Here's a fascinating high definition video that I first saw in 2011 and put on the blog then - there were some fabulous comments at the time. Its been doing the rounds on Facebook and I saw it again yesterday but it is well worth another watch.
You need to listen to the commentary as well - the vet who is commentating is describing the "support" that the shoes are providing but - really - that's not what appears on the video. I find it hard to watch, mostly because of the medio-lateral imbalances and the tremendous strains being transmitted up the limb as a result.
The veterinary hospital that posted this incredibly clear footage is a renowned US equine centre. Its praiseworthy that they - unlike many vet practices - are trying to gather the evidence on which to base their decisions.
But for me there is a gaping hole in their research. They've forgotten that horses didn't evolve with shoes on and that shoes change how feet and limbs load, land and function.
"The big question about shoes is: Do they restrict the expansion and contraction of the hoof capsule? For a question that is central to the discussion of shoeing and barefoot...it has received remarkably little experimental attention." Jeffrey J Thomason PhD "Review of Some Past Present and Possible Future Directions in Biomechanics of the Equine Hoof" AAEP Focus on the Foot, Columbus, Ohio USA 2009
Evidence based veterinary medicine is undoubtedly going to be a huge focus in future and there is a desperate need for it. Before we put bar shoes, wedges, pads and other aggressive interventions on horse's feet, wouldn't it be a good idea to try and evaluate what good - or harm - they do? Certainly the radical and rapid development in feet that we see here as they come out of shoes suggests that shoeing is far from a benign management tool - and yet there are no comparative studies evaluating the physiology of shoeing in place of normal hoof function.