• Prevents horns damaging or wounding other animals.
• Dehorned animals are less aggressive, more peaceful and easier to handle.
• Weight gain of dehorned animals is better.
Dehorning can be carried out on calves or adults.
Up to 4 weeks of age, calves can be effectively dehorned with dehorning irons or caustic preparations. After 4 weeks dehorning forceps should be used.
1. Dehorning irons (debudding bolts) - these have a cone-shaped brass head on a long handle. The head has hollows which fit over the horn bud. The hair around the horn may be clipped if necessary. The iron is heated to red hot then pressed firmly over the horn bud for 3-5 seconds. This method causes transitory pain but calves recover quickly. It is a reliable method of dehorning.
2. Caustic preparations are applied to the horn bud, where they kill the root of the horn and stop further growth. There is a danger that liquid caustic preparations can drip onto the skin or into the eye of the calf causing ulceration, extreme pain and permanent damage. Some forms of caustic may be washed off or dislodged by rain. If caustic is used it should be in a preparation that’s dries quickly and sticks to the bud of the horn.
3. For calves over 4 weeks the dehorning iron may not work if the horn is too developed and forceps should be used. Dehorning forceps have 2 spoon-shaped ends, which lift the horn and root from the skull. Thw wound should be treated with antiseptic powder or spray and should heal in a few days.
To dehorn heifers, bulls and adult cattle a Keystone cutter is used. (See picture opposite.) Local anaesthetic should be injected close to the base of each horn. A strong cord is tied tightly around the horns in a figure-of-8 to include about 1cm of skin. This closes off the blood vessels and prevents excessive bleeding. Each horn is inserted into the ‘keystone’ and severed close to the skull.
The horn stump is covered in Stockholm Tar or antiseptic powder and tightly bandaged. Insecticide should be applied to prevent fly strike. The horns should be checked for infection and the bandage removed after a week.
REF: Handbook of Stock Diseases - Monnig and Veldman