Canadian Equine Research
The University of Guelph, located in Ontario, Canada, is home of the world renowned Ontario Veterinary College (OVC). The university is a research-intensive and student-oriented facility. Its written mission is to serve society and to enhance the quality of life through education with a global perspective. The university offers a wide range of programs, both theoretical and applied, disciplinary and interdisciplinary, undergraduate and graduate, in the arts, humanities, social sciences, as well as professional fields. Among these programs, it recognizes agriculture and veterinary medicine as areas of special responsibility.
Wayne McDonnell, DVM, PhD, of research and graduate affairs, said the Ontario Veterinary College attracts the highest-quality students, faculty, and staff because of the research conducted at the institution and the reputation of the OVC. The University offers the degree program Doctor of Veterinary Medicine (DVM), with classes being offered in the fall and spring semesters. According to McDonnell, the summer months are dedicated to research.
Objectives of the veterinary program, according to university literature, are to "Teach students the ability to solve animal health problems and provide them the understanding of management of domestic animals. Graduates also must be able to communicate effectively in writing and speaking."
The university’s veterinary program is accredited by the Canadian and American Veterinary Medical Associations and by the Royal College of Veterinary Surgeons of Britain. A DVM degree from Guelph is respected by veterinarians throughout the world.
Veterinary Teaching Hospital
An important aspect of the OVC is the Veterinary Teaching Hospital (VTH), said Laurent Viel, DVM, who is the spokesman for the research conducted at the OVC. The VTH is one of the largest and best-equipped centralized veterinary facilities in North America. The hospital acts as an extension of the private clinic system and provides practitioners a resource when intensive care or specialized facilities and experience are required to care for a horse.
In most cases, animals which enter the hospital are referral cases originating from outside veterinary practices. Cases referred to the VTH usually are in need of hi-tech equipment and specialized expertise to treat any number of problems ranging from life-threatening illnesses to reproductive disorders.
It is stated in university literature that, "Providing quality care for our patients is the hospital’s highest priority, and as we heal, future generations of veterinarians learn to follow the same high standards. The VTH has a mandate to teach undergraduate veterinary students, interns, and residents. The development of new treatment methods also is a vital goal. As a result, we depend upon referrals to provide an adequate and varied caseload."
The VTH is broken into three areas. The hospital offers services for large animals, small animals, and ruminant and swine field services. The staff of the Large Animal Clinic treats about 2,000 patients a year, with 75% of those patients being equine. In all of those cases, large animal included, care is provided by a team of clinicians, specialists, animal health technicians, and supervised senior veterinary students. By using this approach, the OVC can ensure the quality care today and in the future. The staff members at the hospital are in the forefront of their respective fields due to research they conduct, as well as teaching, and consulting duties.
Under the guidance of McDonnell and Viel, the OVC is continually producing studies that benefit the horse and its owner.
Viel is very active in research concerning airway diseases. He also was a key organizer in coordinating and carrying out the recent World Equine Airways Symposium that was held at the OVC (see The Horse of October 1998 ). Viel’s research, which he presented at the symposium, includes findings about a horse’s ability to breathe.
Viel believes that one of the unique characteristics of upper airway problems is that the condition affects all horses. In 1995, the University of Guelph’s researchers invented the Equine AeroMask. The AeroMask has changed the way small airway disease (SAD) in young horses and (COPD)—the long term result of SAD which is found in older horses is treated.
Viel said, "Horse owners know COPD or SAD as a condition called heaves, affecting up to 60% of all horses at some point. Similar to human asthma, heaves is caused by an overactive immune system. Attacks occur when the muscles inside the airways constrict in response to external stimuli such as dust, pollen, mold, cold or dry air."
The AeroMask makes use of metered-dose treatments commonly used in humans as an inhaler or "puffer." These metered treatments contains medication to control inflammation or to relax the airway to let normal breathing resume. The mask covers the nose and mouth of the horse, therefore directing the medication to the animal’s lungs where it is most effective.
In the last few years, new research on airway diseases has been instrumental in bringing to the market new and more potent brochodilators for the treatment of these diseases. New medications have proven more effective in treating airway disease in part because they are administered directly into the airway of the horse and no longer have to be injected into muscle. This method causes minimal side effects while more effectively treating airway inflammation. Viel currently is engaged in researching this treatment for respiratory problems.
In order to make anesthesiology safer for horses, Wayne McDonnell, DVM, PhD, MS, and researchers are evaluating the sedative romifidine (trade name Sedivet). Researchers are refining the application process of romifidine to further reduce the risk equine anesthesiology posses.
McDonnell said, "We studied the cardiovascular function of horses during the sedative’s use as a premedication before ketamine--a general anesthetic. We’ve looked at sleep induction, duration, and recovery characteristics resulting from the combined use of romifidine and ketamine."
"We found that romifidine, used on its own and in combination with other drugs, produces fewer negative effects than the most commonly used anesthetic drug regimens, and lasts slightly longer." said McDonnell.
Administering anesthesiology to a horse in a farm environment has the potential for unpleasant outcomes, but with the resarch going on at the University of Guelph the risk of unpleasant outcomes is becoming a thing of the past with the use of modern drugs.
According to McDonnell, who was instrumental in romifidine’s Canadian approval, the sedative which is approved for use in Canada, Australia, and Europe, is not yet available in the United States.
Another project at the University of Guelph is a study of the effectiveness of glycopyrrolate, a drug used in combination with anesthetics to prevent heart rate decreases and to improve blood pressure and oxygen supply to the body’s tissues. Researchers found that glycopyrrolate is effective at increasing blood circulation at much lower levels than is often used in practices.
The study is important because many horses that undergo surgery are given glycopyrrote and later develop intestinal blocks that need correcting due to the use of the drug. From the study, it has been shown that lower doses of glycopyrrote are just as effective and the smaller doses may not cause intestinal blocks.
McDonnell said, "Minimizing the complications of anesthesiology will reduce the need for longer and more expensive post-surgical recovery periods."
In a cooperative effort with human orthopedic surgeons and researchers, a team at the University of Guelph, led by Mark Hurtig, DVM, MVS, is adapting a technique used to prevent arthritis in humans for use in the horse.
Essentially, in humans, the technique allows damaged cartilage to be replaced by good cartilage.
"Hurtig’s team is refining a joint-repairing technique called mosaic arthroplasty for use in the horse. The technique, which allows repair of small cartilage defects before they grow larger, works in the following way: A mechanically driven stainless steel punch is used to surgically remove small variably sized dowels of cartilage and bone from a healthy non-weight-bearing area in a joint. Holes matching the dowel sizes are drilled out of the damaged joint area and are replaced by the healthy plugs of cartilage and bone," said McDonnell.
Hurtig is also looking into other options for joint therapy. Another technique that is used in mosaic arthroplasty uses healthy cartilage from a donor animal. The donor’s cartilage is frozen and later transplanted to a horse with damaged cartilage. In order to reduce the risk of disease from a donor’s cartilage, laboratory grown cartilage could also be used in this procedure.
"These technologies will have big implications for both human and horse medicine," said Hurtig.
Relaxin And Reproduction
Relaxin is a hormone that is produced in the ovarian follicles (the sac-like structures of the female ovary where all mammalian eggs or oocytes grow and mature) of horses--as in most mammals--that was previously thought to only be essential in foaling because it relaxes pelvic ligaments and reproductive organs to prepare the mare for foaling. More recently, after studies were conducted at the University of Guelph by Brenda Coomber, BS, MS, PhD, and associates, that line of thinking is changing. Researchers now believe relaxin plays a role in fertility as pertaining to the follicle in addition to what was previously known about the hormone.
"If it’s true that relaxin has more than one role, then it will change our approach to solving reproductive problems in the mare," said Coomber.
Coomber says the stroma (connective tissue surrounding the follicle) and the follicle control each other. According to information from the research, "The follicle probably allows for its own growth by releasing relaxin to act on the surrounding stroma."
"Learning about relaxin and its stromal effects is important," says Coomber. "If the follicle doesn’t grow properly, an egg will never be released and a foal never produced."
John Prescott, MA, VetMB, PhD, and technician Vivian Nicholson are working on a vaccine for pneumonia causing bacterium. Natural immunity that the foals receive from their environments and a current Rhodococcus vaccine are largely ineffective due to the bacteria’s ability to find refuge in lung cells, which are not affected by the current vaccine and natural immunity often occurs too late, according to the researchers. The researchers found that by administering a special plasma solution the foals can be protected from Rhodococcus bacterium because it effectively eliminates the bacterium in the lungs.
Literature from the university cites, "the researchers administered hyperimmune plasma (HIP)--the fluid portion of blood acquired from adult horses vaccinated against specific components of Rhodococcus--to two-day-old foals. The plasma contains a high level of antibodies to protect against infection. After receiving it, the foals acquire temporary protection from Rhodococcus until they develop their own resistance."
Prescott said, "Once we learn more about how HIP works, we hope to find ways to concentrate the critical components to reduce the cost and to ease administration. In the longer term, we also hope to develop a new convenient and inexpensive vaccine that will work to help foals target these intracellular bacteria."
We’ve only touched on some of the ongoing research at the University of Guelph. Examples of additional research the university is involved with include equine supplements that improve exercise performance, how to warm-up horses before races and cool them down after the race to gain maximum performance, evaluation of the commonly used diagnostic technique called palmar digital nerve block, a study using special sensors and computer modelling to determine the normal structure and strain patterns of the healthy horse hoof, another study to learn more about equine embryos to prevent early pregnancy losses, and several studies dealing with reproduction including frozen embryos and cryopreservation of semen.
Established 12 years ago by the horse industry, the $2-million Equine Research Centre (ERC) is located in Guelph, Ontario on the campus of the University of Guelph. The ERC’s mission is to serve the equine industry with full-time research and to disseminate the information learned from that research to the industry. Andrew F. Clarke, President and C.E.O., said one of the main requirements of research projects at the ERC is that they relate directly to practical application in the horse industry.
The main areas of research at the ERC are lungs, legs, and reproduction. Clarke said, "Maintaining good health and preventing problems in horses are the keys to ongoing research at the Centre."
Many of the studies that originate at the ERC are field-based, which means research-ers are going to local farms and performance events to study horses. The horses are not in a clinical setting, which gives the researchers more "true-to-life" information on which to base their findings. The research facilities at the Centre then allow for comparative analysis in a controlled environment. Furthermore, the studies conducted at the ERC are as non-invasive as possible.
Hosting students working on their post doctorate degrees, the ERC provides a dynamic setting for learning and healing. At any given time the ERC has about 30 volunteers—mainly students from the University of Guelph. Students from all over the world have come to the ERC to learn. Meeting strict criteria for conducting and supervising scholarly research, the ERC is registered as a sponsoring establishment with the Open University of the United Kingdom.
Originally, the ERC was part of the University of Guelph, but in 1997 it became a separate entity no longer receiving funding from the University’s research program, although the two still work closely together.
The nuclear medicine facility at the ERC was established in 1990, and is the only facility of its kind in Ontario. Nuclear medicine at the ERC is used for research and diagnosis. Bone scans are performed on a referral basis by practicing veterinarians to further investigate lameness problems.
You need a 30-40% change in bone to see a problem on an x-ray, said Lawry Riddolls, the Centre’s nuclear medicine technologist. You need far less change to see a glowing red hot spot on the screen in the examination room at the ERC. Nuclear Medicine, or scintigraphy, is used to examine bones in all areas of the horse: limbs, vertebrae, pelvis. In order to obtain a bone scan a horse is injected with a low-level radioactive compound, lightly sedated in order to remain standing throughout a study, and kept at the ERC for 24 hours to ensure that the compound has been fully eliminated in the urine and feces.
The gamma camera, which generates a scintigraph, is unique in its ability to image metabolism in the living horse. ERC’s nuclear medicine research focuses on examining body systems in relation to challenges facing the equine industry. Some examples are studies of gastric emptying of horses given electrolyte supplements and foals with stomach ulcers; respiratory function (or malfunction) of horses with influenza and exercise-induced pulmonary hemorrhage; as an aid in studying nebulizing systems to look at the efficiency of aerosol therapy for treating respiratory problems; and the studies of various imaging compounds, including the most recent highlighting infection/inflammatory processes. Research of more then 300 diagnostic bone scans that have been performed at the ERC continues in order to critique and improve technique.
While at the ERC, John Field, DVM, PhD, applied this technology to study the rate of absorption of lactic acid screws used to repair bone fractures. Field’s studies evaluated bioabsorbable implants against traditional titanium when used separately or in combination for fracture repair. The screw has proven potential for repair of specific fractures, such as saucer fractures. A study of bioabsorbable bone screws for the treatment of "saucer" fractures of the third metacarpal bone is already in place at the ERC. To date, one of two horses treated with the lactic acid implant, the Thoroughbred Count Your Shekels, has returned to racing in winning fashion.
Wendy Pearson, BSc (Agriculture), the ERC’s resident researcher of nutraceuticals and herbs for horses, said there is a very strong desire among the horse industry, as well as the general population, to learn more about holistic medicine. A survey of more than 1,000 horse professionals in Canada that included breeders, trainers, and veterinarians, posed the question, "What is the number one horse health issue in Ontario?" The lack of understanding of alternative therapies came in second only to respiratory disease. In that same survey, alternative therapies and nutraceuticals ranked in the top four answers to the question, "What is the number one horse health subject you would like to know more about?"
To give you an idea of how much this area is growing in popularity among the horse industry, Pearson said, "In 1995, $1.2 billion was spent in this area, in 1996 $5 billion was spent, and in 1997 $10 billion was spent." Pearson said at this point there is no "big" database on herbs from which the public can draw information. Her research will build a foundation of information for the industry. In an effort to meet the demands of the industry, Pearson and the ERC are also active players in the Nutraceutical Alliance (http://www.nutraceuticalalliance.com ).
Studies conducted at the ERC on herbal products are designed to evaluate their effectiveness, study side effects, and consider how they work in conjunction with traditional therapies. Pearson worked with Colorado State University and Selected Bioproducts Inc. designing the trials to evaluate a herbal supplement for arthritis. Results are available from the Centre. The current study is examining an herbal remedy for heaves. (See the Up Front section for research into herbal remedies for joint problems.)
Cooled And Frozen Semen
Deborah Ottier, BSc (Agriculture), is the resident researcher of new technologies in reproduction. The current focus is on cooled and frozen semen. "This area is of importance because in Europe, and increasingly in North America, frozen and cooled semen is being used. Improved management systems and higher conception rates would greatly benefit the industry. Particularly in terms of opening up new markets for breeders." Ottier added that with the aid of artificial insemination (A.I.), more offspring from top sires are possible since one ejaculate can impregnate more mares than can a single live cover. Another reason for its popularity is the ease of transporting a straw of semen compared to transporting a mare, particularly one with a foal at her side.
While use of frozen and cooled semen has advantages, A.I. does have its drawbacks. No matter how careful one is in preparing the semen, it still will not have the same quality or motility of fresh semen, said Ottier. To combat this problem, Ottier currently is conducting research on extenders to determine which works best to preserve semen during the freezing process. The extenders being studied include the Brazilian, German, and Russian versions. "Each of these extenders has its strengths and weaknesses," said Ottier. "Some stallions show much better motility after freezing, depending on the extender used.
There are many techniques used to freeze semen. Ottier is searching for the technique that has the fewest detrimental effects on semen, including optimal temperatures for freezing and cooling semen, and thawing rates. All of these factors affect the quality and motility of semen, hence conception rates. Ottier recommends that a stallion owner have a horse’s semen tested for motility before marketing the stallion using A.I. with cooled or frozen semen. Mare management plays an important role in conception rates, as well.
Ottier is collecting and storing frozen semen from the Canadian Horse, a rare and endangered breed. Preserving equine genetics for future generations may ensure the survival and diversity of rare breeds. Semen can be stored indefinitely, according to Ottier.
Frozen semen has been used in the horse industry for the last 10 years and is gaining popularity. The future holds even more marvels. Ottier said embryo transfer is another "hot topic" for the industry, but currently has only a 20-30% success rate.
Susan Raymond, BSc (Hons), is working on her PhD under the direction of ERC president Andrew Clarke, an expert in equine respiratory health. Raymond has several years of respiratory research under her belt, both in the lab and in the field. She focuses on barn design and management and their influence on the respiratory health of horses. Raymond is studying dust size and the types of particles (such as if it’s plant material or mold spores) which can lead to heaves (chronic obstructive pulmonary disease) in horses.
Raymond’s many clinical trials have examined different hay and bedding products and management systems. It was suggested by many speakers at the World Equine Airways Conference that wet hay greatly reduces dusts present in hay and is a good management practice when feeding horses, and Raymond’s studies have proven this. The practice of soaking hay is highly recommended, especially when the horse suffers from any type of airway disease. Using data from the study, Raymond suggests soaking hay for twenty minutes. She advises that owners not soak the hay too long or important nutrients will be leached out. Raymond stressed that these management practices work best on young horses as a preventative measure to reduce respiratory problems such as COPD (heaves). Mold and dust found in hay are easily reduced with careful management, added Raymond.
Another aspect of barn environment Raymond is studying is ammonia. She looks at all areas of barns to figure out the types of environmental controls to improve the air a horse breathes. Raymond recommends eight to 10 air changes per hour in barn settings. She says, "Even in the winter, ventilate barns eight to 10 times per hour." The barns at the ERC are mechanically ventilated, although other types of ventilation, depending on the design of the barn, also work well.
A study involving bedding is now underway at the ERC under Raymond’s lead. At the end of the study, information on bedding materials such as straw, wood, recycled cardboard and paper, shavings, and hemp by-product will be available. From the information gained, the benefits and drawbacks of each of these bedding materials will be better understood.
Raymond is also completing a study of fresh versus stored hay crop in Ontario. Nutritive values, mold, and mycotoxin levels are being examined on a wide selection of samples, including first and second cut.
How do fluid and electrolyte imbalances affect the performance of horses? This question was the focus of a study by Gayle Ecker, BA, (Hon), Bed, MSc, on exercise physiology. Some of the initial research that centered around the 1996 Olympics in Atlanta, Ga., was performed at the ERC.
Ecker, an endurance rider herself, took her work on the road. With help from the ERC, Ecker traveled across Canada in search of endurance rides in order to study endurance horses at work. In addition to recording body weight, samples of sweat were collected and analyzed during and after a ride to determine the exact composition of the seat in order to better understand electrolytes losses and how to optimally supplement performance horses.
Working to see if supplements are enhancing a horse’s performance, Ecker is trying to answer questions raised by the industry. She has used nuclear imaging to determine how rapidly a supplement leaves the horse’s stomach and moves on to be utilized in replacing electrolyte losses. Blood samples taken from performance horses help to evaluate how much of a supplement is actually being absorbed into the horse’s system. Sweat samples provide data on potassium levels, during performance potassium is concentrated in the muscle as the horse cools itself through sweating. Ecker found 10 times the amount of potassium in sweat than in blood. "If the potassium is coming from the muscle, then it will affect performance," Ecker said. In order to get quality data, Ecker employs the treadmill as well as field studies.
One of Ecker’s goals is to develop a "designer electrolyte" that meets the needs of the individual performance. She is also involved in metabolic profiling of athletic horses at events and will compile data to provide comprehensive information on performance in all disciplines including eventing, jumping, racing, and polo.
Ecker also coordinates the Growth and Development project with head researcher Leslie Huber, DVM. This is a huge field-based project examining mares and foals through gestation and the first year. It involves recording data from several Standardbred and Thoroughbred farms, including diet, management, and skeletal development examined through periodic x-ray of a large number of horses. Results are emerging and recommendations based on the observations are coming to light.
This is but an overview of the ongoing research at the ERC in Guelph, Ontario. More specific information on these topics will appear in upcoming issues of The Horse, and can be found on our web site at www.thehorse.com.
About the Author
Tim Brockhoff was Staff Writer of The Horse:Your Guide to Equine Health Care from 1995 to 1999. His degree is in Agricultural Communications from the University of Kentucky, and his equine experience is with American Saddlebreds.