EHRF research grants, 2010-11

Dr. Steve Manning and his team will investigate whether acupuncture therapy is effective for inducing ovulation in mares this summer. Photo: Michael Raine.

How does arthrodesis affect carpal flexion?
Drs. Spencer Barber and Luca Panizzi, WCVM: Dr. James Johnston, U of S College of Engineering; and Patty Tulloch and Hayley Lang, WCVM students

Injuries to the carpal joints are common in horses and frequently result in arthritis that can be painful and debilitating. Arthrodesis, surgical fusion of the joint, has occasionally been used to treat arthritis or fractures of the carpus. But the animal’s quality of life and its usefulness after the fusion depend on the amount of carpal flexion that remains after surgery. This study will determine how each of three different arthrodesis techniques affects carpal flexion.

Researchers will utilize a biomechanical testing procedure to measure the flexion of the untreated carpal joints on 10 cadaver limbs. In random order, they will then perform three partial carpal arthrodesis techniques on each limb: fusing the antebrachiocarpal joint, fusing the middle and carpometacarpal joint, and fusing the carpometacarpal joint using two bone plates.

After each technique, the research team will use biomechanical testing to measure the amount of carpal flexion. This multi-disciplinary project will help owners of arthritic and injured horses to make informed decisions regarding surgical treatment options and will support the advancement of current treatment methods for carpometacarpal disease and injury.

Is coronary band grafting a speedier treatment option?
Drs. James Carmalt and Imma Roquet, WCVM

Horses frequently suffer injuries to the coronary band – the thin band around the top of the hoof that’s responsible for hoof growth. Clinicians commonly treat the injury and then immobilize the limb in a foot cast. Recovery time varies, lameness may persist and permanent hoof wall defects may occur. This study will investigate if coronary grafting paired with casting could improve and speed healing.

The investigators will surgically remove a square patch involving skin and dorsal hoof from both the right and left front limbs of five horses. They’ll suture one flap onto the defect in the other foot, while the second flap will be transplanted onto a defect in another horse. Both limbs will be placed into foot casts for four weeks. The casts will then be removed, and researchers will assess graft integration and hoof wall growth. They’ll then monitor the horses for eight weeks in paddock conditions, comparing the rate of hoof growth in the grafted sections and the non-grafted sections.

Results could lead to the use of coronary band grafting as a means to speed the healing of chronic defects or acute lacerations and tearing involving the coronary band.

Download a summary of this research project’s findings.

Do western Canadian horses require different deworming protocols?
Drs. Chris Clark, Ela Misuno, Steve Manning, Lyall Petrie, Emily Jenkins and Fernando Marques, WCVM

While intestinal parasitism is a common, worldwide problem of horses, there is little specific information about horse parasites in Western Canada where the combination of long, severe winters and low humidity in the summers may result in fewer numbers. Because of concerns that parasites are becoming resistant to dewormer products, it’s important to understand the life cycle of these parasites in the region so existing products are used effectively.

Researchers will monitor 60 mares and their foals for 12 months, evaluating fecal egg count (FEC) monthly over the summer and twice during the winter months. None of the horses will receive deworming treatments unless individual animals show a high FEC or clinical signs. If this occurs, affected horses will receive ivermectin. A follow-up fecal egg reduction test will establish whether the deworming treatment is effective and will thus detect resistance to ivermectin.

Study results will be used to develop more appropriate deworming protocols and to determine if parasite resistance to ivermectin is a problem in the local horse population. Researchers may use this data for a larger project to develop novel control methods for these parasites.

Can acupuncture induce ovulation in the mare?
Drs. Steve Manning, Nora Chavarria, Claire Card and Manuel Chirino, WCVM

Acupuncture has become a common alternative treatment for many reproductive problems in horses. However, much of the evidence for its effectiveness is anecdotal or pertaining to other species.

WCVM researchers want to objectively investigate acupuncture as an adjunct therapy for equine sub-fertility or infertility. They’ll perform a randomized, controlled and double-blinded trial to scientifically establish if electro-acupuncture is valuable for inducing ovulation.

Thirty mares in estrus will be randomly assigned to three groups: negative control (NC) will receive a sterile saline solution injection, electro-acupuncture (EA) will receive 15 minutes of treatment at discrete acupuncture points once daily until ovulation, and positive control (PC) will receive an injection of human chorionic gonadotropin, a proven ovulation induction agent. Tests including palpation, ultrasound and blood analysis will be performed at regular intervals. Researchers will observe ovulation and compare the mares’ reproductive hormone profiles.

Study results will help veterinarians and horse owners to make sound decisions about using acupuncture therapy for ovulation induction. They may also lead to further trials testing the impact of electro-acupuncture on shortening the normal transitional period and advancing the physiologic breeding season.

Can hair cortisol concentrations indicate stress in racehorses with EGUS?
Drs. Fernando Marqués, José Alberto Ruiz López, David Janz, Brian Macbeth and Marc Cattet, WCVM

Equine gastric ulcer syndrome (EGUS) is common in horses, particularly Thoroughbred racehorses in active training. EGUS has a significant economic impact due to the costs of diagnosis and treatment and its impact on athletic performance. Although gastroscopy successfully diagnoses EGUS, a simpler, less invasive technique is needed.

Since increased cortisol concentration in hair has been successfully linked to long-term stress in primates and wild animals, the multi-disciplinary research team will investigate the relationship between the severity of EGUS and the cortisol concentrations in hair collected from 60 racehorses. They will also evaluate cortisol concentration in serum from the horses — a reflection of acute stress response.

Serum and hair cortisol concentrations from a control group will be compared to those of the “EGUS group” — the horses in which veterinarians have already conducted gastroscopies to identify and grade the severity of EGUS lesions. Study results will advance understanding of acute and long-term stress as EGUS risk factors and will validate a simple, non-invasive technique for identifying horses at risk.

Is gallium maltolate effective for treating equine proliferative enteropathy?
Dr. Julie Thompson, Canadian Light Source; and Drs. Trish Dowling, Don Hamilton and Francesca Sampieri, WCVM

Lawsonia intracellularis (LI) is the bacterial pathogen causing equine proliferative enteropathy (EPE), an emerging intestinal disease of domestic and wildlife species. Prevention of EPE on farms is difficult since exposure to LI occurs through the fecal-oral route, and the location of the bacterium within the intestinal cells protects it from immune response and traditional antimicrobial drugs. Gallium maltolate (GaM), a metal-based compound, may be a viable therapy alternative for intracellular infections.

A WCVM-based research team will attempt to establish that hamsters are suitable as an infection model for horses affected by EPE. Like horses, hamsters are hind gut fermenters so their response to antimicrobial treatment should be similar. Researchers will test for the presence of infection in LI-challenged and healthy control groups of hamsters at regular intervals over 21 days.

The research team will then compare the efficacy of GaM against five antimicrobial drugs commonly used to treat clinical EPE. As gallium is a metal, its intracellular killing action against LI will be investigated using novel radiation techniques at the Canadian Light Source’s synchrotron — a high-energy particle accelerator used to probe the structure of matter. The study’s results could influence treatment of infectious gastrointestinal disease in veterinary patients, and may ultimately be utilized in treating human infection.

Is a novel suture technique for laryngeal tie-back more effective?
Drs. David Wilson and James Carmalt, WCVM

Laryngeal hemiplegia (roaring) is a performance-limiting condition that primarily affects horses over 15 hands in height, including Thoroughbreds, Warmbloods and draft breeds.  Mainly because of nerve dysfunction, the muscles of the larynx don’t function properly affecting the abduction of the left arytenoid cartilage as the horse breathes. This cartilage gets pulled into the airway, thus inhibiting respiratory function and resulting in exercise intolerance.

A laryngeal prosthesis procedure, which is the preferred treatment, often does not maintain the desired degree of abduction over time. In this study, Drs. David Wilson and James Carmalt will evaluate the feasibility of a new technique in which two sutures are placed in a two-loop pulley configuration. This technique should ensure immediate load sharing that will reduce suture tension and facilitate tying a “millers” knot configuration so that the prosthesis will effectively maintain the desired degree of abduction.

Researchers will use a material-testing machine to compare the biomechanical properties of the novel technique to those of the standard technique that utilizes two interrupted sutures. Results could facilitate a new, longer lasting technique for managing clinically affected horses.