Current Research
The board of directors of Grayson-Jockey Club Research Foundation announced that it has authorized expenditure of $2,653,312 to fund 16 new projects and ten continuing projects at 17 universities as well as two career development awards. The 2025 slate of research brings Grayson’s totals since 1940 has provided more than $44.4 million to underwrite more than 450 projects at 48 universities.
Click here for a printable list of our 2025 Projects
Can Smartphone-Based Sensors Provide Reliable And Repeatable Lameness Data
Melissa King, Colorado State University –One Year Grant
One Sentence Summary:
This project will test the reliability and repeatability of body-mounted and smartphone IMU sensors with machine learning and computational algorithms in lame and non-lame horses.
Musculoskeletal injuries remain one of the most important issues in the equine industry, especially considering sport-related activities. There is a delicate balance between a desirable improvement in performance and overstress of specific tissues, leading, over time, to a possible clinical injury. In addition, the recent increase in interest from the general population for an improvement in horse welfare and the social license to operate during equestrian training sessions and competitions reinforces the importance of a better understanding of equine biomechanics. Inertial measurement units (IMUs) are portable wearable sensors (accelerometers, gyroscopes, and magnetometers) attached to different body segments.
In humans, IMU systems have been validated in several sport-related activities, providing real-time spatiotemporal and biomechanical loading information. Several studies using different IMU systems in horses demonstrate promising use of this technology in collecting varying stride parameters (i.e., stride length, stance time, retraction/protraction angles) in orthopedic clinical cases and healthy horses performing diverse activities. In comparison to humans, these tested horse-IMU systems report only limb motion characteristics and have not been used to assess biomechanical loading information. A novel IMU system combined with machine learning techniques and computational algorithms has been able to collect timing, distance, and biomechanical loading in numerous human subjects during various athletic activities, showing excellent correlation to the gold standard optical motion capture systems and force platforms.
Recently, this novel technology utilized sensors embedded in smartphones to collect kinematic parameters in humans and showed a good correlation between the body-mounted and smartphone-embedded sensors. Additionally, the technology using smartphoneembedded sensors was demonstrated to be reliable and accurate in detecting biomechanical parameters during functional tests. There are no previous studies on the reliability and repeatability of this new technology or comparison between body-mounted and smartphone-embedded sensors in horses.
We hypothesize that this novel technology will provide reliable and repeatable output parameters from both smartphone-embedded and body-mounted sensor systems, and the obtained data will be similar between both systems in lame and non lame horses exercising in a standardized protocol. To test our hypothesis, we propose to collect data simultaneously from body-mounted and smartphone-embedded sensor systems with the novel IMU technology in horses exercising on a high-speed treadmill three times per week for a total of three weeks before lameness induction and then starting 2 weeks after lameness induction, once a week for a total of 8 weeks.
Importance to the Equine Industry:
This non-invasive and practical technology will allow equine professionals to detect changes in limb and holistic movement in real-time during both training
and competition. This technology is the “next generation” of gait analysis in the equine athlete and, importantly, is what the field is missing in giving veterinarians clues regarding impending injury
and important information into the biomechanical state of tissues at risk to injury.
Chimeric VP7-VP4 MVA-Vectored Equine Rotavirus Vaccines
Mariano Carossino, Louisiana State University –Two Year Grant
One Sentence Summary: In this study novel chimeric vaccinia-vectored vaccines against equine rotavirus A G3 and G14, the leading cause of foal diarrhea, will be designed and evaluated in mice (proof-of-concept) and mares.
Equine rotavirus A (ERVA) is one of the most common causes of diarrhea in foals within their first 3 months of age. This virus infects and damages the intestinal lining, impeding appropriate absorption of food and water, leading to diarrhea and severe dehydration that requires rapid implementation of medical treatment in sick foals. These sick foals are also very contagious and shed up to 109 virus particles per gram of feces, contaminating the environment. In addition, rotavirus particles are highly resistant in the environment, therefore sustaining transmission to healthy but susceptible foals through the contaminated environment. ERVA is responsible for anywhere between 20% and 77% of diarrhea cases in very young foals, outbreaks occur every foaling season, and can cause important losses to breeding enterprises.
Surveillance efforts around the world have identified that there are two main genotypes of ERVA that cause diarrhea in foals, namely G3 and G14. Control and prevention strategies rely on: 1) enhancing maternal immunity to the foals via vaccination of pregnant mares and 2) biosecurity measures (including hygiene) to interrupt transmission.
There are only 3 vaccines available around the world (one of which is commercially available in the US), all of which are solely based on one of two prototype ERVA G3 strains isolated in the 1980’s. All of these vaccines are inactivated, i.e., based on a killed virus preparation that is poorly immunogenic, which means that it does not elicit a strong immune response by the horse and multiple doses are required to reach adequate immunity. Mares are vaccinated during pregnancy with the hope to induce good maternal immunity. Even after multiple doses, the efficacy of this vaccine is limited as these are poorly immunogenic, induce G3-specific antibodies with limited cross-reactivity with other circulating strains of ERVA, depend on colostrum quality and intake, among other factors related to the mare, foal and environment that influence response to the vaccine.
An additional limitation on the development of rotavirus vaccines is related to the difficulties in isolating and propagating viral strains for use in vaccines. In light of this, there is a critical need to develop more effective, modern next generation vaccines that induce strong and effective maternal immunity and using novel platforms that do not depend on rotavirus propagation in the laboratory and that can be updated easily based on circulating strains. On our previously funded grant, we explored the use of a modified and attenuated vaccinia virus (Ankara) modified to express a highly immunogenic protein of the surface of ERVA specific to G3 and G14 strains known as VP7 in its native form. This attenuated vaccinia virus is non-pathogenic to horses, does not cause disease or is transmitted to other horses, and has proven efficacious in horses against the deadly African horse sickness virus.
We demonstrated that this attenuated vaccinia strain can successfully express ERVA G3 and G14 VP7 types but induces non-neutralizing antibodies (i.e., antibodies that bind to VP7 but do not block virus entry). This is likely associated with retention within the intracellular compartment known as endoplasmic reticulum, and limited exposure of neutralizing epitopes. Based on our preliminary findings, we hypothesize that adding a secretory and anchoring signal to VP7 as well as adding other immunogenic ERVA proteins (VP4 and VP6) will enhance immunogenicity and the generation of antibodies that will neutralize ERVA G3 and G14 strains.
This proposal focuses on developing two viral vectored vaccines that can address the existing issues identified with expression of only VP7 in its native form and improve the vaccine platform proposed by inducing antibodies that can effectively block rotavirus and confer protection.
We plan to evaluate these vaccines first in mice (including their protective efficacy in an ERVA G3 and G14 infection model that we established in neonatal mice) and subsequently assess the immunogenicity of the most promising candidate in mares.
We expect that our novel vaccine design approach will build on our previous work and significantly improve the efficacy of current ERVA vaccines.
Importance to the Equine Industry:
Diarrhea in foals due to equine rotavirus continues to be a significant health issue causing outbreaks of disease in farms during every foaling season. Twenty to 77% of diarrhea cases in foals within their first three months of age are associated with equine rotavirus, while other causes of diarrhea are of lower impact.
The impact of the disease is variable but most frequently associated with high numbers of sick foals (high morbidity), which require intensive medical management. These sick foals are highly contagious and, therefore, control of the disease also requires strict biosecurity protocols to try to minimize the contamination of the environment and continued spread. While vaccination of pregnant mares is a common method of control and prevention, the current available vaccine has limited and controversial efficacy and, therefore, the level of protection is far from optimal, undermining its wide use. No changes to this vaccine formulation have been made since its licensure in order to improve its efficacy and keep up with more current circulating strains of this virus in the horse farms.
Therefore, this proposal brings a novel vaccine platform that can significantly enhance current control and prevention efforts to minimize the impact of this disease in young foals.
Ex Vivo DFTS Adhesion Model To Evaluate Therapies
Lauren Schnabel, North Carolina State University –One Year Grant
One Sentence Summary: This project will advance our understanding and treatment of adhesions that occur in the digital flexor tendon sheath of horses following injury and result in improved prognosis for performance.
Digital flexor tendon injuries are common in horses and can be career ending. These tendons are on the back of the leg and serve to generate motion. They are protected within a structure called the digital flexor tendon sheath which is similar to the lining of a joint and contains fluid which helps the tendons move freely. Inflammation or infection of the tendon sheath following injury often results in the formation of abnormal tissue adhesions, or bands of scar-tissue, within the tendon sheath and attached to the tendons themselves. These adhesions prevent the normal movement of tendons and result in chronic pain and loss of athletic use. This project aims to better understand how tendon sheath adhesions form and to develop more effective ways to prevent and treat them as the current treatment options are often unsuccessful.
Our research will explore how adhesions form and test two promising antiadhesion treatments, enalapril and tissue plasminogen activator (tPA), using a lab-based digital flexor tendon sheath model to ensure they are safe and effective. This model is the first of its kind and provides a controlled setting outside of the body to study how adhesions form and how different treatments work without live animals. This research will give a more complete picture of how adhesions form and how to stop them. It will also provide information on the best dose and number of doses when using these treatments, which is important to help veterinarians select the best treatment with the least side effects.
Overall, this research is a major step forward in improving treatment for tendon sheath injuries in horses. Our findings will be directly applicable to the clinical setting and will also be applied to future studies that will combine antiadhesion treatments with treatments that fight infection and support tendon healing to develop treatment plans based on each horse’s specific needs. This level of care will improve the quality of life for our injured equine patients and will reduce the emotional and financial burden on horse owners, trainers, and caretakers.
Importance to the Equine Industry:
Injuries of the digital flexor tendon sheath and associated deep and superficial digital flexor tendons are common in horses and carry a poor prognosis with only 36-50% of horses returning to their previous level of athletic function. Despite appropriate management and rehabilitation, this may be further complicated by the development of abnormal tissue adhesions, or bands of scar-tissue, that develop within the tendon sheath and attach to the tendons themselves. Once formed, these adhesions prevent normal motion of the tendons, leading to loss of function, chronic pain, and lameness, which can result in humane euthanasia and have a major impact on the equine industry.
This project aims to better understand how tendon sheath adhesions form and to develop more effective ways to prevent and treat them in order to improve outcomes for horses with injuries of the digital flexor tendon sheath. Such information is critical to improve the quality of life for equine athletes and reduce the financial and emotional burdens on those who care for them. Not only will our results be immediately applied to horses in the clinical setting, but they will also be used for future studies investigating combined treatments for combating infection and promoting tendon healing while also preventing adhesion formation. Collectively, this proposal will significantly advance our treatment of digital flexor tendon sheath injuries as a whole and will provide the equine industry with optimized antiadhesion treatments and strategies.
Effects Of SGLT2i On Triamcinolone-Induced Equine ID
Teresa Burns,
The Ohio State University –Two Year Grant
One Sentence Summary: This proposal will evaluate the degree to which joint injections with triamcinolone worsen insulin dysregulation in horses with ID and if use of canagliflozin at time of injection mitigates it.
Laminitis (or founder) is a devastating disease of the equine foot that causes intractable suffering for affected horses and economic loss to the equine industry. Laminitis associated with endocrine disease is the most common form and has been associated with three common conditions: equine metabolic syndrome, equine Cushing's syndrome, and administration of steroid medications (with joint injections, for example).
The biology of these three separate conditions differs significantly in certain respects, but insulin dysregulation (ID) is known to be a single consistent characteristic shared by all three. Very little is known about laminitis that occurs after steroid administration, given that it is uncommon and there is no reliable experimental model to induce it; however, a very large number of horses receive steroids in joint injections, as this is an extremely common therapy used to treat equine osteoarthritis.
Triamcinolone acetonide (TCA) is a steroid that is frequently used for this purpose. Based on the large number of horses receiving joint injections to maintain athletic soundness as they age, cases of laminitis that occur as a complication of this treatment are inevitable. Further clarification of risk factors associated with laminitis in this setting would be helpful to design strategies to make this very useful therapy safer, given that the number of older horses (including those with Cushing’s syndrome and EMS) engaged in athletic pursuits is increasing. The absorption and excretion of TCA following administration by various routes in horses (including in the joint) have been described. However, little is known about TCA''s effects on insulin and glucose metabolism following administration in the joint (even though this is the most frequent route by which it is given, and this effect is highly likely to relate to its perceived risk of inducing laminitis).
Since a consistent experimental model of steroid-induced laminitis has not yet been described, the mechanism by which these drugs create risk of laminitis remains unclear; however, systemic (IV, IM, or oral) steroid administration is known to induce ID.
Recently, new drugs for managing equine ID have been described, including sodium glucose cotransporter-2 inhibitors (SGLT2i; ex., canagliflozin, ertugliflozin, and velagliflozin); while these drugs are potentially very effective, they are expensive and may be associated with adverse effects with long-term use. However, short term use to prevent ID associated with joint injections may be an effective, novel use of these drugs in equine patients.
We propose to investigate the effects of TCA injected in the joint on systemic ID in horses with naturally occurring ID and the ability of canagliflozin (an SGLT2 inhibitor now used frequently to treat EMS patients) to prevent or decrease ID when given at the time of joint injection. Twenty-one adult horses GT 5 years of age will be screened for ID with an oral sugar test, enrolled if ID, and assigned to one of three groups (G1-3, n=7 per group). All horses will receive a joint injection of 20 mg TCA on Day 0, and assessments of systemic ID, including oral sugar test (baseline, Days 1, 3, 7, 10, 14, 30), IV insulin tolerance test (baseline, Days 1, 3, 7, 10, 14, 30), measurements of serum hormone concentrations (insulin, glucose, triglycerides, cortisol; baseline and Days 1, 3, 7, 14, 30), and serum biochemistry (baseline, Days 7, 14, 30) will be performed to determine effects of TCA given in the joint on clinically relevant measures of ID in horses with naturally occurring ID. Horses in G1 will receive TCA only; horses in G2 and G3 will receive canagliflozin (0.3 mg/kg by mouth once daily) starting the day of joint injection (one dose only for G2, 7 days for G3).
The information generated by this work will provide important information about this commonly used drug (TCA), as well as lay a foundation for future investigations of therapies that might be used to minimize ID associated with TCA joint injections and, therefore, the risk of inducing laminitis after this treatment. Further, if the results of this study provide evidence that administration of an SGLT2i around the time of joint injections reduces ID associated with steroid administration, they may then inform further investigation of this strategy to create rational guidelines for risk management when using TCA in this manner.
Importance to the Equine Industry:
Laminitis (or founder) is a devastating disease of the equine foot, and endocrine disease is currently the most common cause of laminitis in industrialized nations. This is a critically important economic and welfare concern for the equine industry worldwide. While equine metabolic syndrome-associated laminitis makes up the majority of cases encountered by equine veterinarians, laminitis associated with therapeutic steroid administration (such as joint injections) remains an important concern of veterinarians and horse owners alike, particularly since this treatment complication has proven difficult to predict and can be catastrophic for affected horses. Administration of steroids in joint injections is an extremely common therapy applied to treat orthopedic conditions, such as arthritis, that occur regularly in equine athletes. Drugs such as triamcinolone acetonide are frequently used for this purpose, and while the induction or exacerbation of laminitis following this type of treatment is thought to be rare, a recent study of laminitis associated with endocrine disease reported that horses that had received treatment with steroid medications in the past 30 days were 5.6 times as likely to develop laminitis than horses that had not received this treatment; this risk is very likely higher in EMS patients.
Given the increasing prevalence of obesity, EMS, and equine Cushing’s syndrome in populations of equine athletes, including horses in active competition, the likelihood that joint injections using triamcinolone might be performed on patients with underlying insulin dysregulation is high, and there is currently little clear information about how this therapy may affect control of the underlying endocrine disease, let alone the risk of laminitis. The risk of inducing insulin dysregulation with triamcinolone via joint injections is therefore of interest to equine veterinarians and horse owners, as well as ways to minimize this risk (such as use of SGLT2i's).
Finite Element Analysis Of SDFT Microdamage
Sushmitha Durgam, The Ohio State University –Two Year Grant
One Sentence Summary: This proposal will study the multi-scale finite element models (FEM) that predict equine superficial digital flexor tendon (SDFT) mechanical behavior that are essential to delineate microdamage mechanisms preceding clinical injury.
Superficial digital flexor tendon (SDFT) injuries are common career-ending injuries in racehorses; are due to tendon overstrain from cumulative damage to tendon microstructure (microdamage). The elastic strength of equine SDFT is mainly due to the sliding motion between type I collagen-rich fascicles that are separated and connected by elastin-rich interfascicular matrix (IFM). This complex hierarchical structure as well as the non-uniform matrix distribution in the fascicles and IFM impart SDFT its elastic strength. Even though cumulative microdamage has been linked to SDFT injuries, the precise changes at the tendon fascicle-IFM and collagen-elastin levels are largely unknown. Our prior GJCRF-funded research has demonstrated that fascicle size decreased and IFM thickness increased in 3-year-old Thoroughbred racehorses compared to 2-year-olds in response to athletic training; tendon tensile strength increased even though IFM elastin decreased.
These findings provide a strong premise to develop noninvasive tools to study tendon microdamage and for gaining insight on tendon injury mechanisms, since, at present, destructive methods like ex-vivo tensile mechanical testing remain the gold standard means to understand tendon loading. For finite element analysis (FEA), any given structure is segregated into smaller, simple, interconnected structures, each with assigned mechanical properties.
We will leverage our expertise in fascicle, IFM and whole tendon histomorphology and experimental tendon mechanics to develop computational finite element models (FEM) that can predict equine SDFT mechanical behavior. Equine bone FEM have proven to be useful to understand distal third metacarpal bone and P1 fracture predilection sites as well as determine load-induced risk factors for fracture. To date, finite element analyses (FEA) of equine tendon have not been conducted; specifically, multi-scale FEM that take into account the complex SDFT hierarchical structure and its non-uniform ECM composition will facilitate evaluation of SDFT internal loading as it is difficult to measure in-vivo.
Fresh cadaveric metacarpal SDFT will be used for the proposed foundational equine SDFT FEA. Intact and elastase-digested specimens will be used to parse out the contributions of collagen and elastin to tendon function. In AIM 1, the dimensions, and tensile properties of fascicles and IFM measured via confocal histology and tensile testing, respectively, will be used to construct fascicle and IFM FEM such that stress-strain properties can be calculated.
These results will be used to develop non-uniform constitutive models that consider both the fascicles and the IFM. Such a model would account for the tendon''''s tensile and recoil (elastic) properties, providing a more comprehensive representation of SDFT load bearing function. In AIM 2, the entire SDFT (quantified via MRI and 3D scan) will be used to estimate fascicle and IFM directionality and construct a multi-scale FEM through optimization methods while also measuring fascicle-IFM frictional properties.
A few published human Achilles tendon FEM describe simple models that only account for the collagen fibers or rely on macro models that predict muscle to tendon force transfer. Therefore, this research proposes FE² (Finite Element squared) method where this multi-disciplinary team will use advanced multiscale models to determine how interactions between fascicles and the IFM influence SDFT mechanics. This foundational FEA are vital not only for further research investigating how SDFT micro- and macro-damage can impact tendon tensile strength, but also for evaluating the efficacy of tendon therapeutics and improve tendon rehabilitation strategies.
Importance to the Equine Industry:
This research is important because, SDFT injuries continue to be a common cause of wastage in Thoroughbred racehorses. Although cumulative microdamage (chronic damage to the tendon microstructure) pathogenesis leads to clinical SDFT injury, mechanisms responsible tendon injury are largely unknown. At present, ex-vivo destructive tendon mechanical testing remains the gold standard method to understand tendon tensile properties and tendon injury development. Therefore, constructing a noninvasive computational technique that considers SDFT’s complex hierarchical structure and non-uniform matrix composition, will be invaluable to gain insights on tendon microdamage and injury development mechanisms.
This research will address this unmet clinical, and research need by constructing multi-scale finite element models (FEM) representing the complex hierarchical structureECM composition and study equine SDFT mechanical behavior, for which currently there is no information. Further, this computational methodology (that has been beneficial to understand bone fracture risk and predilection sites) holds the potential for combining with magnetic resonance-based fiber tractography and enable functional tendon imaging efforts.
This research builds on our (1) prior GJCRF-funded research and (2) laboratory’s overarching goal of understanding tendon microdamage mechanisms causing Thoroughbred racehorse SDFT injuries. The ability to predict SDFT mechanical behavior through FEM (1) will pave the way for equine distal limb dynamic modeling and subsequently be beneficial for reducing injury incidence and associated economic losses, (2) can evaluate the efficacy of novel and existing tendon therapeutics, and (3) improve tendon rehabilitation strategies.
A Molecular Study On Hemorrhagic Anovulatory Follicles
Eduardo Gastal, Southern Illinois University Carbondale –One Year Grant
One Sentence Summary: This study investigates gene and hormone levels in HAFs, the leading cause of ovulation failure in mares, using a novel technique (Follicle Wall Biopsy-Trinity) to collect multiple follicular samples.
In mares, hemorrhagic anovulatory follicle (HAF) syndrome is one of leading causes of ovulation failure and consequent subfertility. During a normal reproductive cycle, a single follicle (the structure that holds and nurses the egg) will grow until ovulation, upon which the structure will burst and release an egg, with the potential of becoming fertilized to form an embryo. For animals that experience HAF syndrome, a follicle that would normally ovulate will instead accumulate blood and expand to form a large structure that persists in the ovary for an extended period of time, until it naturally regresses after two to three weeks. As such, presence of HAFs leads to complete loss of the reproductive cycle for which it is present, since fertilization cannot be successfully achieved unless an egg is released.
For animals used for breeding in industries like showing and racing, this has severe financial implications as timing of reproduction, including insemination and birth, is often tightly controlled to produce high-quality foals as early in the year as possible. In the Thoroughbred industry alone, over 25,000 mares were bred, 17,000 registered foals were born, and the average yearling sold for over $80,000 in the year 2023. As these numbers show, this industry is a high-volume, high-value, and fast paced market where even a single missed reproductive cycle can have detrimental and long-term impacts. While incidence of this syndrome in mares ranges from approximately 5% during the early breeding season to 25% in the late breeding season, other factors such as age, administration of certain drugs, and mare predisposition to this syndrome also greatly affect the incidence of HAFs.
Previous research has focused on characterizing HAFs versus normally ovulating follicles, evaluating risk factors for HAF formation, and development of injections into the follicle as a potential treatment for HAFs. However, no study to date has explored the differences in hormone and gene expression of key factors in HAFs versus normally ovulating follicles to see if the egg and the follicle as a whole can be rescued from anovulation.
To answer these key questions, the current study will use a new, cutting-edge technique to collect several types of samples (tissue from the follicle wall, follicular fluid, granulosa cells, and the egg) from induced HAFs and normally ovulating follicles. To investigate the molecular differences between HAFs and normally ovulating follicles, we will examine various hormones, growth factors, and cell markers to see if there is any potential to save the egg cells or the whole follicle from the negative effects of HAF formation.
We predict that while certain negative markers, like cell death and inflammatory markers, will be higher in HAFs, the follicle itself will be more affected than egg, meaning that perhaps with proper treatment, the follicle can be saved, and the egg may still be fertilizable upon ovulation.
To test these hypotheses, we have designed three experimental groups:
(1) Negative Control Group, with mares that are allowed a natural reproductive cycle;
(2) Positive Control Group, with mares that have an ovulation induced via chorionic gonadotropin (hCG);
(3) HAF Group, with mares that will have HAF formation induced via an already well-established protocol.
When a mare’s follicle becomes large enough, she may be given drugs, and samples will be collected 38 hours later. For this study, we will be collecting six different types of samples: (i) blood, to measure hormone levels, (ii) follicular fluid, to measure hormone levels and markers of ovulation, (iii) follicle wall tissue, to measure expression of growth factor and hormone receptors, inflammatory and cell death markers, and enzymes related to ovulation, (iv) mural granulosa cells (the cells lining the follicle wall), (v) cumulus granulosa cells (the nurse cells surrounding the egg), and (vi) the egg, to measure levels of hormone receptors, cell proliferation markers, and cell death genes in the three aforementioned sample types. To collect these samples, we propose the use of a new, cutting-edge technique that allows for the collection of all six of these samples in the same procedure.
This technique, called Follicle Wall Biopsy-Trinity (FWB-Trinity), recently designed and developed by our lab, ensures that a mare will only have to undergo a single invasive procedure per reproductive cycle, serving to maximize animal welfare and minimize animal use. Furthermore, preliminary studies generated by our lab show that this technique can be performed multiple times on the same mare, allowing for repeated sample collections over time. In summary, by performing this project, we will be able to provide a foundational study on HAFs, with the hope of advancing knowledge on this syndrome and to provide groundwork for eventual development of a treatment.
Importance to the Equine Industry:
For mares used for breeding in industries like showing and racing, every reproductive cycle is precious, as timing of reproduction, including insemination and birth, is often tightly controlled. However, every breeding season, thousands of mares experience fertility problems, often linked to aspects of genetic predisposition and intensive management practices.
In cases of anovulation, where a mare’s follicle fails to ovulate and release a fertilizable egg, the presence of a hemorrhagic anovulatory follicle (HAF) is the leading cause of subfertility. In the Thoroughbred industry alone, over 25,000 mares were bred, 17,000 registered foals were born, and the average yearling sold for over $80,000 in the year 2023. As these numbers show, this industry is a high-volume, highvalue, and fast paced market where even a single missed reproductive cycle can have detrimental and long-term impacts.
Furthermore, in other breed industries like Quarter Horses and Arabians, practices such as ovum pick-up and intracytoplasmic sperm injection are becoming standard; however, the effects of HAFs on the egg cell have not been investigated. By examining the molecular differences between HAFs compared to normally ovulating follicles, we can determine if there is potential to save the follicle from anovulation and rescue these eggs. However, previous methods for collecting follicular samples have involved a mare undergoing multiple invasive treatments in a short time.
Thus, this study will use a novel technique developed in our lab, Follicle Wall Biopsy-Trinity, to collect several different types of follicular samples in a single procedure, serving to maximize animal welfare and minimize animal use. In summary, by performing this project, we will be able to provide a foundational study on HAFs, with the hope of advancing knowledge on this syndrome and to provide groundwork for eventual development of a treatment.
Improving a VapA mRNA Vaccine For R. Equi In Foals
Noah Cohen, Texas A&M University –Two Year Grant
One Sentence Summary: The aim of this study is to improve the design of a mRNA vaccine for foals to provide stronger, longer immunity against Rhodococcus equi, a leading cause of disease and death in foals worldwide.
Great need exists to develop an effective vaccine against Rhodococcus equi (R. equi) pneumonia of foals because of the importance of this disease to the equine industry (please see Importance to the Equine Industry below). Our long-term goal is to develop a messenger RNA (mRNA) vaccine to protect foals against pneumonia caused by R. equi. The vaccine target will be the virulence associated protein A (VapA) of R. equi. The rationale for targeting VapA is that it is necessary to cause disease in foals, it induces robust immune responses in foals after vaccination or natural infection, and antibody activity against VapA in foals is associated with lower odds of rhodococcal pneumonia (i.e, higher anti-VapA antibody levels are associated with protection against pneumonia).
A prototype VapA mRNA vaccine that we developed initially appeared to induce good immune responses in foals, but in a study conducted during 2024 the same vaccine was not highly effective at stimulating immune responses in foals, leaving some foals unprotected against experimental infection of their lungs with R. equi.
In this project, we aim to improve upon our prototype vaccine by designing the mRNA to include a protein known as lycosylphosphatidylinositol (GPI) that will attach VapA protein to the surface of cells at the site of injection. This anchoring will allow for greater exposure of the immune system of vaccinated foals to the VapA protein. In other species of mammals, anchoring with GPI has been demonstrated to result in longer lasting and stronger immune responses to anchored vaccine targets. In our first aim, we propose to demonstrate that the anchored VapA mRNA vaccine – but not our prototype (original) VapA mRNA vaccine - is expressed on the surface of equine cells grown in the laboratory into which the mRNA has been introduced.
In our second aim, we will compare the antibody levels against VapA of foals immunized intramuscularly (IM) at ages 1 and 21 days with our new anchored VapA mRNA vaccine to those
of foals immunized IM at the same ages with our prototype (original) mRNA vaccine. We expect to find that a construct of mRNA can anchor VapA to equine cells and that young foals vaccinated with this anchored mRNA will develop more robust and longer-lasting immune responses. If we are successful, this anchored mRNA vaccine could be advanced to assessing its ability to protect foals against infection with R. equi.
Importance to the Equine Industry:
The horse industry remains an agriculturally and economically important venture in the U.S., generating over $177 billion in total production in 2023 according to the American Horse Council. Producing healthy foals is necessary to maintain and improve the nation’s horse population, and the health of foals is important to the horse industry from a welfare perspective. Infectious diseases are leading causes of disease and death in foals, and pneumonia is a principal infectious disease of foals. Respiratory disease was the most common cause of disease and death in foals in Texas, and ranked 3rd as a cause of morbidity and 2nd as a cause of mortality in U.S. foals 1 to 6 months of age. R. equi is considered the most common cause of severe pneumonia. This disease is important to the equine industry for the following reasons. The disease is endemic at many horse-breeding farms with cumulative incidence often around 20% to 40% of the foal population. Although rigorous, systematic economic impact studies for this disease are lacking, it is widely recognized that the costs resulting from veterinary care, long-term therapy, and mortality of some foals are very high at affected farms. In addition to significant immediate costs, R. equi pneumonia can have a long-term detrimental effect on the equine industry because it has been reported that North American foals that recover from the disease are less likely to race as adults and performance was diminished by this disease for some Australian Thoroughbreds.
Organoid Model For Equine Placentitis Research
Pouya Dini, University of California-Davis –Two Year Grant
One Sentence Summary: This project’s aim is to develop an in vitro model of equine placentitis to advance the study of this condition, ultimately improving diagnostics, treatments, and pregnancy outcomes.
Placentitis, or inflammation of the placenta, is the most common placental abnormality in horses 1–5,10. Most cases are caused by a bacterial infection, primarily by S. zooepidemicus, which is believed to reach the placenta via the birth canal2,3,6,7. This type of placental infection is known as ascending placentitis. The resulting inflammation can trigger premature delivery or abortion in late-stage pregnancy1–5,10. Unfortunately, placentitis often develops subtly, with clinical signs appearing only in advanced stages, making effective treatment challenging.
Our current understanding of placentitis development and progression is primarily based on clinical cases, which typically represent more advanced stages of the disease, as diagnosis occurs only after symptoms become visible. Additionally, while experimentally induced cases are valuable tools, they rely on live animals, raising ethical concerns, limiting sample sizes, and incurring high costs. These constraints hinder the study of the early stages of the disease, particularly the initial infection triggers and the dynamic interactions between the horse placenta and the pathogen (host-pathogen). Consequently, these limitations restrict the development of early diagnostic tools and effective treatment strategies.
To address these challenges, we propose an innovative approach using placental organoids, which are miniature versions of the placenta grown in the laboratory. Over the past decade, organoid cultures have emerged as a vital tool to bridge the gap between in vitro and in vivo studies36–39. Organoids are complex, three-dimensional, self-organizing, and self-renewing multicellular structures that closely replicate the key functional, morphological, and molecular features of the original organ36–39. Even though organoids lack an immune system, they can still detect pathogens and respond to them, similar to the first line of pathogen detection in tissues such as the placenta55. By replicating placentitis in a laboratory setting, we can explore crucial questions such as: How does the bacterium initially infect the placenta? And how does the placenta respond on a molecular level during the early phases of infection? The insights gained from this research could contribute to the development of better diagnostic tools that can detect placentitis much earlier, allowing for prompt intervention before irreversible damage occurs. Furthermore, by identifying specific genes, proteins, and pathways involved in the host-pathogen interaction, we may discover new therapeutic targets or test the efficacy of the current treatment strategies, leading to more effective and targeted treatments that reduce the need for broad spectrum antibiotics and improve outcomes for both mares and foals.
To achieve our goal, we developed an equine-specific placental organoid model and, over the past two years, tested its similarity and function through several independent methods, such as RNA sequencing, single-cell RNA sequencing, hormone production, electron microscopy, protein assays, and fluorescent microscopy53,54. All these methods indicated a high degree of similarity between the in vitro model and the actual placenta. Additionally, we cultured S. zooepidemicus, the same strain used in most experimentally induced placentitis studies, analyzed its genome, transformed it with a fluorescent reporter, and tested its growth in the lab11. In addition to the equine placental organoids and microbial cultures, we evaluated the presence of the microbe in the placenta of both healthy21 and placentitis-affected (preliminary data) horses and found an inactive form of S. zooepidemicus in the healthy placenta.
With this background, we aim to meticulously study the initial interactions of this bacterium with the placenta and the progression of placentitis in the lab. This study will allow us to get insights into the early disease process without the need for live animals, respecting animal welfare (principles of the three Rs)55 while advancing scientific knowledge. In addition, the development of this organoid-based model has broader scientific implications, setting a foundation for similar studies in horses and other species.
Importance to the Equine Industry: Placentitis, the most common placental disorder in horses, poses a significant threat to equine reproduction1–5,10. Most cases result from S. zooepidemicus infections, believed to ascend through the birth canal and infect the placenta, causing inflammation that triggers premature birth or abortion in late pregnancy2,3,6. Placentitis progresses silently, with clinical signs appearing only in advanced stages, making early diagnosis and treatment challenging5–8. Beyond the health risks to foals, placentitis results in significant financial losses for the industry and emotional strain on horse owners. Despite numerous studies on placentitis, many questions remain unanswered, particularly regarding how the infection begins and progresses. Our research aims to fill these gaps by creating an in-lab model of placentitis using placental organoids53,54. We will infect these organoids with S. zooepidemicus to study the initiation and progression of the disease. By analyzing gene expression and metabolite production in both the placenta and bacteria at different stages of infection, we aim to uncover new insights into their host-pathogen interaction over time. We will compare these findings to in vivo cases of placentitis and conventional microbial culture techniques. This proposal will (1) identify how S. zooepidemicus initiates placentitis; (2) analyze the dynamic interaction between the microbe and placenta by identifying important genes and metabolites for the pathogenesis of placentitis; (3) identify gene expression patterns of the host to determine key genes involved in the host response to the pathogen. Overall, by simulating placentitis in a lab setting, our study aims to uncover critical details about the pathogens’s behavior and the host’s response. This research will pave the way for more effective diagnosis and treatments, ultimately reducing losses in the equine breeding industry
Genetics Of Cervical Spine Malformations In The Horse
Carrie Finno, University of California-Davis –Two Year Grant
One Sentence Summary: This study will identify genetic causes for abnormal formation of the cervical spine in horses.
Abnormal formation, or malformations, of the cervical spine are anatomical variations that can be associated with neurological disease, lameness and neck pain in the horse. In this study, we propose to gain a better understanding of these malformations in the horse and to determine the genetic causes. Within the seven cervical vertebrae in horses, the middle vertebrae (C3 to C5) are rather uniform. However, the vertebrae at each end (closest to head, C1 and C2) and (closest to chest, C6 and C7) are specialized and demonstrate different shapes. Interestingly, both of these regions have been associated with malformations. For this proposal, we will focus on two distinct malformations. These malformations include one that affects the first few vertebrae in the neck (occipitoatlantoaxial malformation or OAAM) and malformations that affect the lower vertebrae in the neck (called TC67) malformations. Whereas OAAM is reported in Arabian horses, these TC67 malformations primarily occur in Warmbloods and Thoroughbreds.
Previous work in our laboratory has discovered the genetic cause for OAAM1 in Arabian horses. This genetic mutation resides in a regulatory area of a gene, HOXD3, that is involved in coding for the formation of body structures during embryonic development. This family of homeobox genes direct the formation of many body structures during early embryonic development. However, the OAAM1 variant does not explain all cases of malformation at the first few vertebrae in the neck. We have recently identified a family of Arabians with malformations of the second vertebrae and incoordination as a result of this malformation. These horses tested DNA negative for OAAM1. In Specific Aim 1, we will use whole-genome sequencing to investigate the genetic basis for this malformation in this family of Arabian horses. We hypothesize that a genetic variant in, or regulating, one of the HOX4 genes will be associated with this inherited malformation in Arabian horses. Identifying the genetic basis for this malformation will provide a genetic test for Arabian breeders and expand our understanding of the genetic pathways involved in overall cervical spine malformations.
Current estimates of TC67 approximate that between 20-30% of Thoroughbreds and Warmbloods have this anatomic variant. The genetic cause for this was proposed to be similar to a disease in cattle, called Complex Vertebral Malformation. However, the phenotype in cattle is clearly distinct from TC67 in horses. In Specific Aim 2, we will use whole-genome sequencing of horses with TC67 to exclude the gene that is causing disease in cattle as the gene for TC67 in horses. We will then investigate if there is a genetic basis for TC67 by creating pedigrees of affected horses and examining whole-genome sequences for possible genetic changes.
Importance to the Equine Industry:
Despite varying opinions on whether these malformations, specifically TC67, result in disease or not, young horses are being increasingly euthanized based on this x-ray diagnosis and without associated signs of disease. Once we have identified potential genetic causes for the second vertebrae malformations in Arabian horses and TC67 malformations in Thoroughbreds and Warmbloods, we will expand our study to genetically test horses for these malformations and begin to associate signs of disease and performance success with these genetic malformations. Our long-term goal is to provide diagnostic tests for these malformations in the horse, while working closely with clinicians to define the clinical relevance.
Pharmacokinetics And Efficacy Of Pregabalin In Horses
Heather Knych, University of California-Davis–Two Year Grant
One Sentence Summary: The study seeks to investigate the behavior of an analgesic agent approved for use in humans for the treatment of persistent pain, as a first step in assessing the utility of this drug for pain control in horses.
Pharmaceutical options for pain management, especially alleviation of persistent pain in horses are limited by side effects. Pregabalin and gabapentin are two drugs used extensively in human medicine for the treatment of persistent pain. While both exert their effects in a similar manner, pregabalin is better absorbed. For example, in horses’ gabapentin is characterized by very poor oral absorption whereas pregabalin is well absorbed. A single dose study of pregabalin in horses has been conducted, however the effects of this drug were not assessed. Given the potential benefits to the horse, the current proposal aims to build on the previous knowledge and assess the analgesic effects of pregabalin using well-established experimental models of thermal nociception and lameness following both a single dose and multiple administrations.
The way the horse’s body processes the drug (pharmacokinetics) will also be further characterized. In the first part of the study, 8 university owned research horses will receive a single oral administration of 4, 6 and 8 mg/kg of pregabalin and a 2-gram dose of phenylbutazone paste (positive control) in a 4-way balanced crossover design with a minimum 3-week drug free period in between treatments. Blood samples will be collected up to 72 hours following drug administration, drug concentrations measured, and pharmacokinetic parameters determined. Preand post-drug related behavior, heart rate and gastrointestinal sounds will be recorded. Response to noxious stimuli will be evaluated by determining the time of response to the application of heat and the effect on lameness utilizing a shoe model of mechanical lameness.
In the second part of this study, eight horses will receive multiple oral doses of pregabalin or phenylbutazone paste, every 12 hours for a total of 9 doses, in a 2-way balanced crossover design with a 6-week drug free period between pregabalin and phenylbutazone administrations. The dose of pregabalin will be determined based on the results of the first part of the study. Blood samples will be collected throughout the dosing period for determination of drug concentrations. The effect of pregabalin on response to heat and mechanically induced lameness will be determined throughout the dosing period. For both the single and multiple administrations, statistical analyses will be conducted to assess differences in parameters prior to drug administration and post drug administration as well as to assess differences between pregabalin doses and phenylbutazone.
Importance to the Equine Industry:
Pain control will have potential benefits to the horse while trying to limit the side effects.
Characterization of Antibodies against Equine IL-31
Rosanna Marsela, University of Florida –Two Year Grant
One Sentence Summary: This proposal aims to develop a new treatment for equine insect bite hypersensitivity (IBH) by targeting a key itch mediator, providing an alternative to steroids.
We believe that a therapy targeting IL-31, a key trigger of itching, can greatly improve the well-being of horses suffering from allergies. Some allergies, like insect bite hypersensitivity (IBH), cause intense itching and currently have no treatment options other than steroids. Our team has developed antibodies specifically designed to target equine IL-31.
This proposal aims to further validate these antibodies, which could lead to a new treatment option for itchy horses. Our goal is to create a safe and sustainable alternative to steroids that benefits equine athletes without compromising their health and performance. This new therapy will involve monthly injections of a biologic that selectively binds to and inactivates IL-31. This type of treatment, known as a "biologic," is commonly used in human medicine for various diseases, from eczema to cancer. It is advantageous because it is more targeted than traditional drugs, which can reduce the risk of side effects. Currently, horses have very few options for treating allergies and itching. This treatment could significantly improve their lives and the lives of their owners. The studies proposed in this application are essential for further characterizing the antibodies, which are necessary steps before we can proceed to clinical trials in the future.
Importance to the Equine Industry:
Skin allergies in horses are often treated with steroids, but these drugs can lead to harmful side effects, especially with long-term use. Our goal is to develop a new treatment that avoids steroids and is safe for racehorses and other performance horses. This innovation would be a game-changer for the equine industry, offering a safer, more effective solution that helps horses stay healthy and perform at their best without the risks associated with steroids.
The treatment we plan to develop will be a biologic, specifically monoclonal antibodies designed to target itching. Unlike steroids, these antibodies are not considered performance enhancers in human medicine, so they won’t carry the same restrictions. This means we can provide a healthier option for horses suffering from allergies, enhancing their quality of life and performance.
Characterization Of Laminitis Using PET
Dianne McFarlane, University of Florida –Two Year Grant
One Sentence Summary: This study will validate the use of PET scans for identifying disease pathology and progression in insulin associated laminitis in horses.
The unique and inaccessible anatomy of the equine hoof has been the major factor that has impeded the ability to understand the events that lead to the structural failure of the foot in equine laminitis. The recent adaptation of the diagnostic imaging method, positron emission tomography (PET) to characterize inflammation and metabolism in the equine limb has provided an opportunity to non-invasively examine structural and functional changes during the different phases of laminitis in the live horse.
The goal of this research is to define how PET can be used in diagnosis, prognosis and rehabilitation management for horses with laminitis. First, PET imaging will be compared to clinical, radiological and pathological markers in early experimental cases of laminitis. Next, PET imaging will be used to characterize the acute, subacute and recovery phases in clinical cases of laminitis. Together, completion of these aims will improve our understanding of how clinical and radiological findings relate to PET findings and how PET can be used to better treat cases of laminitis in practice.
Importance to the Equine Industry: Laminitis is a highly painful disease of the equine foot in which the soft tissue structures (lamellae) that attach the hoof wall to the coffin bone fail, leading to rotation and sinking of the coffin bone. There are more than 100,000 cases of laminitis each year in the US, 5-8% of these resulting in euthanasia. Yet despite the importance of laminitis to the equine industry and horse owning population, there are few effective treatments or proven recommendations for management.
In this study, we will examine the utility of a new diagnostic method PET to aid in diagnosis and monitoring of laminitis. Using PET scans to identify the disease processes of laminitis within the equine hoof without a need for invasive or terminal biopsies will have a profound impact on the equine industry. The ability to monitor ongoing functional and structural changes in the foot of the live horse will greatly aid in development of future effective therapies and pharmaceuticals. Using PET scans to recognize clinical cases of laminitis earlier than current methods may mean quicker interventions and more horses with a positive outcome. In addition, data from this study will serve in the generation of specific recommendations on appropriate rest time to ensure resolution of laminitis.
Effects of Inflammatory Cytokines on MSC Homing
John Peroni, University of Georgia –Two Year Grant
One Sentence Summary: This study will investigate how mesenchymal stem cells traffic to injuries after delivery to the bloodstream to inform the best time to deliver cells relative to initial injury in future animal models.
Mesenchymal stem cells (MSCs) are a special type of stem cell that can turn into a variety of cell types, such as bone, cartilage, and muscle cells. They also can help repair damaged tissues, which makes them important for therapies aimed at healing injuries.
One of the challenges in using MSCs for therapy is understanding how they get to the site of injury, especially after they are introduced into the bloodstream—a process called vascular perfusion. Vascular perfusion means that the MSCs are delivered directly into the blood vessels that supply the injured area. Once they are in the bloodstream, MSCs need to "home" to the site of damage in order to participate in the healing process. This proposal aims to address how MSCs move from the bloodstream, across the tissues, and arrive at a site of injury. This information is critical to understanding how to best utilize MSCs to treat localized injuries in horses.
When MSCs are injected into the bloodstream, they don’t automatically go to the injury site. Studying how MSCs move or "traffic" through the body to the injured area helps us better understand the steps that need to happen for healing to begin. Additionally, right after an injury occurs, the body goes through several stages of repair, from inflammation to tissue rebuilding. If we know how quickly and because of which signals MSCs can travel to the injury site, we can determine the best time to deliver them for maximum healing. For example, if MSCs are most effective during the inflammation phase, we need to time their delivery right after injury.
We will engage in a series of experiments aimed at identifying the specific inflammatory signals required for MSCs to interact with the blood vessel wall, migrate across it, and eventually reach a site of inflammation. Eventually we plan to employ cell tracking techniques to follow MSCs after they are introduced into the bloodstream in a horse. For example, advanced imaging technologies can help visualize where the cells go over time, while cell trackers can indicate when the cells arrive at the injury.
Importance to the Equine Industry:
The lower limb and the hoof are the areas in which most performance limiting lameness in the equine athlete are found. Distal limb injury treatments could be improved with biological therapeutics, which are recognized for their potent anti-inflammatory effects and promotion of wound healing. Biologic therapies like Mesenchymal Stem Cells (MSCs) are becoming increasingly requested by horse owners and used in the clinical settings. Despite this, there is currently no agreement on the types of injuries well suited for MSC treatments, ideal treatment delivery methods, or when to give cell treatments after injury. To enhance the effectiveness of MSC therapies, it is necessary to maximize the delivery of MSCs to the target injury. The positive effects of MSC therapies has been shown to improve when more MSCs are delivered to an injury.
As such, it is critical to understand how MSCs move around the horse’s body after being given as a treatment. Many clinicians opt to directly inject MSC into a wound in an effort to increase the number of cells delivered to the area. However, some injuries are inaccessible with a needle. Additionally, this route of administration can lead to complications such as further tissue damage and adverse reactions like swelling or lameness. Regional limb perfusion (RLP) commonly used in equine medicine, and could be used to deliver MSCs to the equine lower limb via the bloodstream. Unfortunately, there is minimal information regarding the efficacy of this technique to deliver MSCs to injured horse legs. This study will investigate how MSCs interact with their environment to travel out of the bloodstream and into the wound site. The study will address gaps that are paramount to creating clinical guidelines for MSC therapies, especially as it relates to timing of cell treatments. Ultimately, our goal is to clarify optimal usage of cell therapies so that better, more accessible cell treatments are available.
Racehorse Stride Changes And Workload During Training
Peta Hitchens, University of Melbourne –Two Year Grant
One Sentence Summary: By determining whether the workload and changes in stride characteristics associated with injury during racing are also present during training, this project may identify injuries prior to race-day.
Understanding the development of limb injuries is important for improving both the welfare of athletic animals and humans alike. Limb injuries in racehorses are the main reason for enforced rest and early retirement and may reduce the likelihood of a secondary career after racing. These injuries account for the majority of racehorses fatalities and have also been identified as the most common reason for serious jockey injuries. Detecting early signs of injury development could therefore help reduce this burden on the horse racing industry, as well as improve our knowledge of injury development more broadly.
Most fatal injuries in racehorses are due to repeated high impact to the bone resulting in accumulation of damage and subsequent fracture. While past injury risk models simply classified horses as injured or not injured at a single point in time, new inertial sensor technology allows for the monitoring of workloads and physiological changes over time. This monitoring provides us with a novel way of assessing signs of injury development.
Our group has demonstrated the potential utility of monitoring speed and strides from race-to-race. We previously found a reduction in stride length and speed occurring approximately six races prior to injury, as well as more varied speeds linked to injury, and no improvement in stride length linked to horses requiring long periods of rest from racing. We have also demonstrated the utility of speed and stride data from racing for calculation of acute and chronic workloads. What we are missing is being able to monitor workloads and physiological changes day-to-day during training.
The proposed research will utilise a large database containing training and veterinary data of over 500 racehorses from Australia’s largest training establishment from 2020 and 2024. The specific aims are: (1) To determine the characteristics of racehorse strides during training and whether any changes in these characteristics are correlated with changes observed during racing; and (2) To develop protocols for estimation and visualization of training and racing workloads based on inertial sensor and training logbook data. These aims are relevant not only to racehorses, but also other animal and human athletes.
Our goal is to develop practical and scalable methods for early injury detection and prevention by using data easily accessible to trainers, veterinarians or regulators for routine monitoring of racehorses. The outcomes of this project may facilitate earlier identification of horses at high risk of injury, resulting in the timely modification of workloads by informing safer training practices, and may lead to the implementation of real-time monitoring systems.
Importance to the Equine Industry:
The horse racing industry faces public pressure to improve, in large part due to high-profile cases of racehorse injuries resulting in death. However, these cases are just one part of a much larger problem. Aside from accounting for the majority of deaths, racehorse injuries are the key reason for forced absence from racing as well as early retirement. These injuries may also affect the possibility of the horse having a career beyond racing and compromise the safety of the jockey.
Identifying early signs of injury development, such as changes in a horse's speed and stride length over time, could help reduce this burden. Using inertial sensor data from racing, our previous research showed that horses decreased their speed and stride length several races before injury. Monitoring these changes during training, not just racing, could allow for even earlier detection of potential injuries, as well as the ability to monitor horses that are yet to have their first race start.
This project will take advantage of a large database containing training, racing, and veterinary data from Australia’s largest training establishment, including detailed information on horses’ speed and stride characteristics collected via sensor and global positioning systems.
The findings from this research will advance our understanding of how injuries develop in racehorses and improve our ability to detect such injuries based on changes in a horse’s speed and stride during both training and racing. We aim to develop methods for early detection and prevention of limb injuries in racehorses using data that are accessible for routine monitoring.
Synthetic Proteoglycan Replacement For Osteoarthritis
Kyla Ortved, University of Pennsylvania –Two Year Grant
One Sentence Summary: This proposal seeks to establish a new class of injectable, cartilage-penetrating compounds made from synthetic polyelectrolytes that replace proteoglycans that are critically lost in osteoarthritis.
Joint cartilage is a remarkably strong tissue capable of withstanding considerable force. The strength of the tissue is conferred by the robust extracellular matrix (ECM) that is composed mainly of proteoglycans and collagen. Despite the impressive strength of cartilage, it is susceptible to damage and trauma, especially in equine athletes. Following joint injury, inflammation in the joint leads to breakdown of the ECM with notable loss of proteoglycan. Early osteoarthritis (OA) is marked by a loss of proteoglycans in cartilage which leads to further cartilage degradation because in healthy cartilage, proteoglycans create an osmotic pressure from their negative charge, which supports compressive loads. Clinical features of OA include pain, decreased range of motion, and joint effusion. In severe cases, permanent loss of joint function occurs. Joint injury and OA are the second leading cause of retirement in the equine athlete and currently there are no effective disease-modifying OA drugs to halt or reverse OA; therefore, there is a critical need for the development of new approaches for cartilage repair and prevention of OA.
In healthy articular cartilage, compressive mechanical loads are supported by a stiff ECM and an internal pressure generated by proteoglycans. Early in OA, posttraumatic inflammation and increased enzymatic degradation result in loss of proteoglycans from the ECM. In an effort to treat OA, approaches have turned towards developing glycosaminoglycan (GAG) and proteoglycan mimics that can restore healthy ECM properties in damaged cartilage, thereby restoring mechanical functions of the tissue and supporting overall joint health. However, despite the immense economical cost and prevalence of OA, and the importance of proteoglycans in cartilage function, there are currently no such proteoglycan treatments that stabilize the ECM. A key technical challenge is that proteoglycan replacements need to be able to diffuse throughout cartilage to achieve therapeutic benefit. However, any proteoglycan replacement that can easily diffuse into cartilage will also easily diffuse out. To overcome this limitation, our team has developed a fully synthetic proteoglycan replacement based on thermal polymers. As a liquid at room temperature, poly(N-isopropylacrlyamide) (PNiPAm) diffuses rapidly through the joint and into the cartilage. As the polymer reaches body temperature, it undergoes thermal gelation and is “locked in” the cartilage. This thermal gelation is a new strategy in OA to overcome the historical challenge of delivering and retaining proteoglycan replacements in the ECM. Although PNiPAm is widely used in drug delivery, and PSS (polystyrene sulfonate) is an FDA-approved treatment for an unrelated disease, the combination of the two into a copolymer is a synthetic challenge and a novel treatment strategy for cartilage damage. Our robust preliminary data in vitro demonstrates the ability of this compound to penetrate cartilage concentrating in areas of proteoglycan depletion, retain in cartilage for up to 5 days and likely beyond, and most critically, restore biomechanical function in degraded cartilage.
Our proposal seeks to evaluate this promising synthetic compound in the horse to establish a new class of injectable, tissuepenetrating compounds made from synthetic polyelectrolytes that will replace the function of lost proteoglycans and, critically, are retained within damaged cartilage for long durations (weeks to months). Our central hypothesis is that by diffusing our polymer into damaged cartilage, and enabling its long-term retention via thermal gelation, the biomechanical properties of cartilage will be enhanced to nearly its undamaged form, thus improving the load-bearing function and reducing a potent contributor to cartilage degradation. Our primary outcome measures will include histological and biomechanical assays, while our secondary outcome measures will assess downstream effects of a proteoglycan stabilization including gait assessments and synovial fluid biomarkers. This proposal has the potential to develop a new treatment option that directly targets the biomechanical function of the ECM, thereby preventing OA progression.
Importance to the Equine Industry:
Joint injuries often have serious, long-term effects that lead to OA which remains one of the leading causes of retirement in horses. Currently, there are no effective disease-modifying therapies that halt or reverse the progression of OA. This proposal addresses this critical, unmet need in the equine industry as it seeks to establish a new therapeutic that will bolster the ECM and preserve the biomechanical function of the joint thereby preventing the progression of OA. Historically, horses with OA were treated symptomatically with rest, systemic non-steroidal anti-inflammatories drugs (NSAIDs), and intra-articular corticosteroids. Although these approaches can temporarily decrease pain and inflammation, they do not reverse joint damage and are associated with side effects including gastrointestinal ulceration and renal damage with prolonged NSAID use, and steroid arthropathies and laminitis with repeated intra-articular corticosteroid injection. Newer generation intra-articular treatments including orthobiologics such as platelet rich plasma, autologous protein solution and stem cells can decrease inflammation and promote healing and homeostasis within the joint. However, there are currently no treatments that directly address the loss of proteoglycan in the ECM and reverse the deteriorating biomechanical strength of the articular cartilage. Here, we seek to establish a new category of joint therapy that can be used in conjunction with anti-inflammatories to provide synthetic support to the ECM and prevent further joint degradation.
SECOND YEAR GRANTS
EQUINE TENDINOPATHY: ADVANCED IMAGING AND TENEX EFFICACY
Brad Nelson, Colorado State University –Second Year
One Sentence Summary: This study will enhance our knowledge of equine tendon repair by comprehensive clinical imaging, while simultaneously assessing a novel tendon therapy, improving veterinary and industry understanding.
Tendon and ligament injuries are a significant cause of musculoskeletal disease in equine athletes, which results in an inability to perform their athletic activities and often leads to early retirement. Once injured, tendons heal poorly, and repair tissue frequently consists of scar tissue. This lack of healing response predisposes horses to re-injure, even after several months of controlled rehabilitation. There are many treatments aimed at improving the tendon healing response, but none do this well enough to prevent re-injury. Percutaneous Ultrasonic Needle Tenotomy (PUNT) with a Tenex device has shown promise in humans with tendon injury by improving the healing process, though it is unknown if it is useful in treating horses. In this study, we propose using a common equine model of the superficial digital flexor tendon (SDFT), a commonly injured tendon in equine athletes, with a modification that more closely represents clinical disease scenarios. This new model will be used to determine whether PUNT has any benefit in horses. Our research team has expertise in advanced ultrasound and MRI techniques and in bench-top tendon analyses. We will use this knowledge to not only improve our understanding of tendon injury and repair, but these methods will also help us critically evaluate if PUNT is an effective treatment in horses. Completing this study will benefit equine veterinarians, owners, trainers and the industry by improving our understanding of tendon disease and has the potential to offer new imaging strategies that can be incorporated into equine clinical practice.
Importance to the Equine Industry: Upon completion of this study, we will be able to provide the equine industry with a more complete understanding of equine tendon healing and the potential benefit of a new tendon therapy for horses. Equine tendon and ligament injuries are frequent, and the long duration of healing needed to return to work and high re-injury rates are a serious problem. This study will provide us with highly detailed imaging data that can be used to better understand the healing response to tendon injury in horses and will inform clinicians how best to intervene to improve healing. These imaging methods have the capability of being incorporated into clinical practice. Furthermore, if this new tendon therapy results in improved healing, it will have the potential to improve the quality of tendon repair tissue and return horses to athleticism earlier with a lower chance of re-injury. Collectively, this work will improve our knowledge of tendon disease in the horse, which we can use to better inform the equine industry and drive future advancements in tendon injury and therapies.
SHINING A LIGHT ON THE BLACK BOX OF EARLY PREGNANCY LOSS
Amanda de Mestre, Cornell University –Second Year
One Sentence Summary: This study will determine how common genetic disorders of the early equine embryo occur as well as identify how they present to veterinarians and key factors that increase their risk.
Whilst progress has been made over the last two decades in getting more mares pregnant, owners and veterinarians still face a significant challenge in preventing pregnancy loss, particularly in the first two months after conception. This lack of progress is significantly hampered by our lack of understanding of the reason a pregnancy fails making treatment and management approaches close to impossible. Previous research has focused on the possible role of the mare’s uterus in providing a suitable environment for the developing embryo, but in contrast, a significant gap exists in understanding all other causes of early pregnancy loss (EPL) which account for around 60-80% of cases. Our lab has been investigating novel reasons why a pregnancy may fail and have approached this by working alongside vets, to pioneer new methods to obtain clinical cases of EPL and determine if their genetic composition is compatible with life.
Veterinarians submit tissue from clinical cases of EPL to our laboratory for assessment. In our first analysis of these failed conceptuses, we found that 20% of clinical cases were associated with a genetic disorder termed aneuploidy, that is, the loss or gain of a whole chromosome compared with the normal number. This condition is very well described in the human literature as a common cause of miscarriage in women but it was the first description of this disorder in cases of pregnancy loss in the mare. An abnormal number of chromosomes results in significant disruption to the genome usually incompatible with continuation of the pregnancy in any mammalian species. It represents the most common single cause of EPL described to date in intensively managed mares finally providing us with a new target to interrogate. We know the genome can be modified from its normal state in many other ways. Exactly if and how these other genetic variations in the genome lead to pregnancy loss in the mare remains unknown. Furthermore, we know very little about the clinical features of genetically abnormal pregnancies, key to vets being able to identify which pregnancies should be maintained, which are better off being terminated and the mare rebred.
This project will investigate two types of genetic disorders termed triploidy and aneuploidy. Instead of a single whole chromosome being duplicated or lost, as is the case of aneuploidy, in triploidy an individual has an extra copy of all the chromosomes resulting in three full sets as opposed to the usual two sets. The project will characterize how these embryos ended up with an abnormal number of chromosomes. We predict this will be very common (30-50% of cases) and it primarily due to a combination of (i) genetic errors in the egg and (ii) an error of the egg that allows two sperm to fertilize the egg, as opposed to the usual one sperm. Studies in women have shown that the source of the genetic defect impacts multiple clinical features of the pregnancy, which is incredibly useful for early detection and clinical management by the veterinarian. Therefore, will also ask the questions: What risks factors (exposures) increase the chance of these genetic disorders occurring? How do these pregnancies present clinically so that they can detected and managed appropriately by the veterinarian? Ultimately this will empower veterinarians with new knowledge that we predict will lead to new diagnostic tests, treatment approaches and ultimately reduce the occurrence of this common but frustrating condition.
The team is uniquely placed to investigate genetic causes of EPL in the mare with a large tissue bank and clear ways to expand these in 2024/2025 achieved through established and strong partnerships with multiple collaborating veterinarians and a track record in reproduction, genomics, epidemiology and Thoroughbred research. An established collaboration with an international leader in equine genomics is also in place for consultation on genomic methodologies.
Importance to the Equine Industry: The ultimate goal of owners of breeding mares is to produce a viable and healthy foal each year she is bred. One of the greatest impediments to achieving this goal is the loss of her pregnancy in the first two months following conception, referred to here as early pregnancy loss (EPL). This condition is incredibly frustrating for the veterinarian and owner alike as it results in increased veterinary interventions and associated welfare implications for the mare, much higher costs for owners, and can be emotionally distressing for owners striving to produce that elusive foal. It can also mean a mare fails to produce a foal that season as a result of poor fertility related to endometrial cup formation, or indirectly due to drifting of the conception date so late in the season that it is no longer viable to breed her in the subsequent year. The first question owners often ask when the veterinarian finds a failed pregnancy is: why did it fail? Unfortunately, we know so little about the underlying causes of EPL that the answer is usually ‘I don’t know’. Scientific studies have shown that in around 60-80% of clinical cases of EPL the underlying cause is not identified using currently available knowledge. In the absence of specific diagnoses of the cause of EPL, stud farm veterinarians have very few options available to them to manage EPL. Generic treatments such as progesterone supplementation is sometimes used in a hope of preventing EPL, although low progesterone is usually not the reason that the pregnancy was lost and therefore in most cases it is ineffective. Further, pregnancies with genetic errors incompatible with life that are treated with progesterone are unnecessarily prolonged, and as a result, the mare may miss the opportunity to be rebred that season. Essential to overcoming these challenges is identification of new explanations as to why EPL occurs informing novel diagnostic tests, therapeutics and management approaches can be implemented in the future.
KETODOXAPRAM AS A TREATMENT FOR ATRIAL FIBRILLATION
Annelies Decloedt, Ghent University –Second Year
One Sentence Summary: This study is to determine if Ketodoxapram is a promising novel treatment method for horses with atrial fibrillation.
Cardiac arrhythmias are frequently diagnosed in horses and can have serious consequences such as collapse or sudden death. Atrial fibrillation is the most common clinically important cardiac arrhythmia in equine athletes. Atrial fibrillation is found in about 0.3% of horses in the general equine population, and in up to 5% of racehorses. Although the mechanisms and consequences of atrial fibrillation are increasingly better understood, drug treatment options remain limited. Even in human medicine, the currently available medication is often ineffective and, in addition, there is a high risk of side effects and relapse after treatment. At the Faculty of Veterinary Medicine in Ghent (Belgium), horses are routinely treated with an intracardiac electrical shock under general anesthesia, with a success rate of about 95%. The electrical shock results in cardioversion of atrial fibrillation to normal sinus rhythm. This treatment can world-wide only be carried out in a few highly specialized centers. To avoid this technical procedure, pharmacological treatment can be performed using drugs. Traditionally, horses with atrial fibrillation are treated with the drug quinidine sulphate, but this medication is increasingly difficult to obtain in many countries: the product is disappearing from the market because of the frequent side effects in humans and animals. Common side effects that occur after the administration of quinidine sulphate in horses include nasal swelling, depression, high heart rates, colic, diarrhea, weakness, laminitis, collapse and even sudden death. The success rate of quinidine sulphate treatment is about 60-80%, which is also considerably lower compared to the electrical cardioversion treatment. Other available drugs are even less effective, with a maximal success rate of about 50%, and also cause different side effects.
Studies in human medicine are currently evaluating drugs which target specific ion channels in the heart, the TASK-1 potassium channels. Drugs which inhibit these TASK-1 channels, such as ketodoxapram, could be a novel treatment option for atrial fibrillation. The TASK-1 channels are mainly expressed at the level of the atria, which minimizes the occurrence of side effects when a TASK-1 inhibitor such as ketodoxapram is administered. Specific blocking of the TASK-1 channels slows down the atrial fibrillation rate and allows cardioversion to normal sinus rhythm. Preliminary results of ongoing research by our group demonstrated that the TASK-1 potassium channel is also present in horses. Moreover, the equine and human TASK-1 channel are very similar. Therefore, intravenous treatment by ketodoxapram seems like an ideal candidate for pharmacological treatment of atrial fibrillation, especially short duration atrial fibrillation after exercise or anesthesia.
We will test ketodoxapram treatment in horses in which atrial fibrillation is induced by a pacemaker. This way we can evaluate the effect of ketodoxapram for treatment of very recently developed atrial fibrillation as well as for atrial fibrillation during two months. The first aim of this study is to demonstrate that ketodoxapram can slow down the atrial fibrillation and treat experimentally induced atrial fibrillation in the horse. Using an implanted pacemaker, we will induce atrial fibrillation during 48 hours. By acquiring minimally invasive atrial biopsies using a forceps introduced through the jugular vein in the standing horse, we will evaluate whether this results in a higher expression of the TASK-1 channels. Next, we will evaluate whether administration of ketodoxapram will result in cardioversion to normal sinus rhythm. We will compare the ketodoxapram treatment to a placebo treatment. In addition, we will monitor different clinical parameters such as heart rate and respiration before and after administration of ketodoxapram (compared to placebo), and evaluate the ketodoxapram levels in the blood. The second aim of this study is to use ketodoxapram to treat horses with chronic experimentally induced atrial fibrillation (2 months). We hypothesize that ketodoxapram administration will slow down the atrial fibrillation, and will convert the horses to normal sinus rhythm. Our ultimate goal is to demonstrate that ketodoxapram is a safe and effective treatment option for horses with atrial fibrillation. Ketodoxapram may become the method of choice for pharmacological treatment of horses with atrial fibrillation.
Importance to the Equine Industry: A novel treatment option for atrial fibrillation is important for the equine industry, especially the sports horse industry of all disciplines (racing, jumping, eventing, dressage,...). Atrial fibrillation often results in decreased sports performance and potentially collapse or even sudden cardiac death. Cardiac disease is the third most common cause for poor performance, and atrial fibrillation is seen as the most common pathological arrhythmia causing performance loss in sport horses. Horses with atrial fibrillation that need to perform at high levels, have abnormally elevated heart rates during exercise or show additional arrhythmias should undergo cardioversion. In addition, prompt treatment after the initiation of atrial fibrillation is important to prevent atrial remodeling. Atrial remodeling stabilizes the arrhythmia and makes it even more difficult to treat. At the Faculty of Veterinary Medicine in Ghent, horses are routinely treated with transvenous electrical cardioversion, with a success rate of about 95%. However, this treatment can only be performed in highly specialized centers and is not available in every country. The other option is medical treatment. Traditionally, quinidine sulphate is used in horses with atrial fibrillation. However, the success rate is lower (60-80% depending on the type of horse treated) and this medication is increasingly difficult to obtain in many countries: indeed, the product is disappearing from the market because of frequent side effects in humans and animals. Other available products give conversion in 50% of cases at most. Moreover, serious side effects are described for each of these products. Therefore, a novel safe and effective treatment for atrial fibrillation is urgently needed. The aim of this study is to evaluate a new drug, ketodoxapram, for the treatment of atrial fibrillation. In the future, ketodoxapram may become the treatment of choice for horses with acute or chronic atrial fibrillation.
NOVEL METHOD FOR DIAGNOSIS OF NOCARDIOFORM PLACENTITIS
Shavahn Loux, Louisiana State University –Second Year
One Sentence Summary: A sensitive and specific diagnostic test for Nocardioform Placentitis.
Placentitis is the most common cause of late-term abortion in the mare, costing the equine industry millions of dollars in lost revenue every year. Despite the devastation caused by this disease, accurate diagnostic tests for placentitis are not currently available. The tests which are available cannot separate affected mares from non-affected mares, leading missed diagnoses, late-term abortions and sick foals. In our previous work, we have developed a diagnostic tool for Nocardioform placentitis which is accurate and sensitive. In this proposal, we are promoting the expansion of this work to include a prospective study to better understand when disease forms and how it progresses, as well as the strengths and limitations of this diagnostic test.
Additionally, we will work to understand why these bacteria are capable of causing disease and how they communicate and interact with the mare during disease. Initial work will be focused on characterizing the proteins and lipids which the bacteria produce in isolated culture as well as when they are infecting the placenta. Our early work shows that these bacteria will modify the mare’s fatty acids to create lipoglycans which are integrated into the bacterial cell wall. As similar lipoglycans cause an immune response as well as drive the progression of disease, identifying these molecules will help create a better understanding of the mechanisms of disease. In the process, we will uncover which specific molecules cause a response of the hosts’ immune system as well as work to improve our diagnostic test while evaluating its strengths and limitations. In total, this work should increase understanding of the proteins and lipids which drive disease and illicit an immune response by the mare. Additionally, we should have a better understanding of when disease starts and how it progresses which should help us improve the focus of future research into Nocardioform placentitis.
Importance to the Equine Industry:
Nocardioform placentitis is a devastating reproductive disease affecting equine populations worldwide. It is characterized by focal sites of infection which are frequently covered by a thick brown exudate. If Nocardioform placentitis isn’t diagnosed in a timely manner, mares will frequently abort their foals or give birth to small, runty foals. Despite its profound impact, diagnosing Nocardioform placentitis remains challenging, often relying on clinical signs such as premature udder development which are nonspecific and may only become apparent late in disease. As such, many farms treat their high-risk mares with antibiotics on a monthly basis whether there are signs of disease or not. Through the development and refinement of a sensitive and specific diagnostic test, we are able to minimize late-term abortion and stunted neonates while working to minimize this unnecessary antibiotic use. This will not only improve the health of pregnancies but will also help prevent the increasing problem of antibiotic resistant strains of bacteria. Moreover, through a more comprehensive understanding of how the disease originates and progresses, researchers working in this area will have better tools available to focus their research in ways to produce better results and better improve the health of the horse.
ADIPONECTIN AS A CLINICAL BIOMARKER FOR LAMINITIS RISK
Melody A de Laat, Queensland University of Technology –Second Year
One Sentence Summary: The aim of this project is to improve early detection of the painful foot disease laminitis, this project will evaluate the value of a promising biomarker for the condition called adiponectin.
Our horses are eating better quality pastures and feeds than ever before, so they are becoming overweight and unhealthy. Just like in humans, diseases of metabolism are increasingly apparent in horses. In particular, metabolic conditions where insulin secretion is increased are increasingly recognized. Researchers do not know exactly what causes the insulin concentrations to reach and remain at these high levels in some horses. High insulin levels are a major problem in horses because they cause the painful hoof disease called laminitis. Laminitis results in lameness, and in about 30% of cases the horse needs to be euthanized.
This project aims to improve our ability to determine the risk of laminitis in an individual animal. To do this we will examine a hormone that is found to be at lower concentrations in horses that are at risk of developing laminitis. We currently do not know much about this hormone in horses, but this project will extensively examine the hormone. We will determine the normal levels and fluctuations of the hormone after eating, and how it changes in animals that have metabolic disease and are prone to laminitis. We will determine whether the hormone concentration differs between horse and pony breeds, and what concentration of the hormone can be used to predict the relative risk of laminitis.
In addition to inappropriate diet, metabolic disease in horses is also likely to be due to underlying genetic variations. Due to the complexity of metabolic disease in horses, it is likely that many genes are involved. However, these genetic factors have not yet been identified. As part of this project, we will examine the sequence of the gene that codes for adiponectin, and determine whether the sequence varies between healthy horses, and those with metabolic disease. If a difference in the genetic sequence between animals is identified, we will determine whether or not this genetic change contributes to the disease. If it does, it could become part of a genetic test that helps to identify animals at risk of laminitis in the future. Overall, this project will improve our ability to predict and prevent laminitis, lessening the impact of this important disease.
Importance to the Equine Industry:
Laminitis is the second most common reason for equine veterinary consultations (after colic), and most cases of laminitis are due to high insulin concentrations (and this is the type of laminitis being investigated here). The disease is intensely painful, and due to a lack of effective drug treatments for laminitis many sufferers do not survive. Losses associated with laminitis are increasing, because diets rich in sugars and starch are more commonly fed, even when the horses are not in work. This excess food contributes to high insulin concentrations, the root cause of disease. Thus, laminitis represents a significant economic, social and welfare burden to the horse industry and horse-owning communities worldwide.
By improving our ability to detect which individuals laminitis is more likely to occur in, this project will enable better management of horses at risk of laminitis. This will ultimately reduce the number of horse suffering from the disease through improved ability to predict its onset and earlier recognition of risk so that preventative measures can be introduced. A reduction in the number of cases of laminitis will improve horse welfare, reduce the costs associated with laminitis treatment and increase the productivity of horse industries, such as racing and sporting associations and breeding facilities.
INSULIN DYSREGULATION: PLACENTAL CHANGES AND FOAL HEALTH
Elaine Norton, University of Arizona –Second Year
One Sentence Summary: This study investigates the role of equine metabolic syndrome on placental function and foal health and metabolic outcomes in order to develop effective treatment and management regimens.
Equine metabolic syndrome (EMS), characterized by insulin dysregulation, is the leading cause of laminitis, affects all horse breeds and is one of the most common diseases facing horse owners. However, we do not understand the impact of EMS in pregnant mares on her foal’s heath or metabolism. EMS is common in broodmares due to their diets, lack of exercise, and the practice of maintaining broodmares at a higher body condition to ensure that the foal is receiving adequate nutrition to grow. Humans suffering from diabetes, a similar condition to EMS, experience long bouts of high blood glucose and insulin levels, which have been shown to significantly change how the placenta functions. These changes increase the risk of the mother going into early labor, having difficulty giving birth, stillbirths, or the baby requiring hospitalization. Therefore, there is a gap in knowledge of the effects of a mare having EMS on placental function and foal health outcomes which prevents owners knowing how to manage their pregnant mares to have a healthy, athletic foal.
In this study, we will investigate the role that EMS has on placental function and foal health and metabolic outcomes in order to develop effective treatment and management strategies. We hypothesize that EMS leads to an increased risk of mare placental dysfunction, which is associated with health and metabolic outcomes in their offspring.
In Aim 1 we will assess the placenta at the microscopic level for changes in cellular structure and damage in mares with and without EMS. We hypothesize that placentas from EMS mares will have changes similar to what has been found in pregnant women with diabetes.
In Aim 2 we will assess changes in how genes are expressed (turned on or turned off) in the placenta of mares with and without EMS. We hypothesize that alterations in placental gene expression in pathways related to inflammation, metabolism and growth will be associated with a mare’s EMS status.
In Aim 3 we will compare events at birthing, neonatal health and metabolic outcomes between foals within their first year of life born from mares with and without EMS. We hypothesize that foals born to mares with EMS will have a higher incidence of adverse events in the first few days of life and changes in growth and insulin resistance in their first year. This is supported by evidence in horses that maternal obesity, a risk factor for EMS, leads to an increased incidence of poor-quality colostrum, fetal insulin resistance, and chronic inflammation.
This project will have a great impact on the horse industry as this is the first time that placental function will be assessed in EMS affected mares at both the cellular and genetic level. This will allow us to link foal health outcomes with placental dysfunction. This will also allow us to identify changes that can be screened during a mare’s pregnancy to help guide timely treatment and management strategies The impact on the horse industry will be notable as EMS affects all breeds, and nearly a quarter of broodmares. If EMS is a risk factor for placental dysfunction, resulting in failure of passive transfer or neonatal disease, early management strategies in mares could prevent foal loss and save owners $5000-15,000 in hospitalization costs and emotional distress. Our strong team with expertise in neonatal, metabolic and reproductive health is well suited to assess the complexities afforded by maternal/ placental/fetal interactions in order to best identify treatment and management strategies needed to improve foal health outcomes.
Importance to the Equine Industry: The industry impact is notable as equine metabolic syndrome affects all breeds of horses and is the leading cause of laminitis, costing the equine industry over $15 million dollars annually. This number is continuing to rise as the reported prevalence of EMS has reached up to 25% in high-risk populations, with our preliminary data confirming that broodmares are amongst the high-risk groups. Impacts on foal health due to placental dysfunction, such as failure of passive transfer, sepsis or dummy foals can have a mortality of up to 25% and cost owners $5000-15,000. Identification of EMS as a significant risk factor for the above has the potential to improve foal health and thus reduce the financial and emotional cost to owners.
POLYACRYLAMIDE FOR JOINT THERAPY–CRITICAL THINGS UNKNOWN
Bruno C. Menarim, University of Kentucky –Second Year
One Sentence Summary: Polyacrylamide for joint therapy–critical things unknown
Osteoarthritis (OA) is the leading cause of lameness in horses. OA is a debilitating disease characterized by chronic inflammation and a progressive loss of the normal joint surface, resulting in pain, lameness or other compromised mobility, which often gets so serious that the horse is euthanized. OA can be very challenging to treat over the long term. Commonly used therapies often work for short periods of time or only provide partial relief of symptoms. There is a critical need for treatments that can not only prevent disease from getting worse but offer lasting effects.
A new treatment called polyacrylamide hydrogel (PAAG) has been investigated as a treatment for OA showing lasting improvements (up to 24 months). Even though clinical improvements from PAAG in the treatment of OA are very positive, how PAAG works to provide joint pain relief is uncertain and debated. Resolving joint inflammation is a primary goal of joint therapies. However, research into how PAAG affects joint inflammation has not been reported. Further, concerns have been raised among equestrian authorities that PAAG could affect pain sensitivity, preventing detection of imminent more serious injuries. Indeed, for Thoroughbred racehorses, a national regulatory rule states, “Intra-articular injections of polyacrylamide hydrogels are prohibited within 180 days prior to Post Time.” A previous study in 3 goats suggested that PAAG-treated joints had normal nerve counts and shape. As such, significant work is still required to characterize how PAAG injection modulates the inflammatory response in joints, and confirm, on a larger scale, that PAAG does not impair proper function of pain-sensing nerves. Therefore, we propose the following studies as high priority questions in addressing concerns from equine authorities and the safe use of this promising joint therapy.
Study 1: Characterize the changes in the inflammatory response of OA joints after treating with PAAG. This will be accomplished by studying mediators of inflammation and pain recognition in the joint fluid and internal lining.
Study 2: Characterize how pre-treatment of joints with PAAG affects the inflammatory response and recognition of pain long term after inducing joint inflammation experimentally.
These are very important question directly related to the safety of intraarticular PAAG therapy in Thoroughbred racehorses and other equine athletes. In addition to studying mediators of inflammation and pain recognition in the joint fluid and internal lining as describe for Study 1, we will use load-sensing boots on both front limbs with experimentally inflamed joints (previously treated with PAAG or inert vehicle), to assess pain recognition.
Our long-term goal is to assess the safety of using polyacrylamide hydrogel (PAAG) to treat equine osteoarthritis (OA). Knowledge generated by this study will provide tools for informed decision making regarding the effects of PAAG and its appropriate use.
Importance to the Equine Industry: Importance to Industry: The equine industry is a huge economic driver in many states in the US and globally. Significant sums of money are invested annually in breeding and training the most outstanding equine athletes. Intensive training and competition pressures frequently lead to joint inflammation and degeneration (arthritis) that prevent horses from reaching their potential or necessitate retirement. Estimated annual financial losses of between 600 million and 1 billion dollars occur due to treatment and early retirement of equine athletes in the US. In addition to the significant economic cost of equine joint disease, there is the very important emotional impact that cannot be quantified and affects most horse owners in their lifetime. Regardless of the cause of the joint disease, the ultimate result for horses and their owners can be devastating.
Despite many advances over the years in the prevention, early detection, and treatment of equine joint disease, a critical need still remains to identify more effective ways to control inflammation in the joint and hold the advancement of arthritis in horses, enabling them to have an extended and good quality of life. The use of polyacrylamide hydrogel (PAAG) to treat OA has shown significant results with remarkably long-lasting effects. Data collected in this study will provide essential information of the effect of this promising treatment, to allow veterinarians, owners and authorities to make an informed decision about the safety of using PAAG to treat arthritis. Should we confirm PAAG provides improvements by resolving inflammation but not masking pain, PAAG treatment could improve the life quality and athletic longevity of thousands of horses.
RISK ASSESSMENT FOR PROXIMAL SESAMOID BONE FRACTURE
Peter Muir, University of Wisconsin–Madison –Second Year
One Sentence Summary: This study will save the lives of racehorses by establishing screening using fetlock standing computed tomography for diagnosis of horses with a high risk of serious injury for personalized care.
Injuries to the Thoroughbred racehorse that lead to euthanasia are termed catastrophic. In 2022 the incidence of catastrophic injury was 1.25 fatalities per 1,000 starts in the USA, representing a loss of hundreds of horses. Stress fracture of the proximal sesamoid bone (PSB) is a common cause of fatal injury. Repair of PSB fractures, particularly biaxial midbody fractures, or fetlock salvage is associated with a poor prognosis. There is, therefore, a critical need to comprehensively improve preventative screening of Thoroughbred racehorses for the presence of concerning bone injuries that increase the risk of catastrophic injury from PSB stress fracture. Our long-range goal is to reduce the incidence of catastrophic injury in Thoroughbreds by improving clinical screening using routine standing computed tomography (sCT) imaging in the sedated horse to check for concerning bone injury in the fetlock, particularly PSB injury that precedes stress fracture. The objective of this application is to develop a sCT screening approach for evaluation of racing Thoroughbreds with concerning fetlock bone injuries using computerized analysis of sCT images to identify horses with high imminent risk of PSB stress fracture and potential catastrophic injury. Our hypothesis is that our computerized virtual mechanical testing approach will be able to identify horses with high risk of PSB stress fracture. Our hypothesis is based on the substantial progress that we have made implementing a similar computer modeling approach for predicting risk of condylar stress fracture.
The rationale for this work is that implementation of sCT screening with computer model analysis of sCT scans in populations of racehorses will lead to substantial reductions in fatal injuries associated with fetlock stress fractures by accurately identifying horses with imminent risk of PSB fracture. An advantage of our research approach is that other information, such as exercise history and information about the training surface are not needed for risk prediction. Risk for individual horses is predicted directly from imaging information. To accomplish our objective, we will perform mechanical testing of PSB specimens after sCT imaging. We will relate the structural changes in the PSB, features that would not be detectable by radiography, to the propagation of a PSB stress fracture, which is a serious injury clinically. We will use these data to build a computer (finite element) model of the PSB to undertake detailed analysis of the mechanical properties of the PSB so that bones with reduced mechanical properties can be easily identified. This work will be undertaken using limbs collected from Thoroughbred racehorses that have euthanatized at the racetrack because of catastrophic injury. Under loading that models racing, mechanical testing of PSBs will be performed. Relevant features in the PSB will be determined from sCT images. This information will then be used to build the 3D PSB computer model and optimize and validate the mechanical predictions from the computer model to identify horses with imminent risk of serious injury. As a prelude to this project, we have designed and built a helical sCT scanning system that enables routine fetlock CT imaging. The proposed research is innovative because it capitalizes on routine availability of sCT imaging. Regarding outcomes, the work is expected to contribute in meaningful ways to the substantial clinical value in routine fetlock CT imaging. Ultimately, the outcomes of this project will save many horses from serious fetlock injury and death. This is a major advance, as the incipient changes in the PSB that increase risk of stress fracture cannot be reliably identified on radiographs of the fetlock, making it impossible for equine veterinarians up to now to effectively screen racing Thoroughbreds thoroughly for concerning bone lesions that represent high risk of injury. Advances from this research will improve the effectiveness of injury prevention programs for racing Thoroughbreds across the world as sCT imaging becomes more widely adopted. We are well positioned to pursue this research because of the expertise of our team regarding injury prevention.
Importance to the Equine Industry: This work will ultimately save the lives of many racehorses. Completion of this project will enhance knowledge of the relationship between specific structural changes in the proximal sesamoid bone and imminent risk of stress fracture propagation, a serious injury that is often catastrophic. Since true standing computed tomography imaging in horses is now routine, this knowledge is directly translatable into clinical practice because racehorses with concerning bone lesions that are not evident on radiographs can easily be identified and managed appropriately without disruption to training and racing schedules. Our virtual mechanical testing approach using computer modeling enables wide preemptive longitudinal monitoring of horses in training to implement improved personalized care for racehorses and reduced catastrophic injury.
THIRD YEAR GRANTS
Use Of Nucleic Acid Vaccines To Protect From EHV-1/EHM
Gisela Soboll Hussey Michigan State University – Third Year
One Sentence Summary: This proposal is to develop a novel mRNA-based equine herpesvirus (EHV) vaccine that protects horses from EHV-1 myeloencephalopathy and will also likely cross-protect against other equine herpesviruses
Equine herpesvirus-1 (EHV-1) infection results in sporadic but devastating outbreaks of neurological disease in the equine population caused by a myeloencephalopathy with a poorly understood pathogenesis. The impact of EHV-1 myeloencephalopathy (EHM) on equine health and the industry is highlighted by a series of major outbreaks in North America and Europe over the past decade, including the two largest outbreaks in 2011 and 2021 in North America and Valencia, Spain. Despite the importance of EHV-1 in horses, effective prevention remains elusive and there is currently no vaccine available to prevent EHM. This is partially a consequence of the absence of a reliable experimental equine model of EHM and partially due to a lack of innovation in vaccine technology in the equine vaccine market in the past 40 years. In this proposal, five investigators with complementary expertise in equine herpesvirus virology, vaccinology and pathogenesis/animal models have come together to close a major gap in vaccine development against EHV infection. The goal of this application is to exploit innovations in RNA vaccine technology that have come about during the COVID-19 pandemic and are currently the first line of defense. We propose to refine this mRNA vaccine technology for immunization of horses. Based on our extensive preliminary data, we will test vaccines containing the parts of EHV-1 that are important for inducing protective immunity in horses. We are ideally placed to accomplish this task because we have previously developed a unique model for experimentally inducing EHM in horses that now allows us to test potential vaccine candidates . Moreover, given the high degree of similarity among equine herpesviruses genetically related to EHV-1, namely EHV-3, EHV-4, EHV-8 and EHV-9, our vaccine candidates, if proven successful, are likely to also offer protection to other equine herpesviruses. Additionally, they could readily be extended as a platform to induce protective immunity against an array of EHVs or other equine viruses.
Importance to the Equine Industry:
The EHV-1 “G” strain (SNP at ORF 30, G2254) has been associated with more severe outbreaks and a greater occurrence of EHM than the EHV-1 “A” strain (A2254 genotype). The enhanced replication capacity with the “G” strain appears to be associated with an enhanced frequency of more severe disease; however, both strains cause EHM. Several factors appear to be contributing to an uptick in EHV-1, particularly in Europe and the United States, with equine venues being closed or quarantined as a consequence. We propose an mRNA vaccine delivered in an extended release, biodegradable polyanhydride vaccine depot. Compared with traditional vaccines, we anticipate that this approach will be more effective and require fewer inoculations.
A Novel DNA Vaccine Platform To Control EHV-1 and EHV-4
Bettina Wagner Cornell University – Third Year
One Sentence Summary: The goal of this project is to develop an effective DNA vaccine for equine herpesvirus to protect horses against infection and disease and to prevent EHV outbreaks in the US.
Ongoing EHV-1 outbreaks, including cases of neurologic disease caused by EHV-1 and called ‘equine herpesvirus myeloencephalopathy’ (EHM), emphasize the fact that currently available EHV-1 vaccines are not fully protective. These disease outbreaks are occurring despite widely used vaccination and many available EHV vaccines on the market. The fact that currently available inactivated or attenuated vaccines have not been sufficient to completely protect from EHV-1 outbreaks has caused the demand for novel EHV vaccine formulations that can prevent horses from infection and severe disease, especially neurologic disease. Here, we propose to design and evaluate a novel DNA vaccine formulation against EHV-1/EHM for horses. We are combining our expertise in equine immunology and EHV-1 research (Dr. Wagner) and virology and vaccine design (Dr. Diel) to first perform a comprehensive analysis of the best DNA vaccine candidate and then test the optimized vaccine candidate for its protective effects in horses. The DNA vaccine platform that we are testing in this project has already been used successfully for induction of immunity and protection from infectious disease in other species. The project will result in an established new EHV vaccine candidate and provide a new approach to effectively protect horses from EHV-1 infection and disease. Overall, the project is relevant to the prevention of disease induced by EHV-1 by increasing immunity and protection in the equine population and reducing severe neurological disease outbreaks in the US.
Importance to the Equine Industry:
Equine herpesvirus type-1 (EHV-1) has a significant impact on animal health and the equine economy worldwide. Every year, several neurologic outbreaks are reported throughout the US (http://www.equinediseasecc.org/alerts/outbreaks). In an outbreak scenario, EHM is first confirmed by an EHV-1 positive diagnostic test in the affected horse(s). The positive EHV-1 test result causes immediate regulatory actions with stringent quarantine and biosecurity of all horses at the facility where the EHM affected horse is kept to prevent further spread of the contagious disease. Quarantine is in place for 21-28 days after the last suspected infection. Currently, all potentially exposed horses at a quarantined location are kept there for the same time for general precaution and preventing the possible spread of EHV-1 to other horses. During this time all movements of horses to and from the quarantine facility stop. Depending on the location of the first affected horse, quarantine can apply to race, show and auction premises, or secondary locations if a potentially exposed horse already moved to another site, and can thus stop the movement of involved horses for weeks. Consequently, EHV-1 quarantine represents a high economic burden for the horse industry through loss of severely affected horses, medical treatment charges of diseased horses, quarantine management efforts, and lost training, racing and/or competition time for all horses involved in the quarantine scenario. EHV-1/EHM outbreaks and quarantine have not only a serious impact on equine health, they also restrict horse transport, racing and competitions, and economically affect horse owners, equine businesses, and the equine industry.
RESEARCH CAREER DEVELOPMENT AWARDS
There are two Career Development Award recipients in 2025.
The Storm Cat Career Development Award, inaugurated in 2006, is a $20,000 grant in 2024 and is designed as an early boost to an individual considering a career in equine research. It has been underwritten annually by Mrs. Lucy Young Hamilton, a Grayson-Jockey Club Research Foundation board member whose family stood the retired champion stallion Storm Cat at Overbrook Farm.
Erica Secor,
Cornell University
Immune Cells In Equine OA and Response to Therapeutics
Faculty supervisor Dr. Heidi Reesink, Associate Professor, Section of Large Animal Surgery
The Elaine and Bertram Klein Development Award is a competitive program intended to promote development of promising investigators by providing a one-year salary supplement of $20,000 in 2025. This program is restricted to one award per year and is named in memory of a renowned horsewoman and her late husband, a Thoroughbred owner and breeder. The first grant was in 2015 and was funded for $15,000 with donations by the Klein family.
Shannon Connard,
North Carolina State University
Harnessing Stem Cell Licensing to Enhance Tendon Healing
Faculty supervisor Dr. Lauren Schnabel, Professor of Equine Orthopedic Surgery
