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July 7, 2023 — If your horse has ever needed preventive or routine care or has had a health emergency, chances are you and your animal have benefited from research funded by Morris Animal Foundation.

Starting as a dog and cat animal health nonprofit organization 75 years ago, the Foundation’s trustees expanded its mission to include horse health in 1959, with its first studies looking at nutritional needs of horses to keep them healthy. Today, the Foundation is a global leader in funding new and improved diagnostics, treatments and preventives to keep your horse happy and healthy throughout their life. We also fund studies to improve the health and well-being of related species, including donkeys, mules and even zebras!

Here is a snapshot of some of the ways our funded studies have helped horses around the world.

  • Our funding helped researchers identify the causative bacteria and the development of the first vaccine for Potomac horse fever.
  • Our equine cancer research has led to screening tests for eye cancer, successful translational melanoma vaccine research and novel therapies for sarcoid tumors.
  • We supported research that informed the development of a novel product to resolve persistent joint infections in horses.
  • Our research is increasing our understanding of genetic factors associated with equine metabolic syndrome, a complex syndrome associated with laminitis, insulin dysregulation and obesity in horses.
  • Our funded researchers mapped out the horse genome which led to the discovery of genetic variations associated with multiple diseases and disorders in horses.
  • Our researchers recently identified a promising new tool to help address antibiotic-resistant strains of foal pneumonia – especially important to farms that are endemic for this difficult-to-treat bacterial disease.

Potomac Horse Fever
First recognized in 1979 in horses on farms adjacent to the Potomac River, Potomac horse fever (PHF) is an important cause of diarrhea and gastrointestinal upset in horses, as well as reported abortions in pregnant mares. By the 1980s, following several outbreaks, Foundation-funded researchers helped identify the causative bacteria for PHF. Findings from multiple studies led to early diagnostics and the development of a PHF vaccine. Today’s vaccine continues to offer some protection against infection, but its primary use is to help reduce severity of the disease in areas where PHF is endemic.

Approximately 80% of reported cancers in horses are associated with the skin or the tissue layer beneath the skin. The three most commonly reported cancers in horses are squamous cell carcinoma, melanoma and sarcoid tumors.

Our funded researchers recently identified a genetic mutation for eye-related squamous cell carcinoma in Haflinger horses (a high-risk breed) that led to the development of a DNA-based screening test for the breed, with more breed-specific tests in the works.

For melanoma, we now know a commercially available canine melanoma vaccine also can help treat this cancer in horses. Horses in our funded study showed dramatic shrinkage of their tumors.

In ongoing sarcoid research, researchers are exploring the feasibility of a novel oncolytic therapy, using a genetically modified virus that infects and breaks down cancer cells, but not normal cells. The new research could be a gamechanger for horses with recurrent lesions.

Joint Infections
Joint infections are often hard to treat in horses, leading to painful irritation and arthritis. Our funded researchers developed a novel platelet-rich plasma lysate from platelets, immune cells and synovial (joint) fluid from healthy horses that can kill bacterial infections within the joint. The biologic also helps the immune system fight off infections and protects vulnerable cartilage from damage. This valuable tool is already helping horses with persistent bacterial joint infections in clinical trials and generating some promising results.

Equine Metabolic Syndrome
Before the early 2000s, Foundation funding supported a suite of studies on laminitis, a condition characterized by inflammation of the hoof structure. Today, we know that equine metabolic syndrome (EMS) is one of the most common causes of laminitis in horses and ponies, and the Foundation's focus shifted toward understanding this complex and previously unrecognized disease.

Our early research in the 1970s focused on creating study models to learn more about acute and chronic laminitis and how to effectively diagnose and intervene to treat this painful condition. By 2009, our funded studies shifted to mapping out the genetics at play in EMS-associated laminitis as well as studying EMS risk factors, including diet, grazing time and the environment. While we still have a lot of research ahead of us, having a better understanding of the genetics and other risk factors for EMS and associated laminitis will improve our ability to identify animals that can benefit from management changes and early therapeutic intervention.

Horse Genome
Thanks in part to Morris Animal Foundation funding, a multi-institutional group of researchers assembled the first horse genome maps, essential scientific tools to study diseases and inherited disorders in horses. This facilitated the discovery of many genetic mutations associated with serious health challenges in horses, including for major muscle disorders, neurological diseases and spinal issues. Some of these discoveries have led to genetic screening tests to help reduce the incidence of diseases and health disorders in specific breeds and horses overall.

Foal Pneumonia
Rhodococcus equi, a naturally occurring bacterium in soil, is a common cause of deadly pneumonia in foals aged 3 weeks to 5 months. Antibiotic-resistant R. equi is an emerging treatment challenge. A practical, long-term solution to this serious health concern is to decrease widespread use of commonly used antibiotics in foals diagnosed with pneumonia.

Foundation-funded researchers recently showed that gallium maltolate, a semi-metal compound with antimicrobial and anti-inflammatory properties, is effective in treating foals with pneumonia due to R. equi. In a clinical trial of client-owned foals with subclinical pneumonia (meaning ultrasound scans found lesions on their lungs but the foals had no clinical signs), researchers showed gallium maltolate minimized the development of antibiotic-resistant bacteria in the gut as measured in stool and soil samples. While further study in foals with severe, symptomatic pneumonia is warranted, researchers hope gallium maltolate will be a promising new tool to help mitigate the emergence of antibiotic-resistant strains of R. equi – especially important to farms where R. equi is endemic.

What’s Next?
Today, the Foundation is making a concerted effort to support behavioral horse research. This is an underfunded area of research but one that could lead to improvements in the well-being and health of horses worldwide.

One new study hopes to learn more about coping strategies to improve horse welfare in stressful situations, which not only cause mental distress but increase likelihood for injuries. Other ongoing studies are focused on developing educational tools for owners, feeding strategies to reduce unwanted behaviors, stable lighting and behavior, practice guidelines for improved interactions with therapy horses, and much more.

The Foundation is also working to improve outcomes for horses with colic, including horses undergoing colic surgery. While many colic cases can be resolved by your veterinarian, we still need better tools to deal with surgical complications for more severe cases. Several new studies are looking to assist recovery and shorten hospitalization time for these equine patients. Additional studies are looking at colic risk factors associated with transporting horses and developing educational materials for underserved owner populations in South America to help recognize early signs of colic.

Here's How You Can Help
We are proud of the work we have done to improve the lives of horses, and we are committed to continued research to make even more progress in the years to come. But we need your help.

Donate today to support horse animal health research or follow us to learn more about our studies. Together, we can help our beloved horses live longer and healthier lives.


Colic – an Emergency for Horse Owners & a Top Research Focus for the Foundation
Sarcoid Tumors in Horses
Giving Horses a Leg Up on Dangerous Joint Infections
Semi-Metal Compound Could Treat Foal Pneumonia without Promoting Multi-Drug Resistant Bacteria
Bacterial Diseases in Horses
Morris Animal Foundation-Funded Study Shows Endocrine-Disrupting Chemicals Linked to Equine Metabolic Syndrome
A Win in the Battle Against Cancer in Horses
Taking on Equine Melanoma and Winning
No Horsing Around with Cancer

Listen to Our Researchers
PODCAST: Episode 4: Equine Eye Diseases and Genetic Testing
PODCAST: Episode 16: What We Know and Don’t Know About Equine Metabolic Syndrome
PODCAST: Episode 19: New Hope for Treating Joint Infections in Horses
PODCAST: Episode 38: Evaluating Chronic Pain in Horses
PODCAST: Episode 46: No Horsing Around – Improving Horse Welfare Through Understanding Behavior