Because the hoof needs to be conditioned to go barefoot if it’s going to be able to go barefoot, and overprotecting the hoof weakens it the same way over trimming it does.
The point at which they’ve self trimmed too much off their feet is the point at which they can no longer walk reasonably comfortably on the footing they’re on. At that point they get boots, but only until they don’t need them, anymore.
Most horses do not have perfect conformation and perfect working conditions. The chances that they balance their feet better by themselves is unlikely, at best. Just go look at some BLM mustangs. My farrier has a BLM cadaver hoof where the horse died from sinking founder at the age of 6-8. Not exactly the standard I would use for my own horses.
And you think that laminitis is caused by lack of trimming, or bad trimming?
The whole point is that horses who self trim will balance their hooves to their own conformation based upon how the hoof interacts with the ground, which is something that farriers and trimmers can’t do because they can only guess at what the horse’s environment is going to be like between visits.
That, and they often need to make the hoof look as smooth and symmetrical as possible for observers, which isn’t always what is best for the horse.
If this were true, farriers would have been out of business 200 years ago.[/I][/I][/COLOR]
There will always be a need for trimmers and farriers, because maintaining a barefoot horse takes a heckuva lot more effort, and sometimes sacrifice, than calling someone to come and nail shoes on or trim overgrown hooves.