Healing of dehorning wounds.

Open wound healing following dehorning using a wire saw was observed in 25 cattle aged between 1 and 5 years. Initially, there was a marked thickening of the scab over the wound as a ridge near the skin margin. A pale yellow to pink membrane then developed from the sides of the frontal sinus opening. Granulation tissue formed to fill the frontal sinus opening before healing by epithelization, followed by wound contraction. In some animals a bony horn stump projecting about 2-3 mm above the wound surface appeared which underwent osteosis; the dead bone gradually loosened and fell off during the healing process; histological sections revealed the presence of numerous osteoclasts lining the bone spicules. The presence of the frontal sinus and the stump of the horn processes left after dehorning are factors that make the healing of an open dehorning wound unique compared with other wounds.