Posted by: barn owl | May 4, 2008

The Cannon Bone: Thoroughbreds vs. Warmbloods

Both critics and fans of horse racing are mourning the death of the filly Eight Belles, euthanized by the track veterinarian after sustaining fractures in both front legs. One fracture involved the condyle of the cannon bone, which is actually the third metacarpal of the equine forelimb; there are two smaller metacarpals (medial and lateral) in the horse forelimb, and the condyle of the cannon bone articulates with the first phalanx at the fetlock. Many blame the track surface at Churchill Downs for such injuries, but I’m more inclined to put the blame on irresponsible breeding and training practices in the Thoroughbred racing industry. I’ll use some horses that I know quite well to illustrate my point about the breeding: this is an unscientific study (with help, I can provide measurements in the future), with a very small “n”, but I think I can start to make a point with some photos. The two Thoroughbreds were bred for racing (which they did, unsuccessfully), whereas the warmbloods were bred for conformation.

Exhibit A is a photo of the forelegs of my 17-year-old Thoroughbred mare; pay particular attention to the diameter of her cannon bones, which you can see as separate from the tendons at the back. She also has a visible birth defect, which causes her to favor strongly one particular lead at the canter, and prevents her from being a decent dressage horse (otherwise she is quite talented at this discipline, for a Thoroughbred). Can you tell what her birth defect is? (I’ll bet Coturnix can spot it)


Exhibit B is a photo of my 9-year-old Thoroughbred gelding. He’s reasonably correct, for a Thoroughbred-perhaps a bit slab-sided, and his pasterns are a little too upright. He’s 16 hh, at the upper limit for polo and polocrosse. He’s developing “Birdcatcher spots”, a few more each year-certainly not a flaw, and rather pretty.


Now we get to the warmbloods. First, my friends’ stallion-I think he is seven or eight years old now- a Cleveland Bay, about 17 hh. Look at the diameter of the bone in his lower legs! (Exhibit C)


Exhibit D is one of the stallion’s offspring, out of a Percheron x Thoroughbred mare; this is a two-year-old filly, still growing (already 17 hh or taller…she will be somebody’s dream eventing horse).


Exhibit E is the second of the stallion’s offspring out of the Percheron x Thoroughbred mare. This is a yearling filly (almost exactly one year old)…look at the bone in her legs!




  1. Nice bones! They do have Percheron in them, though, which is cold-blood.

    My first was a Tb and for a year I could not wash off the stench of various ointments I was applying to various parts of his legs. Then I bought his younger brother who was 3/4 Tb and 1/4 draft horse. I brought him home at the age of 6 months and taught him to hold his feet up for me on the very first day, as I needed to start shaping his right hind hoof, a couple of gentle rasps per week, to alleviate a birth defect similar to your mare’s. A year later, the leg was nice and straight, the foot perfect, and he was ready to be ridden. He enjoyed many years of success as a showjumper after I sold him and left for the States, then a few years doing well in dressage. He is 19 years old now and a favourite school horse. With big legs he had, there was never ever any problem with them.

  2. Apart from her attitude, the Percheron x TB dam of the two fillies is much more like a cold-blood draft horse, in build and movement. I learned how to lunge a horse with her, because she is so well-trained…but riding her is a different matter altogether, especially since she’s been off work as a broodmare.

    The stallion is pure Cleveland Bay, and apparently both the fillies can be registered as CB, even though they are 1/4 Percheron and 1/4 TB. Where I learned to ride in England, they had a CB x TB mare that they called an “Essex Hunter”. I learned basic dressage on that horse…she could do everything. Unfortunately, once I got comfortable riding some of the more difficult horses at the stable, I rarely got to ride the Essex Hunter (who was calm enough for beginners and children).

    My mare’s clubfoot has been improved by a very good farrier that we have now. He has never ridden the horse, but he knows how she “rides”. He showed me how the musculature in her upper leg has been affected on that side. My friend who owns all the CB horses is quite good at dressage, and she can get my mare to do canter pirouettes very nicely. However, if you canter the horse on the right lead, you can feel her “fall” inward, so that the circle gets smaller and smaller…I have to constantly use my leg to counteract that tendency.

  3. Cleveland Bays are famous for having a lot of bone. And their TB crosses are usually fantastic all-round horses.

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