Every winter many horse owners debate shoes vs. barefoot. There should be more to the decision than just the amount of riding time available.
There are several reasons why we shoe horses. One, of course, is to prevent excessive wear of the hoof. If this is the only reason you shoe your horse than pulling the shoes in the winter may be without risk.
Another reason we shoe horses is to improve the weight distribution to the hoof wall and leg. These are horses that have less than ideal conformation. They will have feet that tend to flare to the inside, outside or flare at the toe when left barefooted. They can be horses with collapsed, underrun heels or a non symmetrical foot. The distortion in the foot shape means that the weight of the horse is not evenly distributed in the foot or the leg joints.
There are eighteen ligaments in a horse's foot. A foot that does not distribute the weight evenly across those structures can cause problems. A sprained or torn ligament can be a long-term lameness and at worse a career ending lameness. This can be that non-descript lameness that is almost impossible for the veterinarian to find.
Horses with a long toe/low heel foot physiology need to be kept in shoes to prevent a variety of problems; collapsed heels, navicular syndrome and general caudal heel pain.
Because of uneven weight bearing the horse should wear the appropriate shoes throughout the year. If your horse's feet dramatically change shape over a winter of being barefoot then pulling the shoes would not be advised.
Shoeing a horse can be necessary to protect the foot and foot structures. The width of the shoe and/or the thickness of the shoe can provide protection. Pads placed under the shoe provide concussion relief and physical protection of sensitive hoof structures from ground trauma. Horses with thin soles and thin walls need shoes year around for protection. Horses with flat feet need shoes year around to elevate their sole off the ground.
The hoof wall is designed to support the horse's weight. If the hoof wall deteriorates then the horse's weight is transferred to the sole. Dr. Chris Pollitt of the School of Veterinary Science at The University of Queensland, Australia has shown that a horse bearing all of his weight on its sole compresses the circumflex artery in the foot, interrupting the blood supply to the coffin bone.
If your horse needs to have it's foot and sensitive hoof structures protected then removing shoes for the winter, regardless of the amount of riding time, would be detrimental to the horse's well being.
Horses are also shod to assist in the treatment and prevention of pathological (disease) conditions. If your horse has or has had any condition of the lower leg that required veterinarian intervention and therapeutic shoeing then you should consult your vet and farrier before making the decision to pull shoes for the winter. Even though you aren't riding your horse the systems that support your horse and provide motion are still under stress.
In addition, shoes may be used to enhance traction for the wet and slippery season. Rim shoes, caulks, mud or frost nails are all used to increase traction so your horse can carry you without the fear of slipping or falling.
Leaving a horse barefoot for the winter can create some problems for you and your farrier in the spring. If your horse's feet chip, crack and loose their integrity it becomes difficult for the farrier to shoe your horse with the expectations that the shoes will stay on for a full shoeing cycle of riding and showing. You may need one full shoeing to get your horses feet in shape prior to a quality shoeing that can take the stress of riding and/or showing.
If your horse has poor quality horn and needs supplements then you should continue using them all year regardless of shoes or barefoot. There are no supplements that will replace shoes for the protection of your horse's feet.