Equine Center > Research > Breakthrough Research
Breakthrough Research
Breakthrough Research into Horse Health at the University of Minnesota Equine
Center.
The University of Minnesota's internationally recognized equine research
program includes equine genetic diseases, equine muscle diseases, equine gastrointestinal
diseases,equine infectious disease, pain management in horses, lameness, ultrasonographic
diagnosis for horses, neonatology for horses, and infertility in horses. These
research projects use the vast resources only available from the University
of Minnesota through its numerous Colleges and research centers. Faculty at
the College of Veterinary Medicine in areas such as endocrinology, internal
medicine, orthopedics, colic, exercise physiology and genetics are collaborators
on many groundbreaking studies. Diabetes, Obesity, Muscle Disorders, Musculoskeletal
Research, and Nutrition faculty members within the Academic Health Center participate
in this interdisciplinary approach groundbreaking equine research.
There can be no doubt that advances in the area of equine molecular genetics,
equine nutrition, pain management in horses, when done at an interdisciplinary
level, will have significant implications for all aspects of the horse industry.
For example, an accurate and simple DNA diagnostic test would facilitate a
specific diagnosis of tying-up in many breeds of horses and help horse owners
make informed choices with regard to the purchasing, managing, and breeding
of these horses.
It is very likely that other major genetic disorders of the horse can be better
understood with gene-mapping approaches. Identification of the specific genes
causing any of these disorders could also lead to development and selection
of specific medications to treat the conditions. Advances in equine nutrition,
based on research done in many disciplines, has resulted in applicable therapies
for a debilitating equine disease. Specifically, a high fat, low starch diet
in RER horses results in significantly lower insulin and blood glucose responses
to a meal and significantly less muscle damage during treadmill exercise compared
to a low fat high starch diet. These and other advancements are critical to
equine medicine and place the University of Minnesota’s College of Veterinary
Medicine at the very forefront of equine research worldwide.
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Development of the Equine Genome Map
: Researchers
at the College of Veterinary Medicine Equine Center have played a leading role
in the development of the equine genome map. An international working group
signed on to participate in the Equine Genome Project in 1995. Ten years later
a map of the genes and genetic markers on all the horse's chromosomes was published
with new information being added constantly to provide a detailed description
of DNA sequences in the horse. Leading researchers in this area are Dr. Jim
Mickelson and Dr. Stephanie Valberg, both faculty members at the University
of Minnesota Equine Center.
This area of research is very important in helping researchers understand
the genetic contribution to all biological processes in the horse, including
the development and predisposition to disease. Published studies by
various research centers use gene map information to investigate skin diseases
in Belgian and Saddlebred horses, muscle diseases, developmental bone disease,
allergies, immunity to viral and bacterial diseases, as well as coat color
and physiological processes related to performance in horses. Deriving
meaningful knowledge from the equine DNA sequence will define research through
the coming decades and expand our understanding of biological systems. This
enormous task requires the expertise and creativity of tens of thousands of
scientists from varied disciplines in both the public and private sectors worldwide. |
| Mapping the horse genome |
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| Overo Lethal White Syndrome (OLWS) Overo
Lethal White Syndrome (OLWS) is a condition that occurs in newborn Paint Horse
foals. OLWS foals have blue eyes and are completely or almost completely white
at birth. For the first day of life the foals appear to be normal, however,
soon thereafter they develop signs of colic because of the complete inability
to pass feces. There is no treatment for OLWS, as the entire intestine in these
foals is underdeveloped. For many years, breeders believed this condition was
inherited, but no genetic tests were available to determine if a horse carried
this trait. Research conducted in Dr. Mickelson's laboratory
at the University of Minnesota identified the genetic cause for OLWS and formed
the foundation for a genetic test. (The test has been licenced to
the University of Califoria, Davis, Veterinary
Genetics Laboratory. Further
research showed that a particularly common coat color pattern in Paint Horses
called Frame
Overo is highly associated with carrier status. The
defective gene is found in American Miniature Horses, Half-Arabians, Thoroughbreds,
and Quarter Horses with too much white to qualify for registration. An informative
PowerPoint presentation on the genetics of coat color can be downloaded here.
(You must have a recent version of MicroSoft PowerPoint installed on your computer
to view the presentetion.) |
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OLWS |
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Glycogen Branching Enzyme Deficiency (GBED) is a disorder found in
horses that was first recognized by clinicians at the University of Minnesota
Equine Center. This disorder causes muscle weakness in Quarter Horse
and related breeds. The clinical presentation of this disease is variable.
Late term abortion or stillbirth occurs with GBED. Some foals are born alive,
but are often weak and require warming and assistance to nurse after birth.
These foals may appear healthy for a time, but eventually the may develop
seizures, become too weak to stand, or in some cases, die suddenly. Owners
may note that GBED foals are less active than other foals. In spite of aggressive
treatment, all known cases of GBED were fatal by 18 weeks of age. Dr. Stephanie
Valberg's laboratory recognized that foals with these symptoms have
a unique muscle disease and that all these foals are related to one another.
The discovery of an abnormal sugar within the skeletal muscle of these foals
led the researchers to identify a genetic defect (glycogen branching enzyme
gene) responsible for forming the sugar (glycogen) that provides energy for
numerous tissues in the body. Now owners are able to test their horses to
see if they carry this defect and this can prevent this disease from occurring.
Click here for
more information. |
| GBED |
| More information is available at the Neuromuscular
Diagnostic Laboratory |
| Polysaccharide Storage Myopathy (PSSM) and Recurrent
Exertional Rhabdomyolysis (RER): Researchers identified two distinct forms of "tying-up" that have a familial (genetic) basis. Approximately 5% of Thoroughbred horses suffer from RER, particularly at a young age. Many of these horses are
descended from a common stallion, and computer modeling of these pedigrees provides strong evidence for RER being an autosomal dominant disorder in these families and this breed. Also identified was a form of ER in an extensive Quarter Horse pedigree, characterized by exercise intolerance and the accumulation of an unusual polysaccharide in muscle fibers. This disease
is called polysaccharide storage myopathy. |
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| | Tying-up can affect the performance
of the equine athlete |
EQUINE NUTRITION
Diets for horses with Muscle Disorders
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"Tying-up" is a muscular problem that affects all types of horses.
In its mild form, symptoms may only be muscle cramping, but in severe cases
horses are unable to rise, and may die. Historically the cause of tying-up
was a mystery. Research by Dr. Stephanie Valberg at the University of Minnesota
has now identified several specific causes for tying-up. Polysaccharide
storage myopathy (PSSM) is a common cause of tying-up in Quarter Horse
and related breeds, Warmbloods and draft breeds, among others. Recurrent
exertional rhabdomyolysis (RER) is the most common form of tying-up
in Thoroughbreds, Arabians and Standardbred horses. More information on these
diseases is available at the Neuromuscular
Diagnostic Laboratory.
A breakthrough in the management of tying-up has occurred with the discovery
that lowering dietary starch and increasing dietary fat can significantly improve
the signs of muscle pain in both PSSM and RER horses. Most equine diets contain
grains that are naturally very high in starch. Researchers at the University
of Minnesota, together with nutritionists at Kentucky Equine Research developed
a low starch diet that can supply adequate energy for highly competitive athletes
by substituting starch with natural plant oils. This equine feed (called
Re-Leve™), when combined with regular daily exercise, can practically
eliminate the signs of tying-up in most horses.
The University of Minnesota has licensed Hallway feeds to sell this
product Re-Leve™. |
| Re-Leve was formulated to treating horses with tying-up |
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PAIN MANAGEMENT FOR HORSES
Equine Epidurals
An epidural is the placement of a catheter or spinal needle directly into
the fluid that bathes the spinal cord. It is a common procedure used to control
the pain of childbirth. Anesthesiologists Drs. Natalini and Rude at the University
of Minnesota Equine Center evaluated several different drugs that are safe
to administer over several days as an epidural to control hind limb pain in
horses. Horses with severe hind limb trauma, fractures, joint infections and
laminitis often need a higher level of pain control than can be provided by
commonly used medications such as phenylbutazone. Controlling pain promotes
healing in these horses by decreasing stress. Horses can also bear weight on
both limbs, which prevents the healthy leg from developing laminitis and ligament/tendon
breakdown due to overuse. |
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| Equine sports medicine and performance
in equine athletes |
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IV Lidocaine infusion for reflux and pain management in horses
Investigators at the University of Minnesota Equine Center studied the effects
of intravenous lidocaine infusion on horses with reflux. Reflux is the accumulation
of intestinal secretions in the horse's stomach due to diseases that
disrupt normal intestinal motility. Disrupted motility can occur because of
infections and colic, and is a complication of intestinal surgeries. Since
horses are unable to vomit, the build up of fluid can lead to stomach rupture.
Until gut motility returns to normal, horses cannot eat, drink, or take oral
medications. Previously, veterinarians needed to place a stomach tube every
few hours to relieve the fluid accumulation and prevent the stomach from rupturing.
To find a better way to help horses with poor intestinal motility, Dr. Erin
Malone performed a worldwide multicenter trial to evaluate a constant rate
of intravenous lidocaine infusion as a treatment for motility issues. Horses
on an intravenous infusion of lidocaine became much more comfortable and the
intestinal motility improved significantly. This now widely used treatment
is inexpensive and safe in the hospital environment.
Controlling horses in a great deal of pain safely can be very difficult, and
horses can hurt themselves if they have violent reactions to pain. Traditional
drugs such as banamine or phenylbutazone may not be sufficient to control pain
in horses that are very ill. Lidocaine is traditionally used as a local injection
to deaden sensation in the skin before suturing cuts or around nerves or in
joints to determine sites of pain in lame horses. One of the discoveries made
because of Dr. Malone's research into intestinal motility in colicky
horses was that intravenous lidocaine infusion had a major impact on controlling
the horse's pain as well. As a result, a constant rate of infusion of
lidocaine is now commonly used in practice to treat horses with unrelenting
pain (severe laminitis, horses with muscle injury or tying up or postoperative
pain). It has proven to be reliable, nonaddictive, and inexpensive.
Pain Management University researchers demonstrated
that unrelenting pain in horses can be controlled by administration of medications
via an epidural catheter. In addition, a constant infusion of lidocaine intravenously
was found by University researchers to have a dramatic effect on decreasing
pain and increasing intestinal motility in horses suffering from intestinal
infections, colic and complications of intestinal surgeries. These treatments
are now in use worldwide.
LAMENESS STUDIES IN HORSES
Shockwave therapy for horses
Many veterinarians speculate that shock wave therapy works by causing bone
to remodel, however, the results of this study suggest that there is no evidence
of changes in blood flow or bony remodeling from shockwave therapy. The study
used thermography, radiography, and scintigraphy (bone scans) technology for
gathering data on bone remodeling and blood flow. The investigators conclude
that the beneficial effects of shockwave therapy may be the result of effects
on the nerve supply to the area providing pain relief rather than a direct
effect on the bone itself. Shockwave therapy is one of the treatments developed
to treat horses with a variety of musculoskeletal diseases. Although many people
are convinced of its value in the treatment of lameness, there is little scientific
information in horses to show how or if it works. Dr. Mauro Verna and Dr. Kari
Anderson at the University of Minnesota investigated the effect of shockwaves
on the cannon bones and on the neurovascular bundles in the lower limbs of
healthy horses. Shockwave therapy was proven safe to apply over the closely
united bundle of blood vessels and nerves that supply the pastern and hoof.
Ultrasonographic Diagnosis of Ligament Injuries in the Hoof
Clinicians at the University of Minnesota recently identified a new cause
of lameness in horses that had previously gone unrecognized. Dr. Abby Sage
developed a means to perform ultrasonography on ligaments within the hoof of
the horse. With this new mechanism to examine the ligaments stabilizing the
coffin joint, researchers found a number of horses that were lame due to ligament
strain in the hoof. Recognition of the syndrome and technique for diagnosis
has helped numerous veterinarians identify and treat this lameness.
REPRODUCTION
Endometritis
University researchers identified
a new treatment, the administration of oxytocin, for alleviating post-breeding
uterine inflammation. This therapy has improved mare fertility. In addition,
seminal plasma was found to have a protective effect on post-breeding uterine
inflammation. Collaborations between clinicians and scientists at the University
of Minnesota Equine Center have been instrumental in identifying the cause
and potential treatments for post-breeding endometritis in mares.
This condition, which affects approximately 13% of broodmares, is a major cause
of infertility and decreased reproductive efficiency in horses. University
researchers identified a reduced level of uterine contraction in these mares.
These researchers led a collaboration to explore the mechanisms of post-breeding
uterine inflammation, its effects on the inseminated sperm, and ways to treat
mares and increase their fertility.
Research performed by Dr. Scott Madill, in collaboration with researchers
from New Zealand, identified physiologic levels of oxytocin released
naturally in the mare around the time of breeding. Subsequently, they
conducted a dose-response trial of injected oxytocin to determine the most
appropriate therapeutic dose and schedule. In other projects, members of the
group found that a widely used prostaglandin-based therapeutic option actually
decreased pregnancy rates in mares, resulting in dose and schedule modifications
for equine practitioners.
Dr. Abdo Alghamdi and Doug Foster have examined the interaction between sperm
and the uterine inflammatory response and demonstrated that seminal plasma
has a protective effect on uterine inflammation post-breeding in mares.
They have published the results of their breakthrough in identifying the molecular
mechanisms behind this phenomenon in horses. The next phase of this research
involves a clinical trial, funded by a University of Minnesota Equine Center
grant, to assess the effect of the identified seminal plasma component on uterine
inflammation and fertility in mares.
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