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Why I Now Believe My Warmblood Gelding Had the C6-C7 Problem – Reader Story

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“I went through three years of horror…”

So speaks a Warmblood owner, reflecting upon a truly dreadful period in her life. Like many other owners, she has gained belated understanding of her horse’s problems after reading about research findings into the C6-C7 malformation (article) led by Australian gross anatomist, Sharon May-Davis.

Sadly, this is a bittersweet moment: there is a temporary relief as everything finally makes sense, yet with it comes the realisation that there is nothing that can be, or could have been, done for a treasured horse bearing the more extreme version of this malformation.

Here, Diana from Michigan, USA, gives her story of the desperation and – ultimately – heartache she experienced when trying to find out what was wrong with her horse of a lifetime, a young Oldenburg gelding, “the kindest horse I ever had”.

Note: We are not identifying the lines of the individual horse in this story. If you’re thinking we should, perhaps remember that it’s a litigious world out there.

But for now, over to Diana.

© All text copyright of Jane Clothier, www.thehorsesback.com. No reproduction of partial or entire text without permission. Sharing the link back to this page is fine. Please contact me for more information. Thank you!

 

Diana’s Story

I purchased a stunning 3-year-old Oldenburg to fulfill my dream of developing a young horse through the upper levels in dressage. I cashed in the 401K [retirement savings plan] for the horse and bought a Schleese saddle.

For the first two years (ages 3 and 4) we were champion every time out.

At age 5, however, my trainer noticed he began to drag his left hind toe. Then his impulsion began to deteriorate, and months later he became too unstable to safely handle. He was euthanized at 7 years old.

Looking back, I now believe that all his quirks were directly related to this problem. I am going to briefly list the oddities I experienced with this wonderful horse.

I am not a vet or tech, and am only sharing my experiences in the event that it may help someone else, because my journey was one of the most emotionally draining experiences in my life.

 

Possible Signs of this Warmblood’s C6-C7 Problem

I purchased my gelding on his 3rd birthday and he’d had 30 days under saddle. The oddities of my gelding: he was extremely sweet and willing – the kindest horse I ever had.

He required a tremendous amount of leg every step. Although there seemed to be no ‘self-carriage’, I attributed this to his being green and still learning.

He would buck EVERY TIME he was saddled (I was very conscientious about slowly tightening the girth, tried every type of girth, pads, had adjustable saddle, etc).

Again, I attributed the bucking to youthfulness, and would let him buck out for a few laps, and then wondered if I had created a habit, because this occurred every schooling.

  • If he wasn’t lunged first, he would explode into a non-rideable rodeo with absolutely no warning.
  • He had a very difficult time bending to the left – he would try, but would drift.
  • Two separate times after mounting at the block, he felt like he arched or sucked his back up about 3 inches before walking off.
  • After 25 mins of schooling he would start rooting at the reins, or if the lesson was a short one, as soon as I’d give him his head to cool out.
  • He was a stumbler – not often – again, I attributed it to youth.
  • He could not be shod or trimmed without being sedated.
  • Once, a friend said it looked like he couldn’t put his head down to reach hay. Of course, I thought she was nuts until I witnessed it first hand.

Questions, thoughts or comments? Join us at The Horse’s Back Facebook Group. 

 

Investigating the C6-C7 Problem

During my discovery phase, he was diagnosed with moderate PSSM. So, he and I spent 9 months testing sugar levels in hay, with turnout in a dry lot.

There were periods he would barely walk forward when leading, and at the time I thought he was tying up, but it didn’t seem like what I had read, and I have never witnessed a horse tying up.

Then in his latter days, his neurological issues became more obvious with each passing day.

I did have a myelogram done on him, and it revealed compression of the spinal cord at C3 and C4.

Vets at Michigan State University did finally identify malformations of both C6 and C7 through radiographs. Their report stated:

The intervertebral foramen is severely reduced at C6-C7. A minimal amount of osseous proliferation is noted along the dorsal aspect of the articular processes at C5-C6.

Interpretation: Multifocal cervical articular degenerative joint disease (C4-T1), most severe at C6-7.”

I had a very difficult time with the decision to euthanize him, because his neurological issues would fluctuate. Some days, no evidence all. On other days, he would fall against the stall wall when turning him around in the stall.

In any event, I euthanized him, believing that he was experiencing severe pain from the narrowed foramen at C6 and C7.

I believe they were the reasons for the bucking, for needing to be sedated for the farrier, for not being able to lower his head, for rooting on the reins, for barely walking forward when I thought he was tying up, and the bizarre lifting of his back. He also had a very difficult time holding his right lead, and would swap unless you really held him.

I am so, so glad I ran across this website and article because I will go to sleep tonight knowing that euthanizing was for sure the right thing to do. Thank you!

Diana

 

 

If you’re about to purchase a horse that falls into the ‘at risk’ category for this malformation, do your due diligence as a buyer, and have the caudal cervical vertebrae radiographed as part of your pre-purchase examination. A protocol for radiographing for the malformation is on this site.

The following papers also cover radiographs and CT imaging of the C6 malformation:

Ex Vivo Computated Tomographic Evaluation of Morphology Variations in Equine Cervical Vertebrae, Veraa, S. et al,  Veterinary Radiology & Ultrasound, Vol. 57, Issue 5

Prevalence of Anatomical Variation of the Sixth Cervical Vertebra and Association with Vertebral Canal Stenosis and Articular Process Arthritis in the Horse,
Spriet, M. and M Aleman, Veterinary Radiology & Ultrasound, Vol. 57, Issue 3

 

If you wish to comment, please feel free to do so below, but please do so with respect for an owner who found herself in a nightmare situation. Alternatively, come over the blog’s discussion group on Facebook.

By Popular Demand: Here’s How You X-Ray for the C6-C7 Malformation

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News about the malformation of the C6 and C7 vertebrae has understandably raised a lot of concern. There are major implications for both buyers and breeders of TB and TB-derived breed horses, as outlined in the original article, All You Need to Know About the Hidden C6-C7 Malformation That’s Bringing Horses Down. In response, Sharon May-Davis has very kindly provided us with the English version of a paper she published in the Journal of Japanese Local Government Racing, outlining a preliminary protocol for radiographing this area of the neck and identifying the malformation. (Yes, a single racing authority has taken this issue on board!)

So without further ado, here is the paper in its entirety, the only adaptations being the positioning of images to better fit this site’s blog format.

© All text copyright of the published authors. No reproduction of partial or entire text without permission. Sharing the link back to this page is fine. Please contact me for more information. Thank you!

 

Preliminary Radiographic Protocols for Identifying Congenital Malformations of the Caudal Cervical Vertebrae

Authors: May-Davis S.E.R., Minowa F., Monoe S.

 

Abstract

In 2014, a published study based on dissections and skeletal examinations noted that 19:50 Thoroughbred horses had a congenital malformation of the 6th cervical vertebra (C6). In addition, it was found that in those 19 Thoroughbred horses expressing a congenital malformation of C6, 9 displayed a concurrent congenital alformation of the 7th cervical vertebra (C7). In this study, 3 Thoroughbred horses and 1 Thoroughbred type were clinically examined; 3 were radiographed for limb abnormalities and 2:3 radiographed for the congenital malformation of C6 and C7 prior to euthanasia. Upon dissection, 3:4 expressed a congenital malformation of C6 with 2:3 displaying a concurrent CM of C7. These 2 horses were positively radiographed for the CM of C6 and C7 prior to dissection. The radiographs of C6 were taken in direct lateral orientation with 0 degree of elevation and revealed the absence of the caudal ventral tubercle (CVT) of C6. Re-positioning the horse’s forelimbs caudally with an outstretched neck, C7 was radiographed at a 30° oblique lateral angle in a cranial to caudal direction with 0 degree of elevation; the transverse process of C5 remained cranial to the beam. The caudal aspect of the plate was positioned medial the Cranial deep pectoral and rotated vertically to expand the field of view of the cervical vertebrae, whilst remaining perpendicular to the beam.

 

Introduction

In recent times, 3 Australian studies reported congenital malformations of C6, C7, the 1st sternal rib, along with their associative soft tissue structures. Furthermore, it was noted that these congenital malformations were predominantly breed related and more specifically, to Thoroughbred horses or derivatives thereof. In addition, reports of forelimb proprioceptive dysfunction, neurological impediment and gait deficits were concurrently noted (May-Davis [a,b], May-Davis and Walker). The congenital malformations of C6 appeared as either a left or right unilateral absence of the caudal ventral tubercle (CVT) or as a bilateral absence of the CVT (Figure 1).

 

Left: Normal. Centre: Absent right CVT. Right: Bilaterally absent CVT

Figure 1. View of the ventral aspect of C6, cranial aspect top. Photo credit: Sharon May-Davis

 

The congenital malformation of C7 appeared with either a fully transposed CVT from C6 onto the ventral surface of C7 or a partial transposition of the CVT from C6 onto the ventral surface of C7 (Figure 2) (May-Davis [a]).

 

Left: Normal. Centre: Transposed right CVT. Right: Bilaterally transposed CVT

Figure 2. View of the ventral aspect of C7, cranial aspect top. Photo credit: Sharon May-Davis

 

The congenital malformation of the 1st sternal rib appeared in multiple presentations with gross anatomic variations including; an absent 1st sternal rib; bifid Tuberculum costae (Figure 3); bifid Sternochondral articulation onto the sternum; flared shaft; normal 1st sternal rib inserting onto the cranial branch of a bifid Sternochondral articulating 2nd sternal rib; straight costal shaft and an articulating rudimentary Tuberculum costae with a ligamentous extension replacing the bony shaft and attaching to a rudimentary Sternochondral articulation onto the sternum (May-Davis [b]).

Figure 3. Left costal bifid Tuberculum costae. Photo credit: Sharon May-Davis

Associative soft tissue structures varied according to the presentation of the congenital malformation with the most noted being, the Longus colli muscle, Scalene muscles and neural vessels such as the Phrenic nerve and Brachial plexus (May-Davis [b], May-Davis and Walker).

The congenital malformations noted in these 3 studies were determined via dissection and skeletal examination. They were based on 2 specific skeletal variations in C6 and C7 plus any variation to normal of the 1st sternal rib.

The congenital malformations could appear in C6 as a singular expression with no other anomalies, however, the congenital malformation of C7 only occurred when the CVT was absent on C6. The congenital malformations of the 1st sternal rib only occurred in the presence of the congenital malformation of C6 and C7 (Table 1) (May-Davis [b]).

With this in mind, the premise that if a congenital malformation exists in C6 then there is a 50% chance that transposition will occur on C7. In this format, it would stand to reason that there could also be an anomalous rib. Therefore, this study is designed to identify the absent CVT on C6 and investigate its transposition onto C7.

 

Table 1. Noted observations of 151 horses of mixed gender aged between 0 (stillborn) and 30, exhibiting a congenital malformation of C6, C7 and the 1st sternal rib.

 

Materials and Methods

After evaluation and clinical examination, the 2 horses (1 Thoroughbred and 1 Thoroughbred type) were restrained in cross ties. Detomidine Hydrochloride (Detomovet CEVA Animal Health Pty Ltd) was administered via left jugular vein venepuncture. The dosage was determined by the clinician’s experience and in consideration of the individual’s current health status.

The radiographs were obtained by utilising a Porta 100 HF High Frequency portable x-ray unit (7.8kgs). The kV range was 40-100kV with an mA range of 20-30 mA and a mAs range of 0.3 – 20 mAs. The images were captured on a wireless Rayence 1012WCA Medical Image processing unit (26cm x 32.5cm) and computerised with Vetview Digital Diagnostic Imaging software.

The radiographic angles were obtained with the horse’s neck in full extension and the forelimbs behind the vertical in standing position. With the clinician standing with the x-ray unit on the left side of the neck and the plate positioned on the right side of the neck, the distance between the x-ray unit and plate was 80cms. The x-ray unit and plate remained lateral to the cervical vertebrae determined by the transverse processes of C5.

The first view is a direct lateral at 90 degrees, with 0 degree of elevation whilst maintaining the transverse process of C5 to the left of the beam. 

Remaining lateral to the cervical vertebrae with a 0 degree of elevation, the second view is taken with the x-ray unit positioned at a 30° oblique lateral angle in a cranial to caudal direction with the transverse process of C5 cranial to the beam. The caudal aspect of the plate is positioned medial the Cranial deep pectoral and rotated vertically to expand the field of view of the cervical vertebrae, whilst remaining perpendicular to the beam.

Upon the radiographic evaluation of C6, radiographs of C7 are obtained. The 4 horses were then euthanized and dissected so to verify the radiographic findings. Only those pertaining to the congenital malformation of C6 and C7 are reported in this study.

 

Results

Figure 4. A compressed trachea (white arrow) in Thoroughbred No. 2 at C6 / C7. Photo credit: Sharon May-Davis

Upon euthanasia of the 4 horses, Thoroughbred No.1 was normal. Thoroughbred No.2 presented with an absent CVT in C6 and trachea compression (Figure 4).

Thoroughbred No. 3, presented with a C6 and C7 congenital malformation and a malformed 1st sternal rib. The Thoroughbred type also presented with a congenital malformation of C6 and C7 (Table 2).

 

 

Table 2. Noted observations via dissection of the congenital malformation of C6, C7 and the 1st sternal rib.

 

Left: Radiographic view of C6. Centre: The white line denotes a normal CVT. Right: The white denotes an absent CVT.

Figure 5. The radiographic lateral view of C6 depicting a unilaterally absent CVT in C6. Image credit: Sharon May-Davis

 

Thoroughbred No. 3 C7 radiograph (Figure 6) clearly presents the observer with a transposition of the CVT from C6 onto the ventral surface of C7, furthermore it denotes a reciprocal deviation in the trachea at the point of this transposition.

 

Left: Radiographic view of C7. Centre: The white line denotes the unilateral transposition of the CVT from C6 onto the ventral surface of C7. Right: The white line denotes the deviation in the trachea.

Figure 6. The radiographic view of C7 depicting a unilaterally transposition of the CVT from C6. Image credit: Sharon May-Davis

 

The Thoroughbred type (Figure 7) exhibits the absent CVT in C6. The radiograph clearly indicates an absent CVT that is unilateral in its presentation.

 

Left: Radiographic view of C6. Centre: The white line denotes a normal CVT. Right: The white denotes an absent CVT.

Figure 7. The radiographic lateral view of C6 depicting a unilaterally absent CVT in C6. Photo credit: Sharon May-Davis.

 

The Thoroughbred type C7 radiograph (Figure 8) clearly presents the observer with a transposition of the CVT from C6 onto the ventral surface of C7, furthermore it denotes a reciprocal deviation in the trachea at the point of this transposition.

 

Left: Radiographic view of C7. Centre: The white line denotes the unilateral transposition of the CVT from C6 onto the ventral surface of C7. Right: The white line denotes the deviation in the trachea.

Figure 8. The radiographic view of C7 depicting a unilaterally transposition of the CVT from C6. Photo credit: Sharon May-Davis.

 

Figure 9. Right: Absent CVT on C6 (white arrow) and transposed CVT from C6 onto the ventral surface of C7. Photo credit: Sharon May-Davis

Upon dissection, the Thoroughbred type displayed identical congenital malformations of C6 and C7 as depicted in the radiographs (Figure 9).

 

 

 

 

Discussion

This study was conducted with the view to obtain specific radiographic evidence of the congenital malformation of C6 and C7. Radiographic views of the 1st sternal rib were not possible due to thick and dense musculature in the region. The views obtained of C6 and C7 with exact radiographic angles proved that this region can be radiographed with precision so that the practitioner can make a clear diagnosis should a horse present with a neurological deficit, as previously published (May-Davis

[a, b], May-Davis and Walker]). Furthermore, the asymmetry of the cervical vertebra could exacerbate arthritis in the articular process joints as previously noted (May-Davis [a]). In addition, the incidental finding of the compression of the trachea is an important factor to consider when Thoroughbred racehorses present with compromised airways. An explanation for this occurring is that the Longus colli muscle hypertrophies in support of the weakened structures and due to its proximity to the Trachea, it impinges upon its dorsal surface. This impingement is further exacerbated by the ventral projection from C7 of the transposed CVT from C6.

Since the first publication in 2014, retrospective studies were conducted that added another dimension to the current research. Italian and American studies noted that Warmbloods, Quarter Horses and Arabs were also afflicted with this condition (Santinelli et. al 2016 and DeRouen et.al 2016). It is significant to note that these breeds present the majority of the ridden horse population in Japan extending from Racing, Showjumping, Dressage to Eventing and Endurance. However, a specific Dutch Warmblood study was conducted with fresh cadaver’s that were portioned and CT scanned (Veraa et.al 2016), this also included Oldenburg horses. The congenital malformation of C6 and C7 was present in both breeds with a noted malformed 1st sternal rib in a Dutch Warmblood. Combined percentages of these 3 studies in conjunction with the 3 Australian studies and the current study has the congenital malformation of C6 at; Warmbloods 30%, Quarter Horses 16% and Thoroughbred horses over 40%. 

Aside from the Arabian who is an ancestor to the Thoroughbred, the Warmblood breeds and Quarter Horses all have Thoroughbred lineage in the back line of their breeding. Thus, implying that this condition is heritable as noted by May-Davis [b] and more systemic than just one breed. With this in mind, all critical events should be assessed with the knowledge that a potential congenital malformation could exist in C6, C7 and the 1st sternal rib, as previously noted. With the largest population of horses in Japan being Thoroughbreds, it would be a recommendation to note the studies of several countries including Japan and the severity in percentage of this systemic congenital malformation. Especially in relation to Thoroughbred’ racehorses racing and cornering at speed.

 

Conclusion

This study showed that of the 4 horses investigated, 3:4 horses displayed a CM of C6, 2:3 displayed the congenital malformation in C6 and C7, and 1:2 a congenital malformation of the 1st sternal rib. Even with a small sample of Thoroughbreds, studies from other countries must be measured and it would therefore be a recommendation to radiograph for this condition in the caudal cervical vertebrae in a pre-purchase examination. The purpose of which would be to eliminate this condition so that riders and handlers are not put at risk.

 

Author contributions

Sharon May-Davis, Fumiko Minowa and Sadae Monoe wrote and reviewed this article.

 

Conflict of Interest

The authors have no conflict of interest in the preparation or presentation of this original research article.

 

Acknowledgement

The author wishes to thank Christine Gee for her professional advice on the manuscript. The Nippon Veterinary and Life Sciences University for the use of their facilities and to those authors / editors/ publishers of those articles, journals and books cited in this manuscript.

 

References

Derouen A, Spriet M, Aleman M. Prevalance of anatomical of the sixth cervical vertebra and association with vertebral canal stenosis and articular process osteoarthritis in the horse. Vet Radiol Ultrasound, Vol. 00, 2016, pp 1–5.

May-Davis SER. The Occurrence of a Congenital Malformation in the Sixth and Seventh Cervical Vertebrae Predominantly Observed in Thoroughbred Horses. J Equine Vet Sc 2014; 34:1313-17.

May-Davis SER. The Congenital Malformation of the 1st Sternal Rib. J Equine Vet Sc 2014; 34:1313-17.

May-Davis SER, Walker C. Variations and implications of the gross morphology in the Longus colli muscle in Thoroughbred and Thoroughbred derivative horses presenting with a congenital malformation of the sixth and seventh cervical vertebrae. J Equine Vet Sc 2015; 35:560-8.

Santinelli I, Beccati F, Pepe M. Anatomical variation of the spinous and transverse processes in the caudal cervical vertebrae and the first thoracic vertebra in horses. EVJ 48 (2016) 45–49.

Veraa S, Bergmann W, van den Belt A-J, Wijnberg I, Back W. Ex vivo computed tomographic evaluation of morphology variations in equine cervical vertebrae. Vet Radiol Ultrasound, Vol. 00, 1–7.

 


 

 

All You Need to Know About the Hidden C6-C7 Malformation That’s Bringing Horses Down

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What if you were to learn that your horse is living with a hidden malformation? A skeletal abnormality that could be affecting it every day, changing the way it moves, creating a string of other physical problems, and possibly underlying the hard-to-pinpoint problems you’ve been noticing for months or even years ?

And that might even be causing a level of inherent instability that could be putting the rider in danger?

Sadly, this isn’t a hypothetical question. Instead it’s a reality that is only now being slowly uncovered.

And like the proverbial stone rolling down a mountain, the issue is gathering momentum as the equine industry, owners, breeders and researchers learn about it.

  • It’s a skeletal malformation and it can’t be corrected.
  • It’s congenital, ie inherited, so is present from birth.
  • It has been in some lines of TBs for hundreds of years.
  • It creates biomechanical issues due to asymmetry and lack of anchor points for key muscles.
  • At its worst, it can contribute to neurological issues such as Wobbler syndrome.
  • Some horses are so unstable, they are more prone to falling (not good news for jockeys).
  • It can cause constant pain and associated behavioural changes.
  • It’s primarily found in Thoroughbreds, Thoroughbred crosses and Warmbloods, but has also been identified in European breeds, Quarter Horses, Arabs and Australian Stock Horses.

 

Note: in the years since this post was written with direct support from Dr Sharon May-Davis, research has moved on. The body of literature now includes papers from Sharon and also from other researchers who do not reach similar conclusions about the issues caused by this malformation. I have included a list of journal papers and webinars on the topic at the end of the post, for reference if you wish to deepen your knowledge. You can also go view the full list here (opens in a fresh tab).

 

The problem behind this is ECVM, a congenital malformation of the C6 and C7 cervical vertebrae (ie, base of neck) – and it’s pretty nasty.

I’ve written about the work of Sharon May-Davis on this blog before and here I’m going to do so again. Through her many dissections per year, gross anatomist Sharon has become the first person to comprehensively document and quantify this problem.

In doing so, and publishing her findings in peer-reviewed journals, she has triggered a minor research avalanche as others take up the subject.

Update: since this article was published in July 2017, this malformation has been labelled Equine Complex Vertebral Malformation (ECVM). Some amendments have been made to include this term. To preserve existing links to the page, I’ve not updated the title and URL.

© All text copyright of the author, Jane Clothier, https://thehorsesback.com. No reproduction of partial or entire text without permission. Sharing the link back to this page is fine. Please contact me for more information. Thank you!

 

A hidden problem: this OTTB had the C6-C7 malformation but presented few outward signs.

 

Twenty years + of research into ECVM

Sharon May-Davis’s path with this research began some 20 years ago. In February 1996, a Thoroughbred called Presley came down unimpeded in a race in Grafton, NSW, fracturing his pelvis, a hock bone, and right front fetlock.

Three years later, Sharon examined his bones, and saw something strange in his last two cervical vertebrae and his first ribs.

Fast forward to 2014, when Sharon published the first of her four peer-reviewed papers in the Journal of Equine Veterinary Science, concerning a congenital malformation in the sixth and seventh cervical (neck) vertebrae.

Although the problem had been mentioned briefly in papers, this was the first time that a researcher had accurately described and quantified the problem in its various forms.

Sharon’s unique perspective, gained as an anatomist who dissects between 15 and 20 horses per year, had certainly placed her in a position to do so.

 

The horse’s seven cervical vertebrae – made simple

Horses have seven vertebrae in their necks, labelled C1 to C7. Of these, four have unique shapes. Most horse people are familiar with C1, the first vertebrae known as the atlas, as it can be both seen and felt by hand with its distinctive ‘wing’ at the top of the neck.

Cervical vertebrae from C1 (top) to C7 (bottom), view from above (L) and below (R).

Almost as well-known is C2, the second vertebrae, known as the axis.

Both atlas and axis have unique shapes for a special reason: they support the heavy skull and anchor the muscles that control the head’s movement.

Heading down the neck, C3, C4 and C5 are broadly similar in shape, with each being a bit shorter and blockier than the one above.

However, C6 and C7 are both slightly different on the ventral (lower) side, for here they provide insertion points for muscles arising from the chest.

  • C6 has transverse processes (the protrusions extending outwards) that are different to those of neighbouring bones, with two distinctive ridges running the vertebrae’s length. C6 also has two large transverse foramen, the openings that the arteries pass through.
  • C7 is the shortest and squattest cervical vertebrae of all. Its transverse processes are shorter, while there are also two facets that articulate with the first ribs. C7 has no transverse foramen.

At least, that’s how the vertebrae should be in a normal horse.

 

So, what is wrong with the malformed C6 and C7 vertebrae in ECVM?

In certain horses, these last two vertebrae are rather different, being malformed.

Sharon has identified the manifestations of this problem as a congenital (inherited) malformation affecting some Thoroughbred horses, and horses with Thoroughbred blood in their ancestry.

In C6, there is a problem with the two ridges of the transverse processes, as one or both can be partially absent.

When both are partially missing, it is common for one or two ridges (ie, parts of the transverse processes) to appear on C7 instead.

Also, the articular processes (the oval surfaces on the upper side, where each vertebrae links to its neighbours) can be radically different sizes. There can also be an additional arterial foramen or two.

The level of asymmetry can be radical.

The secondary problems the ECVM malformation causes

Being at the base of the neck, the asymmetry of C6 and C7 can cause alignment problems all the way up the vertebral column, leading to osteoarthritis of the articular facets.

It can also contribute to Wobbler Syndrome (Cervical Vertebral Stenotic Myelopathy), due to narrowing and/or malalignment of the vertebral foramen/canal, the opening through which the spinal cord passes. Not all Wobbler cases have this particular malformation, though.

A further problem is that the lower part of the longus colli muscle, which is involved in flexing the neck, would normally insert on the transverse processes of C6 and C7. When these processes are malformed, the normal insertions are not possible.

This means there is a serious symmetry problem in the junction of the thorax and neck, which can have a deeper effect on the horse’s neurology and proprioception, as well as respiration.

Asymmetry and narrowed vertebral foramen (canal) contribute to DJD and Wobbler Syndrome.

 

In a few cases, horses with both the C6 and C7 problem also have malformations of the first sternal rib, on one or both sides. This can cause problems beneath the scapular and further issues with muscular attachments.

Associated stability problems can have far-reaching consequences for the horse, not to mention some serious safety issues for the rider. The safety issue can’t be stated often enough.

 

Why isn’t ECVM – the C6-C7 problem – more widely known ?

Why hasn’t this problem been noticed in regular veterinary interventions?

The answer is quite simple. While neurological issues may have been diagnosed, the exact cause has often remained hidden.

Both Thoroughbred horses and Warmbloods are known to have higher incidences of Wobbler Syndrome than other breeds, and while this is certainly not always due to C6-C7 malformation, the malformation has been found in some when dissected.

For example, the following dissection image appears in a veterinary account of large animal spinal cord diseases. It clearly shows a malformed C7 vertebrae, very similar to the one in the above image, but without giving any further categorisation.

The difficulty lies in the deep location of the lower cervical vertebrae. While normal radiographs can show all or some of C6, they are unable to penetrate the deeper tissues beneath the shoulder to image C7.

Photo from another online article: the familiar asymmetry of a malformed C7 is clearly visible in a dissected set of vertebrae.  (c) veteriankey.com (click image to access full article.)

 

Nevertheless, the malformation can be identified in radiographs of C6, once you know where to look.

Since Sharon’s first paper appeared, the School of Veterinary Medicine, University of California, Davis, has reviewed its history of radiographs from horses with Wobbler Syndrome.

Researchers found that 24 cases out of 100 (close to 25%) showed malformation of one or both C6 transverse processes. This study also clarified how to identify the problem on standard radiographs of C6.

In another study, the Faculty of Veterinary Medicine, Utrecht University, completed CT scans on horses’ necks and found the various forms of the malformation in 26 horses out of 78 (33%). Unlike radiographs, the CT scans enabled identification of the C7 and first rib issues, although of course this imaging was conducted post mortem.

Is this rare, or are many horses affected?

While the problem has been identified primarily in TBs, it affects most breeds with TB blood in the ancestry to some degree.

Sharon May-Davis reports that to date, published, peer-reviewed journal papers have tallied 136 out of 471 horses as exhibiting congenital malformation of C6.

These have been in a range of breeds including Thoroughbreds (39%), Thoroughbred crosses (27%), Warmbloods and European breeds (30%), Quarter Horses (11%), and Arabs (11%). Standardbreds have also shown the problem, although the numbers included in studies are very small.

A common question is whether it’s known which TB lines predominantly carry this problem. The answer is: Yes. However, it is now so disseminated amongst the modern equine population beyond TBs, that it is of little help to identify them.

It must be remembered that these horses are those already brought to veterinary attention and/or euthanized for a related or unrelated reason, so the percentages may be higher than those for the general horse population. At the same time, the malformation might have played a major part in the horses’ decline, due to the many locomotory and postural problems it can lead to.

 

How do we identify these horses in life?

It’s all very well looking at these bones post mortem, you might say. Yet how can I tell if my horse has this problem? Or a horse that I might want to buy?

Some answers are forthcoming. As Sharon has frequently assessed horses before dissecting them – usually from video – she has been able to observe that many of these horses lack stability. (Indeed, in many cases, it is this very instability has directly led to the horse being euthanized, and ending up on the dissection table.)

As her research has progressed, she has also been able to identify many biomechanical and locomotion traits that make these horses ‘suspicious’ or at least ‘of interest’. Unsurprisingly, these problems have been particularly noticeable in horses with both a malformed C6 and C7.

For owners and equine professionals, here are some signs that can raise initial suspicions. All can also be caused by other problems, so a group of signs is more common than an individual indication.

  • Some of these horses have a problem with standing square in front, and will always keep one foot further forward. This can persist despite all attempts to improve the horse’s body and to train the horse to halt squarely.
  • Horses with the more serious malformations will often stand base-wide. Such horses can become very unbalanced on uneven ground, and sometimes in work. They easily become unbalanced when a hoof practitioner works on a forefoot. 

 

A bilateral C6 – unilateral C7 horse showing a toe-out stance and hoof distortion. The ventral part of the transverse process was transposed onto the left side of C7.

 

  • With such asymmetry in the skeletal structure, these horses have serious lateral flexion issues that can’t be overcome. When required to elevate the forehand, many will experience difficulties, due to the absence of correctly inserted musculature and incorrect articulation through the joints of the lower neck. 
The horse may have one very prominent, widely positioned scapula.
  • A high level of asymmetry may be seen in the shoulders, with one scapula sometimes positioned very wide, with no improvement after chiro, osteopathy or bodywork. This is particularly so with the C6-C7 problem and associated first sternal rib abnormalities.
The ventral aspect of the neck may show some scoliosis.

 

  • There may be scoliosis along the entire spine.
  • There may be an obvious scoliosis to the underside of the neck.
  • The problem may lead to heavily asymmetric loading of the forefeet, so may be accompanied by a severe high foot/low foot issue (this is not in itself a sign of the C6-C7 problem).

If you suspect your horse has the C6-C7 issue

First, note that many horses do just fine with a C6 problem. It is those with the bilateral C6 and unilateral/bilateral C7 issue that tend to show the more worrying problems.

If your horse is showing ongoing signs of instability, it’s important to seek veterinary advice, so that neurological issues can be ruled out. (As this a recently recognised problem, it may be worth printing out the abstracts from the journal articles listed at the end of this page and handing them over.)

If the more severe malformations are identified by radiograph, it is important to remember that in some cases this can cause discomfort and pain to the horse, and it is not going to improve over time.

On the contrary, the cervical vertebrae of some older horses with the C6 and C7 malformations often display advanced osteoarthritis of the articular processes, as shown in the header image of a 19-year-old Thoroughbred’s malformed C7.

 

Where does this knowledge take us?

At the moment, that question is wide open. The findings published by Sharon May-Davis have triggered ongoing research on an international level. There are certainly ramifications for breeders in more than one equine sporting industry.

See Sharon May-Davis’s December 2020 presentation on ECVM here (article continues below):

Connections have been made with a number of falls on the racetrack that have caused injury, and worse, to both horse and jockey, as well as other runners. Similar things can be said for the sport of eventing, where unforced errors can have equally catastrophic effects.

It is entirely possible that at higher levels, pre-purchase examination radiographs will come to include a check on C6. While it’s not possible to radiograph the deeply positioned C7, we do at least know that this will only be present if the C6 anomaly exists.

Vets in some countries are proving faster at picking this up than others. While papers are being published, it clearly takes some time for information to filter down.

And until more is known, this problem is being unknowingly propagated every breeding season.

Of course, many horses harbouring the milder manifestations of this problem at C6 level are functioning very well. All horse owners can do is be aware that this issue exists, make use of this information if a problem arises, and await further research findings.

Literature on the malformation

In no particular order: the following peer reviewed journal articles address ECVM, as it is now known. Please remember when reading papers that no single paper proves one thing – a review of many papers and critical thinking is always essential. Apologies for not having standardized the formatting, but the links should be present.

 

How Much Do You CAIR What’s In Your Saddle?

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How curious are you as a horse owner? Do you want to know how things work, what they look on the inside, and if they’re as good as the makers say – right the way through?

The guts of any piece of equipment are usually less pretty than the exterior, but nevertheless, we’re often happy to take the manufacturer’s word on trust.

Yet when the marketing message is that a particular brand is actually healthier for the horse’s back on account of its inbuilt ‘systems’, it’s definitely time to take a closer look. Consider a message such as this:

“Naturally, horses will demonstrate a marked improvement in performance when changed to a saddle featuring CAIR®.”

http://www.easychangefitsolution.com/saddle_brands/wintec-saddles.html (13/3/2017)

That’s pretty grand, isn’t it? How wonderful if it were only true. But working in Australia, birthplace of Weatherbeeta, Bates and Wintec, and a chain of saddlery stores that sells and fits these saddles, which is owned by that same company, I do find much evidence that persuades me otherwise.

At this point, I must make my usual disclaimer: I have no problem with any saddle that genuinely fits the horse. I do have a problem with misleading claims, intentional or otherwise, as expressed in my earlier article, Debunked: The Lie That’s Told About Adjustable Saddles.

© All text copyright of the author, Jane Clothier, https://thehorsesback.com. 

 

CAIR for the horse – or EASY-Marketing?

Easy flock? More details below…

Google CAIR and you’ll find it described as the “revolutionary CAIR® Cushion System for the ultimate performance panel”.

Navigating a range of websites, you might also discover that it is accompanied in saddles by the EASY-CHANGE® Gullet System and the EASY-CHANGE® Riser system.

Together, these three comprise the EASY-CHANGE® Fit Solution.

Confused yet? No matter, as you can read all about it on the EASY-CHANGE® website…

Crazy as I find the labelling, and let’s be honest, the brand marketing department has gone a bit nuts, what really bothers me is that these much vaunted systems are not doing what it says on the packet. Nowhere near.

 

The problem with systems…

In my view, systems often evolve to the benefit of the people who operate them. That is fine: they make problems easier to understand and easier to navigate – and saddle fitting is certainly a problem when you can’t find the right fit for your horse.

So if a system results in a better saddle fit and, as the website suggests “your horse’s absolute comfort and your peace of mind”, all well and good.

But where systems go wrong is when the function of making life easier for people is given more importance than the problem they were originally intended to resolve.

Or, indeed, when they become an effective way of achieving increased sales through the handy marketing push they make possible.

And this bugs me because the horse’s much vaunted comfort is usually by this stage sliding further and further down the importance pile. Like a growing number of equine professionals, I’ve taken a look inside these saddles, and something simply isn’t adding up between the message and the reality.

At this point, I will say no more, but instead present some of the website content I’ve been reading this month. Alongside it, you’ll find some photos that I and others have taken.

Beyond the photo captions, I’ve made no comment until the last section on flocking. I found that had no choice, because the ‘secret flock sock’ is so secret, I can find no website content about it… Let’s just say that seems a little unusual.

 

“The CAIR® Cushion System”

CAIR panels removed from a Wintec, 5 years ago. Manufacturer’s own parcel tape.

“Fluidly working with your horse’s muscles, the revolutionary CAIR® Cushion System replaces traditional fillings in your saddle with air. The cushioning nature of air encourages your horse to soften, relax and engage. Seated closer to your horse, you become simply an extension of one another. Transcend into a new world of opportunities through the power of true connection. Empower your horse with the ultimate in comfort, and explore your true potential together with the CAIR® Cushion System. ”

http://caircushionsystem.com/noflash.htm  (13/3/2017)



“CAIR: The Power of True Connection”

CAIR panel on original board backing, sliced to show open cell foam inside. 

“Finally a panel system that understands the mechanics of the equine back and the impact saddles have on horse and rider performance. The revolutionary CAIR® Cushion System replaces the traditional fillings in your saddle panel with air. There are two independently sealed Air Cushions within each Saddle Panel. The concept of air, as the ultimate in cushioning for the horse is simple.”

http://caircushionsystem.com/whatIsCAIR/index.htm (13/3/2017)

 

Vinyl sleeve and parcel tape – the tape affected by Australian heat.

“Air being a fluid medium will constantly adapt to the horse’s working muscles. This means that your weight will be distributed evenly across the entire length of the cushion, virtually eliminating pressure points. This extraordinary comfort results in freer movement, better carriage and a happier horse. For such a simple concept the dramatic difference the CAIR® Cushion System makes to a horse’s comfort and performance is profound.”

http://caircushionsystem.com/whatIsCAIR/index.htm (13/3/2017)

 

Foam panel insert, now renamed the EASY-Change Riser System. 

“The award winning CAIR® Panel Insert System was launched to retailers and saddle fitters around the world. Together with the tree adjustability of the EASY-CHANGE® Gullet System, this delivered a whole new level of adjustability in saddles. The insert system enabled retailers and saddle fitters to make adjustments within the panel effectively, efficiently and to the highest professional standards.”

http://www.easychangefitsolution.com/easy-change-story.html (13/3/2017)

 

More recent CAIR panel – outer sleeve and foam insert. (Note: panels are opened, so no air is present in these images.)

“The challenge lies in developing an air system that limits any opportunity for human interference on the performance of the panels.

“The cutting edge Research and Development Team at Bates Australia have spent many years refining and perfecting techniques for incorporating an air cushion into a saddle panel, before reaching a breakthrough in manufacturing method.

The CAIR® Air Cushions are shaped and refined at the point of manufacture to provide an even thickness throughout the panel….”

http://caircushionsystem.com/
whatIsCAIR/evolution.htm (13/3/2017)

Another close up of that foam.

“What is Inside an Air Panel?”

“Air is captured at atmospheric pressure in an open-celled foam and sealed in the Air Panel. Once the air panel is welded the open-celled foam becomes irrelevant, as it is the air trapped in the panel, which is doing the work.

Furthermore, the balance of saddles with the CAIR® Cushion System is easily altered without compromise to the performance of the air panels.”

http://www.caircushionsystem.com/faqs/index.htm (13/3/2017)

 

** Questions, thoughts or comments?
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“How adaptable are the saddles for achieving an optimal fit?”

The riser/shim, board, and CAIR panel combination.

“Extremely, Saddles that feature both the CAIR® Cushion System and EASY-CHANGE Gullet System are unsurpassed in the flexibility they offer for achieving an optimal fit.

Once you have selected the correct gullet size for your horse, the CAIR® Panel Insert System enables you to alter the balance of your saddle without compromising the performance of the Air Panels.”

“Official Fit Disclaimer”

The riser/shims, used to add depth to flat panels (between 2 and 12 have been found in saddles).

N.B whilst the innovative EASY-CHANGE® Fit Solution offers unsurpassed flexibility in achieving an optimal fit, no one saddle can claim to fit every horse. It is always recommended ongoing professional advice is sought on the fit and in meeting the unique needs of each horse/rider combination. Global patents and design registrations apply.

http://www.easychangefitsolution.com/easy-change_fit_solution/index.html (20 Sept 2015)

 

Newer CAIR panel.

“The Current Day…”

“Bates Australia has now developed a means of offering these saddle fitting systems in both saddles featuring high performance CAIR® panels, as well as traditional flocked panels.”

http://www.easychangefitsolution.com/easy-change-story.html (13/3/2017)

 

 But Hang On… “Traditional flocked panels”… What are they talking about?

The current ‘flocking’.

OK, this is where I break my silence. This is where I introduce the flock panel insert.

The thing is that for the past 2-3 years, other company saddlers have been finding these rather strange, stuffed fabric panels inside Wintec and Bates saddles brought in by customers requesting reflocking.

These fabric sleeves, which are the same shape as the vinyl CAIR sleeve, are packed hard and tight, meaning that the usual benefit offered by flocking – ie, ability to mould to the horse’s shape – is lost altogether. You won’t hear about that though, because this is a manufacturer’s secret (shhhh).

 

Where Can We Find the Flocking Info?

The flock sock is well-packed with balls of  synthetic flocking. 

Oddly, and strangely given all the Easy web pages, this ‘flock sock’ doesn’t have its own page and isn’t photographed on any of the Wintec, Bates and EASY-whatever websites.

Why? I’d speculate that the sock removes considerable time and dollars off the manufacturing cost of flocked saddles, without adding much that’s positive at the horse end of the equation.

[ed note. I’ve removed the detail about pricing here, because I made a mistake with it. That obviously isn’t good enough. I’m sorry about that.]

So, why is nobody hearing about this little innovation? The company don’t want to add flocking to saddles as it’s less profitable, but is offering ‘flocking’ (or their own version of it) simply to satisfy customer demand. Unfortunately, with this inner working of the saddles kept out of sight, the customer simply doesn’t know what they’re paying for.

And how good is that for the horse’s interests, we must ask?

 

VIDEO – CLICK TO OPEN URL IN NEW TAB

 

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5 Ways Your Seat Can Screw Up Your Horse Without You Even Noticing

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In this Guest Post, the UK’s ‘Classical Seat’ trainer Heather Moffett looks at how the rider’s seat can make movement harder for the horse. It’s something that saddle fitters know about, but it’s often the last thing riders think of: the riding position as much as the saddle fit affects their horse’s back and movement. 

Heather Moffett has over 40 years’ instruction experience. Chiefly following the French school of classical equitation, which focuses on dressage as an art form rather than competition, she is best known as an authority on the Classical Seat. Recently, she launched The Online Riding School, a library of videos suitable for everyone from complete beginners to advanced riders – visit now to benefit from the introductory offers.

 

We all keep hearing about ‘connection’.  It’s a current buzzword and usually means connecting with your horse on the ground, either through loose or in-hand work.

Many riders assume this will enable them to achieve the same connection once mounted.

There is nothing wrong with that. However, they often then wonder why they lose that connection – sometimes literally, complete with the saddle(!) – once they start riding. The fact is that they are, in ignorant bliss, impeding the horse!

 

The Disconnected Seat

If the rider is out of sync with the horse’s movement, the flow and harmony will always be disrupted as the horse struggles to balance the rider as well as himself.

Or, he endures the discomfort of a rider sitting like a lump of lead, driving with the seat against his sensitive back, or bouncing stiffly in the saddle.

The horse has only one way to show his discomfort or pain, as he is mute, and that is by behaviour that is then construed as ‘misbehaviour’.

I often ask riders who kick and hit their horses if they would do the same to their dog. The dog is able to cry out in pain. The horse cannot, and it is his muteness, throughout history, that has led to his downfall and still does to this day.

 

What Gets My Goat is This

I’ve been a specialist trainer/teacher of the Classical seat for 46 years. In that time, there has been little interest in increasing knowledge of the seat and refinement of the aids.

So many teachers and trainers say that it is necessary to ignore imperfections in the seat until “the horse is going well”. Then they wonder why the horse never progresses, or why force must be resorted to, in order to make the horse submit!

Yes, there is that word submit (or submission) that’s a requirement in a dressage test.

My own teachers soon found that it worked far better to encourage my cooperation in school rather than forcing me into submission! And a horse is no different.

I would like to see the word submission in tests replaced with willing cooperation.

How different would the expression be on many a horse’s face, if he were trained as a partner, and not as an adversary?

So, are you screwing up your horse with your seat, without even noticing? Here are the 5 top points I’d like you to think about.

 

1. Saddle Fit Woes (Yes, Again)

Poor saddle fit can cause the seat to tip back.

No surprises for this one. Saddle fit is probably the most obvious thing that needs to be right, but many saddles are a long way from perfect. That’s true even in my home of the UK, where saddles are most often professionally fitted.

But, what amazes me is the number of saddles I see with clients coming to me for lessons that have faults that make it damn near impossible for the rider to sit either straight or in balance!

Here are the worst offenders.

The saddle is too narrow. This is still one of the most common faults – it pinches the horse and tips the rider’s pelvis backward, aiding a chair seat rather than the ear/shoulder/hip/heel line which is the only position of balance.

Try walking with your butt stuck out behind you and knees up, as though sitting on a chair! It’s hard enough to even remain upright! Your weight will be over the cantle region, making it difficult for the horse to lift and round his back, and causing him to go hollow.

Stirrup bars are, almost without exception, even on many dressage saddles, too far forwards. This is why the rider is constantly being nagged by instructors to “get that lower leg back”!

I do wonder why instructors and even top dressage trainers, never seem to notice that all of their students are not anatomically challenged and there might just be something wrong with the saddle design and balance!! (Don’t get me started!!)


2. An Insecure Seat Sucks (for Both Horse and Rider)

7yo Oldenburg x Irish Sport Horse. 1st day to 2nd day of HM course.

Here’s what I mean by insecure. Riders are not taught to absorb and sync with the horse’s movement.

We hear:

“Sit deeper!”

“Relax your back!”

“Go with the movement!”

“Follow the horse’s movement!”

Well, usually if you are following something you are behind it!

Is it any wonder beginners are confused and often never learn to move in sync with the horse?

If this describes you, fear not. I have had riders here on my horse movement simulator workshops who’ve been riding 10, 20 or more years, and still they have never learned to move in sync with the horse.

 

3. Saddle Seat Glue Hasn’t Been Invented Yet

Gripping the saddle blocks movement.

If you’re bouncing around, or driving with both seat bones to achieve some adhesion to the saddle, or sitting on your back pockets and collapsing the rib cage, you will be making your horse’s life more difficult.

It is so NOT rocket science to learn this!

But until teachers are trained to teach it, the situation will not improve!!

And it is not just novice riders who block their horse through incorrect adhesion to the saddle.

Look at the nodding head, flailing legs (usually with spurs attached) riders to be seen even in the Grand Prix dressage arena…


4. Horses Have the Low Down on Our Weight Issues…

How many times do you hear it said that a horse can feel a fly land on his back? So how much more can he feel his rider, whether good or bad?

For me, my aim – both as a rider myself and also as a trainer – is to be as little burden on the back of my horse as possible.

The horse copes with the crooked rider. Day 1 of HM course.

I aim to do this by sitting lightly, but deeply, in sync with his movement.

If the rider is crooked, possibly due to a problem with the saddle, or is asymmetric due to their own physical problem, the horse suffers.

He has to cope with this and compensate, usually by going crookedly himself.

And there’s more. The use of the rider’s body as a primary aid, is so rarely taught. Yet when utilised, it is the most invisible aid of all. Combined with the seat bones moving in sync with the horse’s back, it is the secret to an elegant harmonious seat, that appears to be doing nothing.

That’s when the horse and rider glide through all the movements as though they are one being – like a Centaur.

 

5. ‘Feel’ Begins in your Backside (I Mean It!)

Hanoverian X. 1st and 2nd day of HM course.

‘Connection’ means being able to feel, and not just when working from the ground. We all have nerve endings in our backsides – if you are taught what to feel and how to feel, it is within the grasp of any rider, even beginners.

And ‘aid’ really means ‘help’. If you learn to use aids that make biomechanical sense to the horse, they do become truly invisible as the horse becomes more and more sensitive with correct training.

BUT, if the horse hasn’t been schooled to respond to specific aids, then is it any wonder he is confused and ‘misbehaves’? It’s a bit like us lazy Brits here, shouting at foreigners in the hope they will understand English then getting annoyed when they don’t!

Your seat can genuinely aid (help) your horse. This happens when you’re taught not only the hand and leg aids, but also:

  • the weight aids for turning,
  • the seat aid for collecting and for downward transitions,
  • the precise positioning of the torso in lateral work and circles/ bends, etc.

At this point, riding becomes a whole language, which almost all horses quickly understand. Why? Because it is working with, not against, their own body.

Moving in sync with the horse allows the rider to learn ‘feel’, that term that often seems to imply that only a favoured few have the ability to learn it.

Rubbish!

 

So, in closing, if you wish to have true connection with your horse, you need to:

a) Absolutely not screw up either his back or his brain,

b) Learn to ride to the best of your ability, and

c) Treat your horse as a partner and friend, and not as a tool merely to win the next rosette.

If winning happens as a by-product of good riding, even better, but if your horse is not progressing, look to your own riding and equipment before you blame your horse. Get these 5 points sorted and you’ll be well on your way to true connection with your horse!


 

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