Test Designed to Detect Equine Disease Shows Promise for COVID-19

Researchers designed the smartphone technology to rapidly identify equine viral respiratory cases. Now, they believe the same technology could help identify COVID-19 in humans.

Test Designed to Detect Equine Disease Shows Promise for COVID-19
Smartphone technology constantly improves, with each new phone touting coveted camera enhancements such as number of megapixels, fast autofocus, and better low-light performance. Those same companies can now add “infectious disease detection” to their lists of camera features. Researchers have discovered a way to use a phone’s camera to detect viruses that cause respiratory diseases such as equine influenza and COVID-19 in humans.“As we have recently witnessed, upper-respiratory diseases can rip through communities quickly, leaving a wake of death, illness, economic losses, and major disruptions to daily life,” said Brian Cunningham, an electrical and computer engineering professor at the University of Illinois at Urbana-Champaign.

One of the major contributors to the rapid spread of upper-respiratory infectious diseases such as COVID-19 in people is the lack of widely available testing that provides quick and accurate results. As such, communities can’t make informed recommendations pertaining to targeted quarantines to best control the spread of disease.

Similar disease outbreaks occur in horses—recall the 2011 equine herpesvirus-1 (EHV-1) outbreak involving 240-plus horse premises in 19 states and two Canadian provinces.

“The key to infectious disease surveillance and control regardless of the affected species is early stage diagnosis,” Cunningham said. “The problem for many infectious diseases is that it takes time to send the test to the lab and have it processed, taking into consideration weekend/holiday hours and backlog of samples.”

Further, many upper-respiratory diseases can present with similar clinical signs, and some patients can be co-infected with more than one pathogen (e.g., equine influenza and EHV-1). Having to test for more than one disease to achieve a definitive diagnosis also delays appropriate control strategies.

“Given the downside of conventional testing protocols for infectious respiratory conditions, novel means of testing for one or more infectious diseases simultaneously that provide rapid, inexpensive, portable, point-of-care results would be advantageous,” Cunningham said.

Cunningham’s research focuses on the development of novel devices and instrumentation for life sciences. In collaboration with equine veterinarian David Nash, DVM; molecular biologist David Hirshberg, PhD, of the University of Washington; and bioengineer Rashid Bashir, PhD, at the University of Illinois, his group developed a novel testing technique for an array of respiratory pathogens affecting horses. Pathogens included Streptococcus equi subspecies equi and zooepidemicus, EHV-1 and -4, and equine influenza.

The test detects viral RNA (genetic material similar to DNA) obtained directly from nasal swabs. The RNA on those swabs is converted to DNA and then amplified in liquid compartments inside a silicon chip. This chemical reaction is called “loop-mediated isothermal amplification” and can generate billions of copies of the original viral nucleic acid sequence in just 30 minutes. During amplification fluorescent markers bind to target sections of DNA copies that smartphone cameras can subsequently detect as green light.

Other compartments within the same silicon chip can perform separate tests that distinguish between different viruses. This means it can test for multiple pathogens simultaneously. Appropriate use of positive and negative controls reduces the likelihood of false positive and negative results.

In sum, veterinarians can use the test to identify several infectious respiratory-disease-causing viruses in about 30 minutes while still at the patient’s side using a smartphone and a chip roughly the size of the phones’ SIM cards.

While the test brings great news for the equine industry, Cunningham noted that “our efforts are motivated by the urgent need to develop rapid point-of-care testing for highly contagious human respiratory viruses such as COVID-19.”

If the test takes off, it would immediately fill a cavernous void in controlling infectious disease spread in horses, humans, or any animal species, he said.

The article, “Smartphone-based multiplex 30-minute nucleic acid test of live virus from nasal swab extract” was published in the May 2020 edition of the journal Lab on a Chip.


Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she’s worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

3 Ways to Help Your Horse Become more Confident and Connected

Slowing down is necessary in life and in horsemanship; here’s how to incorporate rest and relaxation into your rides to create a calmer equine partner.

When and where we rest our horse can reinforce what we want to teach them, build their confidence and relieve their anxiety. (Tracy Barton Photography)

Rest and relaxation; we know how important it is for us as people. We know that when we work too hard it is important to slow down and catch up on some good old R&R. Often, this may look like staying in for an evening and watching a movie (and goodness knows we’ve been doing that enough for the past three-and-a-half months!), or maybe it looks like going on a slow trail ride with a friend, or maybe it looks like taking a vacation where we can leave our worries behind while we listen to the ocean.

Now that more of us are riding regularly again and perhaps even getting ready to compete, the temptation to train-train-train is very strong. Unfortunately, our horses don’t have the opportunity to tell us when they need to take a break from their regular routine to get the rest they need to recharge. The good news is that they won’t need to when we incorporate it into their everyday routine and rides.

Here are 3 ways you can ensure your horse is getting the R&R they need to help them become quieter, more confident and connected:

1. Slow down to go faster.

Have you ever heard the saying, “When you rush a horse, you usually end up at the wrong place faster”? It’s pretty accurate, unfortunately; sometimes we don’t even know what rushing a horse looks like until we end up where we don’t want to be and wonder how on earth we got there when it seemed like things were going so well in the right direction.

Part of slowing down is becoming less time- and task-driven and more driven by what our horse is communicating they need in the present. When we spend all of our time rushing, we miss things that we may have been able to catch if we had our head fully in the game.

So often we head to the barn on stolen time. We know we only have an hour to get in and get out and get something accomplished in the meantime. When time and task are all we think matters, the things we miss can make or break our ride, confidence and connection. We might miss our horse telling us their back is sore by simply labelling their tail swish and pinny ears as “having attitude”, we may miss their need for mental focus and swing a leg over a very disconnected horse and risk stepping into a potentially dangerous situation, or we may miss an opportunity to reward our horse for trying really hard for us, resulting in them becoming discouraged and frustrated. Sometimes we miss our horses telling us we need to slow down and teach a lesson in smaller steps and we miss our opportunity to grow their confidence rather than lessen it.

2. Equal work to rest time.

When we work with our horses it can feel like we are only teaching or accomplishing anything when our horse’s feet are moving. This is completely understandable, but may be the very thing that is stopping us from progressing as quickly in our training as we would like.

Horses learn from the release of pressure because they are comfort-driven. When we allow our horse to stop and rest, it does a lot more than just give them time to air-up their lungs and rest their muscles; it gives them time to think. When we become aware of the importance of release and the impact of rest, we can use our rest time to train our horse more intentionally. Our horse is always learning, so using when and where we rest to reinforce what we want to teach them will also show them that they can rest and relax with us. This will build their confidence and relieve their anxiety.

Resting is hard; I recommend setting a timer. When a horse does something really well, sit for five minutes. It will feel like an eternity at first, but it will not be idle time.

3. Be the example.

Yelling at someone to “Relax!” through gritted teeth and tense muscles never works. What does help us relax, however, is seeing other people relax and understanding that it is okay to do so and we are safe. Our horses are no different.

We must learn how to release tension from our own bodies before we can expect it of our horses. When we learn how to slow our own minds down, connect back to our bodies and relax, we become the leader our horse needs us to be.

Being our horse’s leader requires us to be aware and relaxed, soft and strong, clear and kind. If we struggle to be these things away from our equine partners, we will most certainly struggle with them when we are sitting on our large, living, breathing, prey animal.

Practicing mental and emotional control, grounding techniques and meditation at home will give us the ability to tap into these tools while riding and will allow us to remain calm and lead our horse with more confidence, resulting in them looking to us for help rather than running away from us.


Nikki Porter is an equestrian mindset coach, author of “The Conscious Communicator: The Pursuit of Joy and Human Connection Inspired by the Art of Horsemanship”, host of the “Take the Reins Podcast” and online workshops guiding equestrians on a journey to better communicate with their equine and human partners.

10 Secrets to a Good Vet-Client-Patient Relationship

To help you better understand the ideal VCPR—a relationship that carries a lot of weight in our horsey lives—we’ve sought out the signs of a healthy one. How does yours line up?

10 Secrets to a Good Vet-Client-Patient Relationship

What is a VCPR, and how can it benefit you, your veterinarian, and your horse?

Any relationship can be challenging at times. When a third party comes into the picture, however, the work gets even harder. Let’s say the relationship affects the health of one, the finances of another, the professional reputation of the other, and the general well-being of all three.

When it comes to the veterinarian-client-patient relationship (VCPR), that’s exactly what we’re looking at: three individuals coming together to form a mutually respectful (as much as the horse is capable, of course), long-term bond that focuses on the horse while safeguarding the veterinarian and the owner. It’s not an easy task! And it takes a lot of thought and consideration.

That’s why we’ve gone to the “relationship experts” of the equine veterinary world. To help you better understand the ideal VCPR—a relationship that carries a lot of weight in our horsey lives—we’ve sought out the signs of a healthy one. How does yours line up? And how can you better meet your relationship goals?

1. The horse is the focus.

The VCPR isn’t just a concept; it’s an American Veterinary Medical Association requirement for dispensing medications and a legal requirement for veterinary care in most states. And for good cause: If a VCPR is healthy, the horse is at the ­center—not owners’ competitive, breeding, or business goals; not their efforts to save time or money; and not veterinarians’ professional aims.

“If I could rewrite the VCPR acronym, I’d put the P for patient first, because the key to that VCPR is that the horse always comes first,” says Harry W. Werner, VMD, of Werner Equine LLC, in North Granby, Connecticut. “Certainly we the veterinarians are there for the needs and wants of the clients—but only as long as those needs and wants are legitimate and consistent with the health and welfare of the horse, who is priority.”

A good vet shows compassion—a trait that ranks as high as, if not higher than, knowledge and skills, says Werner. Good owners place the horse’s health and welfare above their own objectives or dreams, whether that means forgoing a competition, skipping a breeding season, or even choosing to humanely euthanize instead of prolonging suffering.

“My definition of a good client is one who wants you there for the horse,” he says.

2. Ethical practice is priority.

Ethical practice means not only doing what’s best for the horse but also maintaining a level playing field in equestrian sport. The humans in the VCPR equation must be prepared to uphold high ethics and support each other in doing so, regardless of the consequences, Werner says.

“There’s a lot of pressure on caregivers and stakeholders to do whatever possible to achieve the highest ranks in performance,” he says. “A good VCPR is an insurance policy against any medical, surgical, or pharmaceutical practices that are designed only to get the horse in the ring and get the ribbon. If owners and veterinarians make ethics the heart of their shared philosophy, this isn’t going to occur.”

Here the concept of “shared” is critical, says Sid Gustafson, DVM, whose equine practice is based in Bozeman, Montana. “The people in the VCPR have to match up in their beliefs and ideologies, without any coercion, pressure, or manipulation, if it’s going to be a successful relationship,” he says.

Veterinarians who refuse certain practices on ethical grounds might not get called back to certain farms or events, Werner says. And owners might have to “wrestle with accepting a lower return on investment.” But he says those potential consequences must pale in comparison to doing what’s right.

“When it comes to ethical veterinary practices, have your radar out, take the high road, and stay on it,” he says.

10 Secrets to a Good Vet-Client-Patient Relationship

3. Communication and trust are key.

Owners and veterinarians need clear lines of communication that allow for and even promote fluid, open conversation about the horse, as well as confidence in each other, our sources say. This means listening well and communicating clearly and in a straightforward manner.

“Email and texting are great tools because they keep the dialogue going without having to be concerned about the other person’s availability,” says Susan Werner, business manager at Werner Equine and Harry’s wife. “They also give a good written record so everyone’s clear on what’s been said.”

Good communication also helps the people in the relationship understand when errors happen, says Gustafson. “Vets and clients alike are human and, therefore, imperfect,” he says. “Of course there will be mistakes sometimes (e.g., interpreting a test result incorrectly). But an open exchange helps reduce the risk of errors and also helps put them into perspective when they do occur.”

As such, strong communication is critical toward building mutual trust, our sources say. “People can really gain confidence just keeping the dialogue going,” Gustafson says.

When things go wrong, or when owners must face difficult decisions, communication and trust become even more essential and help pave the way for an optimum outcome, he adds.

4. The vet is involved in every decision, even at a distance.

Even when one party is absent, there still needs to be continuity of care within the established VCPR, our sources say.

A veterinarian that’s part of a productive VCPR knows a horse’s health history, training and management, nutritional background, and more. This helps build a strong, global picture that allows the veterinarian to give optimum individualized care, says Gustafson.

Unfortunately, we often overlook that when we’re at events. “Something that’s particularly disturbing in today’s equine competition world is the lack of legitimate VCPR in the upper levels,” Harry Werner says. “Certain (veterinary) outfits show up … with a tractor trailer ­pharmacy and pretend they’ve got VCPRs with the horses there, but they don’t.”

Gustafson agrees. “They know little or nothing about these horses, and it’s often the first time they’ve seen them, and there’s usually no physical exam or attempt to know the horse’s background so, in the end, the humans are failing the horse,” he says.

In a good VCPR owners and veterinarians collaborate to ensure good transfer of information even at events, Susan Werner says. That includes long-distance consulting, as well as accurate, thorough record-keeping.

“With modern technology, it’s easy to maintain good records and to share them,” she says. To be useful, records must be timely, comprehensive, and written in language other clinicians can easily understand.

5. All parties related to the horse are in the loop.

The VCPR should expand far beyond the three main parties, our sources say. It must acknowledge the roles of everyone involved in the horse’s veterinary care.

“In a good VCPR, the veterinarian has enfranchised the owner as part of the health care team, as well as the trainer, the farrier, and all other caregivers,” Harry Werner says. “The veterinarian will have identified all the people that affect the condition of the horse—in a positive or negative way—and include them into the team.”

In bad VCPRs the farrier or dental practitioner or stable manager, for example, might get overlooked. And, in some cases, even the veterinarian can be out of the loop. “If more veterinarians were involved in decision-making about conditioning practices, there might be fewer health issues related to training,” Gustafson says.

6. Internet use is ­responsible—and shared.

The internet empowers owners with access to unlimited equine health care information, says Harry Werner. That ­information—provided it comes from reputable sources—can be useful and even helpful in diagnosing and treating a case, but it can’t stand alone, he says. It can’t replace the near-decade of the veterinarian’s professional training and possibly far more years of experience, and it can’t replace the individualized attention that comes through a VCPR.

“I hear about Dr. Google all the time,” says Harry Werner. “It’s important to not dismiss what owners say they’ve read. I’d rather they share the link with me so we can discuss it together, because it’s possible it’s a product I haven’t heard of. This can build confidence and good communication, as well.”

Online veterinary evaluations, however, don’t fit into the VCPR—unless they’re follow-ups to an established relationship, says Gustafson. Telemedicine cannot yield good care for the horse if the veterinarian isn’t part of the VCPR. “So much comes from knowing how the horses live day to day in their home environment, and you just can’t get that information over a computer screen,” he says.

7. Boundaries and roles are respected.

Each member of the VCPR brings his or her own responsibilities and roles to the relationship. It’s up to the others to recognize and respect those, says Gustafson. “I don’t want a client calling me to tell me her horse needs an X ray or saying he wants his horse to take a certain medication because it worked well on his friend’s horse,” he says. “I’m not a pharmacy technician or a radiograph technician. This isn’t respecting my role as veterinarian. Rather, let me evaluate the horse and, when I’m there, ask if that medication or that X ray might be useful, and we can talk about it.”

Likewise, it’s important for veterinarians to respect their clients’ knowledge and capacities, he adds. “Nobody likes to be talked down to, and vets don’t get very far by being arrogant,” he says.

Owners also provide critical information through their observations that veterinarians need to recognize and appreciate, even if it’s just a gut feeling that something’s wrong, Susan Werner says.

On all sides of the relationship, our sources agree that boundaries are important. While it’s good to be friendly, the relationship should remain, above all, professional. “There needs to be some kind of space, so that decisions aren’t made based on how the other person is going to feel about you,” Gustafson says.

8. Parties are transparent about finances.

Money can destroy any relationship, including a VCPR. To have a healthy attitude toward money exchanges, it’s necessary to have full transparency with finances on both ends, says Susan Werner.

“Veterinarians need to be clear from the beginning about what the fees and payment terms are, to avoid unpleasant surprises,” she says.

Equine veterinary care can be costly, but it’s helpful for owners to understand the value they’re getting from advanced, albeit more expensive, technology, says Harry Werner. “If I communicate with owners about the multiple advantages of a technique before we perform it, and they appreciate that, we can avoid sticker shock when the bill comes,” he says.

And clients need to feel comfortable discussing finances openly with their ­veterinarians—including acknowledging that some options are out of their price range. “The goal is for owners to have timely information in a way that they can make informed choices,” Susan Werner says.

9. There’s chemistry.

Even when everyone does everything right, sometimes relationships fail simply because the chemistry isn’t there. And VCPRs are no exception.

“You need to match up with people you get along with,” Gustafson says. “That has nothing to do with medicine or knowledge. Maybe politics, maybe culture, maybe personality, who knows? But that match needs to be there.”

A good way to build that, or at least look for it, is in the physical exam, Harry Werner explains. Like with human patients, the physical exam is an opportunity to evaluate much more than the patient’s physical health. It’s when doctor and patient get to know each other.

“That’s the buying part, so to speak,” he says. “It’s often during that exam that you know if the connection is there or not.”

Sometimes the chemistry isn’t there with the horse, either. “You might have an owner with seven horses, and one of them just doesn’t seem to feel comfortable with the vet,” Gustafson says. “Who knows why? Maybe something in the horse’s past or something we can’t explain. But if that’s the case, the owner should consider a different veterinarian for that one horse—one he gets along better with.”

10. There’s tact, kindness, and respect when ending a relationship.

Not all relationships work out, for a variety of reasons—different ideologies, lack of confidence, poor chemistry, etc. When they don’t, they need to come to a close with tact, kindness, and respect, says Gustafson.

“Veterinarians and sometimes owners are professionals, but they’re also humans, and they have feelings,” he says. “It’s okay to end a relationship, but that needs to be handled appropriately. Sometimes a bad relationship with a client can really ruin a veterinarian’s day while he’s still needing to concentrate on the care of other patients. And that can be similar for owners.”

Whether it’s the veterinarian or the owner that makes the call, it’s important they inform the other party directly and with professionalism, through a tactful letter, email, or telephone call. No need to go into long details about why it’s ending or harp on old problems. No need for rudeness and certainly not for spreading negative information in social circles or on social media. (However, serious welfare concerns do warrant discreetly informing authorities or welfare ­organizations.)

Likewise, the party on the receiving end should accept the departure with tact and respect, our sources say.

Take-Home Message

A positive VCPR plays a vital role in upholding the health and welfare of the relationship’s primary focus: the horse. But it doesn’t happen on its own; it requires thought and effort on the part of all humans involved. Consider the relationship from each party’s point of view, and strive to build a healthy VCPR.


Passionate about horses and science from the time she was riding her first Shetland Pony in Texas, Christa Lesté-Lasserre writes about scientific research that contributes to a better understanding of all equids. After undergrad studies in science, journalism, and literature, she received a master’s degree in creative writing. Now based in France, she aims to present the most fascinating aspect of equine science: the story it creates. Follow Lesté-Lasserre on Twitter @christalestelas.

Mineral of the Month: Zinc

Zinc-deficient horses can exhibit reduced growth rates, inappetence, and skin abnormalities, among other issues.


Although the trace mineral zinc (Zn) was first noted as a new metal around 1374 in India, it had been used for many years prior, extracted in an impure form from zinc-ores to produce brass. Yet, it was not named until the 16th century, when a European alchemist documented it as “zinken.”

The development of a method to purify these zinc extracts led to its use in the medical field, especially for treating inflammatory eye conditions by means of zinc solutions and tablets. Interestingly, researchers know today that the highest concentrations of zinc in the body can be found in the eye’s choroid and iris.

It was only in 1934 that zinc was demonstrated to be an essential nutrient in rats’ diets by Todd et al. Rats fed a low-zinc diet had poor growth rates and abnormal fur coats. The following year, research from the same laboratory showed that supplementing zinc-deficient rats with zinc corrected the “faded, thin, and wooly” fur condition and allowed normal growth rates to resume. These findings were followed by similar research in livestock, exploring zinc deficiencies and establishing requirements. Across species, including in the horse, reduced growth rates, inappetence, and abnormalities of the skin were common observations in zinc-deficient animals.

Today, research across species, including humans, has linked zinc to many different bodily processes. These include fetal development, growth, tissue repair, reproduction, and the immune system, to name but a few. Zinc serves as a catalyst for more than 200 metalloenzymes in the body, explaining in part how it can affect such a range of different processes.

Zinc also fulfills many structural functions. For example, it can be found at the functional site of the enzyme copper/Zn superoxide dismutase, and in a diverse group of proteins called zinc fingers, where a zinc ion stabilizes protein structures involved in functions such as signal transduction and cell proliferation. Zinc has also been shown to affect gene expression regulation.

In areas where soil zinc concentrations are low or marginal, local forages and feeds might subsequently be low in zinc. Feedstuffs commonly fed to horses contain approximately 15 to 40 mg zinc per kg dry matter. The recommended total dietary zinc intake for a 500-kilogram (1,100-pound) mature horse, idle or used for light exercise, is 400 mg per day (National Research Council’s Nutrient Requirements of Horses, 2007). This recommendation increases to 500 mg per day for a lactating mare or heavily exercising horse of similar weight. Therefore, some horses might require additional zinc supplementation to meet their requirements.

Commercial horse feeds are formulated to provide additional zinc to a horse’s diet and could contain either an organic or inorganic form of zinc, as would be indicated on the feed tag. The maximum tolerable concentration for zinc in equine diets has been set at 500 mg/kg dry matter, well-above the recommended amount of zinc required by the horse. However, excessive amounts of dietary zinc could interfere with a horse’s copper status. It is not clear if zinc affects copper metabolism by interfering with absorption through shared transport mechanisms, or post-absorption, but maintaining a reasonable total dietary copper to zinc ratio is important. Commercial horse feeds are formulated keeping this in mind. Therefore, it is always a good idea to work with a nutritionist should you consider adding additional mineral supplements to a balanced commercial horse feed.

Mieke Holder, PhD, is an assistant research professor within UK’s Department of Animal and Food Sciences.

Ration Balancer vs. Vitamin-and-Mineral Supplements

Why is the serving size of a vitamin-and-mineral supplement for horses so much smaller than a ration balancer serving?

Ration Balancer vs. Vitamin-and-Mineral Supplements

QUESTION    . My horse eats grass hay and doesn’t need additional calories. I know I need to add a source of minerals and vitamins to balance the ration. Why do ration balancing feeds have 1-2-pound serving sizes while most of the supplements have 3-6-ounce serving sizes? Why are they so different?

ANSWER    . Ration balancing feeds and vitamin mineral supplements designed to balance rations might appear similar. For example, ration balancing feeds often have a zinc content of between 400 and 600 ppm (milligrams per kilogram), so if feeding 2 pounds per day you would be feeding slightly less than 400 to 600 milligrams. The vitamin and mineral supplements that claim to support a forage-based diet might have 300 or more milligrams per 3-6-ounce serving. The same is true for the other trace minerals such as copper, manganese, and selenium. Similarities exist in the amounts of various vitamins, as well, with both product types tending to provide somewhere between 500-1,000 IU of vitamin E per serving. I understand why the serving sizes being so different, because clearly the difference can’t be explained by these nutrients. Differences become apparent when looking at amounts of macrominerals, such as calcium, phosphorus, magnesium, and sodium. One vitamin mineral supplement guarantees a minimum of 8% calcium and 4% phosphorus. With a serving size of 115 grams, this means each serving provides 9.2 grams of calcium and 4.6 grams of phosphorus. On face value, the amount of calcium in ration balancers looks lower, because it’s typically in the range of 3-4%, while phosphorus is about 1%. But with the larger 1-2-pound serving size, this equates to a possible daily calcium intake of between 13.6 to 36.4 grams and 9 grams of phosphorus.

Daily macromineral requirements are in gram quantities, whereas horses only need trace minerals in milligram quantities. When you have a serving size of up to 2 pounds per day for the ration balancer, manufacturers have a lot more volume in which to add macrominerals. This is especially true when you consider that ingredients aren’t made entirely of the desired nutrient. For example, calcium carbonate is not 100% calcium. In the case of calcium carbonate, just less than 40% is actually calcium, so if 20 grams of calcium from calcium carbonate are needed per serving, the serving must provide 50 grams of calcium carbonate. Adding more macrominerals therefore results in a much larger product serving size.

The same is true when adding protein. Most ration balancers provide protein from soy or another high-protein ingredient. This improves the overall amino acid profile of the horse’s forage-based diet. Again, protein and amino acids are required in gram quantities per day, so adding this protein source increases the serving size. Vitamin-and-mineral supplements typically get around this by providing a pure source of essential amino acids such as lysine and methionine. If ration balancing feeds provide around 2% as lysine and 0.6% as methionine, then a 2-pound serving size includes 18 grams of lysine and 5.5 grams of methionine. The percentage of lysine and methionine in the vitamin mineral supplement might be 3% and 2%, respectively, but that only yields 3.45 grams of lysine and 2.3 grams of methionine per 4-ounce (115-gram) serving.

When you take a more careful look, it becomes clear that if your horse needs amino acid support or to ensure adequate calcium intake, a ration balancing feed is likely the better choice. If these are not concerns or you have an easy keeper and minimizing caloric intake is a greater concern, then the supplement version might be a better solution.


Clair Thunes, PhD, is an equine nutritionist who owns Summit Equine Nutrition, based in Gilbert, Arizona. She works as a consultant with owners/trainers and veterinarians across the United States and globally to take the guesswork out of feeding horses and provides services to select companies. As a nutritionist she works with all equids, from WEG competitors to Miniature donkeys and everything in between. Born in England, she earned her undergraduate degree at Edinburgh University, in Scotland, and her master’s and doctorate in nutrition at the University of California, Davis. Growing up, she competed in a wide array of disciplines and was an active member of the U.K. Pony Club. Today, she serves as the district commissioner for the Salt River Pony Club.

Horse Conformation Changes: From Toeing-Out to Toeing-In

What could cause a change in an adult horse’s leg conformation?


horse conformation

QUESTION         I went to visit a friend and her 8-year-old Quarter Horse, and I noticed the horse was toeing in. I have known this horse since his birth and have pictures of him from over the years. Up to two to three years ago he was slightly toeing out. His legs turned out from the knees. This horse has had soundness issues in the past involving caudal heel pain in the right front and some undiagnosed lameness in the right hind, and he was out of work over the winter because of back issues. When I saw him the other day he was standing base narrow with both feet turning in. My first thought was his farrier must have caused the change, but could soundness issues be to blame?

Lynn, via e-mail

ANSWER        Conformation is a highly judged trait in horses. We evaluate it in the show ring, the sale ring, the foaling pasture—everywhere. Conformation can also be a major determinant of an individual’s athletic ability. For example, a horse with straight, “posty” hind legs may be less able to perform a sliding stop or a rollback turn.

There are many recognized possible conformation faults in the lower forelimbs. The front fetlock and knee (carpus) can have flexural, angular, or rotational deformities. The bones’ growth plates can develop abnormally and lead to angular limb deformities. Once the growth plates are closed (finished growing), there is very little change or correction that can be done—at least in a conservative fashion. Foals very often have some degree of carpal valgus (knock knees) that self-corrects as the chest widens with growth. This is an angular deformity in which the lower leg bends outward (away from the midline) from the carpus.

Many angular and rotational deformities may be irreversible by the time the horse is skeletally mature. This age of maturity varies among breeds, as well as individually. A horse is considered skeletally mature by age 2 or 3 in regard to growth plate closure. However, there is a lesser degree of continued and slow growth through age 4 or 5. This would include very small amounts of bone growth and significant muscle development.

Owners often employ corrective or therapeutic farriery to help treat lower limb deformities in foals and weanlings. As horses age, the potential for this type of correction lessens. Many farriers and veterinarians recognize that trying to correct a deformity via shoeing after growth plates close can lead to pain and lameness. For this reason, a foot should be managed in regard to the conformation after skeletal maturity.

The horse in question has had a noticeable conformation change in a relatively short amount of time. This change has clearly developed after skeletal maturity. Therefore, you can essentially rule out the common causes of growth-related distal limb deformation. A bilateral (affecting both sides) change from “turned out” to “turned in” is uncommon and interesting. A base narrow stance can be a dynamic change and could very well be a response to pain (i.e., possibly on the inside/medial side of each leg). The horse could be shifting weight to the lateral/outside aspect of the joints.

An example of this would be a horse with carpal arthritis, which often develops on the medial aspect of the joint first. In this case, a previous diagnosis of pain related to the caudal heel or navicular region is probably a main key to the answer of this question. Horses with pain relating to this region often protect their heels. They commonly develop a short, choppy gait due to reluctance to extend the stride that naturally would lead to a more aggressive heel strike. We often see heel contraction and reduced hoof size, as well. It would not be surprising that chronic heel pain could lead to a change in conformation due to abnormal forces and leg use by the horse.

Having said this, we certainly cannot rule out an imbalance in trimming and shoeing. At this age, the leg conformation should not change permanently from improper hoof “balance,” but such imbalance can cause the horse to try to compensate for the pain. The hoof may also be trimmed in a manner in which he appears to have a hoof or leg deformity. For example, a flare may not be dressed off completely on one side, leaving the illusion that the foot turns toward the flare.

Further diagnostics should help determine the cause of this horse’s conformation change. I often take radiographs of the foot, fetlock, and even the carpus to determine where angulation or rotation comes from. We should be able to see hoof imbalances in relation to the coffin bone and coffin joint. I have the luxury of taking radiographs before working on the feet and following trimming or shoeing to ensure proper alignment or balance. Although this is not necessary in many cases, I would recommend having your friend’s veterinarian and farrier out to the farm together at the first shoeing session going forward to find the right solution for addressing this problem.


Josh Zacharias, DVM, MS, Dipl. ACVS, ACVSMR, is an Iowa State University College of Veterinary Medicine graduate who practices at Countryside Large Animal Veterinary Services in Greeley, Colorado. His interests include equine lameness, surgery, and podiatry. In addition to working as a surgeon and sports medicine specialist, Zacharias is a farrier with nearly 15 years of experience in therapeutic shoeing applications. Much of his caseload includes Western performance horses.


What scientists are learning about equine parasite resistance to dewormers and how to curb it

Equine Parasite Control: Deworming and Beyond

What scientists are learning about equine parasite resistance to dewormers and how to curb it

In a grassy valley at the foothills of the Blue Ridge Mountains, a light breeze ripples the pasture grasses. A herd of riding horses bury their heads in the spring forage, tearing the blades, munching, occasionally snorting. Grasshoppers pop in and out of the forage. Sparrows pass overhead watching for spiders building their webs in the flowering weeds where the bees come to draw pollen.

Life—active and peaceful life—abounds around this herd of horses. It abounds inside the herd, too. Within each one of these shiny, healthy horses are parasites, carrying out their own unique life cycles in the equine gut. And scattered throughout this idyllic pasture are microscopic equine parasite eggs and larvae, waiting for their moment to find a host that will allow them to thrive.

Wait a minute. Can intestinal parasites really have a place in this harmonious picture? Aren’t they horrible creatures sucking the nutrients out of our beloved animals? And shouldn’t we be fighting back with deworming artillery, creating a battlefield on this otherwise serene pasture? On the contrary, as long as parasite burdens are well-managed, a coexistence between hosts (horses) and worms is quite normal—and peaceful, our sources say.

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Dr. Stuart E. Brown II Joins Keeneland as Equine Safety Director

Brown will lead the effort to develop, communicate, and enforce safety and integrity policies for both racing and sales operations.

Keeneland officials announced June 24 that Stuart E. Brown II, DVM, who cared for an international clientele during his nearly 30-year career with Hagyard Equine Medical Institute, in Lexington, Kentucky, will join Keeneland full-time as Equine Safety Director.

“Dr. Stuart Brown is uniquely talented for the position of Equine Safety Director and to be a leader in enhancing safety practices at Keeneland and throughout racing,” Keeneland president and CEO Bill Thomason said. “During his career, his knowledge and expertise have been sought by horsemen around the world and by top industry and veterinary organizations alike. Stuart’s addition to the Keeneland team further deepens our commitment to the safety and welfare of horse and rider, and his position provides a platform that will benefit the entire horse industry.”

As Equine Safety Director, Brown will lead the effort to develop, communicate, and enforce safety and integrity policies for both racing and sales operations; review all racing-related accidents with the goal of prevention; assess relevant equine health and safety research; and proactively communicate best practices to the racing community and public. His duties will encompass both Keeneland and The Thoroughbred Center.

“During my veterinary career, I have had the great fortune to work with some of the most dedicated horsemen and women in our industry,” Brown said. “I am proudest of these relationships, and those with my colleagues and the team at Hagyard, with whom I have collaborated to provide exemplary care to every horse touched along the way. Most recently, I have had the benefit of serving in several roles in racing alongside many of my racetrack practitioner colleagues, which has allowed me to gain an appreciation for their unique perspectives in the care of the racehorse. It is these experiences shared over time that form the foundation for me to embrace this new and exciting role as Keeneland’s Equine Safety Director.”

During his nearly 30-year practice with Hagyard Equine Medical Institute, first as an intern, then as an associate veterinarian and a partner, Brown has specialized in equine reproduction and ambulatory medicine. With a primary focus on Thoroughbreds, his areas of concentration included equine reproduction, foal evaluations, private/public purchase evaluations, herd health and preventive medicine, federally required import/export protocols, and issues affecting the welfare and safety of equine racing athletes.

“Hagyard Equine Medical Institute is excited to support Dr. Brown in his new position as Equine Safety Director at Keeneland,” said Ernie Martinez, DVM, practice member with Hagyard. “Dr. Brown has been an integral part of Hagyard’s history and success since he started as an intern in 1991, and with the support of the Hagyard veterinary team, he has cared for some of our sports’ most successful racehorses.

“We at Hagyard know Dr. Brown will bring his diverse network of connections and his experience as a veterinarian and as a horse owner to his new position,” he added. “We look forward to seeing the positive changes and innovation he can drive in our industry.”

Throughout his career, Brown has mentored many veterinarians, served on numerous industry and veterinary boards and committees, and represented veterinarians and horses on a national level.

Brown’s memberships and affiliations include the American Veterinary Medical Association (AVMA), American Association of Equine Practitioners (AAEP), Kentucky Veterinary Medical Association (KVMA), Kentucky Association of Equine Practitioners (KAEP), Society for Theriogenology, and Kentucky Thoroughbred Farm Managers’ Club.

His recent appointments include serving as chairman of the Gluck Equine Research Foundation, Trustee for the AVMA Insurance Trust, AAEP delegate to the AVMA House of Delegates, director of the Kentucky Thoroughbred Association (KTA) and Kentucky Thoroughbred Owners and Breeders Association (KTOB), member of the AAEP’s Public Policy and Welfare Council, AAEP liaison to the Thoroughbred Safety Coalition, board chairman of the University of Kentucky Equine Analytical Chemistry Laboratory, and a member of The Jockey Club.

Brown previously served as a  commissioner for the Kentucky Horse Racing Commission (KHRC), chairman of the KHRC’s Equine Drug Research Council, and president of the KVMA, as well as a committee member of the AAEP Racing Committee (and subcommittee chair for Issues Pertaining to the Horse Racing Integrity Act) and the Grayson-Jockey Club Research Advisory Committee.

Born and raised in Central Kentucky, Brown completed his undergraduate work at Transylvania University, in Lexington, and earned his Doctor of Veterinary Medicine from Tuskegee University. He also owns and operates a Thoroughbred breeding, racing, and sport horse farm in Versailles, Kentucky.

Fighting White Line Disease

Untreated white line disease can undermine your horse’s feet, causing lamen

Fighting White Line Disease

Photo: Erica Larson
White line disease sneaks up on you without warning–one day your horse is fine, and the next day the farrier is digging a crater in your horse’s foot, dumping what seems like handfuls of soft, crumbly hoof horn on the floor. You might ask, what the heck is white line disease? Why is it such a big deal? Your horse isn’t even lame, although you fear he might be soon with that new crater in his foot.

This ugly mess called white line disease might not be a big deal initially, but left untreated it can undermine large amounts of your horse’s foot (or feet), resulting in lameness and instability of the coffin bone within the horse’s foot. Bill Baker, DVM, of Equine Associates in Hawkinsville, Ga., discussed the disease and its treatment at the recent Bluegrass Laminitis Symposium, held Jan. 25-28 in Louisville, Ky.

“White line disease doesn’t seem to occur without some sort of mechanical stress (such as long toes or hoof damage from previous disease or injury),” he began. “The only known certainty (about its cause) is that a breach in the hoof wall has to occur for the disease to occur. (Opportunistic bacteria and/or fungi then invade the defect and begin destroying hoof wall from the inside, starting at the bottom and working their way up.) There is no breed, age, or sex predisposition to this disease. It occurs in anything from Minis to drafts, donkeys, and mules. It may invade one foot or all four feet.

“Most cases are diagnosed with physical exam findings,” he went on. “You see a small breach or crack in the hoof, explore it a little with a hoof knife and find cheesy, soft, white horn. You explore further and find that lots of wall is undermined. That soft white horn is why it’s called white line disease, although that’s somewhat of a misnomer because it affects the white inner part of the stratum medium layer of the wall (just outside the white line). It doesn’t really affect the zona alba (white line) at all.”

He noted that the disease initially causes no lameness at all, and that typically a farrier will see this during routine trimming long before a veterinarian will be called. If a veterinarian is called, he/she can radiograph the feet to see how far up the hoof wall the separation has progressed.

White line disease is best battled by resecting (cutting away) the affected area of the hoof to expose the bacteria and/or fungi to the air, said Baker. He recommends shoeing to support the reduced area of hoof wall available for weight bearing after resection. Various medications/disinfectants are also commonly used; he discussed all of these options in turn.

Resection/shoeing “Most people are resecting all abnormal tissue, and if you do that, you better support the foot,” said Baker, noting that this was his preferred approach. “You can’t take the wall off if you don’t support the horse. This is one of the most critical parts of any white line disease treatment.

“Some resect, then rebuild the foot with hoof repair material,” he continued. “But in my experience, when you pull (the repair material) off, the disease is still there. I don’t cover the resection unless I have to; I let them grow out on their own. This is why a radiograph is so handy to help you decide what mechanics you’re going to need for that foot (because it lets you see how far up the damage goes).” He added that antibiotic-impregnated hoof patches have been unsuccessful because they are not effective against the fungi that are often present in affected feet.

Cast the feet He noted that some people will resect the hoof, cast the foot to provide support, then medicate under the cast. Shoes can be nailed into the casting material for further support. “You can put a felt pad under the cast and leave a little sticking out, so you can apply medication to the felt and thus medicate the area every day,” he commented.

Gas the feet Chlorine dioxide is often used in food service to clean vegetables and food processing areas, said Baker, and it has also found some favor in treating white line disease. The theory behind its use for affected horses is that when mixed with vinegar, chlorine gas is produced that can permeate the wall and kill the bacteria/fungi without having to cut away the wall. It is applied once or twice weekly to the foot via a boot or bag for up to 45 minutes, he explained.

Baker reported that several studies have found some success with this method, but none have directly compared it with resection alone, so it’s not possible to say if it’s a better treatment without further study.

“I think you better catch it pretty darn early if you want to get that stuff all the way up the hoof wall,” he commented.

Medications/disinfectants “There are a ton of white line disease medications out there,” said Baker. “Most people are using Merthiolate (thimerosal, an organomercury compound used as an antiseptic and antifungal agent) or iodine as disinfectants, and there are antibiotics and antifungals. Some studies have had poor success with antibiotics because they don’t kill the fungi. Antifungals have some benefit, but they can get very expensive.”

Medication trial Baker discussed a medication trial at his clinic using 21 horses from five to 23 years of age, including five mares, 15 geldings, and one stallion. All the horses (which were of various breeds) had been diagnosed with white line disease in both front feet. Each had one foot treated with resection and support shoeing only, while the other was resected, medicated with Fungidye (a broad-spectrum fungistat for treatment and prevention of infections), Merthiolate or 5% benzoyl peroxide, and supported. Five weeks later, he said, there was no difference between medicated and unmedicated feet in terms of disease recurrence, quality of new hoof, or time to return to soundness.

Baker summarized this disease and its treatment with the following comments:

  • There is no clear pathogenesis for white line disease, but there has to be some mechanical stress in the hoof wall for this to occur.
  • The best treatment starts with supporting the foot. Do not resect without a plan for support!
  • Exposure appears to be the best treatment. Apparently whatever’s causing this likes a low-oxygen environment.
  • No medicines on the market have been proven effective.
  • Research is much needed for this disease.
  • Treatment is effective if early and aggressive.

Christy West has a BS in Equine Science from the University of Kentucky, and an MS in Agricultural Journalism from the University of Wisconsin-Madison.

ess and coffin bone instability.


First Equine Embryo Time-Lapse Images Revealed

Do you think horses are quick to get moving right after birth? Check out what they’re

First Equine Embryo Time-Lapse Images Revealed
Do you think horses are quick to get moving right after birth? Check out what they’re doing right after fertilization.Thanks to new time-lapse videos of equine embryo development, scientists are discovering the milestones associated with future implantation and pregnancy success. They’re also discovering just how active these microscopic equines are.

“We were all surprised by the amount of movement of the embryos and even of the cytoplasm (cell material) within the cells of the embryos,” said Niamh Lewis, BVM&S, PhD, Dipl. ACT, ECAR, equine reproduction specialist based in Dublin, Ireland. “They are by no means static during development. Cellular content and the attached cumulus cells (which surround the fertilized egg) are moving all the time.”

The movement she and her team saw was so significant that the embryos sometimes came in and out of focus or even shifted from one droplet of culture medium (the material in laboratory dishes that help the embryos grow) to another, Lewis said.

Seeing that movement—for the first time in equine science history—was “fascinating,” she said. But that wasn’t the primary goal of the time-lapse experiment. The scientists initially set out to look for specific milestones that could help predict which embryos were more likely to result in successful pregnancies.

Through studying the first several days of development in time-lapse videos, Lewis and her fellow researchers determined that early cleavage (the separation of a cell into two or three cells) is key, she said. Specifically, when the zygote (the single-cell product of egg fertilization) pushes out some of its cytoplasm and then divides within the first 24 hours, it’s much more likely to later become an embryo with a heartbeat.

Previous research had already pointed to this 24-hour window for cleavage, said Lewis. But their study visually confirmed the importance of the timing of this event.

In their study, Lewis and her fellow researchers created 144 equine zygotes through intracytoplasmic sperm injection (ICSI). They placed each injected oocyte (egg) in a droplet of culture medium and set it under a camera that would take images automatically every five to 10 minutes, for about the first 10 days of development. Afterward, they combined the images into a playback mode that generates a video of each embryo’s development.

The procedure allowed them to study, in precise detail, the timing of different developmental events in each embryo and then compare them, she said. For example, the timing of the first cleavage varied dramatically—ranging from 2.4 hours to more than four days after injection.

The 144 injected oocytes resulted in 19 blastocytes (an embryo at a stage that’s appropriate for implantation), Lewis said. They implanted 11 of those 19. Six resulted in pregnancies, and of those six, four reached heartbeat stage.

By following these successes and failures throughout the development process from the very first hour, the scientists were able to identify trends that could lead to better selection of “more promising embryos,” said Lewis.

“Time-lapse imaging can provide great insight into early equine embryo development and aid in predicting developmental potential,” she said. “As we gather more information on the topic, it will be great to be able to choose the embryos with the greatest chance of establishing an ongoing pregnancy.”

Beyond its practical advantages, the scientists are celebrating this important and historic step in equine reproduction science. While time-lapse imaging already exists in human medicine, where it has “taken the human IVF (in-vitro fertilization) field by storm,” it’s new in the horse world, Lewis explained.

“We were among the first researchers to ever view equine embryos under time-lapse,” she said. “It was fascinating to watch them develop in real time and to be able to see blastocyst formation so early on when it was not obvious on still image. That fascination never subsided in looking at each embryo develop, watching a miracle in real time! It certainly was extremely exciting.”

About The Author


Passionate about horses and science from the time she was riding her first Shetland Pony in Texas, Christa Lesté-Lasserre writes about scientific research that contributes to a better understanding of all equids. After undergrad studies in science, journalism, and literature, she received a master’s degree in creative writing. Now based in France, she aims to present the most fascinating aspect of equine science: the story it creates. Follow Lesté-Lasserre on Twitter @christalestelas.

doing right after fertilization.