Dr. Colleen Lewis / July 12, 2017
Quarter cracks can be very frustrating; my fierce little gymkhana pony had one the summer I was about to enter high school that nearly kept us homebound. News-worthy information buzzed the racing forums when Girvin, just 10 days before the 143rd Kentucky Derby, was missing from breezing and training practices due to a quarter crack. Girvin’s trainer, Joe Sharp, unable to predict the following days related, “every crack is different.” Reports indicate that Girvin was fitted with a Z-bar shoe, received hyperbaric treatments and swam in the pool at the Kentucky Equine Sports Medicine and Rehabilitation Center (KESMARC) in the days leading up to the race. Girvin, thankfully, was able to run.
A quarter crack starts at the hair line and courses in a straight line along the tubules of the hoof wall toward the ground, following the natural vertical lines of the hoof. A true quarter crack is the full thickness of the hoof wall, exposing flesh beneath that is prone to pain, swelling and infection. These cracks can be found in horses that endure heavy work, or at least, perform at a level that is beyond the stability of the hoof wall. Horses with angular limb issues or hoof angle problems are more prone to quarter cracks. Drop a plumb bulb on a string down the center of the front of your horse’s leg. Does the cannon bone come straight down out of the knee? Does the pastern drop straight down from the fetlock? Is the toe long or the heel short? In an attempt to offset an angular issue and to improve the horse’s stance, the hoof is often “correctively” trimmed and shod. Unfortunately, some types of corrective trimming can inadvertently lead to irregular hoof pressure. When you start to load work onto an unbalanced foot, the stress of uneven loading can be enough to crack the hoof capsule; the birth of a quarter crack.
While quarter cracks take up to 12 months to grow out, all is not lost. With timely and aggressive treatment, you may not have to miss a performance, a trail ride or a leisure outing. Early intervention is important. Call your veterinarian AND farrier right away, especially if lameness, drainage or instability (crack shifts with the pressure of walking on it) are present. According to Stephen E. O'Grady, DVM, MRCVS, veterinarian and farrier, “The importance of determining the underlying cause, proper trimming of the feet and applying the correct shoe cannot be overemphasized when repairing a quarter crack. Click here to read Dr. Grady’s full article at thehorse.com.
Let’s work through the following checklist to get your horse on the road to a quick recovery.
- Address any infection that may be present with your veterinarian.
- Develop a comprehensive program to combat pain and swelling using an NSAID and ulcer prevention program.
- Investigate the underlying reason for the crack.
- Remove the shoes and decrease the load by lowering the quarter on the affected side, thus, removing the pressure that initially incited the crack.
- Balance the foot. When faced with quarter cracks, talk to your farrier about trimming the foot in relation to the angles of the hoof box and the third phalanx (PIII) bone within it. Arguably, once the growth plates are closed at around three years of age the hoof should be balanced by the foot and not by the leg. This is also considered a form of corrective trimming targeted at balancing the hoof versus trying to compensate for an angular problem of the leg.
- Remove any loose or detached piece that is not closely adhered at the edges of the crack. Pockets and cervices can be contaminated with anaerobic bacteria that lead to infections followed by pain, swelling and delayed wound healing.
- Apply a supportive shoe that distributes the load pressure evenly and prevents the heel bulb on the affected side from moving independently. According to Dr. O’Grady, various versions of the “bar” shoes will work: straight-bar, egg-bar, heart-bar, or Z-bar like the one that Kentucky Derby participant, Girvin, reportedly wore. He also favors gluing the shoe on can help to stabilize the affected quarter without using nails while allowing the hoof a bit of flexibility to expand.
- Provide stability across the crack. Implants such as plates, wire, fiberglass or acrylic materials can be used. Think of the hoof in terms of plate tectonics: every time the two sides of the hoof crack rub together, a disaster occurs. Early, developing scar tissue is damaged or destroyed and wound healing is impeded.
- Supplement your horse’s diet with vitamins when hooves are dry, brittle and prone to cracks. Humans and horses cannot make vitamin B7: biotin. Horses get most of their biotin from foraging, while some is made from bacteria in the hindgut. Horses that pull shoes often, have white line disease, laminitis, or known feed deficiencies may benefit from a hoof supplement. Consider a previous year’s hay to be vitamin deficient. According to agronomist and professor Andrew C. Larson, MS, at Black Hawk College East Campus, “Nutritive values of hay can vary as much from cutting to cutting and field to field as a bale made in a completely different region. Sampling and testing each cutting will help you to make sound, economic, management decisions.”
Monitor your horses’ feet closely for abnormalities, especially when they are active and working. Talk to your farrier about balanced feet and a healthy hoof capsule. You certainly do not want to miss your derby: whatever that may be. Keep your horses’ feet happy and healthy, so that your feet can stay in the stirrups.
About the Author
Dr. Colleen Lewis is a 1996 graduate of Kansas State University, College of Veterinary Medicine. Her career has taken her to many places as a practice owner, consultant, embryologist, and mentor. She enjoys mixed animal practice, teaching, traveling, farming and high school sports with her husband, Andrew and their three boys.
