Understanding how a horse uses his five sense to perceive stimuli can be key to his training and horse-human interactions.
Drs. Maria Vilain Rørvang, Birte Nielsen and Andrew McLean reviewed more than 180 studies that investigated equine vision, smell, taste, hearing and touch, and how information about the horse's environment is perceived. Though horses and humans have the same sensory modalities, how the information gathered from them are perceived can be drastically different.
Understanding how a horse perceives sensory information is key since sensory ability, perception and behavior are closely linked. The researchers determined that horses have a highly developed sense of smell; in some cases, their hearing is better than humans. Additionally, horses have a wider field of vision that people, but they see similarly to humans who are red and green colorblind.
The scientists concluded horses perceive the world in the following ways:
Vision
A horse's vision is adapted for detection of and escape from predators; they have a wide focus that allows them only a small blind spot directly behind them. Horses do not have good acuity, and will lift, lower or tilt their head and neck to focus on an object. Horses also have good vision in low light, seeing details better on cloudy days than during bright, sunny days.
Hearing
Equine ears can pivot toward sounds to enhance their hearing. While larger animals tend to hear lower frequencies well, horses are the exception; the lowest frequency detectable by horses is higher than the lowest sound a human can hear. Conversely, horses can hear higher frequencies than humans can. Horses can also recognize people from vocal cues even if they can't see them.
Smell
Little research has been done on horse's sense of smell. Horses have distinct odor profiles; similar profiles can shape a horse's response for interactions with other horses that have a similar smell. The research team notes that a horse's sense of smell could be exploited to draw the horse to certain locations, limiting the need to manually move horses. Additionally, riding in or around areas where a horse might encounter the smell of a predator may pose a safety risk to the rider.
Taste
Horses rarely breathe through their mouth, so it is unclear if horses can differentiate odor and taste from flavor, like humans. Horses can detect sweet, sour, salty and bitter; it is not known if they can detect umami (savory).
Touch
Horses are sensitive to touch; this sense is the main mode of communication between a horse and human, whether riding or handling. Horses are most sensitive around their eyes, nose and mouth; other areas of the body vary in their sensitivity, with the neck, withers, flank, shoulders and back of the pastern generally being the most sensitive.
The study team suggests that tactile stimulation be used with caution, especially when there is force applied, like during twitching. Future studies may investigate how a horse's age, breed, personality and experience may influence how touch is perceived.
The trio conclude that identifying specific sensory reactions in horses may be a way to optimize management and training to improve equine health and welfare.
Polk County Conservation is pleased to announce that Jester Park Equestrian Center's (JPEC) Horses Helping Heroes program (H3) was awarded the US Department of Veteran's Affairs Adaptive Sports Program for Disabled Veterans and Disabled Members of the Armed Forces Grant in the amount of $107,000.
The Horses Helping Heroes program is an equine-assisted therapy program facilitated by Jester Park Equestrian Center in partnership with the Veterans Affairs Central Iowa Health Care System. The program's mission is to build a Veteran's confidence through a relationship with the horse by creating opportunities to develop skills that can be used in their daily life.
To date, the program has helped over 300 Veterans from the VA Domiciliary collaborate with horses to identify relationships, practice communication, manage challenges and recognize peace. This grant will help the Horses Helping Heroes program expand to meet the needs of the many Veterans who are outpatients in the region and is designed to address trauma and other mental health needs, including substance abuse, depression and improving family relationships.
VA Recreation Therapist Megan Trimble shared the following statement expressing her excitement. “We are so thankful for being considered and awarded this grant, giving us the opportunity to reach Veterans on an inpatient and outpatient basis. Past participating Veterans have shared a quote we use in the session that sums up the positive impact they have felt; 'There are things that the horse did for me that a human couldn't have done. – Buck Brannaman.' I cannot contain my excitement to be able to expand the JPEC partnership and the H3 program to outpatient Veterans and continue assisting them through an array of mental health challenges! I would like to express an insurmountable amount of thanks to everyone involved within the Horses Helping Heroes Equine Assisted Therapy program, to include Sierra and the whole Jester Park staff, VA staff, and all the volunteers and donors that keep this amazing program running.”
In closing, Equestrian Center Manager Claudia Starr adds, “We are so grateful to everyone who helped us secure this grant. There is nothing more gratifying than knowing the peace that our service men and women find through interacting with horses. Our EAGALA certified professional Sierra Carmichael, along with VA Recreational Therapist Megan Trimble and our equine therapists, are helping Veterans find positive ways to navigate the many challenges they face.”
Learn more about Jester Park Equestrian Center's Horses Helping Heroes program here.
After the announcement that top 3-year-old Honor A.P. was retired a few weeks ago due to a tendon injury, many readers had questions. How serious are tendon injuries, anyway? Don't horses come back from them all the time? And what about breeding a horse with a tendon – does it place subsequent generations at risk for the same problem?
As with most injuries, the seriousness of a tendon problem depends largely on the severity and location.
“Tendon will generally swell before it tears,” said Dr. Ryan Carpenter, surgeon at Equine Medical Center in Cypress, Calif. “if you can catch a swollen tendon before it tears, then those horses do very well with time off. your typical juvenile tendonitis, you're going to give them 60 days off, let that tendon “set up” basically the inflammation will go down, and then those horses go on and have very long and successful careers with low rate of recurrence.
The problem comes when it tears.”
Carpenter also added that a tendon has to swell by about 20 percent before it could be perceptible to the naked eye. Fortunately, he said the attention paid to racehorses' legs means they're more likely than many other equine athletes to have a groom notice a change quickly.
It's also possible for tendon injuries to take several days after a race to become fully apparent. When Carpenter gets a call about a condylar fracture, it's usually because someone has noticed a horse looks uncomfortable after walking back to the barn and standing for a bath. Tendons don't tend to spark a lameness as quickly unless there's a major tear present. It's typical for ice boots or wraps to go on after cooling out, and if someone noticed a minor swelling with no lameness the next day, they may try icing it for a day to see if it was normal post-exercise edema before getting really concerned. Horses with tendon injuries may even jog sound initially. Generally, it's when a minor change seems to be stubbornly sticking around that Carpenter gets a call and comes out with his ultrasound machine to find the problem.
If a tear does occur, the location of the tear along the length of the tendon and within the tendon's width makes a difference in the level of severity, as does the size of the tear and whether or not there's fluid built up around the injury.
Tendons connect muscle to bone, while ligaments connect bone to bone. Both are made of stretchy fibers, and their stretchiness is especially important for front legs, which bear 60 percent of a horse's weight. During a gallop stride, a horse's front fetlocks flex and descend nearly to the ground, absorbing the shock of the footfall. That motion is possible because the tendons and ligaments have so much elasticity to them. That stretchiness also stores energy to propel the foot back up and the leg forward for the next stride. The suspensory ligament and the superficial digital flexor tendon are the most important to that process, which is why an injury to these structures is especially problematic.
When a significant tendon heals in a mature horse it must do so with scar tissue which is relatively inelastic because mature animals can no longer create tendon fibers. The scar tissue cells may adapt somewhat over time and become a little more stretchy, but they'll never be as good as the original tendon cells.
“You take what amounts to a rubber band and make part of it a piece of string that won't stretch,” explained Dr. Larry Bramlage, equine surgeon at Rood and Riddle Equine Hospital. “When you do that, the load stays the same, so the remaining tendon has to stretch even farther than it did before because it has to make up for the loss of elasticity in the segment that has the injury. So that means the probability of tearing the tendon again is very high, even higher than it was before it occurred the first time.
“All “bowed tendons” are not equal.”
In Bramlage's experience, tendon injuries in front legs are more difficult to rehabilitate than hind legs – particularly the superficial digital flexor, which he says is the worst soft tissue structure in the leg in which to have an injury. Tendons also don't do as well as suspensory ligament injuries in that they don't respond as well to treatment aimed at reducing the formation of scar tissue.
There are a few treatment options that may be used singularly or in combination, depending upon the injury. Stem cells or platelet-rich plasma may be injected at the injury site with the hope the cells can engineer a better healing process. Stem cells are immature cells which read the local environment and direct the repair. The goal is for them to order the formation of new, healthy tendon cells rather than scar tissue. Bramlage has found that this works better for ligament injuries than tendon injuries; the stem cells can make some improvement, but don't seem to consistently be as good at producing new, flexible tendon cells as they are at directing the formation of new ligament cells. The reason why still evades veterinarians. Some people use platelet-rich plasma, but it tends to promote filling the defect with more scar tissue, something Bramlage likes to avoid.
Some veterinarians may also suggest an operation to cut the superior check ligament (referred to as a ligament desmotomy), which is part of the superficial digital flexor tendon unit. In other species, the superior check ligament is muscle, attaching to the radius and is called the radial head of the superficial digital flexor. But in the horse, all of the muscle in this portion of the superficial flexor has disappeared, replaced with inelastic ligamentous tissue. The superior check ligament is one of the evolutionary wonders that makes the mechanics of the fetlock possible and makes a horse function the way it does. Mechanically, muscle tissue the size of the superficial digital flexor could never withstand the load of a 1,100-pound horse going 40 miles an hour on a lead limb. “Pulled muscles” would be the rule. But the superior check ligament absorbs the load, protecting the muscle above it. This protection comes at a cost, however.
The presence of the superior check ligament creates a tendon of finite length, where the load progresses up the limb from the bone insertion of the tendon, up the back of the cannon bone via the tendon and then is transferred to the check ligament and into the radius in turn. This “unit” is what is able to withstand the stress generated by the size and speed of the horse. But the “unit” has a finite length and therefore a finite amount of elasticity within the tendon which makes the unit function. That elasticity is fine tuned to allow the fetlock to flex enough to absorb the weight bearing stress, but not stretch so much as to injure the fetlock joint during flexion. When the allowable stretch is exceeded and injury occurs.
Hind limbs have no comparable check ligament. Mechanically, they don't need one. That is why it is much easier to treat a hind limb tendon injury than a front limb.
One of the treatment options with a bowed tendon is to cut the check ligament after the bowed tendon occurs, adding some length to the check ligament, which lengthens the “tendon unit” trying to protect the tendon. The idea is that the approximately one centimeter of extra length provided to the wounded tendon will help prevent “over stretch” again. It will also remove some tension from it during healing optimizing healing.
If fluid is present within the tendon at injury, it is best drained to prevent the pocket of fluid from turning to added scar tissue. This procedure is called “tendon splitting” although it doesn't actually involve cutting the tendon fibers. Rather, it refers to the surgeon cutting the thin protective layer of cells around the tendon to let the fluid out. That layer will heal itself.
Regardless of the treatment, the key component of recovery is patience.
“No matter what you do, nothing is going to take the place of time,” said Carpenter. “Time is what you need to get these things to heal. 'Time' on a decent sized lesion is going to be six, eight, months at minimum. That's the frustrating part from an owner's standpoint is you've got a horse that's injured and now he needs a year before he can run again. And when they do run again, a lot of these horses run a race or two and then they reinjure themselves and are back on the shelf again.”
Bramlage echoed those sentiments, referring to a published study finding that of 332 horses that had bowed tendons and underwent superior check ligament desmotomy, roughly two-thirds came back to the races, but only 48 percent made five starts or more. Of black type horses he looked at in unpublished data, only 20 percent ever ran in a black type race again, suggesting it can be very difficult for a horse to maintain class after a lay-off for a tendon injury. The average time from injury to first start was 10.5 months. Veterinarians have since learned to shorten this some since the study, but the degree of injury plays a role.
Carpenter points out that rehabilitation time is the most expensive of all the potential treatments, and it's the one a horse must undergo. In Southern California, he estimates a horse who gets “the works” in terms of treatment may rack up $2,000 for stem cell therapy, another $3,000 for surgery, $10,000 to $15,000 at the farm for lay-up and another $10,000 for training to get back to the races. Those prices make it unlikely a cheap claimer will be brought back. For a top stakes horse, the question is more about opportunity cost than bills.
“I don't know anything about Honor A.P., but in general on a horse of his caliber you ask yourself, is it financially worth him to rehab for a full year to come back?” said Carpenter. “He'd have to run at Grade 1 level, because if he runs at the lower level you haven't accomplished much for him and his value. If we do that now, we've missed our breeding season that's coming, hoping he can do something great that will make him more valuable in the future. The chances of that happening are very low.”
That mostly leaves mid-level stakes geldings or hard-knocking mares available to try laying off and then coming back. It's hard for a horse to return to top form after a lot of time away – age factors into their ability to regain their previous athletic level, but it also may be an indication of how much the healed tendon struggles to keep up, allowing the same level of performance.
So, should those Grade 1 types enter the gene pool? Aren't they just passing along predispositions for the same injury to future generations?
In the case of tendon injuries, there's no evidence of that, according to Carpenter and Bramlage. Uneven or excessive loading of a tendon due to other soundness issues or unexpected abnormally high loads is most likely to contribute to a tendon injury, not genetics. However some conformational issues can make the horse more vulnerable (upright pasterns are one the upright angle comes from the fact the tendon is shorter in those horses). That doesn't mean there is an actual defect of the tendon itself. Injury can also come as a result of uneven footing, especially if it's soft. Bramlage has found though that oftentimes, a bowed tendon occurs secondary to another problem. “Horses with chronic low-grade lamenesses will preferentially load the sound leg and it's normally the sound leg that gets the bowed tendon,” he said.
The good news for a retiring horse with a tendon injury is that they're usually sound for other purposes. Some more severe cases may be restricted in how much they can jump, but others are able to move on to new jobs with no restrictions if they don't head to the breeding shed.
Satins Angel is the hero of a cautionary tale. She fell through the cracks after leaving the racetrack, but overcame the odds with the help of owner/rider Alexa Lee to become a champion show jumper. Last Sunday, she added to her growing list of accomplishments with an eye-catching win in the Jumper division of the $20,000 TAKE2 Hunter/Jumper Finals at the Kentucky National Horse Show in Lexington. Kathryn Currey's A Lil Evil was second, with Cleanth Toledano's No Nonsense Jones finishing third.
Despite the challenges and travel restrictions resulting from COVID-19, 31 competitors from 14 different states converged on the Kentucky Horse Park for the TAKE2 Finals. Satins Angel beat all comers. The handy mare took a nearly impossible inside line that shaved a few seconds off her time in the jump-off to seal the victory; it mirrored the dramatic turn her life has taken since she was found at the Sugarcreek Auction in Ohio four years ago.
“She suffered such abuse, but she still tries so hard to please,” Alexa said. “When I asked her to make that inside turn, she said, 'You're crazy, but I'll do it for you.' And she did. If I could, I would give her my heart. I know that's so corny, but she means everything to me.”
Bred in Louisiana, Satins Angel raced with some small success as Queen Satin. She won three times and ended her racing career in 2013 at little known Mt. Pleasant Meadows in Michigan. That's when things started to go wrong for her.
“She stopped racing because she was a bleeder, and when she left the track she was passed around and was nearly sold for slaughter,” Alexa said, a catch in her voice. “She was beaten so badly she still has the scars on her face. It was awful.”
But luck was with Satins Angel, who was rescued from the Sugarcreek Auction and sent to the barn where she would finally cross paths with Alexa. The connection was instantaneous. Before long, Satin belonged to Alexa and the two were on the road to show jumping glory. Their success took time and hard work and something else that Alexa learned from her equine soul mate.
“I've learned a lot of patience from Satin, that's the biggest thing,” she explained. “When I first got her, you couldn't touch her, you couldn't go near her head. Even now, she really doesn't let anyone else touch her. But when I'm there, with the vet or the blacksmith, she is so much better behaved. She trusts me to do what's best for her. She knows I will never put her in harm's way.”
Thanks to Alexa and to trainer Angela Moore, Satin not only believes in her people, she believes in herself.
“I taught her to have confidence,” Alexa said. “She will jump anything. She doesn't stop and she doesn't spook (knock on wood!). When she is in the arena, she has that attitude – 'look at me, I'm awesome.' When she walks out after she wins, she knows it, and she wants to be the center of attention. She's definitely a queen.”
Satin embodies the best qualities of the Thoroughbred.
“Thoroughbreds are amazing animals,” Alexa said. “People try to label them, that they can only do so much, that they need so much maintenance. Wrong. Thoroughbreds can do anything. I love their heart, their passion and their drive, I love how much they want to give back and please their owner. I want people to know that, I want to spread the word.”
Alexa believes that the TAKE2 Program is doing just that.
“I love what TAKE2 is doing for racehorses, for Thoroughbreds,” she said. “TAKE2 is getting the word out about just what Thoroughbreds are capable of doing. They have so much more to give when their racing careers are over. And I am hearing it more and more – people find out about these classes, they see the money you can win and the fun you can have and they say, 'I need to get a Thoroughbred, I need to get a horse off the track and do this.' There's an excitement to being part of the TAKE2 Program, and the word is getting out there. I love that.”
TAKE2 President Rick Schosberg added, “We are thrilled to see horses like Satins Angel succeed in our program, because they put the spotlight on the mission of TAKE2. We want to promote the work of Thoroughbred Aftercare Alliance-accredited organizations affiliated with racetracks around the country that provide a safety net so that what happened to Satins Angel will not happen to other horses. We want all our horses to have happy and healthy lives when they leave the track.”
