TEHRF research grants: 2019-20

Photo by Christina Weese.

The Townsend Equine Health Research Fund (TEHRF) has allocated more than $68,000 to support five equine health research projects at the Western College of Veterinary Medicine (WCVM). WCVM scientists and their collaborators will conduct the research studies over the next 24 months. Read the following summaries for more details about each study.

What’s the histamine concentration in unmedicated horses after penicillin and guaifenesin doses?
Drs. Tanya Duke and Shannon Beazley, WCVM

Morphine is a useful analgesic (painkilling drug) for use in horses, but it’s also known to cause histamine release — a biological reaction triggered by allergens — in dogs and other species. To learn whether morphine has a similar effect on horses, WCVM researchers recently completed a study comparing histamine release levels between morphine and butorphanol (another type of opioid analgesic) during anesthesia. While morphine is known to cause histamine releases in other species, butorphanol does not.

However, the researchers’ results indicated that histamine concentrations were similar between the two drugs, which means there may be other factors contributing to histamine release. As a continuation of the previous study, the WCVM team will measure the histamine concentration in horses about to undergo surgery in three different scenarios: after no medication (the study’s baseline), following routine doses of penicillin, and after doses of guaifenesin — another potential histamine-releasing drug used in anesthesia.

Findings from this study will help researchers better understand the results of their previous work. Depending on the results, this study may also potentially alert anesthesia teams of other sources of histamine release that could affect equine patients.

How does a new suture technique for equine tendon repair measure up biomechanically?
Drs. James Carmalt, Michelle Tucker and Margot Hayes, WCVM

 Tendon laceration is a common ailment in horses that often occurs from athletic injury and trauma. Recovery rates for horses with tendon lacerations aren’t ideal. While 45 per cent of injured horses return to full health, only 18 per cent of those animals return to regular athletic function.

Suturing these injuries realigns the tendon ends and can result in stronger repairs with improved healing. This treatment option also helps to combat scar tissue build up that can lead to further complications. However, the two most common techniques used to suture a tendon laceration can still fail — resulting in gap formation between the ends when the horse stands and decreased blood flow.

During this study, the WCVM researchers will use a biomechanical model to compare three suturing techniques that have shown promise in reducing gap formation and maintaining repair strength even during motion in people. By comparing these methods to another technique currently favoured by veterinarians, the WCVM team hopes to pinpoint an option that performs better and improves the chances of horses returning to their original level of performance.

Can researchers inhibit EHV-1 protein expression to prevent viral replication?
Dr. Kristen Conn and graduate student, WCVM

Equine herpesvirus 1 (EHV-1) is a highly infectious virus that’s a member of the Herpesviridae virus family. Following an initial infection, EHV remains in a resting state (latent) within the horse for life and can reactivate during stressful situations. EHV is present in most horses and causes no side effects, but one of the most common EHV species, EHV-1, can cause serious illness. EHV-1-associated diseases include neurological disease, respiratory disease, abortion, and neonatal death.

Current vaccines are ineffective at preventing the initial EHV-1 infection and subsequent reoccurrences of disease. While antiviral therapies can help to protect against the initial infection, they don’t stop disease recurrences.

Scientists know very little about the mechanisms that regulate and control EHV-1. Over the next two years, WCVM researcher Dr. Kristen Conn will target that issue — investigating how EHV-1 protein expression is regulated. Findings from this study could be vital in supporting further research toward the development of new therapies to treat diseases associated with EHV-1. 

How accurate are endometrial biopsies as diagnostic predictors for mare fertility?
Drs. Bruce Wobeser, Claire Card and Tasha Epp, WCVM; and Jane Westendorf (DVM-MSc student), WCVM

The reproduction rates of mares are among the lowest in domesticated species at just 60 per cent. Because of this low reproductive rate, breeding management for horses is expensive.

A common component of a reproductive exam that veterinarians use to better understand a mare’s fertility condition is an endometrial biopsy — a biopsy of its uterine lining (endometrium). To evaluate these endometrial biopsies, veterinary diagnostic specialists follow the Kenney-Doig classification system. However, this process is relatively subjective, and as a result, the interpretation of the sample varies between different examiners. This can lead to conflicting conclusions about the mare’s fertility and her predicted foaling success.

In this study, the WCVM research team will explore the degree of agreement between examiners evaluating the same biopsy samples. Through this process, the team will develop an understanding of what factors result in agreement and what factors do not. This investigation will help identify more effective methods to improve the interpretation of endometrial biopsies in mares and increase the procedure’s usefulness.

Can mass spectrometry play a role in septic arthritis therapy?
Drs. Elemir Simko, Roman Koziy and Joe Bracamonte, WCVM; and Dr. George Katselis, USask College of Medicine

Septic arthritis is a debilitating health issue that can affect horses of all ages. The bacterial joint infection can present lifelong consequences such as lameness and the loss of athletic performance.

Through previous research, scientists have identified certain biomarkers as indicators of infection eradication. But treatment for septic arthritis can sometimes alter these biomarkers and produce inaccurate results. This obstacle often leads to prolonged antibiotic therapy for arthritic horses.

To try and overcome this issue, the research team will use mass spectrometry to analyze the protein composition in blood and synovial (joint) fluid samples of horses with experimental septic arthritis. Mass spectrometry is an analytic technique that allows identification of proteins and other biomolecules by precisely measuring the mass and electrical charge of their components. With this more sensitive technology, the researchers hope to identify and quantify more accurate biomarkers for infection eradication.

This project will be a stepping stone toward the goal of developing more effective diagnostic tests that veterinarians can use to detect the eradication of infection in horses diagnosed with septic arthritis — a development that will have a significant clinical impact on their patients.