Shin Bucks in Young Horses: Causes, Treatment, and Prevention

Last updated: May 6, 2026

By: Miles HenryFact Checked

Bucked shins affect roughly 70% of young Thoroughbreds in race training, and about 12% of those cases progress to stress fractures in the forelimb cannon bone. It remains one of the most common reasons young racehorses are pulled from training in their first year — and one of the most preventable, provided the early warning signs are recognized, and workload is managed correctly.

I was walking through the barn last fall, thinking about how we had made it through the whole training season without a single bucked shin case. Usually by that point, I would have had at least one or two young horses sidelined. Something we changed in how we managed early racehorse training was clearly making a difference.

What Bucked Shins Are and How They Start

A fellow racehorse owner called me a few years ago because his horse had stopped wanting to move out of his stall. The vet ran a hand down both front legs and found heat and firm swelling on the front of the cannon bones — classic bucked shins. The horse had been breezing well, and the trainer had not noticed anything wrong until the horse told him himself.

Bucked shins — also called shin buck in racing barns throughout Louisiana and the Gulf South — are tiny stress fractures and acute inflammation on the dorsal surface of the third metacarpal bone, the cannon bone. Early on, the swelling is soft and warm. Left unaddressed, the bone lays down a periosteal reaction, and the area becomes hard and prominent, which is where the name comes from. The horse is in pain at that stage and will often pull the leg away sharply when you run your hand down the front of the shin.

The condition is part of what veterinarians call dorsal metacarpal disease. It occurs almost exclusively in young horses during their first months of speed work — the bone simply cannot adapt fast enough to the training load being placed on it. Repetitive impact during intense works and breezing is the primary driver.

If the condition is caught early and the horse is properly rested, most cases resolve fully. The danger is in pushing through it — micro-fractures under continued training load can result in a complete stress fracture, which can end a racing career or worse.

What Causes Horses to Shin Buck

We started our two-year-olds on the same schedule we have used for years, yet one still shin-bucked while the others stayed sound. Nothing was different in the program — the difference was in the horse. He simply was not ready for the workload at that stage of development. Not every horse adapts at the same rate, and bucked shins are the bone’s way of signaling that training stress has outpaced adaptation.

Overtraining

We have followed a training approach similar to the one outlined by Kentucky Equine Research, which emphasizes that bone is not static — it adapts directly to the type and timing of exercise placed on it. When workload is introduced correctly, the cannon bone responds by strengthening and remodeling over time. When it is not, the risk of a shin buck increases. For a deeper look at how we structure young horse conditioning, that article covers the full approach.

Training builds bone — but only if the bone has time to adapt.

That concept shows up clearly in practice. The horses that stay sound are not always the most talented — they are the ones whose training progression matches their ability to adapt. When that balance is off, the bone is simply asked to handle more stress than it is ready for.

Pushing a young horse too fast is the most common cause of bucked shins in Thoroughbreds. Bone remodeling takes weeks, not days. When workload increases faster than that process, the front of the cannon bone begins to break down under repeated impact.

A study of two-year-old Thoroughbreds in race training found that 56 of 226 horses developed bucked shins — nearly one in four — with most cases linked directly to the rate at which training intensity was increased. Our standard approach: thirty days of walk and slow jog work, then longer jogging sets with walk breaks, then structured jog-and-sprint intervals as fitness allows — always holding each step long enough for adaptation before moving to the next.

Genetics

Certain bloodlines seem to have weaker bone density in the cannon, and Thoroughbreds as a breed tend to have higher rates of bucked shins than Standardbreds or Quarter Horses. I have seen this play out firsthand.

More than 30 years ago I started in Quarter Horse racing — we pushed our two-year-olds hard with very few shin problems. When I later transitioned into Thoroughbreds, that contrast stood out immediately. Far fewer were ready for that kind of early workload, and trying to treat them the same way often led to shin bucking.

We had a filly in training several years ago who was as fast as any horse I had been around. She shin-bucked early, we backed off, brought her back carefully, and she bucked again. We got her sound a second time, and she won her first start — then shin-bucked a third time coming out of that race. At that point, we decided to retire her to the broodmare band rather than put her through another cycle of injury and recovery.

Her first foal was built the same way — exceptional speed, same fragility in the lower leg. That experience convinced me there was likely something in the bone density of that bloodline that careful training alone could not completely overcome. Genetics does not mean a horse cannot race — but it does narrow the margin for error. Some horses can handle a faster progression and stay sound. Others require a more conservative approach from the very beginning. The key is recognizing which type you are dealing with early and adjusting the workload before the shins start to tell you that you have gone too far.

Why Hard Tracks Increase Bucked Shin Risk

Surface firmness matters more than most trainers give it credit for. Each time a hoof strikes a hard surface, the force travels straight up the leg into the cannon bone. On a deep, forgiving track, that energy is partially absorbed. On a packed or sealed surface, it is not — and the bone pays the difference over hundreds of hoofbeats per workout.

Our training track at home has deep, soft footing, and I think it is a significant reason we go through most years without a bucked shin case. I have hauled young horses to facilities with firm training tracks and watched them come back slightly sore in the shins after a single workout. Evangeline Downs ran particularly firm for a stretch a few seasons back, and it showed in the number of young horses coming back after races with sore shins.

How to Treat Bucked Shins in Horses

Before starting treatment, confirm what you are dealing with. Bucked shins and a full stress fracture require different protocols and carry very different prognoses — here is how to tell them apart.

Factor	Bucked Shins	Stress Fracture
What it is	Micro-damage and periosteal inflammation on the dorsal cannon bone surface	Complete or near-complete fracture through the cannon bone cortex
Palpation finding	Heat, soft swelling, flinch response — bone shape intact	Localized sharp pain, possible bony step or deformity, severe response to pressure
Lameness	Often subtle early — shortened stride, not always obvious at walk	Moderate to severe — horse may be unwilling to bear full weight
Diagnosis	Clinical exam usually sufficient; radiographs if unsure	Radiographs required — do not assume from palpation alone
Recovery time	4 to 6 weeks managed rest, then gradual return	3 to 6 months minimum; some horses never return to full training
Risk if pushed through	High — bucked shins become stress fractures under continued load	Catastrophic — complete fracture, surgical risk, career-ending potential

The moment you feel heat and swelling on the front of a cannon bone, the decision is made. Continuing to work through bucked shins is how minor cases become major ones — the treatment protocol starts with removing speed work, not after you have decided how serious it is.

Our standard protocol: we rub the shins down with Super Green liniment — available at most tack shops — and start cold therapy immediately. At the first sign of heat or soreness, we will also apply a poultice and leave it on overnight to help draw out inflammation. That has been a consistent part of our routine for years whenever we catch heat early. For cold therapy, I prefer ice boots — a good set straps on in under a minute and gives consistent cold contact across the entire lower leg. We typically ice two or three times a day for the first week. Some horses also benefit from leg wraps between icing sessions to provide support and help manage swelling.

We have also seen good results with DMSO applied to the affected area. It penetrates quickly and helps reduce inflammation at the tissue level — but if you have not used it before, read up on proper application first, because it carries whatever is on the skin with it. I cover DMSO in more detail in my DMSO guide.

The balance to maintain during recovery is movement without impact. A horse standing in a stall for six weeks will not heal as well as a horse that is hand walked daily and turned out in a small paddock. You want circulation and low-level loading without the concussive force of trotting or cantering on a hard surface.

How to Prevent Bucked Shins in Performance Horses

The year we went without a single bucked shin case was the year we leaned hardest into early sprint work and soft-surface conditioning. It was not accidental — we had read the research and changed our program deliberately, and the results backed it up.

Understanding the research changed our approach more than any single vet visit. How we train racehorses in the first 90 days now looks completely different from what we did a decade ago, and bucked shin rates reflect it. Veterinarian Petrisor Baia DVM outlines the evidence well in his article Understanding the condition of bucked shins so we can take better care of our horses — the core finding is that short, sharp sprint intervals early in training stimulate bone remodeling more effectively than long slow work, producing a denser, more resilient cannon bone before the horse faces full training loads.

Bucked Shins in Horses: Frequently Asked Questions