Conformation Affects Motion
Category: Horse Health
Winter 2022 Horse Health
Fall 2021 Horse Health
Breakthrough laminitis research shows promise for the future
Horse owners usually dread hearing the diagnosis of “Laminitis.” The disease plagues horses of many backgrounds, ages and disciplines. Using genetics, UF/IFAS and University of Pennsylvania scientists have made a breakthrough in the disease thanks to funding from The Foundation for the Horse.
A horse’s hoof has a tough job. It must support a heavy animal which can move faster than 40 mph. Laminitis occurs when inflammation and damage of the tissue takes place between the hoof and coffin bone. It causes lameness, a diminished quality of life and often results in euthanasia.
“Laminitis is a tough problem for the horse and its owner,” said Samantha Brooks, UF/IFAS associate professor of equine physiology. “We have very few tools in our arsenal to manage the disease itself. We treat symptoms, pain and mechanical instability but do not have anything to target the cause just yet.”
Laminitis studies have previously been hindered by the scarcity of genetic information specific to hoof tissues. Scientists tapped into the University of Pennsylvania’s New Bolton Center Laminitis Discovery Database, an archive of data and sample sets from naturally occurring laminitis cases collected since 2008. Using that database, researchers examined 36 archived tissues of 20 Thoroughbred horses treated for laminitis.
There are three types of laminitis, and all impair the structure and function of the horse’s foot. This research provided a snapshot of the active pathways and functions of the hoof, with a focus on supporting limb laminitis – the laminitis to which famous racehorse Barbaro succumbed.
“We understand the situations that trigger an episode of laminitis, but we do not have a good understanding of what is happening in the hoof,” said Brooks. “This study took a very comprehensive view of the processes early in the development of laminitis.”
Using gene expression analysis, researchers catalogued the changes in gene transcription across the 20 horses. Some had healthy feet, some were early in the disease process and others were more severe. Researchers identified trends in the disease process.
“By tapping into my lab’s database and incorporating Dr. Brooks’ unparalleled expertise in equine genetics and transcriptome analysis, we have identified new and promising pathways in cell stress and inflammatory response that significantly enhance our understanding of supporting limb laminitis and its disease processes,” said Hannah Galantino-Homer, VMD, PhD, DACT, senior investigator in Laminitis Research at Penn Vet’s New Bolton Center.
The research resulted in three key findings.
The first related to keratin, an important structural protein that helps maintain the structural integrity of materials like hair, nails and horse hooves. This study was one of the first to examine the changes in the keratin family through the laminitis disease process. Some of the keratin-related genes and regulation of the cell’s manufacturing process started to diminish as the disease began. This could be compared to when a car gets a flat tire; it may still be running but it loses appropriate function and slows down.
Another type of cell machinery often studied in laminitis are a class of enzymes called metalloproteinases; enzymes that help maintain the cytoskeleton. These enzymes must maintain a careful balance. Hooves must be able to grow and not break down under the weight of the horse, which requires a balance of remodeling and building tissues within the hoof. When the metalloproteinases become too active, the hoof begins to lose structural strength. One previous theory for treating this process was to stop these enzymes from becoming too active. But treatment targeted these enzymes might also stop hoof growth, which would likely lead to further issues.
When keratin degrades, inflammation in the hoof leads to laminitis. Scientists found a collection of genes responsible for triggering that inflammation which could pave the way for future medications to treat the inflammation. The genes led researchers to believe that some human inflammatory medications for autoimmune disorders may help horses with laminitis.
Changes in gene expression in diseased tissue are often reflected in changes in the proteins that can be detected in the blood as the disease progresses. For example, specific proteins, or biomarkers, that increase in the blood in humans following traumatic brain injury had increased expression in the samples from the horses with laminitis in this study. Medical doctors have used these compounds to understand the severity of these injuries in humans without using imaging or more invasive testing. Brooks hopes this could be used as a tool to monitor the progression of laminitis in the horse.
“We don’t always recognize that a horse has severe laminitis until things have gotten quite bad,” said Brooks. “Early monitoring tools and ways to combat the disease were exciting findings, but we need further research before these new tools will be ready for use in the field.”
Brooks hopes that this research can lead to a blood test to detect these new laminitis-related biomarkers, and medications that are economical and effective for horses suffering from the disease.
“Ultimately, these new findings point us towards a more targeted approach for future exploration that we hope will help uncover novel solutions for preventing and treating this debilitating disease,” said Galantino-Homer.
“This is a big step in improving our understanding of laminitis,” said Brooks. “Something that could be completely untreatable ten years ago; in another ten years we may be able to intervene and make a significant difference in the disease early on.”
About UF/IFAS
The mission of the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) is to develop knowledge relevant to agricultural, human and natural resources and to make that knowledge available to sustain and enhance the quality of human life. With more than a dozen research facilities, 67 county Extension offices, and award-winning students and faculty in the UF College of Agricultural and Life Sciences, UF/IFAS brings science-based solutions to the state’s agricultural and natural resources industries, and all Florida residents.
ifas.ufl.edu | @UF_IFAS
About Penn Vet
Ranked among the top ten veterinary schools worldwide, the University of Pennsylvania School of Veterinary Medicine (Penn Vet) is a global leader in veterinary education, research, and clinical care. Founded in 1884, Penn Vet is the first veterinary school developed in association with a medical school. The school is a proud member of the One Health initiative, linking human, animal, and environmental health.
Penn Vet serves a diverse population of animals at its two campuses, which include extensive diagnostic and research laboratories. Ryan Hospital in Philadelphia provides care for dogs, cats, and other domestic/companion animals, handling nearly 35,300 patient visits a year. New Bolton Center, Penn Vet’s large-animal hospital on nearly 700 acres in rural Kennett Square, PA, cares for horses and livestock/farm animals. The hospital handles nearly 5,300 patient visits a year, while the Field Service treats more than 38,000 patients at local farms. In addition, New Bolton Center’s campus includes a swine center, working dairy, and poultry unit that provide valuable research for the agriculture industry.
Horse Health: Prepurchase Exams and Selecting Young Horses
You Can Lead A Horse To Water, But Study Shows He’ll Only Drink If It’s The Right Flavor
You can take a horse to water but you can’t make him drink. A new study says adding a little flavor to the water may solve that problem.
Tessa Van Diest, a second-year veterinary student at Washington State University’s Veterinary Teaching Hospital, and Dr. Jamie Kopper, associate professor at Iowa State University, were concerned that hospitalized horses that did not consume enough water could develop colic, a potentially life-threatening condition.
Traditionally, horses hospitalized at Washington State that don’t voluntarily drink are offered water flavored with peppermint, sweet feed, or apple electrolytes. Until this study, no one had documented the horses’ response.
Horse Health
New Equine Virus Tied to Rise in Foal Diarrhea Cases
An existing equine Rotavirus A vaccine offers no protection.
A new Rotavirus not previously seen in horses is the culprit behind a rash of foal diarrhea cases seen during the first several months of the year at farms in Central Kentucky, according to researchers at the University of Kentucky’s Maxwell H. Gluck Equine Research Center and the Veterinary Diagnostic Laboratory.
Because the virus is a different strain it could not be detected using existing diagnostic tests for equine Rotavirus A and also the currently available commercial vaccine does not provide any protection.
“This is not a mutation. This is a whole different virus for horses,” said Dr. David Horohov, chair of the Department of Veterinary Science and director of the Gluck Equine Research Center.
Dr. Slovis’s Six Tips on How To Prevent & Treat EHV-1 In Your Horses
Equine Herpesvirus (EHV-1) causes respiratory disease, abortions and neurological disease. Transmission occurs via the respiratory system, with droplets of the virus being spread by mucus via snorting, coughing and human contact.
If you are in a high-risk area where there’s a greater incidence of EHV-1 cases, the following tips may help ensure your horse is protected from infection. These precautionary strategies come directly from Dr. Nathan Slovis, DACVIM, at Hagyard Equine Medical Institute. As an Internal Medicine Specialist and the Infectious Disease & Biosecurity Director, he has implemented the current Infectious Disease and Equine Emergency Response Programs at Hagyard.
- Start monitoring your horse’s temperature twice daily. Even if your horse has not been exposed, start recording their temperature now to understand what their normal baseline temperature is. A horse’s temperature will usually spike prior to shedding significant amounts of the virus, and typically anything greater than 101.5oF should be considered a fever. If a fever is noted, you should isolate the horse to the best of your ability until a veterinarian can assess. It is recommended that any horse with a fever have both a whole blood sample and nasal swab submitted for PCR assessment for EHV-1 and EHV-4.
- Limit exposure to any stressful situations that are not necessary. Examples include elective surgeries and other medical procedures. Minimizing stress will help protect the immune system so it can better fight off infection.
- If your horse requires the use of corticosteroids, either systemically or intraarticularly, consult your veterinarian to see if it is feasible to stop administration. The continued use of corticosteroids can suppress the immune system and could hinder their ability to effectively fight off an infection.
- Increase biosecurity measures since humans can inadvertently spread the infection on their hands, grooming equipment, etc. EHV-1 can survive on inanimate objects like halters, lead ropes, and tack, but is easy to kill on surfaces with disinfection. Therefore, these simple biosecurity measures can help stop the spread:
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- Wash or sanitize your hands between interacting with each horse.
- Take care when filling water buckets and feed tubs – neither the hose nor the feed scoop should have contact with the bucket or tub.
- Minimize the use of shared equipment, disinfecting tack (bits, bridles, etc.) between horses. Items like water buckets and feed tubs should not be shared.
There are a multitude of safe and effective disinfectants available. A few I recommend are a 1:4 ratio of bleach to water, or accelerated hydrogen peroxide-based disinfectants (like RescueTM) since they are safe for both human and animal use.
- Keep your horse up to date with their EHV vaccine schedule. If you horse has not been vaccinated against EHV three months prior to travelling into an area that has a high incidence of EHV, then I would recommend vaccinating your horse. If you are in a high-risk area, consult your veterinarian about the use of vaccines that have a high antigenic load for herpes virus so you can get a robust immune response. Remember, there is no vaccine on the market that can prevent the neurological form of EHV-1. The goal of vaccinating is to reduce the severity of clinical signs and reduce shedding of the EHV-1 virus if a horse does get sick.
Some inactivated vaccines with the highest number of antigens for virus neutralization include Calvenza®, Pneumabort-K® and Prodigy®. Other vaccines like Rhinomune® are a modified live vaccine, and also have a high virus neutralization response.
- If your horse is exposed or gets sick, contact your veterinarian to see what course of action they recommend. As mentioned, diagnosis requires the detection of the virus from either whole blood or nasal swab samples via PCR testing.
If you are in a barn with a horse that has EHV-1, the use of the antiviral drug valacyclovir may decrease virus shedding and may help your horse from acquiring the infection. Veterinarians have also discussed the use of lysine to theoretically reduce viral replication. Horses can be administered safely 12 grams orally once daily in their feed. This has not been proven to prevent neurological forms of EHV-1.
In the neurologic form of EHV-1, the virus interacts with the blood vessels that supply the spinal cord. This inflammation in the blood vessels can cause a stroke-like event (blood clot), resulting in decreased blood flow to that portion of the spinal cord. To potentially prevent this from happening, veterinarians may prescribe anticoagulants like aspirin and/or heparin to prevent this from happening if your horse becomes clinical.
To learn more about EHV-1, Dr. Slovis recommends referring to the American Association of Equine Practitioners (AAEP) website for accurate information: https://aaep.org/guidelines/infectious-disease-control/equine-herpesvirus-resources.
About Hagyard Pharmacy: Hagyard Pharmacy is a full-service equine pharmacy located in Lexington, Kentucky. It is affiliated with the Hagyard Equine Medical Institute and its 140+ years of equine veterinary experience, making it the number one name in equine health. This affiliation gives Hagyard Pharmacy a unique perspective in providing compounds, over-the-counter pharmaceuticals, and supplements to the equine industry. This has led to the development of innovative products, such as the Resolvet line products that is inspired and developed by pharmacists to address specific needs for equine supplements and performance aids. The Resolvet line includes Relyne GI for gastric support, Reflex HA for joint support, Revyve digestive support, Relyte HA electrolyte paste, Relieve intestinal adsorbent, Repair hoof oil, and Resolve antimicrobial spray. For more information, visit hagyardpharmacy.com and resolvet.com.
About Hagyard Equine Medical Institute: With more than 50 veterinarians and 145 years behind it, Hagyard Equine Medical Institute is the oldest and one of the largest private equine veterinary practices in the world. Based in Lexington, Kentucky, the facility, located across the street from the Kentucky Horse Park, boasts superior ambulatory services, the world-renowned Davidson Surgery Center, McGee Medicine and Fertility Centers, Hagyard Laboratory, Hagyard Sports Medicine & Podiatry Center, and hyperbaric medicine facilities. For more information, visit hagyard.com.
Proper Training Doesn’t Just Make Horses Faster — It Changes Their Organs
Proper training of the equine athlete can produce results in more than just muscle mass: it can and should create physiological changes in the lungs, spleen and heart.
Proper athletic conditioning can increase the actual size of the heart, which is a factor in cardiac output. Cardiac output is a combination of heart rate and stroke volume. The more blood that pumps through the heart, the more oxygen arrives at the muscles.
A horse that has been trained properly will have healthy lungs, which can take in more oxygen. The oxygen is then carried by the blood and distributed to the muscles. Called maximum oxygen uptake, this process provides power for a longer time. If all other equine systems are in order, the horse’s performance level is directly related to maximal oxygen uptake, which can increase by 35 times between rest and intensive exercise.
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