of DSLD and Injury in the Peruvian Horse.
NAPHA SUB-COMMITTEE REPORT
Rich Ovenburg, Carol Borden, Tina Woodworth, Carol Hayden, Bill Chase.
words in purple italics is added and not part of the original document)
ISSUE BEING EVALUATED
The purpose of this report is to
alert both Peruvian Horse owners and veterinarians of the reported growing incidence
of misdiagnosis of Peruvian Horses. Because of the increasing proliferation of
misinformation, some veterinarians are applying a different standard to the Peruvian
Horse when diagnosing routine injuries. We also want to provide information to
owners about some of the most common equine injuries and their effects, in order
to assist them in seeking diagnosis and treatment for horses that may have been
Disease: Illness or sickness often characterized by typical
patient problems or symptoms and physical findings or signs. Any condition that
prevents the body from working as it should other than direct injury.
May be applied in medicine to damage inflicted upon oneself or someone else. The
term "injury" may be synomynous with the wound or with trauma.
HISTORY OF THIS ISSUE:
Horse breed in the United States has done such a good job of making the general
public aware of DSLD that it has become, in many people's minds, the number one
characteristic associated with the Peruvian horse. Peruvian horse owners have
spent close to three-quarters of a million dollars in the last six years to discover
just what DSLD is, with very little success. The fact is, DSLD has not even been
scientifically isolated as a disease.
In the latest privately-funded
research from the University of Georgia, ( see attached charts#1) that cost the
Peruvian Horses breeders over two hundred thousand dollars, bio-chemist Dr. Jaroslava
Halper, writes about how they "suspect" an accumulation of "unidentified
proteoglycans as being the cause of DSLD. However, on closer examination, there
is as much accumulation of this proteoglycan in the connective tissue of the unaffected
Peruvian control hose as there are in the affected ones. A nuchal ligament test
that a worldwide press release claimed was successful turns out to test positive
in six of the seven unaffected control horses! No one seems quite sure what the
normal level of this proteoglyan is because it is yet to be identified. Proteoglycans
occur naturally in connective tissue and are beneficial in healing injuries/ they
have never before been associated with disease in equines. The use of glucosamine
can raise the level of proteoglycans by over 150% in some horses, making this
study even more confusing.
A quarter of a million dollars was spent
by Peruvian horse breeders on a two-year genetic study, completed at the Univeristy
of Kentucky in 2005. Researchers found no genetic cause or link between the affected
and unaffected horses they were given. Dr.Cothran's co-researcher Kathryn Graves
states, " Initial results identified a promising area containing several
genes associatedwith ligament structure. However further testing did not support
any of these initial findings." And yet, we still hear from many people talking
about having a genetic test and isolating the DSLD gene. Dr. Cothren would, of
course, like more money to try again. However, the real fact of this issue is,
scientists would first have to discover what causes DSLD, before the gene could
The most widely-read study ( see attached study #2:
Veterinary Database Search) used to prove the Peruvian Horse has a higher incidence
of this "disease" than other breeds, was actually a veterinary data
search for suspensory ligament injuries, - not disease or DSLD- over a ten-year
period from 29 veterinary hospitals across the United States. They found only
24 reported suspensory injuries in Peruvian horses from 1987 to 1997 or a little
more than two a year, compared with 707 of these injuries for Standardbreds, 469
for Thoroughbreds and 443 for Quarter Horse. Though this study claims that these
injuries are codes for disease and tries to relate these injuries to the population
of Peruvian horses, there is absolutely noting in this study that relates these
injuries to the general population.
However, Dr. Jeanette Mero, (
see attached letter ##) still used this study to solicit funding from Peruvian
horse breeders and validate her claims that the Peruvian Horse breed was "predisposed"
to this condition, completely ignoring the nine other breeds that had many more
of these types of injuries than the Peruvian horse. Even though the veterinary
data search was for injuries, Dr. Mero's study of twenty Peruvian horses gives
no consideration to injuries, hoof care, conformation or nutrition deficiencies
and assumes these horses have a disease that she states "is particular to
the Peruvian Horse.". This misleading-study can be found in several places
on the internet today and has been the constant source of confusing and negative
articles about the Peruvian Horse.
The fact is, we really don't
know any more now, than we did seven years ago. All the researchers, in order
to get funding have promised a test" the protocol from Dr. Mero, a DNA test
from Dr. Cothren, a nuchel ligament test from Dr. Halper. However, so far, there
is no test. As Dr. Halper clearly states in he 2006 study "Presently, there
is no reliable method of diagnosing DSLD in asymptomatic horses."
what have we purchased with all our time and money? We now have a public relations
disaster of such gigantic proportions that it threatens the very existence of
the Peruvian horse breed in the United States. At a recent all breed equine fair
in California 80% of the questions about Peruvian Horses were about the "Peruvian
horse leg disease." A researcher at the University of Kentucky was "confidentially"
told that some ranches had 40% of their horses affected with DSLD. Paso Finos
and other gaited breeds are warning people not to buy our horses because "most
Peruvian Horses have DSLD, and all the bloodlines are all infected." Dr.
Jeanette Mero, who is described in the American Association of Equine Practitioners
magazine as "an activist in promoting DSLD," has written several articles,
for major equine publications unfairly connecting this condition with the Peruvian
Horse . These articles claim, with absolutely no proof, that the Peruvian Horse
is "predisposed" to what is described as an incurable, deadly disease,
rampant in the bloodlines of our horses. Many of these publications are delivered
free to veterinary clinics across the country and in some cases they go around
While other gaited breeds are growing and enjoying unparalleled
financial success including the Peruvian Horse in Central America and in it's
native country of Peru, this negative publicity has had a drastic effect on our
numbers here in America. We now have only 1200 two, three and four year old registered
Peruvian horses in the United States compared to 2200 eight, nine and ten year
olds. This means that in three years we will be trying to support our shows and
a $300,000 NAPHA budget, with half as many horses.
publicity has, of course, reached the veterinarians, who diagnose our horses and
thing of DSLD with regard to every Peruvian horse they examine, along with a horse-owning
public who now thinks every abscess or swollen fetlock in a Peruvian horse is
The following are some actual case histories of how this results
in the misdiagnosis of our horses. We picked these three cases out of the many
we have received information on, because w could document their stories and also
because some of the members of this committee have had similar experiences with
this kind of misdiagnosis
Gloria Eby had shoes put on her six year old trail
riding gelding for the first time in his life. And now he was lame and she was
A well-known lameness clinic was only a mile or two away
from her boarding stable, so she took her gelding there and ultrasounds were done.
The veterinarian had no experience with Peruvian horses so he sent the untrasounds
to Dr. Jeannette Mero for a second opinion. They came back confirmed positive
for DSLD. Gloria was shocked and heartbroken. The vet wrote a full-page diagnosis
explaining DSLD and informing her that the prognosis was eventual euthanization.
Gloria was grief stricken, gave the hors away; she cold not bear to have him put
down and couldn't afford to keep a horse she couldn't ride.
owners treated the gelding as in injured horse and took one year to rehabilitate
his injury. They sent the untrasounds to their veterinarian and to a clinic in
California without revealing the breed of the horse. The diagnosis from the ultrasounds
came back from the two other vets as suspensory desmitis, an injury. When the
original vet was asked about the other two diagnosis, he said "that's what
I saw too, but it was a Peruvian horse. I thought there could have been something
else going on." The gelding two years later remains very sound and strong
and has been wining gait classes in shows.
Jenee DeMers' twelve year old mare was
lame and one of the fetlocks was swollen. She wanted a vet to examine her. She
took the mare to Washington State Veterinary School in Pulman, Washington. When
she got there, a vet started examining her mare and was describing the injury
and treatment. When a second vet appeared and asked her what breed of horse she
had, she responded " Peruvian". At that point everything changed. She
was told her mare had a confirmed case of DSLD and was given forms from DSLD Research,
Inc. to fill out. Jenee, in disbelief, took her horse to the Peruvian farrier,
coco Fernandaz, who trimmed her horse and put orthopedic shoes on her to stabilize
the injury and gave it six months to heal. Nine months later Jenee was showing
Tina Woodworth's eighteen year old Peruvian horse was
diagnosed with DSLD by her vet, and she was told he may have to be "put down".
Tina took her horse to another vet to get a second opinion, she had some blood
work down and discovered his problem was a selenium deficiency. Tina started using
a selenium supplement; her gelding is now fine.
The tragedy of these
cases of misdiagnosis is significant, not onlyh for our breed of horse but for
the individuals who euthanize their horses because they were incorrectly confirmed
WHY IS THE VETERINARY COMMUNITY CONFUSED ABOUT DSLD?
are some quotes from research papers and articles explaining injuries and DSLD.
These veterinarians are all describing exactly the same symptoms, only Dr. Mero
is describing an incurable disease in Peruvian horses and the other veterinarians
and researchers are describing suspensory INJURIES in all equines. In the first
example, Dr. Mero is doing both.
#1 Dr. Mero's Protocol for Diagnosis of DSLD
four steps: Palpation of the suspensory ligaments, observance of baseline lameness,
fetlock flexion tests, and sonographic examinations of the suspensory ligament
at mid-cannon and both branches. These four steps accurately provide the information
needed to make a diagnosis of degenerative suspensory ligament desmitis (DSLD)
in Peruvian Pasos Dr. Mero; Journal of Equine Veterinary Science.
the leg for pain
2. Observe the leg for lameness as he moves freely
Assess his soundness using a flexion test
4. Perform an ultrasound examination
steps aren't unique; they are all part of the normal, standard physical exam"
Dr. Mero, from Equus Magazine: October 2005
"This protocol was
not designed as a screening tool
At this point we do not have any good means
to screen large numbers of horses for DSLD- the numbers of false positives and
false negatives would be too high". Dr. Mero, DSLD Research Inc. website.
#2 Dr. Mero Explains bilateral and quadrilateral involvement in DSLD
one key component to diagnose ( in Peruvian Paso's) Is that unlike injury or other
diseases, DSLD occurs bilaterally ( both fronts or both hinds) or quadrilaterally
( all four legs). It often starts in one limb only and appears to be one-legged
( often causing misdiagnosis at that point), but given time, always spreads."
Subtle behavioral changes may be early indicators. Some horses resist having their
legs touched or feet picked up. Many resist having their legs extended to the
front or rear for trimming. Some just seem "off" or "cranky".
Involvement in Suspensory Ligament Injury Sarah E. Powell, MA. Vet MB,
MRCVS, Deidre M. Carson, BVSc MRCVS and Sidney W. Ricketts, LVO. BBc, BVSc.
" Clinical signs vary with the site of the injury and the severity of
the damage. When the origin of the suspensory ligament is damaged (known as Proximal
suspensory desmitis) the condition is often "bilateral" i.e. in both
fore or both hind limbs. There is usually no heat or swelling but there may be
some pain when the area just below the back of the carpus (knee) or hock is pressed
firmly with the leg in a flexed position. In these horses the lameness may be
subtle and " especially in the hind limb) often develops gradually and goes
undiagnosed for some time"
#3 Dr. Mero: Suspensory Ligament enlargement from her 2002 study on DSLD
is unique to Peruvians is the progressive enlargement of the suspensory ligament
primarily involving both branches over time in more than one limb. There is a
diffuse loss of echogenicity and poor fiber pattern images noted throughout the
affected portions of the ligament."
DAVIS Ultrasound and Musuloskeletal Injuries in Horses
The clinical signs of a tendon or ligament injury can be quite varied. Lameness
can range from mild to severe and may be somewhat transient, sometimes lasting
only a few days. Chronic injuries often result in persistent thickening of the
tendon or ligament and an intermittent or persistent lameness".
SUSPENSORY LIGAMENT DAMAGE
Sarah E. Powell, MA,
VetMB, MRCVS, Deidre M., Carson, BVSc, MRCVS, and Signey W. Ricketts, LVO, BAc,BVSc.
injury to the branches, there is usually thickening of the affected region. Warmth
and tenderness may o rmay not be present. If the ligament is ruptured, the fetlock
will "sink" towards the ground, fully or partly, depending on the completeness
of the rupture. Ligaments are made up of fibers that run along their length in
a regular, well-organized manner. When the fiber are damaged some heal in an irregular,
crisscross pattern rather than lengthways. Also, the repaired tissue is different
in structure and mechanical properties than the original, healthy ligament tissue.
Therefore the ligament will always be compromised in structure and function rendering
it susceptible to re-injury."
Dr. Mero: The Cellular
Changes with DSLD (Gaited Horse Magazine)
" Change first
occur at the cellular level. In the first line of repair, cells called fibroblasts
lay in a form of collagen known as TYPE III- a small, weak, not very pliable molecule.
As damage inceases, they progressively build up to installing stronger, larger,
more elastic TYPE I collagen. But for some unknown reason, these cells change
in DSLD horses. They fail to lay in the stronger type of collagen. As the suspensories
in DSLD horses become dominated by type III collagen, they weaken"
Tendinosis Cycle: Cellular Changes with Tendinosis ( Tendinosis.Org)
is a slow accumulation of little injuries that are not repaired properly and leave
the tendon vulnerable to yet more injury. The tendinosis cycle begins when breakdown
exceeds repair. Repetitive motion causes microinjuries that accumulate with time.
Collagen breaks down and the tendon tries to repair itself, but the cells produce
new collagen with an abnormal structure and composition.
collagen has an abnormally high Type III/Type I ratio. Experiments show that the
excess Type III collagen at the expense of Type I collagen weakens the tendon,
making it prone to further injur. Part of the problem is that the new collagen
fibers are less organized into the normal parallel structure, making the tendon
less able to withstand tensile stress along the direction of the tendon.
Changes: The pathogenesis of Tendinopathy. A molecular perspective
G. Riley, Oxford Journal of Equine Medicine
Matrix changes in tendon pathology could be attributed to intrinsic factors, such
as changes in cell activity with age, or extrinsic factors, such as 'overuse',
repetitive strain and micro trauma injuries. In degenerative tendon there is an
increased rate of collagen matrix remodeling, leading to a qualitatively different
and mechanically less stable tendon, which is susceptible to damage. Thus tendon
degeneration may result from a failure to regulate specific MP activities in response
to repeated injury or mechanical strain."
the Equine Superficial Digital flexor Tendon Responds to Physiologic Challenges
and Physical Therapy, Yi-lo Lin and, A. Barnveld, Prof. Phd, Dvm Univeristy of
"The scar tissue that is induced is of inferior
quality compared to the original tissue due to alterations in biochemical composition
and structural organization, compromising the functional restoration of pre-injured
structure. This leads to high re-injury rates when athletic activity is resumed."
"The equine superficial digital flexor tendon and suspensory
ligament can be considered as the most vulnerable structures of the entire equine
body" Dr. Yi-lo Lin.
Most ligament and tendon injuries are accumulations
of smaller injuries or micro-injuries that lead to a breakdown, and not one traumatic
event. Dr. James Hamilton, DVM of South Pines Equine Associates in North Carolina,
describes it this way, "damage (to tendons and ligaments) most often, is
cumulative, starting with minor traumas that weaken tendon fibers and cause mild
inflammation without lameness or detectable soreness." He likens the process
to a rope with individual fibers breaking/ "eventually" he says, "
you would reach a critical threshold of weakness." At that point the horse
becomes lame swelling begins around the injury and the horse will then need a
lot of care and a long recuperation.
Any injury will degenerate if
it is not stabilized. Any injury in one leg may become bilateral, unless both
legs are stabilized. In other words when one front leg is injured and wrapped,
you must always wrap the other one so the horse doesn't overload the sound leg.
The race horse, Barbaro, was put down because of complications in his left leg.
His right leg was the one that was broken, but Barbaro's condition quickly became
bilateral. As Pulitzer prize winning equine author, Jane Smiley, writes about
equine ijuires, "(Horses) are engineered so close to the margins of what
is physically possible that when one ting fails, it can cause the failure of the
Injuries to suspensory ligaments can be hard
to diagnose and lameness can come and go, but the injury is still there. Suspensory
ligament injuries are also hard to heal. Many will take months, not weeks or days,
and when they do heal they are often easier to re-injure, resulting gin a chronic,
recurring problem. A second opinion and long recuperation periods are always good
ideas. Because there is no test for DSLD and no study has ever been done that
states the Peruvian horse is more prone to any disease or injury, finding out
exactly what DSLD is, can be very confusing for horse owners and vets alike.
better than the successful rehabilitation of a tendon or ligament injury? The
answer is: Preventing an injury from happening in the first place. Peruvian horses,
with their tremendous brio and willingness to please make it even harder to detect
injuries. While it's impossible to completely avoid injury in athletic horses,
these precautions might help to minimize your horse's chance for injury. Tendon
and ligament injuries take the longest to heal, and some never do, so prevention
is the key.
1. Good horses are good horses in any breed. Learn the
principles of conformation and breeding. What are good angles? What does a post
legged horse look like? Why is a short back better than a long one?
the veterinarians at Alamo Pintado say, "The simple answer to this problem
is not to breed bad-legged horses to bad-legged horses, or to breed any horse
with a severe inherited conformation fault. Once that becomes obvious, the problem
2. Learn to recognize the subtle signs of an injury
before it becomes severe. Identify any abnormal heat or swelling in your horse's
legs by carefully feeling his legs every day before you ride and taking note of
any changes. You should also pay close attention to any lame steps or obvious
changes in his behavior. If you think something feels wrong when you ride, call
your vet. By doing so, you'll prevent a minor strain from becoming a catastrophic
3. Proper, timely trimming is perhaps the most important
thing you can do to safeguard the health of your horse's feet and legs. Not all
farriers are created equal, so get recommendations from someone you trust. Many
Peruvian horse's hooves grow forward and can become unbalanced quickly. Bad trims
can cause micro-injuries to accumulate while your horse is standing in his stall
or walking in a pasture by increasing pressure on suspensory ligaments. As soon
as you suspect a problem, address it. Horses should never be sore after a trim;
master farrier, Coco Fernandaz, trims horses the day before a show. He says, "They
should be better after a trim, not worse."
4. Careful conditioning
is critical. Regular long, slow, distance work-walking-helps keep tendons and
ligaments tight and healthy. AND, even though you want your horse to look good,
you are not his friend by feeding him too much. Excess weight stresses joints,
tendons, and ligaments.
5. Work footing needs to be deep enough to
lesson concussion, but not so deep that it strains tendons or ligaments. Avoid
rocky or slippery surfaces and footing you can't see.
6. Always warm
up your horse thoroughly before you ride. Plan to walk him a minimum of 10 to
15 minutes before you start to work.
7. Protect our horse's legs
with polo wraps or sports medicine boots; they provide good support and protection
when applied properly. Ask your vet about recommendations for your horse. He/she
can also advise you on measures such as icing, and applying stable bandages after
We can all agree that educating our members to
these steps would be beneficial, but just listing them in a paper is not the answer.
We need to be pro-active in educating our members. NAPHA needs to sponsor and
support activities like the Peruvian Horse Congress held in Lompoc, California
in 2006. At this Congress several successful breeders and experts in their equine
specialties came together and shared their knowledge.
judges, veterinarians, and farriers, altogether in one places answering questions,
demonstrating good and bad conformation with real horses, a farrier demonastrating
a good trim and educating owners to the needs of Peruvian horses, trainers talking
about conditioning and good equitation, showing us the proper way to wrap our
horse's legs, veterinarians talking about injuries and showing members how to
correctly palpate tendons and ligaments for soreness. This should be going on
every year in a different part of the country with local veterinarians invited
We also need to have a positive educational presence on
the internet. A place that promotes the same values that are demonstrated in these
congresses and are displayed for the general horse owning public to reference.
The breed very much needs a central website that is dedicated to just these issues
and is promoted by NAPHA.
And finally, we need to stand up and support
our horses, to other breeds, to other owners, and especially to the veterinary
community that is misdiagnosing our horses.
have a strong, wonderful horse that is getting some very bad publicity. We need
to educate the veterinary community as well as the owners of these great horses
and not let a small group of negative people be the only ting the public hears.
Alamo Pintado is a world renown veterinary clinic that sees more Peruvian Horses
than probably any clinic in the world, and after thirty years, following is what
they have to say about Peruvian horse:
" In our experience,
the Peruvian Paso, as a breed, is a very tough, durable and sound breed of horse
when compared to all the other breeds of horses we see at Alamo Pintado Equine
Medical Clinic." Doug Herthel DVM, Mark Rick DVM, Greg Parks DVM, Ed Hamer,DVM.
Judy Carter DVM.
is the control horses chart used in the Dr. Halper study.
is the list of DSLD affected Peruvian Paso horses. The Proteoglycan levels are
very similar to those of the control horses.
charts are the summary of Dr. Halpers study.
According to Dr. Halper,
the accumulation of unidentified proteoglycans throughout the body is what makes
DSLD a systemic disease and the accumulation of this proteoglycans in the nuchal
ligament is where a biopsy can be taken for a DSLD test. This test was described
as a breakthrough in a national press release.
However, by simply
looking at Dr. Halper's own charts we can see that the unaffected Peruvian control
horse has this accumulation in as many places as the affected horses and five
of seven of the unaffected control horses would test positive with a nuchal ligament
biopsy. Also all of the young horses had one or both of their parents broken down,
which could only mean that these breeders were breeding broken down horses to
each other and producing broken down offspring
a not very surprising result.
As the vets at Alamo Pintada say "don't breed bad legged horses, to bad legged
horses and the problem goes away."
Also included is a e-mail
from someone who had a necropsy done by Dr. Halper and was told her mare had extensive
DSLD but had NO accumulation in the nuchal ligament or any of the other organs.
#2 Veterinarian database Search
is the actual data from the veterinary schools recording INJURY not DSLD.
is an example of how faulty research creates misinformation and how it can hurt
our Peruvian horse breed for years.
This is a data base search of
suspensory INJURIES; suspensory ligament desmitis, suspensory ligament sprain
and suspensory ligament rupture, in veterinary colleges in North America. These
are injuries, they are not codes for disease, and there is nothing in these statistics
that normalizes them to a population, only to the horses injured. However, by
the time we have finished reading this survey, these horses have been diagnosed
with suspensory ligament disease and Peruvian horses have the second highest percentage
of this disease, just below Standardbreds.
What do these statistics
really show? That there were only 24 suspensory injuries reported to these veterinary
colleges for Peruvian Paso horses, over a ten year period
and that's all.
research was done in 2002 and was taken from the DSLD/ESAD information web page
This misinformation has been referenced many times, including
the PPHRNA RAM meeting in 2003 and , most recently, in an article on gaited horses
in Horseman News (October 2005). It is part of the Golden Gaited web site and
is used in describing Peruvian Horses.
Below are results of a query of the Veterinary
Medical Data Program, done by Alice J. Wolf. DVM., DACVIM, DABVP. Information
is compiled from veterinary colleges in North America. The data below represents
a survey of 10 years of data from 1987 -1997. the percentages come from a comparison
of all the horses of each breed that were brought to these schools for any problem
to the number that were subsequently diagnosed as having suspensory ligament disease.
That normalizes the percentages to the number of horses in the population.
query specifically searched for the following diagnoses: Suspensory ligament Desmitis,
Suspensory Ligament Rupture, Suspsensory Ligament Sprain, and Suspensory ligament
Laxity. At the time of this query, there were the only codes for suspensory ligament
disease in the veterinary computer databae Breeds are listed by frequency of incidence
for these problems. Breeds where no individual was diagnosed with suspensory ligament
disease are not listed. Breeds with less than 10 individuals seen per year are
also not listed as the number is statistically insignificant.
Return to the Equine Suspensory Apparatus Dysfunction home page.
report went on for several more pages providing copies of misleading letters posted
to Dr. Mero's web site and other distorted articles giving misleading information
on various web pages of so called "experts" in the horse world. These
erroneous reports, documents, letters and internet comments are all based upon
the distortion of documentation created from the original injury data collected
over a ten-year period from all the veterinary hospitals in the United States.
Data is only as good as the compilers integrity. To leave out bits or to change
factual evidence is to give a misleading impression of the situation.
the distortion continues so does the request from many of those publishing this
data out of context for contributions to fund further research for themselves.