Livestock dehorning: The ins and outs
Why dehorn?
Dehorning is the removal of the horns from cattle. It is a labour-intensive, skilled operation with important animal welfare implications. Horns are detrimental to cattle from a welfare and production perspective, and pose a potential safety risk to cattle handlers.
Dehorning should only be done when necessary to minimise the risk to the welfare of the cattle, particularly pain and distress. Breeding polled cattle is a longterm solution to the problems commonly associated with horned cattle and the issue of dehorning.
Horned or tipped cattle (as compared to hornless cattle):
*Can cause injuries to other cattle, especially in yards and when in transport. *Can cause significant damage to hides and carcass quality.
*Cause more damage to infrastructure on average.
*Need more space during transport. *Harder to handle in yards and crushes and can be more aggressive to other animals.
*Potentially more hazardous to people. *Tipping (removal of the insensitive sharp end of the horn) is not dehorning. It does little to reduce the disadvantages of having horned cattle, for example it does not reduce bruising, and tipped cattle can still be a danger to other cattle and handlers.
Hygiene
*Good hygiene (facilities, hands, handling and instruments) is very important to prevent infection after dehorning. Disinfectant should be used and changed frequently. *Muddy and dusty yards, wet days, dirty equipment, high fly activity are all factors which lead to infection. *All equipment should be cleaned thoroughly after use.
Age
*The younger the animal at the time of dehorning, the better it is for the animal and the easier the job for the operator. There is less pain and stress for the animal and there is less risk of infection or fly strike the smaller and younger they are, particularly if they are going back to their mothers. Smaller animals are also much easier to handle and restrain.
*Removing horns from older cattle, yearlings and adults is time consuming, painful for the animal and increases the chances of a setback. It is not recommended to dehorn animals over 12 months of age unless undertaken by a veterinarian and is illegal in some states and territories.
Condition of the animal Dehorning is not recommended when an animal is in poor condition, or if it has other health problems. In this case the animal should be dehorned when it is in better health/condition as it will heal more quickly.
Anatomy of the horn
The horn core is a bony extension of the skull and the hollow centre of the core communicates directly with the sinuses of the skull. The horn grows from the skin around its base, just as the wall of the hoof grows down from the skin of the coronet. To ensure no horn regrowth, it is essential to cut away 1cm of skin around the base of the horn.
Method
The method of dehorning should be matched to the size of the horn and the age of the animal for optimum effectiveness. The key to successful dehorning is the removal of a complete ring of hair (~1cm wide) around the horn base. The level of skill of the operator and personal preference for a particular method will also be a consideration. There is no one method for a particular animal age or horn size.
The dehorning iron
The use of dehorning irons does not result in an open, raw wound. Dehorning irons are made like number ‘O’ branding irons and can come in a variety of sizes but usually have a diameter of 50mm. The iron must be approximately 1 cm bigger than the horn bud all around.
The hot iron is placed over the horn bud and the surrounding tissue and twisted a few times. This technique ensures that the blood supply will be seared off and the horn bud area will die and drop off. This technique is only suitable for calves up to about 2 months, because the horns become too big for the dehorning iron .
Guillotine dehorners, surgical wire, horn saw and tippers
Guillotine dehorners, surgical wire, horn saw and tippers are used on adult cattle with larger horn growth and should only be used for tipping. Horn saws, parrot teeth tippers and surgical wire should only be used to tip the horns of adult cattle i.e. remove only the insensitive part of the horn.
If used to remove more horn, or dehorn cattle, these instruments should then only be used by a veterinarian, or under the direction of a veterinarian. Local anaesthetic should be used.