They worked long enough to heal my horse's hock ulcers but they started to wear off after wearing them for protection for about 3 weeks. His pen is hard and serious when dry, and when you see what it did to those shields, it's no wonder he had ulcers on his hocks! He has a small paddock with a litter box, but prefers to ride on hard material! They wash well, which I had to do often as the boil was oozing and the medicated ointment the vet put on me was making the coat rough and rough. Perhaps the material wears out faster due to washing and stickiness.