Marion Dupont Scott Equine Medical Center Announces 2006–07 “Tuesday Talk” Schedule
Article Outline
- Morris Animal Foundation—Your Donations at Work: for Horses
- Equine Consortium Hits the Trails
- Exercise Study Reveals Anatomical Potential for Fetlock Injury
- Learning to Breathe Easier
- Seasonal Tying-up: Toxins or Deficiency?
The Marion duPont Scott Equine Medical Center has announced its 2006-07 “Tuesday Talks” schedule. This series of lectures is designed to provide veterinarians, horse owners, and horse professionals with valuable insight and practical advice related to a wide array of equine health care topics.
“Equine Neurological Issues Over the Life Course”—December 5, 2006, by Martin O. Furr, DVM, PhD, Diplomate ACVIM, Adelaide C. Riggs Chair in Equine Medicine, Marion duPont Scott Equine Medical Center.
“Acupuncture and Pain Relief for Horses”—January 16, 2007, by Alison A. Smith, DVM, Diplomate ACVA, Clinical Assistant Professor in Anesthesia, Marion duPont Scott Equine Medical Center.
“New Treatments for Equine Tumors”—February 13, 2007, Kenneth E. Sullins, DVM, MS, Diplomate ACVS, Professor of Equine Surgery, Marion duPont Scott Equine Medical Center.
“Detecting and Treating Lameness”—March 6, 2007, Nathaniel A. White, II, DVM, MS, Diplomate ACVS, Jean Ellen Shehan Professor and Director, Marion duPont Scott Equine Medical Center.
All “Tuesday Talk” lectures will be held at 7:00 pm in the Marion duPont Scott Equine Medical Center's library. No fee is charged for attending, but seating is limited and pre-registration is required. To register, e-mail Amy Troppmann at atroppmann@vt.edu or call (703) 771-6843. Additional information regarding the center and its services is available online at www.equinemedicalcenter.net.
The Marion duPont Scott Equine Medical Center is a Leesburg, Virginia-based full-service equine hospital that is owned by Virginia Tech and operated as one of three campuses that constitute the Virginia-Maryland Regional College of Veterinary Medicine.
The Virginia-Maryland Regional College of Veterinary Medicine (VMRCVM) is a two-state, three-campus professional school operated by the land-grant universities of Virginia Tech in Blacksburg and the University of Maryland at College Park. Its flagship facilities, based at Virginia Tech, include the Veterinary Teaching Hospital, which treats more than 40,000 animals annually. Other campuses include the Marion duPont Scott Equine Medical Center in Leesburg, Virginia, and the Avrum Gudelsky Veterinary Center at College Park, home of the Center for Government and Corporate Veterinary Medicine. The VMRCVM annually enrolls approximately 500 Doctor of Veterinary Medicine and graduate students, is a leading biomedical and clinical research center, and provides professional continuing education services for veterinarians practicing throughout the two states. Virginia Tech, the most comprehensive university in Virginia, is dedicated to quality, innovation, and results to the commonwealth, the nation, and the world.
This story can be found on the Virginia Tech News website: http://www.vtnews.vt.edu/story.php?relyear=2006&itemno=631
For more information, contact: Marjorie Musick (703) 771-6881, mzmusick@vt.edu
Morris Animal Foundation—Your Donations at Work: for Horses
For 2007, thanks to our generous donors, Morris Animal Foundation will grant $4.3 million to leading veterinary scientists worldwide to tackle many of the animals' most urgent health problems. Here is a brief look at two of the studies your donations are helping to fund. Together, we are making a difference for animals.
Eye Infections—Investigator: Dr. James K. Belknap, The Ohio State University, Status: Year 1 of 1
What is it? Horses with corneal trauma or ulcers are also prone to secondary corneal infections called fungal keratitis. If not treated quickly, this disease can cause loss of eyesight and even of the eye itself. Early detection of this fungal disease is critical to saving the health of the eye. Unfortunately, current tests take up to 4 weeks for an accurate diagnosis. By then, the horse's eye may be too damaged to treat.
How will this study help? Investigators hope this study can establish a test that will provide an accurate and more timely diagnosis of the disease. The team will compare corneal DNA of horses with fungal keratitis with the corneal DNA of horses with healthy eyes to determine the normal levels of fungal organisms in the horse's eye. Once they have determined these parameters, they hope to develop a clinical test for infection that would provide a faster diagnosis and increase the chances of preserving the vision of horses with fungal keratitis.
Pain Management—Investigator: Dr. Bernd Driessen, University of Pennsylvania, Status: Year 2 of 2
What is it? The alleviation of pain is an important aspect of equine orthopedic and trauma surgery because it decreases stress and reduces postoperative complications. Also, when horses experience pain in their distal forelimbs or hind limbs, they frequently overload the opposite limb with weight, which puts the normal leg at risk for laminitis. Currently, long-term pain management in horses suffering from tissue injury in their front limbs involves giving the horse anti-inflammatory drugs. These drugs are often ineffective and are also associated with harmful side effects.
How will this study help? Horses with injuries to their hind limbs are often treated with local analgesic techniques, such as epidural analgesia, but this method is not available for pain originating in the forelimbs. Investigators hope to develop a simple and safe technique for placing continuous nerve-block catheters along nerves in the horse's forelimb that will be used to deliver a continuous infusion of different local anesthetics. Continuous infusion has the potential to effectively obliterate pain without impairing motor function. By receiving maximum comfort and better conditions for tissue healing, horses who have undergone surgery can recover more quickly and painlessly.
Reprinted with the permission of Morris Animal Foundation Animal News, Vol. 6, No. 4, 2006.
Equine Consortium Hits the Trails
Horses, horse owners, and equine veterinarians and scientists have reason to celebrate with the launch of Morris Animal Foundation's Equine Consortium for Genetic Research grant. We have selected the University of Minnesota's College of Veterinary Medicine to receive the $2.5 million in funding for the Foundation's first-ever multimillion dollar equine consortium grant.
The proposed Equine Consortium for Genetic Research will be led by University of Minnesota equine professors Jim Mickelson and Stephanie Valberg, both recipients of previous Foundation grants. A total of 32 scientists from 18 elite academic institutions throughout nine countries will collaborate on the project's development and completion. The University of Minnesota pre-proposal received the highest score out of 27 multi-institutional applications reviewed by our ad hoc scientific board.
Because genetic diseases affect horses of every breed, this project has tremendous potential. The research team will use the sequenced horse genome to identify genes and mutations that contribute to heritable diseases, such as musculoskeletal disease, laminitis, recurrent airway obstruction, and bone disease.
“This project will benefit the entire horse industry, offer new diagnostic and therapeutic approaches to reduce animal suffering, and promote equine health and welfare,” says Dr. Mickelson, consortium director. “We will be able to do for the horse what we already can do for human and canine research.”
You Can Help. For information on donating to this critical project, please contact Deborah Tatum at 859-268-4778 or e-mail her at dtatum@MorrisAnimalFoundation.org. One hundred percent of your gift to the Equine Consortium for Genetic Research will go directly toward funding this project.
Reprinted with the permission of Morris Animal Foundation Animal News, Vol. 6, No. 4, 2006.
Exercise Study Reveals Anatomical Potential for Fetlock Injury
by: Erin Ryder, TheHorse.com December 2006, Article #8259
Previous studies have shown that bones develop to suit the purpose routinely required of them; therefore, would young horses in regular work from the time they are foals have stronger musculoskeletal tissues than those left to mature in pasture? Chris Kawcak, DVM, PhD, Dipl. ACVS, and the Global Equine Research Alliance researched this issue. Kawcak presented their findings regarding osteochondral tissues at the 15th Annual Kentucky Equine Research Conference.
The group divided 33 Thoroughbred foals into exercise and pasture groups. The exercise group was conditioned 5 times per week from 10 days to 18 months of age, increasing the speed of the workouts over time as the foals grew. This group of foals was turned out in pasture when not in work. The other group also grew up in a pasture environment but was not asked to work.
Study results were mixed. The researchers used a technique called confocal laser scanning microscopy, which scanned the horizontal layers of cartilage and showed live and dead cells as points of different color. This technology showed that the horses in the exercise group had 14% more viable cells on the surface of the cartilage in the fetlock joint, which was the area under scrutiny in this study. However, this difference in cell makeup did not appear to have any effect on the cartilage's function or structure.
Whereas the data on osteochondral tissues did not show a strong trend for or against early exercise, the research did reveal an anatomic anomaly that could be a major factor in catastrophic injuries.
Horses in both groups showed a marked density pattern that might help to explain why condylar fractures occur. Within the fetlock joint there is a prominence of bone called the sagittal ridge. Researchers found that bone density and cartilage quality are at their worst in the parasagittal grooves (depressions on either side of the ridge)—precisely where the majority of condylar fractures occur. This finding was consistent in both the exercised and pastured groups of young horses. Cartilage in this area also showed degeneration, leading the researchers to conclude that this is an area prone to damage and that early exercise was neither protective nor damaging to that area.
The researchers measured bone density using a computed tomography (CT) scanner, with files exported to a custom-designed program for three-dimensional analysis of the joint. This program allowed the researchers to analyze disarticulated joints from all angles.
“I don't know that there's anything we can do to protect that condylar area,” Kawcak said. “But at least we know (exercise) didn't hurt them.”
Although this report covered only the osteochondral tissues, results of the tendon and ligament analyses are pending. Half of the horses from each group have gone on to racing careers under a trainer who is unaware of which group each horse belonged to in the study. Kawcak says the results of that portion of the study should be available next year.
Reprinted with permission of The Horse; visit www.TheHorse.com for more horse health news.
Learning to Breathe Easier
by: Christy West, TheHorse.com December 2006, Article #8254
When your horse has heaves or inflammatory airway disease, you often feel utterly helpless. As he stands there with his head low, huffing and puffing, what can you do to quickly help him breathe easier?
Sarah Gardner, DVM, PhD, Dipl. ACVIM, associate professor in Equine Medicine at North Carolina State University (NCSU), is trying to find out. Her research investigates the pathophysiology of heaves, treatments, and delivery devices for those treatments. Her current work on a novel delivery device and medication for heaves is not ready to be discussed yet, but her insight into heaves and inflammatory airway disease from her past research, clinical work, and pulmonary (lung) function testing service can help horse owners better understand the disease. And she is part of an ongoing discussion among veterinarians about a possible link between airway disease and anhidrosis (failure to sweat; more on that shortly).
Heaves and Inflammatory Airway Disease
Both of these conditions compromise a horse's breathing, although in different ways. Heaves is generally more severe and affects older horses, and inflammatory airway disease (IAD) affects younger horses and is often mistaken for a poor physical response to training. Luckily, the more severe heaves condition is less common.
“Abattoir (slaughter horse) studies have shown the prevalence of heaves to be up to 12%,” says Gardner. “Other studies in young Thoroughbred and Standardbred racehorses have shown the prevalence to be 22–50% for IAD; it is quite high.
“We do not know as much about IAD as we do heaves, because it is much more recently recognized,” she adds. “But it has a lot of similarities to heaves. Probably allergens are involved, as well as other dust particles that cause a nonspecific inflammatory response or airway hyperreactivity. There is probably a lot more IAD out there than we recognize, but it is just seen as exercise intolerance and cough. If a horse is working at a low level, his condition might not be noticed, but when he starts working harder, then his pulmonary limitations show up.
“In clients' horses here (at NSCU), primarily what we see is IAD,” she reports. “We do not often see outright heaves; usually the horse we see only has signs of exercise intolerance or cough. Those horses we are able to tease out (find) with our pulmonary function testing service.”
Pulmonary Function Testing
When a horse undergoes a pulmonary function test at NSCU, his pulmonary resistance—the ease with which air flows in and out of his lungs—is measured. “In a normal horse with nice, wide-open airways, resistance is very low, whereas in a horse with bronchoconstriction or airway obstruction associated with pus, mucus, or fluid within his airway walls, the airways will be small and have increased resistance to airflow,” explains Gardner.
Once a horse's baseline pulmonary resistance is measured, he will receive a dose of histamine (which causes bronchoconstriction and increased pulmonary resistance) via nebulizer (a medication inhalation device), then he will be tested. Then he will get a double dose and be retested; this process repeats until his airway resistance doubles. The entire test takes about 30 minutes.
“A normal horse will double his baseline pulmonary resistance at a concentration of histamine greater than 6 mg/ml,” she says. “A horse is defined as having airway hyperreactivity if he doubles his baseline resistance below 6 mg/mL.
“If a horse has an elevated initial baseline resistance (ie, has heaves), we do not do a histamine challenge test,” she continues. “Instead we will do a bronchodilator challenge test (using medicine that opens airways). That gives us an idea about the reversibility of the bronchoconstriction and is also an indicator of how he will respond to that bronchodilator if you prescribe it.
“For a horse with heaves, pulmonary function testing can help you monitor response to therapy, and for a horse with IAD, it can help you diagnose him and monitor his response to therapy,” she explains.
Additional testing includes bronchoalveolar lavage or “washing” a part of the lung and collecting the fluid to evaluate inflammatory cells (and other cells) present in the lung. Horses with IAD will have an elevated level of inflammatory cells. Radiographs might be done to evaluate lung structure, and a complete blood count also might be done to rule out infection.
“If I were buying a decent upper-level adult performance horse, I would want (Gardner) to test him in the pre-purchase examination,” says Dick Mansmann, VMD, PhD, clinical professor and director of NSCU's Equine Health Program. “You are going to put years of investment in him, and you are hoping to go to Rolex, the Olympics, or whatever high-level competition, and the last thing you need is a horse that has hyperreactive lungs and cannot be around hay with all the traveling and training.”
What tells you to consider calling a veterinarian to evaluate your horse's lung function? Gardner suggests:
Managing Heaves/IAD
These respiratory diseases are very hard to manage, primarily because of lack of owner compliance or inability to comply based on management situation, says Gardner. She recommends the following for affected horses:
“Many times, if these horses' environments are managed, they do not need to be treated with drugs,” says Gardner. “That is always my goal. In some cases, management does not allow that, and pasture-affected horses usually need some type of treatment (generally a steroid, and possibly a bronchodilator).”
Airway Disease versus Anhidrosis?
“When most people see a horse that is breathing hard, they think pulmonary disease, but in fact he might not be sweating (partially or completely anhidrotic) and he is just trying to cool down,” says Mansmann. “And his heart rate is going to be high. This is certainly a major problem in the South. Some people believe these (anhidrotic) horses have a higher incidence of heaves and other respiratory disease, and that there might be an actual tie between the mechanisms of nonsweating and some form of chronic respiratory disease.”
“Several horses I have seen had both IAD and partial anhidrosis,” comments Gardner. “When I take a horse's history, I really question the owner about how much the horse sweats. The sedative we give during a pulmonary function test induces sweating, so it is a nonspecific test as to whether the horse sweats. If he does not sweat during his test, I am always suspicious of anhidrosis. We have a hard time determining whether these horses' (respiratory) problems are due to partial anhidrosis (panting to cool down) or IAD (panting to get enough air), especially during summertime.”
Is there really a link between respiratory disease and anhidrosis? No one knows yet, but perhaps research in respiratory laboratories such as Gardner's at NCSU will one day provide an answer.
Reprinted with permission of The Horse; visit www.TheHorse.com for more horse health news.
Seasonal Tying-up: Toxins or Deficiency?
by: Chad Mendell, TheHorse.com December 2006, Article #8293
In Minnesota, cases of pasture myopathy (muscle disease caused by pasture) associated with severe non–exercise-induced rhabdomyolysis (also know as tying-up) are often attributed to the toxins found in white snakeroot. However, researchers at the University of Minnesota said factors other than white snakeroot could be causing the syndrome.
“In Europe, there is a condition called ‘atypical myopathy’ (AM) that is characterized by the same clinical signs as white snakeroot toxicity,” explained Carrie Finno, BSc, DVM, one of the researchers involved in the study (she is now a resident at the University of California, Davis). “However, the white snakeroot plant is not found in Europe.”
Atypical myopathy is often reported during the fall months after inclement weather. The study horses (14 in all) had clinical signs similar to the European cases, which included sudden muscle stiffness that progressed to the point that the horse was unable to stand, and this often resulted in the death of the horse.
“The other striking similarity between our cases and cases of AM is that they all occurred during the fall months (September–November) when there was often inclement weather,” she said.
Specific causes for atypical myopathy are still unknown, but weather-related toxin accumulation in pasture plants is thought to be the cause. Changes in weather can cause plants to store nutrients or toxins in higher concentrations than they would normally, as a defense mechanism against the elements. This usually causes the plant to be less desirable to horses; however, in situations where food is scarce, horses might still eat the plant.
Finno said her greatest concern with pasture myopathy is the fact that signs can progress rapidly.
“The progression is very fast, with most horses becoming recumbent in less than 12 hours without treatment,” Finno said. “Any horse with signs of pasture myopathy should be treated aggressively with intravenous fluids, antioxidants, and anti-inflammatories because the progression of the condition is rapid and often fatal.
“In pastured horses in the Midwest, it is important to supplement their diet with hay in the fall, as grass becomes scarce, to discourage the horses from grazing on less palatable—and potentially toxic—plants,” Finno said. “Pasture myopathy should be considered in any horse that is housed primarily on pasture in the Midwest and presents with the following clinical signs: dark red urine, muscle fasciculations, overall weakness, or recumbency, and signs of colic or choke.”
Researchers who completed the study published in the Oct. 1 issue of the Journal of the American Veterinary Medical Association were Finno; Stephanie Valberg, DVM, PhD, Dipl. ACVIM; Arno Wunschmann, Dr.Med.Vet., Dipl. ACVP; and Michael Murphy, DVM, PhD.
Reprinted with permission of The Horse; visit www.TheHorse.com for more horse health news.
PII: S0737-0806(07)00004-4
doi:10.1016/j.jevs.2007.01.002