FARRIER TAKEAWAYS
- Traditional grip materials are not always necessary thanks to improved understanding of horse conformation, shoeing materials and footing.
- Some slipping during the horse’s stride is acceptable — it helps the horse’s body dissipate energy from the impact of stepping on the ground.
- Using grip devices when the horse will be used on pavement causes worse slippage.
- Any use of grip materials will cause the horse’s hooves to stay on the ground for a longer period of time for each step, which can cause interference from hind hooves if the effect is too severe.
- Grip devices can be beneficial to reduce injuries, but they can also exacerbate other types of injuries if not used properly.
- Studs should be applied appropriately on the hoof in relation to the horse’s conformation, used only when working, and the severity should be adjusted to suit the horse’s task.
- Always err on the side of using less traction rather than more.
Even while treading on steady ground, horses slip slightly during their footfall pattern, but it’s not always dangerous. Known as a microslip, this act dissipates energy in the foot. However, making even minute changes to the horse’s shoes can have a big impact on the animal’s overall performance and long-term soundness. Consider the pros and cons of adding traction devices to shoes before applying them to avoid detrimental results for the horse.
Chris Pardoe, a British farrier and Ph.D., shared his research at the 2014 International Hoof-Care Summit.
Tradition Isn’t Always Best
Farriers have a long history of adding gripping materials to the shoes of working horses or high-level athletes of certain disciplines. Like other farriers, Pardoe has seen good examples of traction devices from the past, but he’s also seen some dangerous materials, like shoes with far too severe of traction added.
Pardoe believes that scientific methods are important in horseshoeing, and farriers contribute by applying their craft.
“We’re all empirical scientists,” Pardoe says. “Every day we go out, make an evaluation and we look at the data. We make adjustments accordingly.”
The horse’s natural grip on the ground follows the laws of physics. Pardoe says the horse steps forward on the ground with little weight on the hoof. Using force plate data, Pardoe notes how as a horse moves its weight on top of its leg, the fetlock joint stabilizes the leg. Once the hoof is loaded and the leg is vertical, the reaction force of the ground pushing upward prevents the hoof from moving. As the horse moves on, the load starts to diminish and is transferred to other feet.
“While the digital flexor tendon is starting to ramp up its tension,” Pardoe says, “there is a point at maximum force where the foot has to let the heel come up. That starts the process of breakover.”
Pardoe says the mass of the horse moving at a walk, trot or gallop gives it inertia. Dynamic friction, also called connected friction, is the moving friction between two surfaces that have relative motion, such as the ground and the horseshoe.
“If the resultant force from these two (the horse and the ground) is great enough to overcome the friction, that horse has to slide,” Pardoe says. “How much friction do we need to stop something?”
Studying Slip Vs. Grip
At the Royal Veterinary College in the United Kingdom, Pardoe launched a study to examine slippage. Previous to this study, a rubber-topped runway was used. For his work, Pardoe primarily used a pavement runway and a forceplate with the same surface material. For comparison, a concrete runway and concrete-coated plate also were tested, as well as plates embedded in an arena.
The forceplate measures the magnitude and angle of force it encounters from the horse’s hoof. The study used horses of the same size and build from the Royal Army.
The horse’s legs were outfitted with retro reflective markers. Together with the forceplates and cameras, these tools paint a picture of the interactions between the ground and hooves when a horse moves.
The horses were shod using different shoe materials: rubber, plastic and steel. These materials have different frictional properties, which are reflected in the distance the foot slides between impact and coming to rest (slip distance) and time taken for this to occur (slip time).
“Obviously steel was used because that’s what farriers mostly use,” he says. “We used a rubber shoe because there was existing research on this shoe (Ollov shoe).” Using industrial adhesive, the Ibex plastic shoe was glued on.
The Research Findings
The team found that the horse’s stride was similar for rubber and steel, but the plastic-clad hoof traveled slightly farther. Pardoe deduced that some slipping was occurring after evaluating the results.
“We can conclude from this study that the foot slides after impact,” Pardoe says. “It also slides before it takes off, because the hoof gets to a point where it overcomes friction, flicks back for a second and takes off at breakover to accelerate away. Breakover is complex — it’s not a simple thing.”
With grip devices, we might not be doing exactly what we think …
Some slipping is actually important, Pardoe stresses. That initial slip dissipates energy after impact.
“This is one of the methods that the horse has evolved to dissipate energy before it gets to the hoof capsule,” Pardoe says. “When the hoof capsule starts to flex, the laminae start to stretch and move, the digital cushion (compresses) and so on. But before all of that is activated in the hoof, by the time the impact hits that leg, most of it is dissipated. So we have to be careful of what we do to alter that result.”
The Role Of Grip
The team also studied the effects adding traction devices to the steel and plastic shoes would have on the horse’s stride. They added carbide to the tips and heels of the shoes. The addition of studs contributed to keeping the hoof on the ground longer, and the slip actually was higher on the paved runway.
The research relied on using steel, rubber and plastic shoes on Royal Army horses. The subjects were trotted across a paved runway with a forceplate coated in the same paving material.
Next, they tried tungsten pins on the horses’ shoes. Coming into the stride, the horses stepped nearly identical to grip-free shoes. Examining the data, Pardoe adds that the horses seemed to become more confident, recognizing that they weren’t going to slip.
“The problem also is that the horses need to slip, or might need to slip, but they can’t,” Pardoe adds.
On the other end, where the foot takes off again, the stride was delayed. Pardoe said this is a danger, because a horse accelerating will drive forward with its hind legs and it needs those front legs to move out of the way. If this doesn’t happen, the horse could hit itself and enter a dangerous situation.
“With grip devices, we might not be doing exactly what we think,” Pardoe reasons. “As farriers, we think we might be helping them with grip, but we might actually be injuring them. We have to be aware of the consequences.”
Pardoe says all grip devices affect the end of the stance because they delay the foot leaving the ground again. The degree this occurs is related to factors such as grip materials, ground, speed and conformation.
The study also found that the shoe material and presence of traction devices had an effect on the dissipation of energy.
“What we put on the foot can influence how much energy is dissipated,” Pardoe says. “So likewise, we can increase it or decrease it. It’s not a passive event.”
Horses have some control over slipping by using the muscles on the top of their legs. Pardoe says shoes with grips require the horse to exert more energy in their muscles to create movement.
“We’ve been giving them grip, and their muscles are probably really getting more tired trying to move the body,” Pardoe adds.
Caution Required When Adding Grip
Pardoe says the lack of education for using studs, caulks and other traction devices is one of the reasons he warns against their overuse by farriers.
“Some professional people have to use them,” Pardoe says. “I’m not against caulking and studs. Some event horses and jumpers won’t jump without them. Once they realize they don’t have their studs in, they will stop dead.”
Some polo players often only use one stud in the hind of their horses because they need to turn quickly. Pardoe says these horses with short, strong legs can still risk a torsional injury with studs, but the players consider those risks carefully.
“We have to educate our clients on these measures, balance and put them in the right place, and choose the right stud for the job,” Pardoe says.
Pardoe likened using grips without education to buying blade soccer shoes that are designed for professionals for a child soccer player who is used to wearing regular cleats. The professional athlete has physiotherapists, years of experience and he’s aware of how he can and can’t move in them. A child will be completely unaware of those things, and can seriously injure its knees from constantly stopping dead due to the shoes.
Addressing The Need For More Traction
Dave Farley says today’s high-tech synthetic footing in jumping competition arenas provides plenty of traction, reducing the need for long studs for that particular sport. The Coshocton, Ohio, and Wellington, Fla., shoer says farriers today need to become educated on how and when studs should be used.
“History has us doing things because it was routine and regular and that’s the way it’s always been done,” Farley says. “Now, with the newer bred horses, better conformation and the new surfaces, it’s a whole different ballgame. There’s been more advances in technology with horses and traction in the last 10 years than there was in the 400 years previous.”
Farley does drilling and tapping for his clients’ horses. He drills holes in the shoes and plugs them when not in use.
“If we have horses that go to an event that has grass or dirt, they have to have traction,” Farley says. “So we shoe them where the shoes are drilled and tapped so the traction can be applied at the time.”
This type of shoeing allows the owner or handler to change out the size of the grip devices every day to suit conditions and the horse’s tasks.
“If it’s just a little slippery, the grooms put a small traction device in,” Farley says. “If it’s very deep and really grassy, and deep underneath, they put an ice caulk on, which is really tall and really sharp. They can be interchanged.”
Even with many options for the height of the stud, Farley still customizes the hole placement for each horse.
“I look at the conformation of the horse,” he adds. “The horse’s conformation dictates where the caulk holes go. Horses with the long, low heels have a tendency to slide forward a lot more. I’ll bring those holes back a bit. A horse with normal conformation or upright conformation, the heels go forward a little bit.”
His biggest advice is to err on using less grip than you think you need, rather than grabbing the bigger studs without knowing if they’re absolutely necessary.
“Unless the horse is in a very slippery condition or environment, less is usually plenty,” Farley says.
“We can say that the frictional property in shoes will affect the timing and magnitude of the forces and the acceleration of the foot after breakaway can be lower if we shoe them for grip,” Pardoe says.
In his work as a farrier, Pardoe has seen major back problems and lameness in horses as a result of being unable to balance on improperly fitted studs. And walking on certain kinds of pavement can be very dangerous with studs or caulks.
We have to educate our clients on these measures, balance and put them in the right place, and choose the right stud for the job …
“Please be careful with some of these grip tools,” Pardoe says. “Don’t get me wrong, they’re very useful tools, but it’s the old adage: read the instructions.”
Deciding On Grip
Grip devices do have their place, especially with sport horses, as Pardoe mentions. The research doesn’t provide a conclusive answer due to the nature of shoeing each horse for its individual needs, but reiterates the need for farriers to apply these devices after careful evaluation of each individual horse.
“We know that grip can be beneficial,” Pardoe said. “It can prevent injury and it can make the rider’s experience safer. But it can be detrimental — it can exacerbate injuries.
“This is where our skill and expertise comes in. We have to look at each animal as an individual, we have to use our skill and research into modern materials, but we have to be aware of what the long-term consequences are of using those materials.”
