*Note: This post is based on the notes I took at the seminar with Dr. Bowker. It was a lot of information to take in, and I am still processing it all. As such, I'm sure there are things I missed. I hope I have captured the spirit of what was said though, and hope you will take the time to dig into Dr. Bowker's work yourself!
“The hoof wall is a decoration.”
“The hoof wall is a decoration.”
With that opening statement to a room full of farriers, veterinarians and trimmers, I knew Dr. Bowker was going to turn traditional thinking on its head at the two day Hoof Health Seminar held on October 24 and 25, 2018 at the Western College of Veterinary Medicine in Saskatoon.
Dr. Robert Bowker is the recently retired director of the Equine Foot Laboratory at Michigan State University in the USA, a world-leading expert of the equine hoof, and a scientist who has made significant discoveries that will revolutionize the way we look at our horses’ hooves and husbandry practises. He has also been someone who’s work I have followed since I started getting serious about hoof care, someone I have a lot of respect for, and someone I was very excited to meet and learn from. Dr. Bowker has done extensive studies on the anatomy of the equine hoof, navicular syndrome and other hoof pathologies.
|Dr. Bowker giving the lecture on the first day.|
Day 1 began with a lecture. The amount of information packed into my head will take a lot of time to digest, but the following are some of the key points that I took away from the discussion.
- If you have a healthy caudal portion of the foot (the rear portion), you have a healthy foot. The digital cushion is filled with thousands of tiny blood vessels, which are too small to be detected on x-rays (only 5 – 25 microns in diameter).
- Navicular syndrome and laminitis are man-made problems, and neither is a death sentence for the horse. Just because you see something catastrophic in the hoof does not mean it will not heal if given the proper conditions. Dr. Bowker no longer believes that navicular horses cannot recover because he has seen the rehabilitation at work.
- Navicular begins 8 – 10 years before the clinical signs show up. The digital cushion is full of ligaments, which attach to the lateral cartilages to create a “hammock” that supports the bony column. These ligaments are destroyed over time, which is the very early stages of navicular.
- Don’t be afraid to come inside the white line when trimming! SHORT TOES ARE KEY TO A HEALTHY FOOT. Dr. Bowker’s physiological trim includes coming inside the white line every second or third trim and bevelling the wall from that point. If the toes are too long, it pulls the foot forward and remodels the coffin bone. Over time, the coffin bone will actually grow longer and bone density will decrease.
- To properly utilize the frog, it needs to just kiss the ground with each step. Too much pressure will cause the frog to atrophy, but without pressure, the blood flow is compromised to the back of the foot. When pressure is applied to the frog, the ligaments in the digital cushion become taut, which creates the negative pressure in the vessels to draw blood through the foot. When the frog recedes into the bulbs of the foot, the pressure approaches zero and the blood flow is compromised.
- Don’t trim the frog or the sole! Every time you trim the frog, it gets smaller. It will grow if you don’t trim it. Take the toes back, and trim the hoof to change the tissues on the inside of the foot. Frequent trims with small changes are key to affecting the inner tissues. Long toes will lead to lameness because it destroys the blood vessels under the coffin bone.
- One of the key functions of the back portion of the horse’s foot is to dissipate impact energy when it takes a step. The tiny blood vessels in the digital cushion dissipate the energy. Putting fluid through small tubes dissipates far more energy than putting it through large ones. Just imagine the damage to your garden if you turned a fire hose (large tube) on it rather than a sprinkler (many small tubes dissipating the energy). Fewer vessels result in less dissipation of energy.
- Only 5 – 20% of the horse’s weight should be on the hoof wall. The hoof wall is NOT designed to be a primary loading structure! This finding contradicts the traditional way of looking at the foot, but it is so important. The sole, bars and frog should all share the load in a healthy foot.
- If you trim a hoof frequently enough, you can actually modify the bone. The inside of the foot will adapt to what you do on the outside. The calcium in human bones is replaced every 5 years, and equine bones are similar.
- In the barefoot vs. shod debate, it is important to understand that a barefoot hoof has more even stresses within the hoof and on the wall than a shod hoof. The stresses are greater on a shod hoof as it can’t relieve them. High vibration caused by the impact of the shoes on the ground (in the range of 2500 – 3000 Hz) will damage the tissues in the foot. Loading the foot at the wall will also cause the coffin bone to become more porous and, therefore, weaker. Porous coffin bones become osteoporotic. Barefoot hooves have been shown to have less porosity than shod ones as the larger surface area creates less internal load on the structures of the hoof.
Carrying all this new information in our heads, we went down to the anatomy lab to look at actual hoof specimens that had been cut apart to show the internals in different ways. Actually seeing and feeling the ligaments in the digital cushion was an eye-opener for me. I was able to feel the difference in the quality of the tissue. We were also able to see differences in bone density between specimens.
|One of the hoof specimens we studied.|
|A closer look at the ligaments in the digital cushion.|
|Dr. Bowker discussing the specimens.|
|There were thirteen of us "Hoof Geek" students there along with our mentors, Christine and Francine.|
On the second day of the seminar, we began with another lecture where Dr. Bowker talked to us about creating a good-footed horse. Some of the points that really clicked with me were:
- Navicular is an entire foot problem. It starts in the frog with the deterioration of the ligaments, caused by long toes, and eventually affects the navicular bone. However, horses can survive even damage to the bone.
- A horse with navicular will have 1/3 less bone density than in non-navicular horses. The coffin bone is continually remodelling through the horse’s life, and a thicker bone can support the weight of the horse better. The most dense bone should be in the caudal (rear) part of the coffin bone. Navicular horses also have much thinner lateral cartilages. In a healthy foot, the lateral cartilages will make up 25 – 36% of the width of the foot. In navicular horses, it is closer to 10%.
- All young horses have thick lateral cartilages with ligaments in the frog up until they are 3 – 4 years old. At that point, when we begin working with them, what we do can cause the lateral cartilages to disintegrate and liquefy. If trimmed properly with the frog on the ground and the toe kept short, the ligaments can be strengthened instead of destroyed. Thick lateral cartilages have more blood vessels inside them, which make them better at energy dissipation. If energy isn’t dissipated in the foot, it stays there and destroys the structures.
- When heels become underrun, the impact of each step hits in front of the lateral cartilages and impacts the bone instead of the digital cushion.
- The navicular bone is a major loading (weight-bearing) structure. It is very susceptible to damage as it is suspended by just two ligaments. Too much vibration will produce movement of the deep digital flexor tendon in the navicular bone, which damages nerves and causes pain. When the impar ligament and deep digital flexor tendon start to disintegrate, holes in the bone begin. Most of the pain associated with navicular syndrome is caused by soft tissue damage, not bone damage.
- The laminae in a horse’s foot aren’t evenly distributed around the foot. The laminae will come in thicker where stresses are higher or biomechanical loads are higher. Laminae are generally closer together at the toes, especially when toes are left long or toe clips are used. This is because the hoof modifies itself to create more structure to support the stressed area.
- Most navicular horses can be cured!
Following the lecture, we had an opportunity to look at some live horses and hear Dr. Bowker’s thoughts on their feet and how he would trim them to promote a healthy foot. It was very interesting to see the difference between a traditional farrier trim and a barefoot trim, both of which were completed by seminar participants. Dr. Bowker watched each trim and then discussed how he would modify the trim for those of us watching.
|Looking at feet on live horses.|
One of the horses that day, diagnosed with navicular, had her shoes removed that morning and a trim following Dr. Bowker’s method applied. The owner would like to try rehabilitating the hooves barefoot because the shoes have not solved the problem. Her farrier is interested in working on it with her, and she got a lot of good advice on how to proceed. The trim done on the horse was minimal as she needs time to let her hooves decontract from the shoes before major changes are made.
To say that this seminar was an eye-opener and packed full of excellent information is a major understatement. If you ever get the opportunity to listen to Dr. Bowker speak, I highly recommend it. It will take me a lot of time to process everything I learned and apply it to my trimming technique, but I am excited to try.
We are in a very interesting time in the history of equine hoof care, and I am excited to be there on the forefront. It’s not an easy place to be, questioning the methods used in the past and looking for better ways to improve the health and longevity of our horses. But it is a place worth going, for the sake of our animals. I challenge you all to think about the effects our actions have on our horses, try to minimize the adverse effects of our husbandry practises, and be open-minded when new research comes to light. The new research doesn’t have to be feared!
|Meeting one of my hoof heroes.|