Add up the total weight of the horse, rider, and tack. Our example: Horse + rider + tack= 1188 pounds
Measure the circumference of the cannon bone midway between the knee and fetlock. Our example: 7.5 inches
Divide the total weight by the circumference. Our example: 1188 / 7.5 = 158.4
Divide the result by two. Our example: 158.4 / 2 = 79.2
Values below 75 are great! Values from 75-80 are acceptable. Values over 80 indicate weaker legs and a need to train carefully, especially downhill. At this level a rider needs a horse with more substance.
* Reference: The Heavier Riders’ Guide by Beverly Whittington and Rhonda Hart-Poe
In our example the horse rated near the end of the acceptable range and should be able to carry the rider comfortably. However, how the horse has or has not been conditioned in addition to how it will be ridden should be considered.
Note that cannon bone circumference (as overall bone substance) increases with the horse’s fitness level, so if he is borderline, as in the example, it doesn’t necessarily mean you’re too big for him. By “slow racking” up, Long-Slow-Distance (LSD) miles, which builds up bone over time, he may measure up yet. Be patient. It can take up to three years for bone to remodel. (This is not for the weekend rider and only for the committed horse person.)
When shopping for a horse, you will find that the average horse has been lounging in the field or paddock. The overweight or out-of-shape horse must be conditioned, slowly, prior to carry a heavy load.
Unfortunately, the average “back yard horse’ is generally not in any better condition than the average “weekend rider”, which includes a lot of us. Such horses should not be expected to carry 20 percent of their body weight. Add a rider who is heavier, and possibly less balanced and/or less athletic, and it becomes obvious that the stouter and/or better conditioned horse will be more able to carry the person comfortably, safely, with the less chance of injury. (Providing the cannon bones measure up to the right size.)
Have your veterinarian perform a thorough “soundness” exam. Explain that the horse will be carrying extra weight and ask him or her to be especially thorough in his evaluation of the horses back structure and suspensory ligaments in the legs. Be careful of the veterinarian you choose! They do not study the structure of the horse versus the rider’s weight in vet school. The vet can determine if the horse is sound for riding, only, not the right size horse for you.
The rider should be very concerned about finding a lightweight saddle that fits both the horse and him/herself. Many saddle manufacturers still think the heaviest rider is going to weigh 150 pounds and it may be difficult to find a large enough seat for your horse and for you too. If you are stuffed into a saddle that is too small, you can easily damage your knees and hips. You will not be able to balance in the saddle.
HPS sees the results of the damage done to horses that were not conditioned and were ridden too hard., that had too heavy riders, or were asked to go at speeds for too long a period of time compared to the horse’s body condition. Many of these horses have been destroyed and will never be able to carry any rider again.
The suspensory ligament carries too much of the stress and weight causing injury that will result in an illness called DSLD. (Degenerative Suspensory Ligament Desmitis)
You can click here to read the full research done at the University of Georgia. (You will need to have Adobe Reader.)
I will cut to the chase concerning the research. DSLD not only affects the suspensory ligament, but the degeneration spreads through out the whole horse affecting many areas. There is no cure. Once it gets started there is no hope for the horse and it can expect a life of pain and continuing degeneration. HPS will have to euthanize at least one horse a year because of this illness.
More Paso Finos were used in this study than any other breed of horse. Think of the size of the people who originally bred Peruvian Paso Fino and the size of the average person in this country who is riding this breed. The Criollo is the smaller type Paso and many are under 15 hands. HPS has one of each type of Paso Fino. The large one could carry 145 to 150 pounds. Remember this includes saddle, bridle, blanket, and rider.
The good news is that more large boned horses are being bred for the jumping and the hunter disciplines. Not all of the horses will work out for what they have been bred. The draft type horses usually have wonderful personalities.
These bigger horses are often crossed with Saddlebreds and Thoroughbreds. Some are the draft type horses crossed with Quarter Horses. Carry your tape measure with you to check the cannon bone. Some of the crossed breeds may have inherited the smaller leg bones. The other important thing to think about is that the heavier horses do not mature as fast as the lighter weight horses. They should not be started under saddle until they are at least four years old, providing they have been fed correctly to promote the correct growth at the correct time. If the horse has been started too early the damage may already be starting.
There are many draft horses available across the country for sale. Be careful! Many have arthritis from being over worked in the fields for many years. The vet check is well worth the money before the purchase is completed.
DSLD use to be called ‘coon footed’ and was thought to be a conformation problem. Currently, the common name is ‘dropped pasterns’. The worst part of DSLD is that a horse may have this condition and the owner may not realize it since not all pasterns will drop. At times the suspensory ligament will thicken and not drop. There is now various equipment that your veterinarian can use to test the horse’s tendons for this condition.