The one form of disarmament that makes sense, is the removal of cattle horns. In this short two-part series we discuss the reasons for and ways of dehorning.

Horns and their growth

Horns are the pairs of hard, bonelike, permanent growths projecting from the heads of cattle. They grow from a unique area of skin cells at the base of the horn. At about two months of age, horns become attached to the frontal bone of the skull. A sinus lies within the skull beneath the horn bud. As the horn grows and attaches to the skull, this frontal sinus joins into the adjacent portion of the horn.

Some cattle breeds are naturally (genetically) hornless because they do not grow horns at all. Dehorning of horned cattle is the process of removal of their horns or the process of preventing their growth. A polled animal is one that grew no horns or one that was dehorned. Dehorning removes the horn and horn-producing tissue after horns have formed from the bud.

Cattle are dehorned to:

• reduce the risk of injury and bruising to herd mates
• prevent financial losses from trimming carcasses damaged by horned feedlot cattle during transport to slaughter
• require less space at the feed bunk and in transit
• decrease risk of injury to farm workers, horses and dogs
• gain a price advantage by offering hornless cattle at auctions
• produce docile cattle that are easier to handle
• decrease aggressiveness at the feed bunk
• facilitate easier use of handling facilities

Dehorning cattle at a very early age decreases the risk of death, illness and setback caused by dehorning.

Managing horned cattle

Owners may choose to manage their cattle with or without horns. For beef cattle, the selection will depend on the available handling facilities, the producer’s abilities, the awareness of dehorning effects, and the market available for the calves.

Owners with guaranteed buyers willing to purchase green calves (horns and testicles in place) at the same price as processed calves (castrated and dehorned), might be advised to avoid these procedures. However, this buyer is very rare. Most purchasers of green calves are well aware of the risks associated with processing older calves and routinely bid less at auctions. Preconditioned (castrated, dehorned, vaccinated, bunk-adjusted) calves may bring a premium price. Generally, horned cattle are discounted at auctions.

Naturally polled dairy animals are very rare. Therefore, dehorning is a common management practice on dairy farms. Most housing systems and milking parlours are designed for dehorned cattle.

Dehorning age

Dehorning at a young age minimises hazards to the calf, the cow-calf producer, and the feedlot owner. Hazards for calves and owners include:

• sickness or death following dehorning of older calves
• decreased liveweight gains in the weeks following dehorning of older calves
• loss of productivity

Many producers choose to dehorn new-born calves because:

• techniques are easier for the operator
• dehorning is less stressful on newborn calves
• of concerns for animal welfare

Although there is no evidence that pain differs between young and older calves, there is less risk with dehorning of young (less than eight weeks) calves.

The cow/calf producer’s decision to dehorn and the timing (age) will be influenced by his or her facilities, available labour, expertise with the techniques, awareness of the impact of the procedure on calf health and productivity, the market for the calves, and the breed and nature of horns on the calves. Some breeds have stronger horns, and others softer horns.

The feedlot purchaser is able to selectively purchase horned or dehorned (polled) cattle with price as well as some of the above factors influencing the decision. In general, dairy calves receive intensive care and producers have an opportunity to dehorn their calves at a young age. It is each owner’s responsibility to ensure humane and safe completion of the dehorning procedure on the calves entrusted to his care.

Welfare significance

Livestock owners and veterinarians recognise that some people consider dehorning offensive. Nonetheless, dehorned cattle create a safer workplace for herdmates, handlers and workers – a benefit that outweighs the short period of discomfort at dehorning time.

• Young calves recover quicker and have fewer complications than older calves.
• There is no evidence to show young calves experience less pain than older calves.
• Local anaesthesia prior to dehorning eliminates acute pain for a few hours after dehorning.
• Local anaesthesia, combined with a sedative and an analgesic (pain reliever), may provide the best pain relief.
• Use of pain relief is an additional cost for producers. Pain relief may be limited by the availability of drugs for farmers to use and the scarcity of veterinarians in farm animal practice.
• Use of polled bulls is a welfare-friendly alternative to dehorning.
• Control of bleeding is essential when dehorning older calves.

Choices in anaesthesia and pain relief include:

• a short-acting, local anaesthetic (eg lidocaine sential) with an effect for about 60 to 180 minutes
• a sedative (alpha-2 agonist, eg xylazine) given on its own or in conjunction with a local anaesthetic will provide analgesia for a few hours
• a combination of local anaesthetic, a sedative (alpha-2 agonist, eg xylazine) and non-steroidal anti-inflammatory drug (NSAID) provides pain control of longer duration
• inclusion of a sedative with the local anaesthetic could eliminate the need for physical restraint during dehorning.
• Treatment with an analgesic by itself prior to disbudding (dehorning) with caustic paste is not effective in controlling pain.

Blocking the nerve to the horn

One nerve provides feeling to each horn. Blocking the nerve makes dehorning easier on the calf and on the person doing the job. You must block one nerve on each side of the head. Lidocaine anaesthetic is a prescription drug and is only available from your veterinarian. This procedure requires clinical training and practical experience. Local anaesthetic should be given by a veterinarian, a trained veterinary technician, or a trained operator.

Technique

• Restrain the calf with a halter tied to a ring, a post, or a neck clamp.
• Preferably, sedate the calf with an injection of an appropriate dose of a sedative and a non-steroidal anti-inflammatory drug as per label directions.
• Locate the injection site for the local anaesthetic by putting your thumb on the skin just beside the outside corner of the eye. You will feel a soft depression at this site. Now, move your thumb backwards toward the horn. You will feel a small groove that runs in the bone of the skull. The nerve runs along and under this groove. The injection site is in the upper third (closer to the horn bud) between the corner of the eye and the base of the horn.
• Disinfect the site with an alcohol swab.
• Use a 20 or 18 gauge, 25 to 37 mm needle.
• Use a 6 or 10 cc syringe.
• Use from 3 to 10 cc of 2 per cent lidocaine with epinephrine for each horn. The volume depends on size of calf.
• While holding the head steady and with the needle on the syringe, push the needle through the skin at the injection site. The needle should penetrate perpendicular to the skull at the site. Once you are through the skin, pull back on the plunger to be sure the needle is not in a blood vessel; then inject about 1,5 cc of lidocaine. Push the needle in about 6 mm and inject another 1,5 cc. Push it in about another 6 mm and inject the remaining lidocaine. Then withdraw the needle. If you hit the bone with the tip of the needle, withdraw it slightly and inject the last of the lidocaine.
• Repeat on the other side of the head. The lidocaine is similar to the product used by dentists to anaesthetise your tooth.
• You may need to wait several minutes for it to take effect. The upper eyelid usually droops if the correct injection techniques are employed. Failure may occur if the injection went too deep at the site.
• Proceed to block the nerves on other calves and then return to dehorn the first calf.

The farmer has various choices of how to dehorn his cattle.The choices of dehorning techniques range from genetic to surgical. The risks to the calf and the operator vary with each technique. Many producers choose to dehorn new-born calves because the techniques are easier for the operator, less stressful on the calves and they demonstrate concern for the animals’ welfare.

In our next issue we will discuss different methods of dehorning.

ProAgri acknowledges Neil Anderson, Lead Veterinarian, Disease Prevention, Ruminants/OMAFRA in Canada as well as the SA Tuli Journal 2016 for the information used in this article.