A cow’s horns are made up mostly of special growth of touch skin material called “keratin.” The nails on your fingers and toes are made of this materials. So are the claws and hooves of animals. The horns keep growing throughout the animal’s life.
Since cattle can use their horns as weapons, they are sometimes dehorned to make them safer for cattlemen to handle. The cattle are also less likely to injure each other. Some breeds do not grow horns. Cattle born without horns, or whose horns are removed, and called “polled” cattle. – Dick Rogers