2005-2006 Projects

Osteoarthritis: estrogens and cartilage interactions in the horse.
Dr. Jim Raeside

An epidemiological investigation of horseracing wastage due to musculoskeletal injuries in Ontario.
Dr. Antonio Cruz

Peptide receptors in the equine large and small intestine.
Dr. Iona Sonea

Identification and prediction of canon bone fractures in 2 and 3 year old racehorses.
Dr. Mark Hurtig

The role of Clara cells in the pathogenesis of equine airway disease.
Dr. Dorothee Bienzle

Surveillance of equine influenza virus prevalence and antigenic drift in young performance horses in Ontario.
Drs. Laurent Viel/Joanne Hewson

Quantifying the hoof’s response to loading during exercise: changes in external shape, growth rate and internal anatomy.
Dr. Jeff Thomason

Characterization of nutritional factors affecting the rate of post-exercise muscle glycogen synthesis in horses.
Dr. Ray Geor

The molecular basis of early conceptus adhesion to the mare’s endometrium in relation to the success and failure of pregnancy.
Dr. Keith Betteridge

Effects of handling and housing on trainability and behaviour of young racehorses.
Dr. Suzanne Millman
Aggression and stereotypic cribbing, weaving and boxwalking, are common behavioural problems in the equine industry. Factors causing behaviour problems are complex and multidimensional, and young racehorses are particularly at risk. This research program explores prevalence and risk factors for behaviour problems, specifically stereotypies and aggression, in racehorses. Effects of caregivers and stall design will be explored in detail, and opportunities for improvement will be identified and assessed.

Correlation of MRI and necropsy findings in horses with suspected wobblers.
Dr. Stephanie Nykamp
Wobbler syndrome or Cervical Stenotic Myelopathy (CSM) causing spinal cord compression is a common and devastating disease affecting horses, especially young Thoroughbreds and Standardbreds. It causes progressive ataxia which often results in juvenile wastage either by euthanasia or retirement from training. This study will produce the first atlas of MRI anatomy of the equine cervical spine and also develop Magnetic Resonance Imaging (MRI) criteria for diagnosing wobbler syndrome in horses. The importance of this study is the increased accuracy, in the live animal, of diagnosis of CSM and increased knowledge in the development and progression of the disease.

Evaluation of a novel laparoscopic technique for collection of full-thickness small intestinal biopsies in standing sedated horses.
Dr. Ludovic Boure
Diagnosing and identifying the cause of colic remains a challenge for equine veterinarians and researchers. Full wall thickness of small intestinal biopsies is a procedure, which could provide valuable information used to diagnose chronic intestinal disease and to research the underlying mechanisms of intestinal disease (colic) in horses. Laparoscopy (the passage of a small device (less than one-quarter inch) through the abdomen to visualize the intestine) is a well-established minimally invasive surgical procedure in horses with insignificant post-operative pain and complication in horses. This study aims at establishing standing laparoscopy, as the standard technique to collect full-thickness small intestinal biopsies in horses. The project is linked to Dr. Geor's project.

Equine therapeutic cloning to treat cartilage defects/injuries in the horse.
Dr. Dean Betts
In horses, it is generally recognized that cartilage lesions over a certain size do not heal spontaneously and no universal treatment of osteoarthritis (OA) or cartilage defects exists today. Equine models of cartilage repair utilizing bone marrow stem cells for transplantation and various other cartilage grafting techniques have showed promising results. Our objectives are to: 1) Derive and maintain equine embryonic stem (ES) cell lines from in vivo-derived blastocysts; and 2) Characterize the ability of putative equine ES cells to maintain the undifferentiated state and to differentiate into various somatic cell types, including chondrocytic cells (joint cartilage cells).

Small intestinal adaptive responses to grain feeding: Implications for colic.
Dr. Ray Geor
Both the level of grain-concentrate feeding and a recent (within 2 weeks) change in grain feeding have been identified as important risk factors for colic in horses. We believe that slow and/or inadequate adaptation of the horse's intestinal tract to increased grain feeding contributes to the development of colic. However, at present there is very little information on the ability of the horse's intestinal tract to quickly respond to dietary changes, such as an increase in grain feeding. Our studies will provide important new information on the time course, extent and molecular mechanisms of adaptations in small intestinal carbohydrate digestive and absorptive function in response to increased dietary starch, and assess potential variations in the expression of these functions in horses with some forms of colic.

Effect of mechanical stress on laminar junction remodeling.
Dr. Jeff Thomason
Mechanical stresses occur in hooves with every footfall, usually leading to adaptive responses over time. That is, the living and inert components of the hoof are remodeled to continue to withstand the imposed stresses. Like bones and muscles, the hoof has a need for some mechanical stimulation, but not too much or too little. Stresses in a beneficial range promote vascular activity and apparently adaptive remodeling. What this study will describe is how the laminar junction remodels in response to stress in a beneficial range. In conjunction with previous work on stresses and strains during different activities and on different substrates, the results will indicate the levels of exercise that are appropriate for good hoof function and structure.

Comparison of continuous infusion with intermittent bolusing of cefotaxime in neonatal foals.
Dr. Joanne Hewson
Septicemia is the most significant cause of foal illness and death in the neonatal period (< 14 days of age). This study will continue to advance intensive care of the septicemic neonate, with the hope to improve short-term and long-term survivability of these foals by optimizing medical therapy and minimizing potential sequelae. To this end, the information provided by this study will allow veterinarians to determine the optimal method of administration of cefotaxime in critically ill neonates to treat various complications of septicemia, including peritonitis, septic arthritis, and pneumonia.

Evaluation of a rapid test for identification of methicillin-resistant Staphylococcus aureus (MRSA) colonization in horses.
Dr. Scott Weese
MRSA infection and colonization appears to be widespread and increasing in prevalence in North America. With any emerging infectious disease, rapid identification of affected animals and early implementation of infection control measures can prevent or reduce the introduction of the pathogen into a population; be it a farm, veterinary clinic or geographic region. While culture is now used to detect MRSA colonization, the availability of a test with a rapid turnaround time would allow for earlier identification of carriers. This study will evaluate a potentially valuable diagnostic tool that could be used to assist with MRSA eradication and control in horses.

Does prognosis for future performance in cases of longstanding equine atrial fibrillation justify treatment by transvenous electrical cardioversion?
Dr. Peter Physick-Sheard
While drug therapy is often effective in the treatment of recent onset atrial fibrillation (AF) in the horse and carries an excellent prognosis, the prognosis for horses with longstanding AF (>4 months) is generally considered to be poor. However, a newly developed technique at the OVC called transvenous electrical cardioversion (TVEC) has been shown to successfully treat AF. The objective of this study is to determine whether horses with longstanding AF, that are successfully treated with TVEC, will subsequently remain in normal heart rhythm through training and return to regular athletic activity.

Vaccination against Rhodococcus equi pneumonia in foals.
Dr. John Prescott
Rhodococcus equi pneumonia is an important bacterial infection of foals. Current control procedures are expensive and inconvenient. What is needed is an active vaccine but developing such a vaccine is challenging. We have used targeted gene mutation to develop mutants that are attenuated for pneumonic disease in foals. This project will evaluate the value of these mutants for their ability to immunize foals against infection.