Does hand walking promote gut motility?

(c) Abby Khoriaty Dreamstime.com

 Hand walking in horses is a widely practiced exercise often used during recovery after surgery, and in rehabilitation. Its potential effect on gut motility may have benefits for horses prone to colic or recovering from gastrointestinal issues.

Amelia S. Munsterman and colleagues from the Department of Large Animal Clinical Sciences at Michigan State University's College of Veterinary Medicine in East Lansing, MI, conducted a study to evaluate the effects of hand-walking exercise on the myoelectrical activity in the cecum and left ventral colon (LVC) of healthy, fasted horses confined to stable rest. The research is published in the Journal of the American Veterinary Medical Association.

 

The researchers assessed gut activity using electrointestinography (EIG), a method that measures the electrical activity of the gastrointestinal tract. They also used ultrasonography and auscultation to monitor caecal and LVC contractions.

 

The study involved eight clinically healthy horses. To qualify for inclusion, the horses underwent a thorough physical examination and abdominal ultrasonography to rule out any gastrointestinal abnormalities or previous abdominal surgery.

 

The horses, which had previously lived out on pasture, were housed in 3m X 3m box stalls for the study, and fasted for 12 hours, with free access to water.

 

After a 30-minute baseline electrointestinography (EIG), horses were either stall rested or hand walked for 15 minutes. The research team repeated the EIG immediately afterwards and again after two hours. They also monitored caecal and LVC activity using ultrasonography and auscultation.

 

Their findings revealed no difference in gut motility between the box rested or hand-walked groups

 

The researchers conclude: “Brief hand walking as a single strategy to increase gastrointestinal motility did not affect contractility or EIG in normal horses.”

 

They suggest that further research is needed in clinical cases to confirm any benefits of hand walking.

 

 

For more details, see:

 

Munsterman, A. S., Rogers-Tirado, J. M., & Kottwitz, J. (2024). Electrointestinography, ultrasonographic contractility, and borborygmi of the cecum and colon are not altered by a single episode of hand walking exercise in healthy horses. 

Journal of the American Veterinary Medical Association (2024). 

https://doi.org/10.2460/javma.24.07.0486

Y chromosome reveals the global spread of Oriental stallions

(c) Sergey Uryadnikov Dreamstime.com

The development of modern horse breeds has been strongly shaped by stallions, making the male-specific part of the Y chromosome (MSY) a key genetic marker for studying their origins and spread.  

Researchers from the University of Veterinary Medicine Vienna (Vetmeduni), along with international partners, traced the lineage of modern breeds through stallions. They found that most horse breeds in Europe, Asia, and the Americas share common male ancestors, whose influence became widespread only in the past few centuries.

 

A full report of their work is published in the journal PNAS.

 

Horses have been deeply significant in human history, shaping cultures and geopolitical developments. Over time, human activities like migrations, diverse breeding goals, and selective breeding centered on stallions have created a complex genetic ancestry in horses. The Y chromosome, passed down through male lines, offers insights into the origins and historical impact of specific stallions on horse populations.

 

For their study, the researchers analysed a large number of modern breeds and reconstructed their paternal lineages over the last 1,500 years. The scientists identified three major recent breeding influences and highlighted two fundamental historical routes driving the spread of Oriental horses.

 

The research team analysed data from 1,517 stallions across 189 modern horse breeds, covering a wide range of traits and geographic areas. They were able to decipher the enormous influence of Oriental stallions over the last few hundred years, demonstrating the origin and widespread distribution of Arabian, English Thoroughbred and Coldblood stallions, and exposing the consequences of intense linebreeding.

 

“The majority of stallions worldwide carry Y lines that can be attributed to an only approximately 1,500-year-old so-called Crown haplogroup. The predominance of Crown lineages in modern horse breeds is the result of the enormous impact of stallions of “Oriental origin” in the past millennium,” the study’s first author, Lara Radovic from the Centre for Biological Sciences at Vetmeduni, explains. 

 

“The spread of Oriental horses was complex and started with the Muslim expansion. The similar spectrum of paternal lines in horse breeds from the Iberian Peninsula and the New World confirms the enormous distribution of horses of Oriental origin via the Iberian Peninsula after the Middle Ages,” Radovic adds. The survey also revealed a second major historical dissemination of horses from Western Asia, accompanied by the expansion of the Ottoman Empire. 

 

“Our study shows that MSY analysis can uncover the complex history of horse breeds,” says the study’s last author Barbara Wallner from the Centre for Biological Sciences at Vetmeduni. “By tracing the legacy of Oriental stallions, we have demonstrated the inseparability of horse and human history and deciphered former unknown connections between geographically and phenotypically different horse breeds. We have also highlighted the consequences of intensive animal breeding, which have led to the loss of breeding lines,” Wallner adds. 

 

According to Wallner, the work also presents new opportunities for capturing the historical development of breeding populations as a basis for meaningful decisions in breeding management in the future.
 

 

For more details, see:

 

L. Radovic, V. Remer, D. Rigler, E. Bozlak, L. Allen, G. Brem, M.Reissman, G.A. Brockmann, K. Ropka-Molik, M. StefaniukSzmukier, L. Kalinkova, 

V.V. Kalashnikov,  A.M. Zaitev, T. Raudsepp, C. Castaneda, I. von Butler-Wemken, L. Patterson Rosa, S.A.Brooks, M. Novoa‐Bravo, N. Kostaras, A. Abdurasulov, D.F.Antczak, D.C. Miller, M.S. Lopes, A. da Câmara Machado, G.Lindgren, R. Juras, G. Cothran, B. Wallner, 

The global spread of Oriental Horses in the past 1,500 years through the lens of the Y chromosome, 

Proc. Natl. Acad. Sci. U.S.A.(2024) 121 (49) e2414408121,

https://doi.org/10.1073/pnas.2414408121 

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.

Do horses have “senior moments”

(c) Mariia Itina Dreamstime.com

As people age, they often experience what are commonly known as "senior moments - instances of forgetfulness,
confusion, or a general decline in mental sharpness. This deterioration of cognitive faculties is a natural part of the aging process in humans. 

With advances in veterinary care and improved management practices, horses, like humans, are also living longer than ever before. Traditionally, horses have been considered to become old around 15 years of age. However, it is not unusual now for horses to live into their 30s, with some even exceeding 40 years of age.

 

This raises an interesting question: do horses show similar age-related cognitive changes? Can older horses display signs of reduced memory or recognition skills, and do they sometimes seem to "forget" familiar routines or places?

 

Researchers at the University of Pisa in Italy conducted a study to evaluate the cognitive abilities of horses as they age. They employed a behavioural assessment known as the Target Touch Test to measure both learning capacity and memory (short- and long-term) in adult and senior horses. The study is reported in the journal Animals.

 

The study included 44 clinically healthy horses from local riding schools. These horses were divided into two groups according to age: 21 adult horses (aged 5–15 years) and 23 senior horses (aged 16 years and older). All participants were free from stereotypic behaviours and had no prior exposure to clicker training to ensure uniform baseline conditions.

 

The Target Touch Test involved multiple stages to evaluate how well the horses could learn to interact with a specific target and retain that knowledge over time. The procedure was as follows:

 

1. First Phase – Clicker Training:

Each horse was trained to associate the sound of a clicker with a reward (a piece of carrot).

2. Second Phase – Initial Target Training:

Horses were trained to touch a target—a tennis ball affixed to a stick—held in front of them. This phase aimed to reinforce the learned association between touching the target and receiving a reward.

3. Third Phase – Independent Target Interaction:

The target was placed in a visible location within the horse’s stable, and the handler moved away. Each horse was given up to three minutes to approach and touch the target to earn a reward. The time taken to successfully touch the target was recorded.

 

Phases 2 and 3 were repeated two more times to assess consistency in performance and retention of the learned behaviour. The entire test sequence was carried out on day one (T1).

 

Ten days later (T10) the research team repeated phase 3 of the test to evaluate the horses’ long-term memory. Horses were allowed three minutes to touch the target and earn a reward.  Again, the test was carried out three times.

 

Analysis of the data showed that both the adult and senior horses quickly associated the click with the reward in phase 1, demonstrating that even senior horses are capable of associative learning.

 

During Phase 3 of the test on the first day, researchers found no significant difference in the time taken to touch the target between adult and senior horses.

 

However, after ten days, the senior horses did not perform as well as the adults. Each attempt by the senior horses was much slower than the adults and two senior horses failed to complete the test in any of their three attempts. 

 

There was considerable variability in the performance of senior females after ten days, but the researchers did not observe a significant difference between males and females in the time taken to complete the test.

 

The researchers conclude “even senior horses are capable of associative learning, maintaining the memory of this learning even after 10 days. However, they show slower recovery times for recalling memorised information compared to animals under 16 years of age.”

 

 

For more details, see: 

 

Cellai S, Gazzano A, Casini L, Gazzano V, Cecchi F, Macchioni F, Cozzi A, Pageat L, Arroub S, Fratini S, et al. Felici M,  Curadi MC, Baragli P.

The Memory Abilities of the Elderly Horse. 

Animals. 2024; 14(21):3073. 

https://doi.org/10.3390/ani14213073

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

Could flatter saddles improve welfare in ridden horses?

(c) Nicole Ciscato Dreamstime.com

 A new study has indicated that flatter-shaped saddles may be more suitable for horses that
spend most of their ridden time in motion.

The research, which observed significant changes in the shape of horses' backs while stationary and during movement, found that horse backs become considerably flatter during motion compared to when they are standing still.

 

Back pain is common among ridden horses and is frequently linked to poor saddle fit. A properly fitted saddle is crucial for distributing the rider’s weight evenly and reducing pressure on the horse’s back.

 

Saddles are typically fitted to horses while they are stationary and then checking the fit by observing the horse in motion.

 

The research team, made up of experts from the Royal Veterinary College and the University of Southampton, used an advanced camera array to measure the saddle region of five horses' backs while standing, walking, and trotting. These measurements captured the differences in back curvature. To validate their observations, the researchers reconstructed a life-sized model of a horse using laser scans.

 

The findings are reported in the Journal of the Royal Society Interface.

 

The study confirmed that the shape of horses' backs is not static. Instead, it changes significantly, with certain areas deforming by several centimetres.

 

Despite notable deformations in some regions, the saddle area remained relatively stable during movement, showing only minor changes of a few millimetres. This suggests that the deformable padding in saddle panels is likely sufficient to accommodate these small variations.

 

The study also found that, among regions relevant to saddle fit, the withers exhibited the most movement. The withers elevated and depressed more than four times as much as other areas that could interact with an English saddle.

 

These findings emphasise the importance of ensuring proper withers clearance, as outlined in current saddle fitting guidelines, due to the significant mobility observed in this area.

 

This research provides a foundation for further studies into whether similar back-shape changes occur at faster gaits such as canter and gallop, and how a rider’s weight affects these changes. The team aims to test whether saddles fitted to horses in motion can better distribute pressure.

 

Dr Jorn Cheney, Lecturer in Natural Sciences at the University of Southampton and lead researcher of this study, said: “I am reassured that a lot of key principles of saddlery held true. At least during walk and trot, saddles can be stiff, and they cover areas of the back that don’t move. Now the exciting question is, ‘do we improve upon the design by fitting to the moving animal?’ and if so what’s the best way of making that technique accessible?”

 

The study was funded by a grant from the Worshipful Company of Saddlers.

 

For more details, see: 

 

Smirnova, K. P., Frill, M. A., Warner, S. E., & Cheney, J. A. (2024). 

Shape change in the saddle region of the equine back during trot and walk. 

Journal of the Royal Society Interface, 21(215).  

https:doi.org/10.1098/rsif.2023.0644