Managing thin soles in performance horses

(c) Matz et al 2024

 Thin soles and poor palmar angles are common issues in performance horses, significantly impacting their comfort, movement, and hoof health. Horses with thin soles are more prone to lameness due to increased sensitivity, pain, bruising, and a higher risk of developing solar abscesses.

Managing thin soles can be challenging for farriers and hoof care professionals. Many owners turn to protective footwear, while supplements rich in biotin, methionine, and zinc are often used to promote hoof growth. 

One potential therapy gaining attention is Pulsed Electromagnetic Frequency (PEMF) therapy. Widely used in equine therapy, PEMF promotes healing, reduces pain, and supports overall health and performance. Could it also play a role in managing thin soles?

 

A recent pilot study led by Madelyn Matz, published in the Journal of Equine Rehabilitation, explored the effect of PEMF therapy on hoof parameters in ten adult horses of various breeds. The horses were divided into a PEMF group (n=6) and a control group (n=4).

 

All horses underwent standard hoof trimming the day before the study began, with no further farriery work during the trial. Radiographs were taken before treatment and again 30 days later, measuring sole depth and palmar angles (see figure).

 

The PEMF group received treatment at a frequency of 22 Hz for ten minutes per session, applied to both hooves three times a week (on Monday, Wednesday, and Friday) over a 30-day period, while the control group received no intervention.

 

The study found no significant differences between the PEMF and control groups in terms of sole depth under the apex of the proximal phalanx or palmar angles. However, there was a trend towards increased sole depth beneath the distal processes of the right hoof in the PEMF-treated horses.

 

While this pilot study showed no significant improvement overall, the trend towards increased sole depth suggests that PEMF therapy may offer some benefit. 

 

The researchers concluded that further investigation is warranted, as PEMF therapy could become a non-invasive option for managing thin soles in horses.

 

 

For more details, see:

 

M.M. Matz, D.L. Alexander, J. Moore, C.E. Fedorka,

Evaluating the effect of pulsed electromagnetic field (PEMF) therapy on sole depth of the equine hoof: A pilot study,

Journal of Equine Rehabilitation, (2024) Vol 2,100010,

https://doi.org/10.1016/j.eqre.2024.100010

Advances in imaging distal limbs

PET, CT and MRI images of navicular / middle phalanx. (c) EVJ

Radiography has been used for imaging horses’ legs for over a hundred years. Recent technological advances have
delivered new imaging modalities.

The publications Veterinary Radiology & Ultrasound (VRU), Equine Veterinary Education (EVE) and the Equine Veterinary Journal (EVJ) have combined forces to celebrate the evolution in equine imaging with a free special collection to reflect some of the most significant advances in distal limb imaging from the past five years.

 

Advances in Imaging of the Equine Distal Limb 2017–2022 comprises a total of 20 papers which have been selected by Mathieu Spriet, Ann Carstens and Tim Mair. It is accompanied by a comprehensive editorial from the EVJ summarising the major historical technological developments in imaging of the foot and fetlock, embracing all the modalities.

 

The evolution of computed tomography (CT) allows the imaging of the distal limb without anaesthesia. CT scanners are also now used in surgery rooms bringing significant progress in orthopaedic surgery.  Six papers look at advances in CT including addressing some of the challenges of the ring design of this modality.

 

Positron emission tomography (PET), the latest modality to be introduced to equine imaging, has opened a whole new field of possibilities for bone and soft tissue imaging in racehorses and sport horses. Five papers look at how PET brings functional information to the table, allowing early detection of abnormalities before the occurrence of structural changes and distinguishing between active and inactive lesions when structural changes are present.

 

MRI has been a mainstay in orthopaedic imaging for many years; six important studies are included in the collection and show how the optimisation of scanning techniques is constantly improving this modality. 

 

Ultrasound is steadily improving; one of the papers looks at the important technical evolution involving the imaging of limbs in non-weight bearing position as well as under the classic weight bearing position.

 

Radiographs remain the most commonly used imaging technique, despite the modality being more than 100 years old. One of the papers confirms why radiographs remain a valuable imaging tool.

 

The role of scintigraphy has decreased in the past 20 years with the emergence of advanced cross-sectional imaging, but it remains an essential tool especially for comparative imaging studies. One of the papers examines agreement between scintigraphy and MRI to identify the source of foot pain.

 

“The content of this virtual issue represents an amazing amount of new knowledge that with no doubt will contribute to improve equine welfare and safety,” said Mathieu Spriet. “With the increase availability and versatility of all the imaging modalities, the knowledge base appears to increase exponentially. We are very excited to see what the next five years will bring. We hope the readers will enjoy consulting this collection as much as we enjoyed putting it together.”

 

“During the past five years close to 100 equine imaging papers have been published between EVJ, VRU and EVE, covering a wide variety of topics,” said Professor Celia Marr, Editor of the EVJ. “The EVJ is proud to have been able to work collaboratively to bring this definitive distal limb imaging collection to life, giving clinicians easy access to some of the most pertinent work in this area.”

 

The virtual issue is free for 12 weeks and can be found at https://beva.onlinelibrary.wiley.com/doi/toc/10.1001/(ISSN)2042-3306.equine-distal-limb

Assessing welfare of horses owned by travellers and gypsies

The welfare of Traveller and Gypsy owned horses in UK and Ireland may be better than is sometimes thought, according to a recent study.

 

It has been suggested that horses owned by travellers and gypsies are particularly exposed to reduced welfare, with practices such as fly-grazing, tethering, abandonment of animals and indiscriminate breeding being seen as common. However, there has been little work to investigate the well-being of these animals.

 

Researchers at the Royal (Dick) School of Veterinary Studies, and the Roslin Institute, both at Easter Bush near Edinburgh, Scotland, conducted a study to identify the welfare status of Traveller- and Gypsy- owned horses and to determine the factors that are considered risks to horse welfare in this community. 

 

Marie Rowland and colleagues used a new approach, called ‘Qualitative Behaviour Assessment’ (QBA), to assess the horses’ behaviour and its affective state. A report of the work is published in Animals, as part of a special issue dedicated to equine welfare assessment.

 

They explain that Qualitative Behaviour Assessment is a “scientific approach used to measure the expressive quality of an animal’s behaviour and affective state. It is a ‘whole animal approach’ and is used to measure how the animal is expressing behaviour, often referred to as an animal’s ‘body language’. An animal’s mood or emotional state is communicated through its body language and is assessed using terms that describe their emotional repertoire. This is then applied to interpret an animal’s physical and psychological state.” 

 

The research team assessed horses at different locations throughout the UK and Ireland, including Appleby Horse Fair, (England), and Ballinasloe Horse Fair (Ireland). They also saw horses at British Horse Society (BHS) horse health clinics, and horse owners’ homes and yards.

 

To ensure a standardised procedure was used, all horses were assessed visually from 1.5 metres away.

 

The overall assessment indicated that horse health and welfare was of a good standard, with an optimal body condition score and the absence of skin conditions observed in most horses. Signs of poor hoof care were the most frequently reported welfare problem. Nearly a third of horses showed hoof changes such as hoof wall cracks and defects and long toes.

 

In conclusion, Rowland and colleagues write: ”This study is the first of its type to begin to quantify the welfare of Traveller and Gypsy owned horses. Although further research is required to ensure generalisability to all horses within this population, these results are a good starting point on which to engage with stakeholders who previously identified Traveller and Gypsy owned horses in the UK and Ireland to be particularly vulnerable to poor welfare.”

 

 

For more details, see:

 

The Welfare of Traveller and Gypsy Owned Horses in the UK and Ireland

Marie Rowland, Neil Hudson, Melanie Connor, Cathy Dwyer, and Tamsin Coombs. (2022)

Animals 12, no. 18: 2402. 

https://doi.org/10.3390/ani12182402

Causes of contracted heels investigated

A recent study found that heel contraction was more common in shod than in barefoot horses, but did not confirm that metal horseshoes were to blame.

Contracted heels have been defined by the ratio of frog length to frog width. The foot can be described as contracted when the frog width is less than 2/3rds its length. The affected foot is less able to absorb concussion and may lead to lameness.

Magdalena Senderska-Płonowska, with colleagues at the Wroclaw University of Environmental and Life

Sciences, Wrocław, Poland, assessed the influence of shoeing and other risk factors, such as age, access to paddock, and breed, on heel contraction.

The 114 horses included in the study were of various warmblood  breeds, and were being used as riding-school horses, pleasure horses, and sport horses. They were considered to be sound by their owners or riders, were at least three years old, and came from yards across Poland.

One group had been kept barefoot all their lives; the others had been regularly shod with metal shoes for at least the previous year.

Dr Senderska-Płonowska measured the width and length of the frog of all four feet of the horses in the study. She found that individual horse features, such as yard and breed, had the most significant impact on the width:length ratio of the frog.

There was a significant difference in occurrence of heel contraction between yards. Breed was also an important factor. Silesian and Arabian horses had significantly greater frog width: length ratio compared with other breeds.

Being shod did not affect the frog width: length ratio.

A full report of the research is published in the Journal of Equine Veterinary Science. Senderska-Płonowska concludes: “heel contraction is a multifactorial problem, mainly caused by breed and unknown features correlated with the individual. The results disputed the popular myth of metal shoes being main cause of contraction, an important factor for all hoof-care providers to be aware of. “

Because of the significant difference in incidence of contraction between yards, she suggests the need for more research on larger groups of well-defined phenotypes of horses from yards with low and high incidence of heel contraction to identify the environmental factors responsible.

For more details, see:

Do Metal Shoes Contract Heels? - A Retrospective Study on 114 Horses
Magdalena Senderska-Płonowska, Paulina Zielińska, Agnieszka Żak, Tadeusz Stefaniak
J Equine Vet Sci (2020) 95:103293.
https://doi.org/10.1016/j.jevs.2020.103293

Free access to gait analysis articles.

Historically, assessing the severity of lameness has been a matter of opinion. The various gait analysis systems that are now available provide a more objective way of doing so.

Quantitative gait analysis involves the use of electronic sensors, enabling the assignment of numerical values to motion, with the application of kinetics and kinematics.

Interest in gait analysis has grown;  it now has applications beyond the pure assessment of lameness. Gait analysis is being used to assess the value of new therapies and in scientific studies that have implications for horse health and welfare.

The exceptional capacity of the horse’s locomotor system largely led to its domestication as a working, sport and leisure animal. It has resulted in a continuing fascination with equine performance, whether physiologically in terms of footfall patterns in different gaits or pathologically, when locomotion may be impaired.

Articles on gait analysis that have been published in the Equine Veterinary Journal, have now been brought together in one place. This virtual collection will be free to view online for one year from 4^th  October 2019.

Topics covered include:

• Combined influence of expertise and fatigue on riding strategy and horse-rider coupling during the time course of endurance races
• Head and pelvic movement asymmetry during lungeing horses with symmetrical movement on the straight
• Does ‘hacking’ surface type affect equine forelimb foot placement, movement symmetry or hoof impact deceleration during ridden walk and trot exercise?

“We have now reached a stage in which technical developments have permitted the introduction of user-friendly quantitative gait analysis techniques in clinical practice,” says Professor René van Weeren, who jointly edited the collection with Dr. Constanza Gómez Álvarez. 

“Accuracy and reliability of these techniques have increased to improve our performance in the assessment and monitoring of equine locomotor performance. However, these developments also urge us to reconsider our position as clinicians and pose new challenges in terms of interpretation of the data that are generated.”

Professor Celia Marr, Editor of the EVJ said: “The breadth and substance of this research shows how far we have advanced with equine quantitative gait analysis. It has moved far beyond solely being a tool for objective lameness assessment and continues to develop as an exciting method for the support of equine welfare and performance.”

Dr. Constanza Gómez Álvarez added: “Today, objective, quantitative gait analysis in the horse has outgrown the laboratory and is infiltrating all horse-related activities.”

The virtual collection is available at:

https://onlinelibrary.wiley.com/doi/toc/10.1111/(ISSN)2042-3306.Practical_uses_of_quantitative_gait_analysis

Fresh insight into hoof growth

So many factors affect the way the hoof grows that it can be difficult to unravel the mystery.

A recent study into hoof growth has approached the subject from several directions: equine medicine, maths, physics and stem cell biology have all played a part.

The findings have revealed a clearer understanding of how equine hooves grow and how abnormal hoof shapes may develop.

The study entitled ‘Physics of animal health: On the mechanobiology of hoof growth and form’ was conducted by the School of Veterinary Medicine and Science at the University of Nottingham in collaboration with the WALTHAM Centre for Pet Nutrition and the Royal Veterinary College. A full report is published in the Royal Society Interface Journal.

Lead author Dr Cyril Rauch, of the School of Veterinary Medicine and Science, University of Nottingham, said: “With new scientific inputs from physics, mathematics and biology, this study provides an entirely new paradigm regarding hard growing tissues such as the horse hoof, which can be applied across cattle, sheep and other species, to unify a set of apparently disparate conditions and clarify the roles of physics and/or biology.”

Nicola Menzies-Gow, of the Royal Veterinary College, said: “We believe that this novel approach has the potential to provide alternative directions to follow with respect to understanding chronic hoof pathologies.”

Laboratory -based studies looked at how the synthesis of the hoof capsule starts from the coronet with the soft papillae undergoing gradual transition through three interpapillary regions into hard keratinised tissue.

Mathematics, physics and cell biology were then used to explain and describe how the dorsal hoof wall can grow in a curved manner rather than the usual straight manner as a result of faster growth from the coronary band at the quarters compared to the toe region.

A field study looked at one hundred and twenty-nine horses. All were at least 5 years old and under 144 cm (less than 14.2hh) high with shoes. They were healthy at the time of evaluation and none had a history of laminitis/hoof conditions, or pre-existing health conditions; neither had they been treated for pituitary pars intermedia dysfunction (PPID - Equine Cushing’s disease).

The research team recorded horse weight and Body Condition Score, hoof width and they measured the curvature of the dorsal wall from standardised photographs. This allowed the influence of body weight on the balances of the stresses affecting hoof growth to be evaluated. The results suggest that being proportionally heavier may promote straighter hoof growth and that being too lean may precipitate poor hoof growth and the development of a hoof with a dorsal curved shape.

The study also showed that a high concentration of insulin stimulated equine progenitor keratinocytes (the cells responsible for producing the hoof wall) to grow in culture. The researchers suggest that if this happens over time in the live animal, it is possible that it could affect the growth stresses within the hoof and so promote a dorsal curved hoof shape.

“These results taken together can explain how the hoof grows and how it is possible for it to develop a dorsal curvature,” said Dr Menzies-Gow. “However, it should be acknowledged that this does not take into account the genetic or metabolic influences on hoof growth nor the role of hoof trimming and shoeing in maintaining a mechanically healthy hoof. It is appreciated that the underlying biology of hoof growth remains an essential factor for hoof pathologies.”

Dr Cyril Rauch continued: “Given that the hoof is a weight bearing element it is essential to untangle the biology from the physics in this system; only then can meaningful biological and/or physical causes be prescribed for particular hoof shape. Removing the cause(s) when physically or biologically possible is essential to resolve hoof conditions.”

For more details, see:

R Al-Agele; E Paul; S Taylor; C Watson; C Sturrock; M Drakopoulos; R C Atwood; C S Rutland; NJ Menzies-Gow; E Knowles; J Elliott; P Harris; C Rauch. (2019) Physics of animal health: On the mechanobiology of hoof growth and form.

Journal of the Royal Society Interface, (2019) Vol 16 Issue 155

http://doi.org/10.1098/rsif.2019.0214