids attended by the participating veterinary practices were prescribed an antimicrobial licensed for systemic administration.  Potentiated sulphonamides were the most commonly prescribed class of antibacterial agent. 


However, nearly nine per cent of treated equids received a Category B antimicrobial. The use of these agents, such as quinolones, 3rd- and 4th-generation cephalosporins and polymyxins, is restricted to try to ensure they remain effective for treating serious illness in human medicine.


Bacteriological culture and sensitivity testing was found to be rarely employed, despite its importance in protecting against antimicrobial resistance, by identifying the most appropriate antimicrobial to use. Fewer than one in five antimicrobial courses that included a Category B antimicrobial were supported by culture and sensitivity testing.


The study also identified several important risk factors for increased antimicrobial usage.  The research team found that the highest usage groups of Category B antimicrobials were equids under one year old, Thoroughbreds and racehorses. 


Meanwhile, the most common disorders that were treated with antimicrobials were urogenital (urinary and genital tracts), integumentary (skin and gland organs) and respiratory (airways, lungs and blood vessels) conditions.


Dr Allen said “The surveillance of equine antimicrobial usage helps the veterinary profession demonstrate their commitment to the responsible prescribing of antibiotics in the horse. We hope that by reporting on how commonly antimicrobials are prescribed to horses, and demonstrating where stewardship may be improved, others will look to compare and better their own prescribing of these vital medicines.


She suggests that more needs to be done to encourage the use of culture and sensitivity testing prior to treatment, especially when Category B antimicrobials are concerned. This will help ensure they remain effective and will reduce the risk of antimicrobial resistance developing.


For more details, see:


Use of antimicrobials licensed for systemic administration in UK equine practice

Sarah E. Allen, Kristien L. P. Verheyen, Dan G. O'Neill, Dave C. Brodbelt

Equine Vet J (2022)



Sunday, December 18, 2022

Steaming hay can lead to protein deficiency

 Hay can be treated with steam to reduce the horse’s exposure to inhaled allergens that cause
respiratory disease. Steaming kills potentially harmful microorganisms and binds fungal spores and dust particles to the hay making them less likely to be inhaled

However, new research shows that steam treatment can have an adverse effect on the digestibility of protein in the hay. 


A team of scientists from Martin Luther University Halle-Wittenberg (MLU) has discovered that steam treatment causes a chemical reaction that damages the proteins in the hay and makes them harder for horses to digest. This can lead to signs of nutrient deficiency in the animals and, for example, impair growth or muscle development. A report of the work is published in the journal Animals.


Professor Annette Zeyner from the Institute of Agricultural and Nutritional Sciences at MLU explains: “Many horses suffer from lung problems such as equine asthma. The steaming process virtually eliminates all of the living microorganisms and particles in the hay that could be inhaled during feeding and damage the lungs. In theory, the end result is a very good forage," 


However, her team discovered that the treatment also has its disadvantages as the steam damages the proteins in the hay. 


"A high proportion of the proteins, and the crucial amino acids contained in them, can no longer be digested by the small intestine - in other words the horse lacks these proteins as a result of the steam treatment. However, some of these protein components are essential for horses and they cannot be absorbed in the large intestine," Zeyner continues. 


The researchers demonstrated this by examining various hay samples collected from central Germany. In the steamed hay, they found an increased number of products that are generated by the Maillard reaction, an indication that the proteins in the hay have been damaged. This is a reaction that also takes place when food is cooked, baked or fried and is responsible for browning or the development of flavours. 


"Proteins are composed of amino acids. The steaming damages them and they form new complexes with sugars in the hay," explains the first author of the study, Caroline Pisch, from MLU. This makes them difficult for horses to digest. According to the researchers’ analyses, the treatment reduced the amount of protein that can be absorbed by the small intestine by almost half. The pre-caecal digestibility of the essential amino acid lysine was over 50% lower after steam treatment.


According to Zeyner, this can lead to an undersupply of essential amino acids from the feed, which can be a problem for growing horses or lactating mares; young horses need proteins to grow, and mares need them to produce milk. To make matters worse, protein deficiency causes very unspecific symptoms in the affected animals. These include impaired muscle development and a dull or shaggy coat with so-called "hunger hair" - long isolated hairs in the horse’s coat. 


She suggests that horse owners can counteract this risk by enriching the animals’ diet with protein-rich single feedstuffs such as yeast and soybean meal or high-quality protein-rich compound feeds. 


The report concludes: “steamed hay is still a proper and sometimes the only possible roughage for horses suffering from respiratory diseases such as equine asthma. Essentially, horse diets based on steamed hay should be balanced accordingly."


For more details, see:


Effect of Hay Steaming on the Estimated Precaecal Digestibility of Crude Protein and Selected Amino Acids in Horses

Caroline Pisch, Monika Wensch-Dorendorf, Uwe Schwarzenbolz, Thomas Henle, Jörg Michael Greef, and Annette Zeyner. 

Animals(2022) 12, no. 22: 3092. 


Saturday, December 17, 2022

Help wanted for Canadian quarantine research

(c) Anna Cvetkova Dreamstime.com
Horses travelling to competitions present a risk of bringing infections back home. At the event they encounter other horses and may pick up infectious diseases. As events often last only a few days, horses may return home while incubating the disease, and subsequently infect their stable mates. 

Researchers at the University of Guelph, Canada, are seeking participants for a study entitled “Effectiveness of Equine Facility Quarantine Procedures Following the Arrival of a New or Returning Horse”

The research, conducted at the Ontario Veterinary College, is funded by the Natural Sciences and Engineering Research Council (NSERC), and the Canada Research Chairs program. Principal investigators are Dr. Amy Greer, and Dr. Terri O’Sullivan aided by PhD candidate Gabrielle Turcotte. 

They explain that the research “seeks to examine the effectiveness of a quarantine protocol for an equestrian facility in the case of a potential spread of an infectious pathogen. We also hope to interview equestrian facility owners about the perceptions of risk of travel to off-property equestrian events and existing biosecurity procedures at home facilities.

“With most events in Ontario lasting no more than 4 days, horses can then return to their home facility before showing clinical symptoms of disease, putting the home facility herd at risk. This research study could help your facility evaluate its ability to maintain equine herd health and welfare. Additionally, your insight can have an impact on expectations and importance of quarantine protocols and help inform existing network simulations for equine infectious disease.”

So, if you are based within 90 minutes of Guelph or Toronto, with a horse facility housing between 5 and 20 horses, with more than one horse owner, that engage in off-property events, the research team would like to hear from you.
For more details, go to:

Wednesday, December 14, 2022

Horse training survey

(c) Silviu-florin Salomia Dreamstime.com
How do you train your horse?

Ella Bartlett at the University of Bristol is conducting an online survey looking into different horse training approaches, to see how widely they are used, and how people within the equestrian industry view them.


This study forms part of a PhD project which aims to improve our understanding of how horse owners make decisions in relation to the training of their horses.


The questionnaire is open to anyone aged over 18 years, who owns a horse, or has at least one horse on loan/ lease. Participants are welcome from around the world.


Twenty-two questions address topics relating to different horse training methods, including asking about your own approach, training beliefs and role in the equestrian industry. It should take approximately 15 minutes to complete. All responses are anonymous.


To take part, or for more details, see:



Sunday, November 27, 2022

Common drug could increase risk of sudden death in racehorses

(c) Donald Blais Dreamstime.com
A drug that has been widely used in Thoroughbred racehorses in North America could increase the risk of sudden death according to a new study.  

The research also identified other risk factors associated with sudden death, relating to the circumstances of the race and individual histories of the horses.


Conducted by Dr Euan Bennett, of the University of Glasgow’s School of Biodiversity, One Health and Veterinary Medicine and Prof Tim Parkin of the University of Bristol Vet School, the study is the first large-scale study of sudden death in Thoroughbred racehorses.


The work was funded by the Grayson Jockey Club Foundation. A report is published in the Journal of the American Veterinary Medical Association.


The study analysed over four million starts in horse racing over a 12-year period, using data recorded in the Equine Injury Database (EID), which contains details of nearly all official race starts made in the USA and Canada. About one in 10,000 race starts resulted in a racing-related sudden death for a horse.


For this study, “sudden death” was taken to include any fatality occurring within three days of racing, where the cause of death recorded in the EID was sudden death, pulmonary haemorrhage, exercise-induced pulmonary haemorrhage (EIPH), post-exertional distress/heatstroke (PED), or cardiac arrhythmia. Fatalities due to catastrophic musculoskeletal injury were not included.


The researchers identified a notable risk factor related to race day medication. Horses that were recorded as being administered furosemide were 62% more likely to experience sudden death compared to horses that weren’t on furosemide.


Furosemide (also known as frusemide and by the trade name Lasix) has been used to prevent exercise-induced pulmonary haemorrhage (bleeding in the airways). It is also associated with enhanced racing performance. As a result, 94% of horse starts in the study were on furosemide.

The ethics of race day medication are controversial. Furosemide is already restricted or prohibited on the day of racing in certain circumstances, depending on jurisdiction.


The results also suggest that it might be possible to identify horses at risk of sudden death before they experience it – for example, due to previous injury and interruption to training/racing. 


Amongst other findings were that the risk of sudden death was greater for stallions compared with mares, and for horses five years or older compared with horses three years old or younger. Other risk factors identified include season and value of race and race distance.


Dr Bennett said: “Over the last 12 years, the overall risk of fatality within three days of racing has decreased by over 30%, but the incidence rate of sudden deaths has not changed significantly. This suggests that while interventions have been made which have contributed to a reduction in catastrophic injury, there are different sources of risk for sudden death which have not yet been identified.


“This study suggests that a risk profile, identifying which horses are at the greatest risk of sudden death, may be possible. Given how rare the outcome is, further work is required to establish any potential interventions which might contribute to a reduction in sudden deaths.


“On the association between furosemide use and sudden death, the fact that furosemide use is so common makes this result particularly remarkable given the statistical power of this large-scale study. Discussions around the ethics of race day administration of drugs should factor in potential risks such as those identified here, and further work is required to understand exactly why we identified this association.”


For more details, see:


Fifteen risk factors associated with sudden death in Thoroughbred racehorses in North America (2009–2021)

Euan D. Bennett and Tim D. H. Parkin

Journal of the American Veterinary Medical Association (2022)

Saturday, November 26, 2022

Eye worm infection in Europe

(c) Anjajuli Dreamstime.com
Eye worm infection (Thelaziosis) may be a neglected disease in Europe, according to a recent report.  

Thelaziosis is a parasitic disease caused by nematodes (round worms) of the genus Thelazia (typically Thelazia lacrymalis in horses). 


In the United States, the infection rate for cattle and horses in has been estimated at 15% to 38%. In Europe, equine thelaziosis has been reported occasionally in countries such as Russian Federation, England, France, Germany, Sweden and Italy.


Eyeworms live in the tear glands, conjunctival sac, and under the eyelids. The intermediate hosts are non-biting flies, such as Musca autumnalis, which swallow the larvae as they feed on the lachrymal secretions. Larvae become infective within 2-4 weeks and are deposited on the horse’s eye when the fly feeds. In about 10 weeks the adult worms produce more larvae and the cycle continues. 


Infections may occur year-round, but disease outbreaks usually are associated with the warm season when the flies are more active.


Infections often produce no obvious signs. However, inflammation of the conjunctiva and eyelids can occur, and more severe cases may show inflammation, swelling, and cloudiness of the cornea.


A study in Romania, examined post-mortem specimens from 273 horses. The work, by Vlad-Dan Cotuțiu, and colleagues, is reported in Parasites & Vectors.


They found 12 infected horses (4.39%). They recovered 87 worms, which they identified as T. lacrymalis. They report that the intensity of infestation varied between one and 33 nematodes/animal. Five animals were infected in both eyes.


The numbers found were too low to reach statistically significant conclusions. However, the authors suggest that altitude may be a factor in the occurrence of thelaziosis. “In this study there were no infested animals originating from the alpine ecoregion (0 of 45); therefore, a plausible explanation could be the decreased vector abundance and shorter seasonal activity at higher altitudes.”


They also suggest that the widespread use of oral deworming protocols, including macrocyclic lactones or fenbendazole, probably contributed to the low prevalence. 


The authors conclude: “We consider equine thelaziosis a neglected disease in Europe, which requires more attention from veterinary practitioners mainly from an animal welfare point of view due to the potentially severe clinical impact.”



For more details, see:


Thelazia lacrymalis in horses from Romania: epidemiology, morphology and phylogenetic analysis. 

V-D Cotuțiu, A M Ionică, M Lefkaditis, C D Cazan, D H Alina, A D Mihalca.

Parasites Vectors 15, 425 (2022). 


Friday, November 25, 2022

Horses Inside Out annual conference - Call for posters

 There’s still time to submit posters for presentation at the 2023 Horses Inside Out Conference.

Posters, relating to the theme “Upwards and Onwards’, will be displayed at the Horses Inside Out Conference on the 18th and 19thFebruary 2023 at the Holywell Conference Centre, Loughborough, LE11 3GR. The author or a representative should be on hand 11.00 – 11.45, 12.45 – 14.00 and from 15.00 – 15.30 on both Saturday and Sunday to answer delegates questions about their poster. 

Posters can be submitted by students, lecturers, research professionals or companies. They can be about research conducted by the author or literature reviews about the chosen subject. Posters that have been presented at previous conferences can be submitted.

A competition for the best scientific poster will be judged by Dr Andrew Hemmings and Dr Jessica Kidd.

To download the submission guidelines and an application form click here

For more details of the Horses Inside Out Conference 2023, go to:


Thursday, November 24, 2022

Funding available for PPID research

 Morris Animal Foundation is now accepting proposals for studies focused on all domesticated equid health topics, with a special interest in pituitary pars intermedia dysfunction (PPID also known as equine Cushing’s disease).

PPID is the most common endocrine disorder of older equids, affecting more than 20% of aged horses, ponies and donkeys. Applicants considering submitting a research proposal focused on this disease are directed to learn more about research questions of interest as identified during a PPID priority-setting partnership workshop.


Participants at the workshop reached a consensus on the top 10 questions of interest. These focused on long-term prognosis, diagnostic accuracy, efficacy of pergolide treatment, alternative treatment/management strategies and potential treatment options for poor responders to pergolide (see below.) 


A report* of the workshop is published in PLOS ONE. The quantity of questions generated indicates that there is still much to find out about the diagnosis, treatment and prognosis of PPID. 


All proposal topics should seek to advance the health and overall welfare of domesticated horses, ponies, mules, or donkeys. Applications are reviewed and rated based on impact and scientific rigor by the Foundation’s scientific advisory boards, made up of topic experts in the veterinary community.


Applications will be accepted until December 16, 2022. Interested researchers can find the proposal guidelines, proposal template, and other information at Morris Animal Foundation Apply for a Grant.


*For more details, see:


Equine pituitary pars intermedia dysfunction: Identifying research priorities for diagnosis, treatment and prognosis through a priority setting partnership. 

Tatum RC, McGowan CM, Dean RS, Ireland JL (2021) 

PLoS ONE 16(1): e0244784. 


Sunday, November 20, 2022

Immune response to single housing

(c) Abby Khoriaty Dreamstime.com
Horses moved from group housing to individual stabling showed stress-related changes, recent research has found. 

The horses had shifts in their white blood cell counts typical of a stress response and higher levels of plasma cortisol. These changes could make them more vulnerable to infectious disease.


In the study, conducted at the University of Hohenheim in Stuttgart, Germany, Sonja Schmucker and colleagues followed a group of twelve horses through a series of management changes, and monitored alterations in their immune response and behaviour. The research is published in PLOS ONE.


Twelve warmblood geldings, aged 2-3 years old, completed the study. Before the start of the investigation, they had been living together in a group on pasture.


In the first phase of the study, the horses were divided into two groups, each maintained on two separate paddocks so that horses in one group could not see the others. After the eight days trial period both groups were returned to their original setting. 


After a further eight weeks on pasture, the horses entered the second part of the study. They were moved to individual stables, where they were able to see and touch their neighbours through barred windows. For the first week after housing, horses were allowed 30 minutes daily exercise in groups of 6 in an indoor area of the stable. From the second week onwards, the horses were exercised by lunging.

The research team collected blood samples for analysis of immune cell numbers and cortisol concentrations from all animals on days 1 and 8 after both changes in housing conditions. In addition, in the stabled group they collected samples 7 and 6 days before, and again immediately before, the beginning of the stabling phase.


They found that moving to individual stabling led to acute stress-induced immune changes but dividing the larger group into two smaller ones did not.


“The number of eosinophils, monocytes and T cells declined, whereas the number of neutrophils increased resulting in an increased N:L ratio. This pattern of change resembles the well-known picture of an immunomodulation induced by acute social stress.”


Plasma cortisol concentrations did not change after dividing the pasture group into two smaller groups However, moving the horses to individual stables was associated with an increase in cortisol concentrations one day after housing which had returned to previous levels after eight days.


The researchers report “Although cortisol concentrations returned to baseline level after 8 days, the alterations in most immune cell numbers persisted, pointing to a longer-lasting effect on the immune system of the horses.”


They also monitored the horses’ behaviour during the study and noticed that signs of stereotypical behaviour started to appear amongst the housed animals.


The authors conclude “relocation to individual stabling represented an intense stressor for the horses of the present study, leading to acute and lasting alterations in blood counts of various leukocyte types. In contrast, fission of the stable group did not result in behavioral, endocrine or immunological stress responses by the horses.”


“The results of the present study therefore strongly indicate that social isolation is a chronic stressor with negative impact on welfare and health of horses and highlight the advantage of group housing systems in view of immunocompetence.”


For more details, see:

Schmucker S, Preisler V, Marr I, Krüger K, Stefanski V (2022) 

Single housing but not changes in group composition causes stress-related immunomodulations in horses. PLoS ONE 17(8): e0272445. 


Saturday, November 19, 2022

UK senior horses survey findings

Owners and carers of senior horses and ponies responded in their thousands to a survey,
organised by feed company Spillers.  

More than 12,000 participants completed the survey, displaying their loyalty to, and care for their precious equine oldies.


The survey revealed that 32.7% of respondents’ horses were 25 years old or more and that 65.6% of owners considered their horses became “senior” at 20+ years. The results will help the feed company understand more about supporting the growing sector of senior horses nutritionally, to help them live longer healthier lives.


The survey showed that the participants are faithful to their seniors with 58% having owned their senior for 11+ years and 5.7% having owned their oldie for more than 26 years. 99.3% intended to keep their senior horse for the rest of their life.


Senior horses were also shown to be predominantly healthy and active: 78% were considered to be in good condition, with 10% of the remainder being classified as overweight and 12% as underweight.


A total of 25.8% of seniors included in the survey had no known clinical issues or health-related problems. However, 44% showed signs of stiffness or arthritis. 15.2% were recorded as having Pars Pituitary Intermedia Dysfunction (PPID – “Cushings disease”), while dental issues were experienced by 15.2% of senior horses.


In terms of exercise 62.8% were still in ridden work but 72.9% of these were in light work or slowing down.


A diet designed specifically for older horses was fed to 37.2% of respondents’ horses were eating a senior specific feed and of these 53.7% had opted for a senior mash.


“Congratulations to all the owners and carers of senior horses as well as the equine industry as a whole for playing their part in helping our treasured senior horses and ponies grow old gracefully,” said Claire Dyett Marketing Manager for SPILLERS.


“It’s a real achievement that our seniors are ageing later and staying healthy and active in their older years. While almost a third are recorded as having PPID or dental issues, this is perhaps to be expected because horses are living longer. That more than a third of the respondents are opting for a senior specific feed, predominantly a mash, indicates that nutrition choices are helping to support health as horses age and encounter metabolic and dental problems. The results will help us in our perpetual mission to make the world a better place for horses.”

Tuesday, October 25, 2022

Atypical myopathy and acorn poisoning warning

 Horse owners are reminded of the seasonal risks of grazing around oak and sycamore trees. Ingestion of sycamore seeds or acorns can cause rapidly fatal illness in horses.  

“The extreme weather over the summer may have contributed to the production of greater quantities of sycamore masts and acorns than normal,” warned British Equine Veterinary Association president David Rendle.  

“High winds over the next few weeks will likely serve to increase the risk further. Ideally horses should be kept away from grazing around oaks and sycamores but if no other pasture is available supplementary feed should be provided. If horses that have access to sycamore seeds or acorns show signs of illness, veterinary attention should be sought immediately.” 


Seeds (“masts” or “helicopters”) from the common sycamore tree (Acer pseudoplatanus) contain a toxin called Hypoglycin A, which can still be 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. 


Horses with atypical myopathy show variable signs of muscle soreness, stiffness, weakness, difficulty breathing, dullness, lethargy, muscle trembling, colic-symptoms, and characteristically, brown or dark red urine. Suspected cases need immediate veterinary attention. Around three quarters of affected horses will die, often despite extensive veterinary treatment but those surviving the initial period will usually go on to make a full recovery.


Acorn “toxicity” is less common and less well understood than hypoglycin toxicity. The apparent increase in cases seen recently may be an unfortunate combination of the extreme dry summer weather and normal variation in acorn production.  Just like all fruit and nut trees, oak trees can produce variable amounts of acorns from year to year, with ‘mast years’ of unusually high production. 


When a group of horses are exposed to acorns from the same oak tree, only one or two horses will fall ill. This may be because individual horses are particularly susceptible, or that some trees, or even certain acorns, are particularly toxic. Protection from acorn toxicity in other species, such as pigs, comes from the production of tannin-binding salivary proteins. These proteins are not normally produced by horses, but it is possible that some individuals have them and are protected in this way. 


The toxic effects of acorn ingestion can be severe and prompt veterinary attention is essential. Clinical signs include moderate to severe colic or colitis, lethargy, dehydration, and dark urine which can be a result of kidney failure. Signs may develop extremely rapidly, and death can occur within a further 12-24 hours. 


Horse owners are advised to take practical steps to prevent the diseases by limiting access to sycamore seeds and acorns:


  • Identify trees both around grazed fields as well as those in close proximity. 
  • Collect seeds or exclude horses from affected areas using electric fencing or stabling. 
  • Feed supplementary hay to try and prevent horses from excessive foraging for short blades of grass and inadvertent ingestion of seeds. But ensure that hay does not become contaminated by seeds.
  • Don’t fell trees when laden with seeds as this can cause a sudden and massive contamination of the pasture. 
  • 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 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


And see the British Horse Society’s fact sheet on Acorn Poisoning: 




Monday, October 24, 2022

Could stem cells be used to treat equine asthma?

(c) Callipso88 Dreamstime.com

Equine asthma is a common respiratory disease of horses, brought on by repeated exposure to dust and moulds. Although the signs may be improved by medical treatment, this is unlikely to achieve a permanent cure.


Doctor Dorothee Bienzle of the Ontario Veterinary College, University of Guelph, has been investigating stem cells as a potential treatment option, working with a group of researchers at the University of Slovenia who have expertise in growing stem cells. The research is published in Stem Cell Research and Therapy.


She says, “This is not for the casual investigator because it takes some experience to have the right culture conditions to make sure those cells are clean.  They are not cultured for very long, and when the final preparation is administered to an animal, it must be free of cell culture components that could make inflammation worse.”


The study used stem cells derived from subcutaneous fat tissue (“adipose-derived mesenchymal stem cells”: AD-MSC), which were placed directly in the lower airway.


Twenty horses with severe equine asthma (SEA) were divided into two groups: ten horses receiving a single application of autologous AD-MSC; and ten given oral dexamethasone daily for three weeks.


Horses were assessed before treatment and three weeks later. The research team also monitored the horses for recurrence of SEA over the following year.


They found that AD-MSC administration improved the clinical score and decreased the expression of inflammatory markers (such a IL-4, IL-1b) in the broncho-alveolar lavage fluid. 

It took longer for signs of SEA to return in horses treated with stem cells. The researchers noted exacerbations of SEA in the dexamethasone-treated  group shortly after discontinuation of treatment, while most horses in the AD-MSC treated group remained stable for at least 300 days after treatment.


They conclude: “In this study, the intrabronchial application of autologous AD-MSC had a modest short-term therapeutic effect and a possible positive long-term effect on SEA.”


Speaking about the work in an Equine Guelph webcast* Dr Bienzle added: “Stem cell therapy is a proof of concept at this point. It is not widely available and we don’t want to mislead people ..that this is a commonly available therapy. We’re a long way from that, but horses may get there before humans do.”


For more details, see:


Effect of intrabronchial administration of autologous adipose-derived mesenchymal 

stem cells on severe equine asthma 

Neža Adamič, Sonja Prpar Mihevc, Rok Blagus, Petra Kramarič, Uroš Krapež, Gregor Majdič, Laurent Viel, Andrew M. Hoffman, Dorothee Bienzle and Modest Vengust

Stem Cell Res Ther. 2022; 13: 23.