Lightning learning

Eequine-focused graduate students at the Western College of Veterinary Medicine (WCVM) recently participated in a “lightning rounds” session — part of the college’s annual EquineED Talks series.

By Jessica Colby

Photo: Christina Weese.

Each student gave a five-minute talk summarizing their research for an online audience of horse owners and enthusiasts. 

Comparing effectiveness of ACE inhibitor drugs in horses
Dr. Nicole van der Vossen (graduate supervisor: Dr. Julia Montgomery)

Only angiotensin-converting enzyme (ACE) inhibitors can slow the heart’s failure — there’s no surgical option for horses. When a horse’s heart begins failing, the heart compensates by producing angiotensin I. Angiotensin I becomes angiotensin II, which turns into aldosterone. This steroid hormone causes fluid buildup and high blood pressure.

ACE inhibitors block angiotensin I from becoming angiotensin II, slowing the process of heart failure and prolonging the patient’s life. Of the two main ACE inhibitors (ramipril and benazepril), ramipril is cheaper — but it may not be as effective.

In her study, van der Vossen used three groups of healthy horses to study the drugs: one group received benazepril, the other group received ramipril, and third control group received a placebo. After analyzing the horses’ blood and urine samples, she found that only 82 per cent of aldosterone was blocked when using ramipril.

Detecting Chlamydia in aborted tissues from western Canadian horses
Dr. Madison Ricard (graduate supervisor: Dr. Bruce Wobeser)

For 25 years, the bacterium Chlamydia psittaci wasn’t considered a significant cause of equine abortions, with rare cases identified in Europe. But in 2014, an outbreak of psittacosis (the human version of Chlamydia psittaci) occurred at an Australian veterinary school after students were in contact with equine aborted placental tissues. This outbreak led to the discovery of numerous cases of Chlamydia abortions in Australia that previously went unidentified.

The presence of Chlamydia in abortions is well described in sheep, but in horses, testing for C. psittaci isn’t part of routine testing. It requires a specialized test to identify its presence in equine abortions.

Using 99 randomly selected aborted equine tissues collected from equine cases between 2009 and 2020, Ricard analyzed each one for the presence of Chlamydia. While she wasn’t expecting any tissue samples to test positive for Chlamydia, 26 samples tested positive. However, most of these tissues tested positive for a different strain of Chlamydia: Chlamydia abortus, another potentially zoonotic pathogen. What’s still unknown is whether Chlamydia caused these equine abortions or if the bacterium was just present in the aborted tissues.

Using alpha 2 agonist and lidocaine versus using lidocaine alone in horses
Dr. Antonio Guerra (graduate supervisor: Dr. Keri Thomas)

Guerra’s study tested two different methods to extend the “half-life” of lidocaine, a local anesthetic and numbing agent, used in horses. Half-life refers to the time that the numbing effect will last in the patient’s body, reducing sensation.

On its own, lidocaine has a half-life of about 30 to 60 minutes. In this study, Guerra combined 0.4 millilitres (ml) of xylazine (drug used for sedation and analgesia in veterinary care) into a 50-ml bottle of lidocaine. This combination resulted in a large increase of the medication’s duration or numbing effect: the team’s findings showed that combined drugs delivered up to 135 to 180 minutes of pain management, with an average of 171 minutes. Guerra used two different types of stimuli (electricity and pressure) to determine the level of pain blockage in the numbed area within safe margins to avoid damaging the skin.

Solving the strongyle puzzle: new diagnostics for an old problem
Toni-Anne Saworski (graduate supervisor: Dr. Emily Jenkins)

All horses have parasites, and veterinarians currently rely on fecal egg counts (FEC) to measure how many eggs per gram of feces that a horse is shedding.

Saworski is specifically studying large and small strongyles, a family of parasites that includes bloodworms and cyathostomins. However, each of the 53 species of strongyles has the exact same egg in appearance — an issue that makes it especially difficult for veterinarians to determine which parasites are affecting a horse. As well, results from FECs can’t indicate the dangers or health impacts facing the horse.

As part of her master’s work, Saworski is working to identify the DNA of each of these strongyle eggs. So far, Saworski has identified the DNA of 35 of the 53 strongyle species. 

Describing biomarkers of endocrine function in healthy horses in Saskatchewan
Dr. Paula Viviani (graduate supervisor: Dr. Julia Montgomery)

Pituitary pars intermedia dysfunction (PPID) and equine metabolic syndrome (EMS) are two common endocrine disorders that can be diagnosed by measuring a horse’s levels of adrenocorticotropic hormone (ACTH) and insulin, respectively.

Viviani is working to establish a hormone baseline specifically for western Canadian horses with Dr. Julia Montgomery, her graduate supervisor. Measuring the ACTH and insulin of healthy horses, Viviani is analyzing these numbers to create a hormone baseline for horses in Western Canada based on specific factors that fluctuate based on season, weather and time of day.

The study’s first phase, where horses were sampled twice a year, has concluded. During the project’s second phase, horses will be sampled once a month over a 12-month period until July 2023.

Iodine’s importance in pregnant mares
Dr. Maria Jose Terol Monar (supervisor: Dr. Claire Card)

In horses, iodine is critical for both thyroid function and fetal development during pregnancy. But unfortunately, the Canadian Prairies are known for being deficient in natural iodine. While more studies are needed, previous research has linked musculoskeletal diseases such as congenital hypothyroidism dysmaturity syndrome (CHDS) to inadequate iodine uptake.

In this study, Monar worked with two randomized groups of six pregnant mares. Starting mid-pregnancy, the research team supplemented one group of the mares’ feed with four milligrams of iodine. No iodine was added to the feed of the other group of mares. The research team observed the mares from that midway point of their pregnancy to one month postpartum. Analysis of the project’s data continues.

The goal of this project is to describe the effect of iodine supplementation on concentrations of iodine in serum, urine, colostrum and milk in pregnant and early post-partum mares. Findings will help to develop reference levels that can be used to recommend changes in supplementation practices and to establish new guidelines for pregnant mares.

Click here to view video recording of the WCVM EquineED "Lightning rounds" session