Friday, September 28, 2012

How Research Works: Sport Horse Suspensory Ligament Study Involves Real Dressage Horses and Riders

A call for dressage riders offered a free analysis of joint motion, rein tension and  rider balance  in exchange for riding a horse of a specific age and dressage level on two different arena surfaces. The researchers are gambling that dressage riders will want to be part of equine research that targets the function of the suspensory ligament, one of the most common sites of lameness in dressage horses. (AHT photo)

You read the research. You look at the data. You note the summary.

But did you ever want to know more?

Researchers often list their protocols, including the number of horses or cases evaluated. Some will give some data about the horses--sex, age, use--but that may not tell you much.

If you've ever been to a vet college, you know that they often have a herd of research horses. Some are more athletic looking than others. Some are more sound than others. Some are all one breed, while at others, the herd is made up of mixed breeds. At some schools, the horses in the "research herd" look like they are seen by a farrier about once a year.

When you read about sport-related research, you trust that the research was actually done on sport horses. Most researchers will now give much more background data on the horses used in the trials, because they know this is necessary for the credibility of their findings.

Unfortunately, the numbers of horses in studies is usually small because of the difficulty in obtaining horses to test and the labor-intensive aspect of equine research. Large retrospective studies of cases are possible for injuries, but what about when the subject is gait analysis or sports performance?

And even for studies that are data analysis of cases treated at a university or vet hospital for a certain condition, or treated by a certain procedure, a considerable number of cases are lost to follow up because they were sold, died or the owners didn't answer a researcher's questions.

So an announcement that was circulating on the internet seemed interesting. The Animal Health Trust (AHT) in Newmarket, England has done several studies on injuries to the suspensory ligament. In fact, the letters PSD--for proximal suspensory desmitis--are closely connected with the letters AHT.

The suspensory ligament (sometimes called the interosseous) is show in white; it is a common site of lameness in performance horses.  Jumping horses commonly injure the branches of the ligament, shown at right, but the ligament can be injured at any point along its length and in either of its branches. (Illustrations are 3-D animations from Glass Horse: Elements of the Distal Limb)

The Animal Health Trust is known for taking a rider-centric view of equine lameness. The rider may be asked to school the horse as part of the lameness exam. That may not be enough to satisfy clinician Sue Dyson, who has trained horses at the elite level of eventing and ridden Badminton herself. She employs a professional rider to participate in the lameness evaluation so that the rider's balance, ability or mental state can be ruled out as influencing the horse's gait.


The first line of the announcement read:

"Would you like to get a free assessment of your horse’s gait, symmetry and exercise programme with your travel costs covered? And also help prevent suspensory ligament injury in dressage horses for the future?"


If you think like an equestrian, that sounds like a pretty good deal, with a feel-good factor thrown in for good measure.

But from someone who follows sport horse medicine, it could only get better when the study was outlined in this way:

"The Animal Health Trust is looking for horses and riders to be filmed at trot using high speed video on two different (but good quality) arena surfaces as part of an important investigation into suspensory ligament function in horses of different levels and with different types of movement.

"For the project we are looking for combinations which fit into the following groups and would be willing to travel to Keysoe, Bedfordshire (travel costs would be covered) on 8th, 9th, 12th or 13th November and can allow approximately two hours for the testing, from arrival until completion."

Remember the comment about some horses used in studies being sketchily described in the papers?
Consider this precise description of exactly what horses were being sought for this study:

1. Young horses (seven years old and under)
• Very extravagant moving (achieving scores of 7 or 8 and above for paces) or
• Less extravagant moving (achieving scores of 6 or less for paces)

2.  Mature horses (10 years and above), training at advanced level (working Intermediate 1 and above)
• Very extravagant moving (achieving scores of 7 or 8 and above for paces)
• Less extravagant moving (achieving scores of 6 or less for paces)

The requirements don't just describe the qualities of the horses needed. It also describes what the rider needs to be prepared to do.

"Horses will need to be ridden by their normal riders in a straight line in collected/working, and medium/extended trot (and piaffe and passage for any horses trained to that level) on two different surfaces."

For their effort, the riders are to be reimbursed for their travel expenses (remember that British gas is at least twice what it costs here in the USA) and this promise of a report:

"Feedback for the rider will include information on the gait (including joint flexion angles) and symmetry of the horse, rein tension, and rider position, plus advice on exercise programmes and performance if the rider would like this information."

I can't think of any dressage riders who wouldn't like that information.

The closing message rolled out the feel-good factor:

"The results of this study would enable us to provide immediate and beneficial advice on training practices to dressage trainers, riders and owners, in order to reduce the risk of suspensory ligament injury.

"Based on the number of horses that suffer from suspensory ligament injuries, and the variable outcome of treatment/management, any work which improves prevention strategies would have a considerable positive effect on dressage horse welfare."

What the text doesn't mention is that the Animal Health Trust is a charitable organization that depends on donations. By inviting and potentially involving citizen dressage riders to participate in the study, the AHT is opening the door for future donations from the riders and also creating a culture of transparency and awareness of the dressage community's problems with suspensory lameness.

When the study is complete and the researchers publish their findings, the British dressage community will have a sense of knowing the horses and riders who participated and of having been part of some important research. Everyone reading the study will know exactly what level and type of horses were in the study.

If you live in England and would like to be part of the study, you can apply by sending an e-mail to vvicki.walker@aht.org.uk; telephone: 01638 751908 or 07825 005125.

Vicki noted that horses from the local area will be accepted first to try and minimise travel expenses.

To learn more:

All about suspensory ligament injuries by Sue Dyson FRCVS
Suspensory Ligament Injuries in Horses, a UC Davis Center for Equine Health special report (free PDF download).


© Fran Jurga and Hoofcare Publishing; Fran Jurga's Hoof Blog is a between-issues news service for subscribers to Hoofcare and Lameness Journal. Please, no use without permission. You only need to ask. This blog may be read online at the blog page, checked via RSS feed, or received via a digest-type email (requires signup in box at top right of blog page). To subscribe to Hoofcare and Lameness (the journal), please visit the main site, www.hoofcare.com, where many educational products and media related to equine lameness and hoof science can be found. Questions or problems with this blog? Send email to blog@hoofcare.com.  
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Disclosure of Material Connection: I have not received any direct compensation for writing this post. I have no material connection to the brands, products, or services that I have mentioned, other than Hoofcare Publishing. I am disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: Guides Concerning the Use of Endorsements and Testimonials in Advertising.

Thursday, September 27, 2012

Chronic Laminitis Research: Comparison of Normal vs Chronic Laminitis Horses Shows Difference in Immune, Digestive and Laminar Proteins

"Laminitis is not limited to the foot and chronic laminitis should be considered a multi-system disease" -- Steelman, Chowdhary, 2012


Chronic laminitis treatment usually focuses directly on the feet. The authors define chronic laminitis as the condition of horses who survive acute laminitis but are left with after-effects like coffin bone rotation. They state that 75% of horses with acute laminitis go on to the chronic stage, which they describe as causing permanent lameness. (file photo, courtesy of Vetmoves)

A new paper from the world of laminitis research finds that the anti-inflammatory protein apolipoprotein A-IV (APOA-IV) is raised in chronic laminitis, which suggests that the chronic form of the disease is linked to a more general inflammation, especially of the digestive system, than was previously documented.

Most research into laminitis is conducted on horses suffering from acute laminitis, usually after the ingestion of a large doses of fructans or black walnut in a controlled setting. Chronic laminitis is usually studied because of links to insulin resistance and/or equine metabolic syndrome and Cushing's disease, with minimal testing of systemic findings in horses with lameness in their feet. The focus of most chronic laminitis research is on how the endocrine system's irregular function affects the laminar tissue of the foot.

According to research published this week in the open-access journal BMC Veterinary ResearchDr Samantha Steelman and Professor Bhanu Chowdhary from the College of Veterinary Medicine at Texas A&M University, found 16 proteins that have different levels in the blood of horses with chronic laminitis, but which are not reflected in normal horses. They compared nine foundered horses with 30 healthy control horses collected from horses residing at the private Hoof Diagnostic and Rehabilitation Clinic in Bryan, Texas, where horses are in treatment under the direction of David Hood PhD DVM.

Horses in both groups were in good health, apart from the laminitis. Eleven of the 16 proteins measured are involved in response to wounding, coagulation and inflammation. The remaining proteins included fetuin A and B, both of which are involved in acute immune response, immunoglobin, an indicator of increased antibody levels, and most importantly APOA-IV.

Dr Steelman explained, "APOA-IV is produced by the small intestine. One of its functions is to tell the animal when it is full. It also has antioxidant and anti-inflammatory properties, which might explain the raised levels of APOA-IV."

At 2011's Sixth International Equine Conference on Laminitis and Diseases of the Foot in West Palm Beach, Florida, Dr. Steelman presented a poster titled, "Characterization of laminar, gastrointestinal, and immune system dysregulation in chronic equine laminitis", which was related to the research detailed in today's paper.

In the abstract accompanying her poster, she wrote that it was her team's goal to study the immune system, the gastrointestinal system, and the integumentary system (laminar tissue) using a combination of proteomics, next-generation DNA sequencing, and real time PCR, rather than to focus solely on the foot.

Steelman and Chowdhary's comparative study found interesting variations in all three systems between the laminitic and normal horses. Ultimately, their results support their hypothesis that localized laminar inflammation may be linked to systemic alterations in immune regulation, particularly in the gastrointestinal system.

Research published in BMC Veterinary Research that laminitis is linked to general inflammation, especially of the digestive system, via elevated levels of an anti-inflammatory protein that was not present in horses that do not have laminitis. Proteomics is the study of protein's presence, type and activity level in a condition. (Image courtesy of BMC Veterinary Research)

In other words: Chronic laminitis may show up most in displacement of the coffin bone, prolonged or intermittent lameness and hoof capsule deformity, but the digestive and immune systems are also affected. Most treatment of chronic laminitis currently focuses on making the feet more comfortable.

"From these data we conclude that the pathology of chronic laminitis is not limited to the foot and that chronic laminitis should be considered as a multi-system disease," was Steelman's interesting conclusion in Palm Beach. She recommended that her data be used in developing a more directed therapeutic approach as an alternative to current treatment strategies.

To learn more: Increased Plasma proteomics shows an elevation of the anti-inflammatory protein APOA-IV in chronic equine laminitis by Samantha M Steelman and Bhanu P Chowdhary. (full paper, free download) in the journal BMC Veterinary Research, an open access, peer-reviewed journal.

Dr. Steelman is curator of the Equine Tissue Sharing Program at Texas A&M.

Dr Chowdhary is an expert on equine genetics and also collaborates on research at the Laminitis Institute at PennVet's New Bolton Center, where he collaborates with Drs. Hannah Galantino-Homer and Chris Pollitt.

Dr. David Hood Launches the Hoof Diagnostic and Rehabilitation Clinic in Texas

© Fran Jurga and Hoofcare Publishing; Fran Jurga's Hoof Blog is a between-issues news service for subscribers to Hoofcare and Lameness Journal. Please, no use without permission. You only need to ask. This blog may be read online at the blog page, checked via RSS feed, or received via a digest-type email (requires signup in box at top right of blog page). To subscribe to Hoofcare and Lameness (the journal), please visit the main site, www.hoofcare.com, where many educational products and media related to equine lameness and hoof science can be found. Questions or problems with this blog? Send email to blog@hoofcare.com.  

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Disclosure of Material Connection: I have not received any direct compensation for writing this post. I have no material connection to the brands, products, or services that I have mentioned, other than Hoofcare Publishing. I am disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: Guides Concerning the Use of Endorsements and Testimonials in Advertising.

Monday, September 24, 2012

AVMA Statement in Support of USDA's Efforts to End Soring

The following text is published as provided by the American Veterinary Medical Association in a press release:

Sole bruising (pink/red discoloration) from possible pressure shoeing. Courtesy of USDA

SCHAUMBURG, Ill. --The American Veterinary Medical Association (AVMA) issued the following statement in support of the United States Department of Agriculture's (USDA) ongoing efforts to end the inhumane practice of soring.

"The American Veterinary Medical Association appreciates ongoing efforts by the United States Department of Agriculture's Horse Protection Program to keep its stakeholders informed regarding enforcement activities associated with the Horse Protection Act (HPA), including the recent posting of preliminary inspection results for the 2012 Tennessee Walking Horse National Celebration.

"Inspection results, when compared over time, can be an important measure of progress in achieving the goal of eliminating the inhumane practices associated with soring of horses. Unfortunately, these statistics from the 2012 Celebration reaffirm that soring remains prevalent in the industry more than 40 years after passage of the HPA. A violation rate of close to 10% is symptomatic of an industry that continues, decade after decade, to fail in its responsibilities to protect the welfare of these horses.

"Representatives of the AVMA attended the 2012 Celebration and observed enforcement activities in the inspection area. They found the USDA veterinary medical officers conducting inspections to be skilled and professional in the conduct of their activities. And, in contrast to allegations of selective enforcement at this year's Celebration that have been levied by some of those in the industry, congruence between violation rates for 2011 (9.5%) and 2012 (9.0%) suggests the USDA's approach to enforcement is consistent. Consistency among results provides further evidence that abuse within the Walking Horse industry is a systemic problem, not an isolated one.

"The AVMA urges the USDA to actively and effectively enforce the HPA while the agency continues to search for improved detection methods. Ultimately, the AVMA believes that elimination of action devices and the so-called performance packages from the show ring would be the most timely and effective way to stop this inhumane practice."

For more information about the AVMA and its programs, please visit www.avma.org.

Soring: Unethical and Illegal (AVMA Fact Sheet) (download)

Click to go to ordering page for full details; 3-D hoof anatomy educational software
© Fran Jurga and Hoofcare Publishing; Fran Jurga's Hoof Blog is a between-issues news service for subscribers to Hoofcare and Lameness Journal. Please, no use without permission. You only need to ask. This blog may be read online at the blog page, checked via RSS feed, or received via a digest-type email (requires signup in box at top right of blog page). To subscribe to Hoofcare and Lameness (the journal), please visit the main site, www.hoofcare.com, where many educational products and media related to equine lameness and hoof science can be found. Questions or problems with this blog? Send email to blog@hoofcare.com.  
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Disclosure of Material Connection: I have not received any direct compensation for writing this post. I have no material connection to the brands, products, or services that I have mentioned, other than Hoofcare Publishing. I am disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: Guides Concerning the Use of Endorsements and Testimonials in Advertising.

University of Tennessee Equine Orthopedic and Rehabilitation Center Rises in Knoxville


 
News broadcast from WBIR-TV in Knoxville previews the new equine orthopedic and rehabilitation center at the University of Tennessee College of Veterinary Medicine.

The University of Tennessee's College of Veterinary Medicine is growing. The well-established vet school on the UT campus in Knoxville expects to open an ambitious new 85,000 square foot veterinary medicine center by February 2013.

The equine hospital is the jewel of the campus's new crown, and will be next door to an impressive equine lameness diagnosis and rehabilitation facility, which is about twice its size.

Within the new campus of the Equine and Large Animal Hospital and Rehabilitation Center, an Orthopedic Diagnostic Center is nearing completion, as featured on the video. It is a state-of-the art imaging center with spiral CT scan capabilities for large and small animals, and new space for the vet school's ambulatory field service.


The new veterinary center at the University of Tennessee features the new equine lameness diagnosis and rehabilitation facility, shown in this drawing as the building at far right
New facilities require funds, and the new construction is expected to cost $20.9 million. If you'd like to be part of it, the university is offering naming rights to departments in exchange for donations. If you'd like to be known eternally in Knoxville, the farrier services unit can bear your name for just $150,000. A stall in the equine ICU looks like quite a bargain at just $15,000. Then again, for a $4 million donation, your name will be on the marquee of the Equine Orthopedic Diagnostic and Rehabilitation Center.

  
UT has always been recognized for its research and treatment of equine lameness, including laminitis, and rehabilitation. This is an older promotion video for the vet school. Notice that they promote their farrier's journeyman status. Dudley Hurst is shown rasping a hoof wall in the video.

You can keep an eye on the construction and watch the progress; the university web site posts a high-definition photo of the construction every hour.
Click for full page information on contents and ordering information.


© Fran Jurga and Hoofcare Publishing; Fran Jurga's Hoof Blog is a between-issues news service for subscribers to Hoofcare and Lameness Journal. Please, no use without permission. You only need to ask. This blog may be read online at the blog page, checked via RSS feed, or received via a digest-type email (requires signup in box at top right of blog page). To subscribe to Hoofcare and Lameness (the journal), please visit the main site, www.hoofcare.com, where many educational products and media related to equine lameness and hoof science can be found. Questions or problems with this blog? Send email to blog@hoofcare.com.  
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Disclosure of Material Connection: I have not received any direct compensation for writing this post. I have no material connection to the brands, products, or services that I have mentioned, other than Hoofcare Publishing. I am disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: Guides Concerning the Use of Endorsements and Testimonials in Advertising.

Sunday, September 23, 2012

Equine Gait Analysis: The Ghost of Muybridge's Racehorse Gallops Again

A vaguely-familiar and yet ghostly horse and rider gallop through the streets of Palo Alto, California in this trailer for next week's Palo Alto International Film Festival. Why this particular horse and rider? Because Stephen Jobs wasn't the first genius to live in Silicon Valley. The first one made his mark with horses' hooves.

Legend has it that it all started on a bet.

The year was 1878. A wealthy industrialist named Leland Stanford believed that there is a point in a horse's gallop when all four hooves leave the ground.

His opponents called him mad. Artists and sculptors argued that time does not stop and even if it did, how could something as heavy as a horse defy gravity?

They believed that one foot had to stay in touch with the planet at all points in the horse's stride. Horses didn't fly.

But how could you prove it? Or disprove it?

A funny thing happened on the way to proving what happens to horses' hooves when they gallop. From the pudding of that proof that resulted, the motion picture industry was born.

Equine gait analysis was born in Palo
Alto, California in 1878.
To prove he was right, Stanford imported English photographer Eadweard Muybridge, who had been experimenting with making the mechanism we now know as the camera shutter.

Back at that time, every photo required a long exposure, which is why you often see blurred photos. Cameras had no shutters. The photographer merely removed the lens cap and replaced it when enough light had entered to expose the sensitive plate. If you were posing for a portrait you had better hold your breath.

And galloping horses? Trotting horses? Their legs were just a blur in old photos, and even the word's finest painters had it all wrong when they depicted horse limbs at different gaits.



Muybridge set out to use science to prove that Stanford was correct. He set up twelve cameras connected to trip wires that crossed the horse's trajectory. Muybridge was anything but an overnight success with this method: he and Stanford struggled with experiments for five years until they mastered the method of stopping motion.

But they still had to be able to stop it in just the right phase of the stride in order to prove their point.

On the day of reckoning, horse racing fans and the curious press assembled at Stanford's Palo Alto Stock Farm in Palo Alto, California to see what Muybridge's results would be.

The series that made history that day was captured of a trotter hitched to a two-wheeled cart; the suspension phase of the trot was clearly illustrated.

All four of the horse’s hooves were off the ground at the same time. Victory was Stanford's.

Watch a horse gallop. Is it any wonder it took thousands of years for someone (and science) to figure  it out? This is a still from the video of Occident.
It was a trotter that day but the galloping racehorse is the image most closely identified with Muybridge.

It sounds obvious to us today, but it was not obvious back then. Muybridge's flying hooves were the first recorded movement in visual history.

Studying Muybridge is something that film history students do. Equine gait analysis students do it, too. Animation students still use his frames as blank canvases for their own horses. The galloping horse and its flying hooves have become an icon.

And this week, their ghost gallops through Palo Alto again.

Note: the special trailer for the film festival was made with the assistance of French animators who would like viewers to know that there was no post-production involved.

To learn more:
June 15, 1878: Muybridge Horses Around With Motion Pictures (Wired Magazine)
Muybridge animal locomotion  collection at the University of Pennsylvania


Click to go to order page and PayPal link. We'd love to send you this poster.
© Fran Jurga and Hoofcare Publishing; Fran Jurga's Hoof Blog is a between-issues news service for subscribers to Hoofcare and Lameness Journal. Please, no use without permission. You only need to ask. This blog may be read online at the blog page, checked via RSS feed, or received via a digest-type email (requires signup in box at top right of blog page). To subscribe to Hoofcare and Lameness (the journal), please visit the main site, www.hoofcare.com, where many educational products and media related to equine lameness and hoof science can be found. Questions or problems with this blog? Send email to blog@hoofcare.com.  


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Disclosure of Material Connection: I have not received any direct compensation for writing this post. I have no material connection to the brands, products, or services that I have mentioned, other than Hoofcare Publishing. I am disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: Guides Concerning the Use of Endorsements and Testimonials in Advertising.

Wednesday, September 19, 2012

Paynter Watch: How Is Post-Colitis Laminitis Different from Common Chronic Laminitis?


TVG interview with champion Thoroughbred Paynter's owner Ahmed Zayat of Zayat Racing, taped the morning of September 19, 2012, explains the timeline of Paynter's illness and suggests the severity of the colt's illness.

All types of laminitis are similar in two ways: First, the epithelial cell system in the foot’s interlaminar zone is damaged.

Second, that damage causes horses great pain. The common analogy of standing and bearing weight on a ripped toenail is an apt one.

But the most common types of laminitis are rooted in the horse’s endocrine (hormone-producing) system.

© Hoof Blog colitis graphicHormonal imbalances are aggravated by environment, diet, exercise and seasons. Damage to the laminar junction may be slow but steady, with varying intensity.

With this type, horse owners are stunned when told their horses have laminitis...and that they have had it for months or even years. It just didn’t cause enough pain for the horse to be noticeably lame.

The farrier may have noticed a stretched white line or hoof wall ridges, or that a normally-quiet horse is irritable while being shod. The rider might have thought the horse wasn’t as free-striding as he once was.

A horse that once was hard to catch is suddenly an easy catch. But the owners don't sense that these horses are lame--until they are. Then the subtle signs and the loss of performance start to make sense.

How can this be?

B0005542 Human HeLa cancer cell, apoptosis
The progressive stages of programmed cell death, or apoptosis, in a human cancer cell. (Image courtesy of Wellcome Images library)

Cellular death in endocrine-related laminitis is by the process known as apoptosis. Cells in the lamininar zone are under assault. Some may contract and die. Some may stretch and deform. Some may be unaffected and remain attached. One by one, the cells die.

The horse is more lame one day, less lame the next. The blood supply may be disrupted and the diseased hoof grows abnormally and loses its form. As the seasons change, the horse is better, or worse. Low-grade chronic laminitis can go on and on for months or years.

Another form of cell death is seen in the horse that has received a severe insult to its body’s system from the inflammation, shock and dehydration of colitis. Instead of the drip-by-drip influx of insulting factors into the foot, a flood arrives and the result is the traumatic cell die-off process known as necrosis.

Apoptosis and necrosis are flip sides of the coin of cellular death. Both are associated with the process known as laminitis, but one is a systematic death of cells, while the other is swift and deadly and immediate. One text described apoptosis as cellular suicide, and necrosis as cellular homicide.

The recent case of top three-year-old colt Paynter has been captivating the racing world. Paynter has been in a veterinary hospital in upstate New York near Saratoga since Labor Day weekend. His condition has improved but his owner reports persistent fever and diarrhea bouts, and the colt was diagnosed with laminitis in three of his four feet.

Equine podiatry specialist Dr. Bryan Fraley from Lexington, Kentucky went to New York to work on the horse; his feet are now in casts, which have been reported to be successful. Reports after the first week were that there was no rotation or sinking in the feet. The casts are due to be changed later this week.

Many of us have been there...and done that, when it comes to watching a horse struggle with the severe colitis and resulting dehydration of colitis. Too many of us have lost horses swiftly and tragically in the days following a successful survival--not to colitis, but to the severe laminitis that so often follows.
What is colitis?
Colitis: inflammation of the colon, usually due to infection. Diarrhea, colic pain and rapidly progressing dehydration are usually the result. Treatment focuses on relieving symptoms and preventing dehydration and shock while identifying and treating the underlying cause, if possible. (Definition: American Association of Equine Practitioners)
To understand colitis-related laminitis better, we turned to David Hood DVM, PhD of The Hoof Diagnostic and Rehabilitation Clinic, a laminitis research and treatment center outside College Station, Texas.

Dr. David Hood
Dr David Hood during a panel discussion at the Sixth International Equine Conference on Laminitis and Diseases of the Foot in 2011. (Dick Booth photo)

One of the world's most highly respected laminitis researchers, Dr. Hood’s focus is on understanding the process of laminitis and, in particular, how the foot tissue is damaged by the disease.

Dr. Hood explained that the difference between apoptosis and necrosis is central to understanding why a horse has such a sudden and devastating form of laminitis after colitis--and why the laminitis doesn’t occur until the diarrhea has stopped.

Dr. Hood mentioned that the chief culprit in colitis is that the horse goes into shock. In response to the inflammation in the bowel caused by colitis, the horse’s system demands that a large volume of fluid be pulled out of cells all over the body. It is pumped to the bowel to replace the fluid lost there but, as a result, the circulatory system is left with a deficit of fluid.

When treated by a veterinarian, the sick horse will receive lifesaving intravenous fluids. The circulation is refueled or rehydrated. But that is the cue for laminitis to begin.

plastination of chronic laminitis limb/plastinate.com
This plastination specimen illustrates
chronic laminitis and typical hoof
capsule deformity. 
As you can imagine, the dehydrated body system is shocked by the massive and sudden rehydration, which is necessary to counter the loss of body fluid through the diarrhea, but still a shock to the system. The reperfusion of the cells with the fresh fluid is connected to necrosis, or a sudden traumatic death of cells within the laminar interface of the horse’s foot.

It is in the reperfusion stage that necrosis in the foot tissue takes place. This is why the onset of laminitis seems to follow the diarhhea in the medical timeline of the disease.

Not only is laminitis by necrosis sudden and traumatic, the cellular death in the laminar zone causes a collapse of the foot’s ability to support the weakened horse, and severe pain is obvious and extreme.

“By the time you see that it has happened, there’s not much to do except start rehabiliation,” Dr. Hood commented. “It’s like a patient who just had a heart attack: the damage is done, and the patient’s prognosis depends on how much damage was done.”

Dr. Hood noted that post-colitis laminitis is also very different from the third form of laminitis, known as "support-limb" laminitis. “That’s also a slow onset,” he remarked. “And the cellular death is not necessarily necrosis. The foot is almost anesthetized while the horse is standing continually on it. It’s not until the blood flow comes back that the horse begins to show signs of pain.”

Do post-colitis cases tend to demonstrate sinker syndrome rather than the rotation type of coffin bone detachment seen in typical laminitis? “It all depends,” Dr. Hood said, “on the amount of damage and the percent of lamina that have experienced acute necrosis.”

Endotoxin has been implicated as a factor in post-colitis lamintiis but Dr. Hood discounted it. “Research data indicate that while endotoxin can make a horse sick and can cause shock,” he stressed. “it--alone--does not induce laminitis.”

Are there facts that are known about colitis in horses? Dr. Hood agreed that much is known about post-colitis laminitis and fired off a quick list: horses do survive it. It’s a painful condition. It’s hard to control. Horses undergo rapid and radical damage to their feet. There are different varieties. Rehabilitation of damaged hooves after colitis can take months or even years. The more the foot is damaged, the harder it is to fully rehabilitate the foot.

In endocrine-related laminitis, on the other hand, Dr. Hood said the situation is reversed. The feet are relatively easy to treat. It’s the disease condition that is difficult.

Laminitis, in any of its forms, is a medical emergency and a critical juncture in a horse's medical history and athletic potential.

We all hope that Paynter will continue to successfully fight both colitis and laminitis.

Thanks to Dr. Hood for his time and expertise in sharing and preparing information for this article. Plastination specimen courtesy of Christoph von Horst, DVM PhD.

To learn more:

Dr. David Hood Launches the Hoof Diagnostic and Rehabilitation Clinic in Texas
Paynter Watch: Top Thoroughbred Colt Diagnosed with Post-Colitis Laminitis in New York
Paynter Laminitis Watch: Podiatry-Vet Fraley Amazed at Progress Since Hoof Casts Applied


© Fran Jurga and Hoofcare Publishing; Fran Jurga's Hoof Blog is a between-issues news service for subscribers to Hoofcare and Lameness Journal. Please, no use without permission. You only need to ask. This blog may be read online at the blog page, checked via RSS feed, or received via a digest-type email (requires signup in box at top right of blog page). To subscribe to Hoofcare and Lameness (the journal), please visit the main site, www.hoofcare.com, where many educational products and media related to equine lameness and hoof science can be found. Questions or problems with this blog? Send email to blog@hoofcare.com.  
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Disclosure of Material Connection: I have not received any direct compensation for writing this post. I have no material connection to the brands, products, or services that I have mentioned, other than Hoofcare Publishing. I am disclosing this in accordance with the Federal Trade Commission’s 16 CFR, Part 255: Guides Concerning the Use of Endorsements and Testimonials in Advertising.