Two of the main causes for a reduced life expectancy of the domesticated horse (in Europe, about 1/3 of the natural lifespan) are hoof and leg problems -- Yvonne Welz.
Wow, that's a scary thought.
What is scarier is the thought of all the repercussions to the hooves and legs that arise from horseshoes! Yet horse owners are frequently told, "if you want to ride that horse then you're going to have to have him shod!".
FACT: Hooves will condition to the ground to which they become accustomed. So, soft ground = soft hooves. Hard, resistant ground = hard, resistant hooves!
Where does that leave the hooves wearing shoes?
Photo from blue-heron-farm.com showing the contracted hoof (on left) to the decontracted hoof (right)
So many of the older illustrations of 'healthy' hooves depict small, contracted hooves! Why? According to Bracy Clark of the London Veterinary College, each year the hoof is shod, the hoof will contract regardless of the aptness of the application!
In 1983, Luca Bein studied the shock absorption of hooves that were barefoot, shod and "alternately shod". He found that the regularly shod horse showed an absence of 60-80% of the hoof NATURAL shock absorption. He also demonstrated that the shod foot on asphalt at just the walk receives 3 TIMES the impact force as that of a barefooted horse. He also found that the shoe vibrates at about 800 Hz which is strongly damaging to living tissue.
Even when properly and correctly shod for the individual hoof, the circulation in the hoof is diminished as the blood is not supplied in the normal fashion but, instead, through an alternate route that the hoof has developed. (Dr. Chris Pollit)
It has also been shown that wearing shoes will damage the corium of the hoof, thus weakening the laminae that connects the hoof capsule to the foot, itself. (Zierold, DVM)
Think of how the shoe is applied - Generally with 4 nails on each side of the hoof. The hoof, in its natural form, expands and contracts with each footfall. Nails are binding, of course, so imagine how the expansion of the rear of the hooves is restricted. The last nail is place right in the quarters that *should* be naturally arched just for proper expansion. That's in addition to the nails putting holes into the horn of the capsule -- a capsule that is 'designed' to be solid and protective of outside elements.
The shod hoof lands flat, or, more commonly, toe first. The shock of a toe first landing goes directly up the front of the leg where there is little structure to absorb the shock. But if we look at a barefooted horse we'll see a hoof that lands a bit on the lateral heel side then breaks over at the tip of the coffin bone. The shock is absorbed right through the digital cushion that is comprised of fibrocartilaginous tissue that will take the shock efficiently and pass what's left through other soft tissues in the rear of the leg.
The barefooted horse has full circulation to feed new and healthy hoof growth.
The barefooted horse can expand fully thus stimulating good circulation.
The barefooted horse absorbs the shock efficiently
The barefooted horse can 'feel' more of the ground thus giving a more secure footfall.
The expansion of the bare hoof forms a 'suction' for better traction on slippery ground.
The bare hoof can utilize full function for traction, 'skid brakes' thus allowing for full strides and more correct movement.
All contrary to the effects of shoes on hooves.
So, once again, the adage "no hoof, no horse" stands to reason for the early demise of many domesticated horses.