What is breakover when talked about as a trimming landmark?
Breakover is trimmed at the forward most part of the hoof at the toe. It is the very last part of the hoof to be touching the ground as the horse breaks over and lifts the leg into the swing phase of the stride. It is usually trimmed as a bevel or roll into the hoof wall, but occasionally is trimmed back farther into the golden line or even the sole if the sole is very stretched forward.
How do you know where to set breakover?
There are a couple of ways. This picture shows the angle of new growth at the coronary band and if we were to follow it all the way down, breakover should be where the hoof wall would be if it were well connected. Follow the green line down and it shows the beginning of where I trimmed breakover in line with that upper growth.
Another way I determine breakover is by reading the sole’s concavity. Solar concavity mimics the coffin bone concavity, so following the concavity out until it plateaus is sometimes also an indicator of where breakover should be, but there are a few exceptions to this method. For instance a foundered horse will have very little to no concavity, and a horse with retained sole may not show the concavity properly.
The following video is a good example of setting breakover on a healthy hoof based on solar concavity. This process would be somewhat similar on a foundered hoof or a hoof with a lack of concavity, but we must make sure not to trim too short as generally hooves with less concavity have a thin sole and a lack of hoof wall connection. In those cases I find trimming breakover according to the new growth at the coronary band more accurate.
The picture above shows breakover set at the edge of the sole along the top of the ridge of concavity. There is a little bit of excess sole at the tip of the frog, or just behind what we would call the toe callous, but if you could envision the concavity on either side wrapping around and meeting up underneath it, the bevel or breakover would be along that edge.
In my opinion setting a proper breakover is probably the single most important part of the trim, and one of the main aspects of trimming that I find a lot of professionals get wrong.
I get asked about pulling shoes a lot and the following video shows two different techniques that I use. I use the same method for pulling composite shoes as well! I usually prefer to use a pair of old nippers or nail cutters and an old rasp.
This photo is a great illustration of trimming a tall vertical bar in order to allow downward expansion of the hoof during the peak impact phase of loading.
I like to trim the tall vertical bar to ramp downwards from just in front of the heel surface along the natural concavity of the sole.
[The natural function of the hoof to dissipate impact energy works like this:
First the heels and frog strike the ground. This allows the digital cushion to absorb the brunt of the impact because it is made up of elastic fiber-rich dynamic tissues. These tissues are able to compress and store energy under load.
The hoof then rolls over onto the solar surface allowing the digital cushion to further compress and the natural arch of the hoof to expand downward. This includes the expansion of both the heels and the collateral grooves.
The hoof then breaks over at the toe, allowing the digital cushion to use this stored energy to drive recoil back to a resting state.]
The solar arch on the bottom of the hoof allows this downward expansion to happen without restriction. We also have to consider is the horses willingness to weight the hoof during this phase of the stride. If we leave the bar high and vertical, when the hoof rolls over onto the solar surface the bar can act as a pressure point and cause excess pressure on the DDFT and navicular bone. This can then alter the horse's stride and cause them to land laterally or toe first. Altered landings can cause the impact energy to have to be absorbed by the horse's joints and muscles and lead to further issues.
It is important to recognize that over trimming, just like under trimming the bars, can also have negative implications to the hoof. The bar makes up half of the collateral groove and the frog makes up the other half. If we trim the bar too low, the grooves will become shallow and reduce the natural concavity that the hoof needs in order to expand downward. Over trimming the bar can also thin the bar and lead to sensitivity of the bar's corium.
Bar trimming is probably one of the most contentious issues between different methods of barefoot trimming.
Personally I like to keep it simple: trim where needed, don't where it's not and most importantly, do no harm.
Overlaid or embedded bars grow out laterally over the sole. They often tend to grow over and into the sole creating bruising and sometimes abscessing.
The above picture on the left shows vertical bars and the right shows embedded bar.
Embedded bars are difficult to deal with and left unchecked can lead to bruising, discomfort and abscessing. Embedded bars show up more as a lump overtop of the sole and need to be trimmed so that they aren't causing a pressure point during peak impact. This is easier said then done as they often become ingrown into the sole and have to be trimmed out little by little in order to avoid over thinning the bar/sole junction and causing sensitivity to the bar's corium.
I generally trim embedded bars down to match the natural concavity of the sole, but no lower. I trim frequently and let the sole push them out gradually.
Some horse's are more sensitive and the bar tends to fold over more often then others. In these sensitive horses the bar can bruise and cause discomfort so I tend to trim it more often. I have a mare with PPID and no matter what I do her bars fold over and abscess if left for 4 - 6 weeks. I manage her with bi-weekly trimming just to keep the bars in check and she manages well.
The following short video shows the difference between trimming vertical and embedded bars.
Published in Saddle Up Magazine in two parts, April 2015 and May 2015
Nature seems to have a way when it comes to getting things right. The mathematical simplicity that exists when you break a hoof down into sections is quite amazing. At the Okanagan School of Natural Hoof Care we teach a trimming method called the Hoof Print Trim. This method was created by Cheryl Henderson, founder of the Oregon School of Natural Hoof Care. The Oregon School was the first of its kind in North America. A center devoted to the practice of Natural Hoof Care and a better life for our equines. Cheryl Henderson has spent many decades developing and researching her method and has proven it again and again with thousands of dissections and case studies. Our program teaches this method and also relies on the ability to “read” the hoof and each horse’s specific conformation to adapt the trim to their needs. This system allows us to teach the fundamentals of trimming in a short time frame.
The formula of a healthy hoof is as follows: the width at the fulcrum (widest point on the bottom of the hoof) equals the length heel to toe. This means that the hoof should be a perfect circle, hind hooves abide by this measurement also but the hoof tends to be more spade shaped. The frog should equal 2/3 of the solar view of the hoof from the back to the front, the remaining sole to the dorsal (front) hoof wall is the other 1/3. The hairline should be at a relaxed 30 degree angle to the ground. All hooved animals have a naturally occurring 30 degree hairline that only becomes distorted through genetic defect, altered living environments and lack of movement, or human trimming error. These formulas have been proven again and again through the study of wild horses’ hooves and as well through countless dissections and case studies. Even the most distorted hoof shapes follow these parameters and can often be brought back into balance in just a few trims depending on the severity of the distortion. This does not mean however that we just measure and cut. These guidelines must be paired with our “reading” of the hooves’ clues to help us determine each horses’ needs. For instance some horses have club feet, therefore this physical deformity will impact the heel height and the angle of the hairline. This is where reading the hoof and determining the best approach for each specific horse is extremely important. A deformity like club foot can sometimes be corrected or improved, but many times is just something you have to work with and adapt your trim around.
The Hoof Print Trim is a great starting point for those learning to trim because you can measure and draw where the healthy hoof should be and then train your eyes to “read” the hoof and evaluate using both sets of clues where you should trim. This method starts with evaluating the baseline. The baseline is the rearmost part of the hoof, where we will trim our heel height down to as well as where we take our measurement from heel to toe after establishing the width at the fulcrum. To find our baseline we measure from the back of the heel bulbs at the hairline to the collateral groove exit. On most average sized horses this measurement equals 1 ¼ inches. It varies for ponies or smaller horses and the taller horses and drafts but this is just an average, and again not a measurement we would simply just cut without “reading” into the rest of the hoof first and accounting for and deformities or pathologies etc. After establishing the correct baseline by evaluating the frog health, the periople wear marks, the heel surface, and sole thickness in switchback at the rear of the hoof, we can measure our fulcrum to establish our toe length.
The fulcrum is simply the widest part on the bottom of the hoof. It is almost always about ¾ inch behind the apex of the frog occurring at the mid-point of where the coffin bone sits inside the hoof and is not usually distorted by flaring or stretched lamina. We measure the fulcrum from the golden line on one side to the golden line on the other side, not from wall to wall. If the measurement was 4 ½ inches, we would then measure from our baseline forward 4 ½ inches and mark where our golden line should be at the toe. In a balanced hoof that has been trimmed regularly and correctly, this mark will line up with the golden line at the toe. I just want to reiterate that this is also not a cut line, we still have to add our wall thickness to determine where the cut line will be. We also must “read” the hooves’ wear patterns and toe callous before deciding where to cut. Now that we have determined the circumference of the hoof we can establish the 2/3 to 1/3 balance. The baseline to the apex of the frog should be 2/3 of the overall hoof length. Frogs can get stretched forward into the sole’s 1/3 and occasionally need to be trimmed back. This measurement will determine if the frog has migrated forward. However all of our measurements to this point would be inaccurate if we had measured our baseline wrong, so caution must be taken to measure correctly and confirm we are right by reading” the clues and wear marks in the hoof.
After establishing the baseline and the heel height we must determine the length of the toe. We do not use the white line as a determining factor as it can stretch and migrate forward giving a false location for the toe length. In order to determine the proper length we measure the fulcrum width from white line to white line on either side of the hoof. A front hoof should be the same width as length. So if the fulcrum is 4 ½ inches from white line to white line then our measurement from the baseline at the rear of the hoof to the toe would be 4 ½ inches. This is not a cut line though, we still have to add the thickness of the hoof wall to this measurement. A lot of times in a run forward hoof the white line can stretch forward and this measurement can seem extreme. However even though the wall flares forward and the white line stretches, the internal structures do not move or migrate. The coffin bone can rotate and sink lower in the hoof capsule in a laminitic or foundered horse, but even in those cases the geometrical mapping will establish the location of the coffin bone before we start to trim and we can work to bring balance back to the hoof.
Another factor we have to consider when aligning the bones of the hoof and lower limb is the hairline angle. All hooved animals in nature have a 30 degree hairline in their natural environment (barring rare genetic defects) and the horse is only an exception when trimmed and managed ineffectively. Studies of wild horses in the US Great Basin have shown that when allowed to naturally wear their hooves in their wild environment they almost always have a 30 degree hairline. The few horses with this exception have a genetic defect of a club foot. A club foot is a coffin bone with a steeper dorsal angle and therefore creates a hoof with a steeper dorsal hoof wall angle and a higher heel. Both of these pathologies will affect the hairline angle.
After evaluating the baseline, the fulcrum, the toe length and the hairline angle, we finish our trim by defining and trimming the bars and putting the mustang roll on the front of the hoof. The bars function is for support in the rear of the hoof and it is important that they are not over trimmed, however they must also not be left to grow over the sole as they can cause bruising and abscessing. A mustang roll is a rounding of the hoof wall at the toe to remove any leveraging forces on the hoof wall and to create a smoother breakover. The mustang roll is one of the defining differences between a barefoot trim and a traditional farrier trim.
Published in Saddle Up Magazine February 2015
For many horse owners, evaluating and trimming their horse’s hooves is a task left up to their farrier/trimmer. But how do you know that the person that you have hired is doing a good job? You have to be able to evaluate your horse’s hooves beyond the scope of how sound the horse moves. While soundness in the present is important, the horse’s long term hoof health is also a major factor owners must consider. I see many cases where long term incorrect hoof shape or function has lead to irreversible damage while the horse appeared sound until it was too late to correct. However I also see a lot of horses that I am able to rehabilitate and return to use after a deformed hoof has broken down.
There are 5 key points horse owners can use to evaluate their horses’ hooves:
Heel Placement – The heels should be positioned at what we call the baseline. The baseline is an invisible line that runs across the back of the frog and collateral grooves, and in a well-trimmed hoof also aligns with the heels rearmost surface. When heels are allowed to overgrow or migrate forward from this line, the balance of the hoof is distorted and excess stress and tension is placed on the horse’s joints, tendons and ligaments. Long or forward heels can also shorten stride length.
Frog Integrity – When a horse moves forward, their natural stride should allow them to land heel first. If the heels are in the correct position as mentioned above, the heels and frog will contact the ground simultaneously. The frog’s primary function is to protect the digital cushion. The digital cushion lies underneath the hard calloused frog and is a large pad of fatty tissue. The digital cushion absorbs impact and dissipates energy. If the frog is infected with thrush or bacteria, or underdeveloped from long heels keeping it elevated and not touching the ground, this portion of the hoof’s function cannot be performed. Without the energy dissipation of a healthy frog and digital cushion excess stress is placed on the horse’s joints.
Wall Connection – A well connected hoof wall supports the coffin bone and allows the hoof to function as intended. The hoof wall grows downward from the coronet to the ground and should not flare or deviate in angle as it descends. A hoof wall that changes its angle part way down the hoof will have a poor connection and decreased concavity in the sole. A disconnected wall can lead to the coffin bone sinking down into the hoof capsule causing inflammation in the sole resulting in sensitive hooves.
Sole Thickness – Sole thickness is key to soundness and comfort. A thick sole protects the coffin bone and pads the hoof. The sole should be firm and calloused, you should not be able to flex it when pressing with your fingers. It should have a smooth appearance, and it should have a slight concavity. Concavity varies for each individual horse dependent on their coffin bone shape but the bottom of the hoof should not be flat. A flat hoof signals a balance issue, perhaps in the wall connection or a problem with overgrown bars.
Bar Definition – The purpose of the bars are to support the back of the hoof upon impact. The bar is an extension of the hoof wall as it wraps around from the heel surface. The bars should run at a downward slope from the heel to the mid-point of the frog. The bar should also be upright and defined, not laid over or blended into the sole. When bars invade the sole it can cause many different issues, the most common are: sensitivity on hard ground and reoccurring abscessing. In rare cases embedded bar can also cause navicular like symptoms.
Horse owners must learn to recognize what a healthy hoof looks and functions like. Hoof care is a fundamental component of horse ownership and you must know how to recognize a problem before it causes long term damage.
Kristi Luehr is a barefoot trimmer, author, and founder of the Okanagan School of Natural Hoof Care. She is certified by the Canadian Farrier School as well as the Oregon School of Natural Hoof Care, and also has certification in equine massage and dentistry. Her focus is to educate owners about hoof anatomy, function and proper barefoot trimming that supports and grows healthy and functional hooves specific to each horse's individual needs. She is the author of two online courses specific to hoof care and is always striving to create more educational content for students to learn from.