Lameness main cause of vetting “failures”

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Research from the Royal Veterinary College (RVC) has found that lameness ranks as the most common adverse
finding in pre-purchase examinations (PPEs) conducted on horses in the UK.

The aim of the prepurchase examination is to carry out a thorough clinical examination of the horse on behalf of the potential purchaser to identify any cliiinical issues that might make the horse unsuitable for its intended purpose, whether that be elite competitions, breeding, or leisure riding.

 

In the United Kingdom, PPEs generally consist of either a two stage (two stage vetting [2SV], i.e., general physical examination at rest and basic trot in-hand) or a five stage-examination (five stage vetting [5SV], i.e., general physical exam at rest and after exercise, lameness evaluation including strenuous exercise with re-evaluation after a period of recovery).

 

In the United Kingdom, The standard PPE consists of five stages, (five stage vetting [5SV],ie general physical examination at rest; walk and trot in hand;  strenuous exercise; rest and a second trot up)

 

Sometimes it may not be possible to complete all five stages or the purchaser may request a limited examination, in which case the examination can be limited to the first two stages (two stage vetting, 2SV).

 

PPEs yield recommendations based on the veterinary surgeon's assessment at the time of examination. As such, PPEs are largely subjective and often the subject of impassioned debate.

Despite their widespread use in equine practice, PPEs have been the subject of limited research.

 

The research team from the Royal Veterinary College (RVC), comprising Dr. David Bolt, Senior Lecturer in Equine Surgery; Dr. Jason Tupper, Head of the RVC Equine Practice; and Annabel Shelton, a graduate of RVC's BVetMed program in 2023, scrutinised 133 PPE certificates belonging to a mixed, non-racing horse population sourced from three primary equine practices. 

 

The analysis encompassed an evaluation of the examination format (e.g., 2SV or 5SV), use of diagnostic imaging modalities (e.g., radiographs), purchase price, animal characteristics, intended use of the horse, PPE outcomes, and any prejudicial findings uncovered during the examination.

They found that a 5SV was performed on 68.5% of horses compared to 34.1% which underwent a 2SV.

 

Of the 133 horses examined, 57.1% had prejudicial findings, the most common of which was lameness. Other prejudicial findings included diagnostic imaging findings (14.5%); respiratory system findings (6.6%); skin conditions (5.3%); and cardiac abnormalities (3.9%).

 

Unsurprisingly, horses with a higher purchase price were more likely to undergo the full 5SV, and undergo pre-purchase radiography. They were also more likely to have prejudicial findings identified.

 

Dr Tupper said: “A pre-purchase examination can discover a number of issues before buying a horse. This study reveals lameness to be the commonest issue. Few horses are perfect when it comes to temperament and health. The vetting process determines the issues and the vet can then help the purchaser weigh up their significance and decide if they can compromise and accept the issues or not. Further studies can now focus on the cost/benefit of radiology as part of the vetting procedure and the potential use of gait analysis.”

 

The researchers hope that their work will stimulate future investigations into the merits of 5-stage (5SV) and 2-stage (2SV) PPE formats, as well as the diagnostic techniques employed. This will, in turn, help to better inform prospective horse buyers when considering their purchase.

 

For more details, see:

 

Prejudicial findings regarding suitability for intended purpose during pre-purchase examinations in a mixed horse population—A retrospective observational study in the United Kingdom. 

Shelton AV, Tupper J, Bolt DM. 

Equine Vet J. 2024.

https://doi.org/10.1111/evj.14061

Effect of day length on growth

 Can the growth and maturation of yearling Thoroughbreds be accelerated by artificially extending the day length? A Japanese study has been exploring this possibility.

Hokkaido, the mostly northerly of Japan's main islands, is the primary breeding ground for over 97% of Thoroughbreds in the country. Hokkaido experiences cool summers and cold winters, with shorter days during the winter season.

 

Mutsuki Ishimaru and colleagues conducted a study to examine the impact of artificially extending daylight on changes in body composition in young Thoroughbreds raised and trained in Hidaka, Hokkaido, Japan. 

 

The study involved 73 horses aged 21-24 months.

 

The treatment group, comprising 41 horses (22 colts and 19 fillies), underwent extended photoperiod (EP) treatment from December 20 to April 15. This was achieved by placing a 100-watt white bulb in each horse box, providing 14.5 hours of light and 9.5 hours of darkness. 

 

A control group of 32 horses (16 colts and 16 fillies) remained under natural light conditions with no additional lighting. All horses had 1-2 hours of pasture time daily and followed a standardised training program.

 

The research team assessed body weight (BW), rump fat thickness (RFT), fat-free mass (FFM), and percentage of fat (%F) as indicators of body composition. 

 

In the control group, there was a moderate increase in BW and FFM, but no significant difference in BW and FFM between December and later months. In contrast, the EP group exhibited continuous growth until April, with significantly higher BW and FFM in February, March, and April compared to December.

 

The researchers suggested that the hypothalamic-pituitary-gonadal axis was activated earlier in the EP group, leading to elevated circulating IGF-I or gonadal hormones. 

 

They concluded that young Thoroughbreds under extended photoperiod conditions in Hokkaido may tolerate more high-intensity training than those under natural light conditions during the winter season. Additionally, there is potential for these horses to perform at an early stage in 2-year-old racing.

 

For more details, see:

 

 

Effects of an extended photoperiod on body composition of young Thoroughbreds in training. 

Mutsuki Ishimaru, Atsushi Okano, Akira Matsui, Harutaka Murase, Kenji Korosue, Kentaro  Akiyama, Kazuyoshi Taya. 

Journal of Veterinary Medical Science, (2024), Vol 86, pp 58-65, 

https://doi.org/10.1292/jvms.23-0349 

 

Study: Curly Horses promote immune tolerance in allergic individuals

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 American Bashkir Curly Horses are claimed to be hypoallergenic, but this has not been clinically proven. 

The origin of these horses remains uncertain, with their additional name "Bashkir" stemming from the misconception that they were originally imported from Russia to America. Some theories suggest a Spanish immigrant origin in South America.

Established in 2010, Curly Farm Klappholz combines Dr. Wolfgang Mitlehner's medical practice specialising in internal medicine, allergology, pulmonary, and bronchial medicine with a holiday home and riding school featuring Curly horses. This facility provides a safe environment for allergic riders to interact with and ride Curly Horses.

 

Dr. Mitlehner has conducted studies on allergic patients who have ridden Curly horses to investigate their allergic responses to these animals.The work culminated in a report published in the journal Pneumologie

 

This collaborative study involved Susanne Mitlehner from Curly Farm Klappholz, Dr. Wolfgang Mitlehner, Alexandra Mitlehner, Hans Caspar Mitlehner, Peter Stoll, and Ines Swoboda from the University of Applied Sciences in Vienna, along with Monika Reissmann from Humboldt-University of Berlin.

 

The team examined the impact of exposure to Curly Horses on 141 patients allergic to horses by assessing their lung function and nasal patency during interactions with the animals. They discovered that repeated engagement with Curly Horses, including activities such as riding and grooming, resulted in a reduction in allergic riders' reactivity. This improvement was evidenced by enhancements in FEV1, PEF, and PNIF measurements.

 

PNIF, FEV1, and PEF are standard measures used to evaluate nasal obstruction, allergic rhinitis, and lung function, particularly in conditions like asthma.

 

Repeated interactions with Curly Horses, including riding and grooming, resulted in decreased reactivity among allergic riders, as evidenced by improvements in FEV1, PEF, and PNIF measurements.

 

Further visits, involving extended periods of riding totalling up to 40 hours or more, continued to reduce reactivity to Curly Horses. It's noteworthy that allergic reactions to horses occurred in only 72 out of 1312 riding hours, with the majority occurring within the initial ten hours of riding.

 

In a subset of 41 out of the 141 patients, additional investigation explored whether repeated exposure to Curly Horses could induce tolerance to other horses. These patients participated in a tolerance induction study and underwent annual testing for horse allergy using a nasal provocation test. The results revealed that exposure to Curly Horses led to immune tolerance to other horses in 88% of patients who completed the study.

 

Dr Mitlehner elaborates “To understand the mechanism causing hypoallergenicity, we performed IgE immunoblots to determine whether Curly Horse hairs contain IgE binding proteins.” 

 

IgE immunoblots play a significant role in allergy diagnostics. By examining the pattern of IgE antibodies adhering to various allergens on the membrane, clinicians can identify the specific allergens to which a patient is sensitized. This information is vital for diagnosing allergies and formulating suitable treatment plans, such as allergen-specific immunotherapy (allergy shots) or recommendations for allergen avoidance.

 

The study revealed no differences in IgE reactivity between Curly and non-Curly Horses. Additionally, patients participating in the immune tolerance induction study did not exhibit reduced IgE reactivity to hairs from Curly or non-Curly Horses, despite having developed tolerance.

 

“However, we did find increasing levels of anti-horse IgG antibodies in the study patients.” Dr Mitleehner added.

 

“Overall, our data strongly suggests that continuous exposure to Curly Horses can induce immune tolerance, rendering these patients non-reactive to horses. The reason for the reduced clinical allergenicity of Curly Horses remains unclear, but the data suggest that blocking IgG antibodies may be of importance for immune tolerance development.”

 

For more details, see:

 

Horse allergy: Curly Horses can mediate immune tolerance

Alexandra Mitlehner, Caspar Mitlehner, Monika Reißmann, Peter Stoll, Ines Swoboda, Wolfgang Mitlehner

Pneumologie (2024); 78(01): 47-57
https://doi.org/10.1055/a-2101-9533

 

https://www.curlyfarm.de

 

Assessing the effects of chiropractic manipulation

 Chiropractic care in horses involves the application of manual manipulations, adjustments, and therapies to address musculoskeletal issues and promote overall well-being.

It is believed to offer several potential benefits, including improved range of motion, reduced pain, enhanced performance, and a positive impact on the horse’s overall well-being. 

 

While anecdotal evidence suggests positive outcomes, scientific research on the efficacy of chiropractic care in horses is limited. Some studies have shown potential benefits, but more research is needed to establish its effectiveness conclusively.

 

A study by Olivia Lorello and colleagues investigated the effect of chiropractic manipulation on stride characteristics and heart rate, and on rider-perceived quality of ridden work.

 

Thirty-eight hunter-jumper (show jumper) horses were recruited for a blinded randomised controlled trial. All horses participating in the study had no reported performance or medical issues.

 

Exercise tests were conducted the day before and two days after either chiropractic treatment or a sham procedure. Each horse was ridden by its regular rider in their typical riding setting. Riders were unaware of the treatment administered to their horse.

 

During the tests, horses wore fitness trackers and parameters such as stride length, rate, and symmetry, as well as heart rate were monitored. Each horse-rider combination underwent the test protocol four times.

 

Complete sets of before and after data were available for analysis from 27 horses.

 

More riders reported an improvement in the quality of the ridden work after chiropractic treatment than after sham treatment.

 

However, the research team found no difference in measurements of stride length, stride rate, stride symmetry, or heart rate between the two treatment groups.

 

They suggest that the quantitative variables chosen may not have enough sensitivity in a group of sound horses that were in routine ridden work when entering the study.

 

Additionally, differences in terrain, weather conditions, and rider characteristics among horses may make small changes difficult to identify. 

 

They suggest more sophisticated and in-depth motion measurements may be valuable for this purpose.

 

 

For more details, see:

 

Chiropractic effects on stride parameters and heart rate during exercise in sport horses

Lorello, Olivia; Rule, Emily; Haughan, Joanne; Wang, Kai; Niu, Mutian; Brown, Kara; Navas de Solis, Cristobal

Equine Veterinary Journal (2024)

https://doi.org/10.1111/evj.14043

Strip grazing delivers more consistent nutrients than free grazing

(c) Sarah Shephard

A recent study has revealed that strip grazing can provide horses with a more consistent nutrient supply
compared to unrestricted grazing once rapid spring grass growth subsides. This finding adds further insight into the potential effectiveness of strip grazing as a tool for managing weight in horses.

The research, conducted by Dr. Annette Longland from Equine Livestock and Nutrition Services in collaboration with the WALTHAM™ Equine Studies Group and the SPILLERS brand, builds upon previous work by the same team. Earlier research* demonstrated that strip grazing could effectively restrict grass intake to aid in managing the body weight of pastured ponies, although the underlying reasons were not fully understood. This follow-up research highlights the benefits of consistent nutrient intake achievable through strip grazing.

 

In this study, twelve ponies were individually grazed in long, narrow paddocks specifically designed to provide herbage equivalent to 1.5% (dry matter) of the ponies’ body weight per day over a 28-day period from late June to late July, once the rapid growth phase of spring grass had finished.

 

For the first two days, all ponies were grazed on freshly mown "start paddocks" before being allocated to one of three grazing regimes for the duration of the study: unrestricted grazing (total allowance; TA group), or one of two strip grazing methods. In the first strip grazing method, a lead fence was positioned across the width of the paddock and moved daily to allow access to fresh grass. The second strip grazing method involved both a lead and a rear fence, with the rear fence moved the same distance daily as the lead fence.

 

Weekly evaluations were conducted to assess pasture nutrient levels and estimated digestibility.

 

The results showed that strip grazing provided herbage of more consistent nutritional quality throughout the trial compared to when ponies had unrestricted access to the same amount of original herbage. The findings also reiterated the potential value of strip-grazing as an effective tool for weight management.

 

Throughout the study, the start paddocks remained leafy and green, while the nutritional value of the remaining grass declined as it matured, consistent with typical trends for mixed-species pastures in the UK. Notably, strip grazing prevented the aggressive selective grazing observed in the total allowance (TA) group, where ponies consumed the more nutritious herbage early on, leaving less nutritious herbage for the latter part of the study period.

 

As a result, the calculated digestible energy intakes of the TA ponies in weeks one and two exceeded requirements by 42 % vs. 8 % by the strip-grazed ponies. Over the course of the study, the TA ponies gained three-four times more weight than their strip-grazed counterparts, with over 70% of the TA ponies’ weight gain occurring in the first two weeks. In contrast, strip grazed ponies gained significantly less weight overall at a more consistent rate.

 

“This study gives us some important practical take home messages regarding weight management and potentially the management of associated disorders such as insulin dysregulation and laminitis,” said Sarah Nelson, Product Manager at Mars Horsecare, home of the SPILLERS brand. 

 

“Strip grazing in this study prevented rapid weight gains by providing gradual access to fresh pasture of decreasing nutrient value and preventing aggressive selective grazing. This work shows how strip grazing, if carried out appropriately, can be an effective weight management tool especially once the very rapid, spring growth is over. However, it is important to remember that even strip grazing on high non-structural carbohydrate (NSC) containing pastures may not be suitable for some laminitis prone equids, especially those that are at high risk or at certain times of year.” 

 

For more details, see:

 

Longland, AC, Barfoot, C, Harris, PA. Strip grazing: 

Changes in biomass, nutrient content and digestibility of temperate, midsummer pasture by strip-grazed or ‘free’-grazing ponies, over 4 weeks.

Journal of Equine Veterinary Science (2023) Vol 131, 104957

https://doi.org/10.1016/j.jevs.2023.104957

 

*Longland, AC, Barfoot, C, Harris, PA. 

Strip-grazing: Reduces pony dry matter intakes and changes in bodyweight and morphometrics. 

Equine Vet J. 2021; 00: 1– 8.

https://doi.org/10.1111/evj.13416

 

(Edited press release)

Investigating injectable omeprazole for gastric ulcers

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Gastric ulcers pose a significant concern in horses, particularly those engaged in high-
performance activities or those under stress. 

The horse’s stomach is divided into two distinct regions, the squamous and glandular mucosa. The upper (dorsal) portion of the stomach is covered by squamous epithelium. The glandular mucosa that lines the lower (ventral) portion of the stomach contains gastric glands that secrete hydrochloric acid, pepsinogen, histamine, mucous, and sodium bicarbonate. 

 

Omeprazole is commonly used, in conjunction with management changes, for treating gastric ulcers in horses. Classified as a 'proton pump inhibitor,' omeprazole functions by inhibiting the hydrogen-potassium adenosine triphosphatase enzyme system, usually known as the 'proton pump.' This enzyme system is found in the cells of the glandular mucosa that produce stomach acid. Omeprazole disrupts the normal operation of proton pumps, resulting in a reduction in stomach acid production.

 

Omeprazole is typically administered orally, using daily paste formulations or enteric-coated granules. An increasingly popular treatment for equine squamous gastric disease (ESGD) and equine glandular gastric disease (EGGD) involves the weekly administration of an extended-release injectable omeprazole formulation (ERIO*) which is available in some countries.

 

Tania Sundra and her colleagues conducted a study to assess the impact of ERIO formulation treatment administered at 5- or 7-day intervals on ESGD and EGGD. They reviewed clinical records from Avon Ridge Equine Practice, Western Australia, covering gastroscopic examinations conducted from July 2020 to November 2021, identifying horses that had been treated with ERIO.

 

Gastroscopic images, anonymized and graded by a researcher unaware of the treatment group, were used for comparison. Univariable ordered logistic regression was employed to analyze responses to the two treatment schedules. 

 

The findings, indicating a higher proportion of EGGD healing with ERIO administered at 5-day intervals compared to 7-day intervals, were reported without an apparent rise in complications. However, no significant difference was observed in the proportions of ESGD healing between the two treatment regimens.

 

A detailed report of this study can be found in the Equine Veterinary Journal. The authors suggest that the use of ERIO at 5-day intervals might be more appropriate than the 7-day interval that is used currently.

 

 

For more details, see:

 

Five- versus seven-day dosing intervals of extended-release injectable omeprazole in the treatment of equine squamous and glandular gastric disease

Tania Sundra, Erin Kelty, David Rendle 

Equine Vet J (2024) Vol 56(1):51-58.

https://doi.org/10.1111/evj.13938

*Extended-release injectable omeprazole . BOVA Australia

New Morris Animal Foundation research grants

 Morris Animal Foundation announced its selection of 10 new grants dedicated to enhancing the well-being of domesticated horses, ponies, donkeys and mules.

Morris Animal Foundation's mission is to bridge science and resources to advance the health of animals. Founded in 1948 and based in Denver, Colorado, it is one of the largest non-profit animal health research organizations in the world. 

 

Applications were reviewed and rated based on impact and scientific rigour by the Foundation’s scientific advisory boards, which are made up of topic experts in the veterinary community.

 

"We are excited to fund these research proposals that will advance equid health," said Dr. Kathy Tietje, Chief Program Officer at Morris Animal Foundation. "Through these grants, we aim to elevate the quality of life, ensuring a brighter, healthier future for horses, ponies, donkeys and mules."

Research topics being supported include separation-related anxiety in horses, equine metabolic syndrome, and equine protozoal myeloencephalitis.

 

The full list of grants awarded is: 

 

Claire Ricci-Bonot, University of LincoIn, United Kingdom; "An Exploration of the Nature of Separation-Related Problems in the Horse." Researchers will use survey tools to learn more about separation anxiety in horses, including its different forms and situational triggers.

Angela Gaesser, University of Pennsylvania; "What Role Does Epidermal Growth Factor Receptor Pathway Play in the Pathogenesis and Treatment of Equine Osteoarthritis." Researchers will study if a signalling pathway contributes to the progression of osteoarthritis and if a novel treatment targeting this pathway can help affected horses.

Edward J. Knowles, Royal Veterinary College, United Kingdom; "Insights into the Pathogenesis of Equine Metabolic Syndrome: Plasma Amino Acid and Acylcarnitine Profiles in Ponies with Insulin Dysregulation." Researchers will learn more about insulin resistance and laminitis in horses and develop cost-effective tools to monitor these patients better.
 
Serena Ceriotti, Auburn University; "Effect of Omeprazole Treatment on the Pharmacokinetics of Orally Administered Flunixin Meglumine in Adult Horses: A Pilot Study." Researchers will study the anti-ulcer drug omeprazole, often prescribed with the NSAID flunixin meglumine and its impact on the latter drug's ability to reduce pain in horses effectively.
 
Izabela de Assis Rocha, University of Kentucky; "Investigation of the Immunopathogenesis of Equine Protozoal Myeloencephalitis." Researchers will study why a small percentage of horses infected with the causative parasite Sarcocystis neurona are afflicted with a severe neurological disease called equine protozoal myeloencephalitis while other infected horses are unaffected.
 
Sriveny Dangoudoubiyam, Purdue University; "Determining the Role of Dense Granule Protein, SnGRA9, in Sarcocystis neurona Infection." Researchers will study how a protein helps the parasite Sarcocystis neurona grow and reproduce in infected horses.
 
Breanna Sheahan, North Carolina State University; "Identifying CFTR Inhibition as a Treatment for Equine Diarrhea Using an In Vitro Patient-Derived Organoid Platform." Researchers will use an organoid platform, a 3D cell culture, to study a potential new treatment for severe diarrhoea in horses.
 
Kristen Conn, University of Saskatchewan, Canada; "Understanding the Chromatin Regulation of Lytic Equine Herpesvirus 1 (EHV1) Gene Expression." Researchers will work to understand better how EHV1 causes disease and use this information to inform the development of improved treatments.
 
Carrie J. Finno, University of California, Davis; "Unraveling the Genetic Etiology of Equine Neuroaxonal Dystrophy in Quarter Horses and Warmbloods." Researchers will search for causative genes associated with a common neurological disease in horses called equine neuroaxonal dystrophy/degenerative myeloencephalopathy or eNAD/EDM.
 
Thilo Pfau, University of Calgary, Canada; "A Team-Based Approach to Monitoring Gait Symmetry: Hoof Care Providers, Horse Owners and Veterinarians Working Toward Prevention of Lameness." Researchers will partner with hoof care providers, veterinarians and owners to evaluate the feasibility of using video technology to monitor horse gait changes.

 

 

(Edited press release) See:

 

https://www.morrisanimalfoundation.org/article/foundation-announces-grant-recipients-equine-health-studies