This may be said, in the majority of cases, to be a form of grease, though generally it may be unaccompanied by any increase of the oily secretion of the skin. The hollow of the pasterns is the part where the cracks usually occur, and the tendency of this part to become affected is greatly increased by trimming the heels, and exposing the skin to cold and damp; sometimes it may be due to derangement of the stomach. Cracked heels are much more common in cold, wet weather, and especially if the horse is working on muddy, chalky, or sandy ground; also if the legs and feet are washed with cold water and not thoroughly dried. There are great pain and lameness, the horse going on the toes, the cracks in the skin discharging a watery fluid, and even bleeding when the horse is moving. When the pastern is handled the horse jerks up his leg, which often becomes swollen above the fetlock. It is customary in big towns, during the winter, when the roads are slippery, to melt the ice on the track of tramways by sprinkling salt; this, mixing with the mud, produces a very acrid compound, which is particularly active in producing cracked heels, and even sloughing of the skin.
In very mild cases a little oxide of zinc ointment, or carbolised oil, may be rubbed into the skin once or twice a day; if the skin is broken it should be thoroughly cleansed by washing with soap and water before applying these. Should the inflammation be rather intense, and the lameness great, after washing, a linseed-meal poultice should be applied for a day or two, when the dressing may be used. Should the cracks show a tendency to become chronic, they may be touched with nitrate of silver or pure carbolic acid, after which the ointment or carbolised oil may be applied; pledgets of tow, smeared with these, may be tied round the pastern. In very bad cases, the application of a high-heeled shoe will greatly expedite recovery. To prevent cracked heels, a little vaseline or lard rubbed into the hollows of the pasterns, and around the coronets, is very useful. To prevent injury from salted roads, white lead, made into a thin paste with common oil, is an excellent application when smeared around the pasterns. These parts should not be deprived of the hair, nor yet washed in cold water, but the mud should be removed with a wisp of straw when the horse returns to his stable.