Bone Remodeling And Bucked ShinsBy Jeffrey Rolo
Bone remodeling is one of those technical subjects that most horse owners don't bother learning about… it just sounds so scientific and dry! Although understandable, I suggest you gain a basic knowledge of remodeling since it can help minimize your horse's chances of being afflicted with smaller problems like bucked shins or far more serious problems like permanent lameness.
Before diving right into the topic of bone remodeling let's take a peek at a related topic – the body's ability to adapt to physical pressure and stress. When we participate in an exercise program to improve our health and physique, in reality what we are doing is purposely stressing our bodies in a controlled manner. Aerobic exercises steadily increase our lung capacity and the body's ability to utilize oxygen, while body building tears our muscle fibers so that they may grow back bigger and stronger.
Exercise is very healthy for humans and animals alike since the controlled stresses force our bodies to become stronger and more efficient. The problem arises when we overexert ourselves by applying more stress than our body currently has the capacity to handle or adapt to. Too much stress can lead to sprains, torn ligaments/tendons and bone microfractures, which leads us to the main point of this article: bone remodeling.
It may surprise many people that our bones adjust to added stresses and loads just as our other bodily systems, albeit at a slower pace. Over time as bone is subjected to increased loads it will develop additional strength and mass to help the body handle the higher demands as well as protect the bone itself against potential fractures and microfractures. As a side note, bone remodeling is actually a regular occurrence as old bone is stripped away and replaced by new bone – exercise just prompts increased remodeling in areas that see the most stress, such as the knees and metacarpal (cannon) bones.
Clearly bone remodeling provides a benefit to a growing horse as it better prepares them for the rigors of competition and/or extended riding. The more stressful the action, the more bone remodeling that will take place. Just remember that like humans, horses can suffer from overexertion and suffer bone fractures, torn tendons and other maladies as a result. This segues perfectly into our next topic: bucked shins.
Bucked shins are a result of accelerated bone remodeling along the cannon bone that is prompted by vigorous exercise and demands. The new bone that grows is far more prone towards developing microfractures when subjected to heavy stresses. A microfracture is not the same as a full-fledged bone fracture – human athletes can develop them also when they push themselves too hard. They do make movement very painful, if not outright impossible, until the microfractures heal, though. Inflammation and heat along the shins may indicate your horse is suffering from microfractures or ligament/tendon damage.
So far not one of my young horses has ever suffered from bucked shins when being introduced to saddle work, whereas in the Thoroughbred racing industry bucked shins is commonplace among young horses. The difference is racehorses are often started under saddle as early as 18 months of age, far before their bodies have matured to the point where they should be exposed to competition-level stress loads. Whereas controlled exercises and bone remodeling can aid a young horse's health and development, overstressing them can create unnecessary pain and injuries.
I do not want to give the impression that bucked shins is a problem unique to younger horses, for it can happen to any horse that is subjected to too much work before the horse's body has had time to strengthen and adapt. It is just far easier to overstress a young and developing horse than it is to overstress a fully mature and developed horse.
Overall I don't recommend serious saddle work before the age of three (on average since all horses can vary), but if you take it slow and avoid overstressing a younger horse you can safely introduce them to the saddle earlier.