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

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

Navigating the Equine Breeding Season: Mares Webinar

Are you new to horse breeding or looking to expand your knowledge? Join the American Association of Equine Practitioners (AAEP) for a free, informative webinar on the equine breeding season.

The webinar is directed toward horse owners/managers either new to breeding horses or those with limited experience. It will cover the basics of reproductive biology of the horse, logistics of the breeding season and what to expect when breeding your mare. 

The presenter is Dr. Dale Kelley, board-certified reproduction specialist at Oklahoma State University, College of Veterinary Medicine.

 

Access is free, but registration is required.

 

Details:

• Date and time : 

 

(USA) Wednesday, Oct. 30, 8:00 p.m. ET

(UK) Thursday, Oct. 31, midnight (00:00) GMT

 

• To register go to:

https://aaep-org.zoom.us/webinar/register/WN_CHkvKjmpTlGOiPMbwhEtBA#/registration

 

• Submit questions in advance through the registration form.

 

If you miss the live event, a recording will be available.

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.