Horns in cattle have no place in modern, intensively managed beef production, but problems associated with injury and bruising can be avoided by removing them. In the second part of this series, Chris Nel introduces the subject of dehorning, and discusses pertinent research, methods and precautions.
Australian data show that beef cattle in horned herds have twice as many bruises as those in hornless herds. In fact, the presence of a few horned animals in a herd significantly increases the incidence of bruising. One study found discountable bruises in 10,5% of feedlot cattle, of which between 25% and 50% had horns. It was noted that eliminating horns could decrease this figure to between 2% and 5%.
Some cattlemen believe that horned cattle are genetically superior to polled cattle. The US Department of Agriculture (USDA) Beef 1997 survey found that 27,8% of the calves born in 1996 still had horns, but that 61,1% of cattle born with horns were dehorned before being sold. Of those cattle with horns arriving at feedlots, 74,4% had the tip of the horns cut off, while only 2,3% were dehorned at the feedlot. The remaining 23,3% presumably underwent neither procedure and retained their full horns, which would mean that approximately 2,5% of US cattle still had full horns at slaughtering. More recent National Beef Quality Audit data indicate that 31% of feedlot cattle in the US have horns. A 1995/96 survey of four Canadian abattoirs recorded 14,8% of cattle with full horns.
Allaying perceptions of some cattlemen, research has demonstrated that horned and polled cattle are similar for traits associated with reproduction, growth and behaviour. There are thus enormous benefits in a horn-free beef cattle herd, especially in reducing the incidence of bruising and injury.
Long-term hornlessness can be achieved by breeding polled cattle. In the meanwhile, dehorning is a solution.
Dehorning or the breeding of polled cattle can be encouraged through economic incentives. A producer will be more motivated if he gets a premium price for hornless calves. In feedlot cattle, bruising was halved after a switch from selling by live weight to selling by carcass weight. In Australia, Cattlecare accreditation requires producers to dehorn all calves.
Dehorning entails removing the horn by removing or destroying the keratin-producing cells and structures at the base of the horn. Tipping entails the removal of the insensitive part of the horn.
Contrary to popular belief, tipping does not reduce the incidence of bruising. In any case, it is painful to steers and reduces weight gain. If done at all, it should be done at an early age.
When to dehorn
Calves should be dehorned before the age of three months, earlier if possible. The younger the calves, the more easily they can be handled and the less stress they suffer. The procedure, if properly carried out, causes no or little bleeding and the wounds heal quickly. The older the calves, the greater the stress and potential for problems such as developing infections, and occasionally dying of blood loss. In addition, calves dehorned after two months may require two weeks to return to their pre-dehorning weight. In Australia legislation bars dehorning over the age of twelve months without the use of anaesthetic, as it is considered a cruelty offence under animal anti-cruelty legislation.
A short calving season allows calves to be dehorned at approximately the same age. If calving is spread out over a long period, groups of similar age must be selected for dehorning.
General remarks and precautions
Calves should be dehorned on dry, cool days to dry the wound quickly with the minimum risk of infection. The best time is late afternoon, in winter or early spring, when fly activity is usually low. Never dehorn in wet weather, as this delays healing and increases the risk of infection.
A well-designed calf cradle will restrain the calf, minimising stress and effort for both the operator and the calf. Dehorning must be done last – after vaccination, marking and castration.
The specific procedure depends on the age of the calf. Disbudding, or destruction of the horn bud, is preferred for calves younger than 10 weeks. It entails applying a hot iron cautery or caustic paste to the horn bud. Dehorning or horn amputation by means of a scoop, saw, shears or wire, is suitable for older calves. Because tissue is damaged, all methods of disbudding and dehorning are probably painful.
Extensive research has gone into dehorning pain and various ways to alleviate it. One study showed that, in six-week-old calves, scoop disbudding caused a more prolonged rise in the concentration of the stress hormone cortisol than did hot iron cauterisation. Cauterisation gave a lower cortisol response in eight-week-old calves than did a caustic preparation in four-week-old calves. In another study, behaviour and cortisol levels showed that calves dehorned by both methods suffered intense pain and discomfort. Yet another study showed that calves dehorned by hot iron cauterisation suffered more pain than calves undergoing the caustic paste procedure. Therefore, while cauterisation appears to be less painful than scoop disbudding, the difference between cauterisation and caustic paste is unclear.
Research has also documented benefits of analgesia and anaesthesia in reducing pain. Local anaesthesia combined with wound cauterisation reduces the acute distress of dehorning by the scoop method in older calves. In the UK, local anaesthetic must be administered to calves older than seven days. However, in the US the care and handling guidelines of the National Cattlemen’s Beef Association (NCBA) do not require or recommend anaesthesia or analgesia for dehorning, but they do recommend that calves are dehorned before 120 days. But the USDA Beef 1997 survey found that the average age for dehorning in cattle enterprises was 130 days, with 58,6% of them dehorning calves at 123 days or older, and 19,4% dehorning at 215 days and older. A USDA National Animal Health Monitoring System survey of cow-calf management practices in the US, also in 1997, showed that the average age of dehorning calves was 162 days.
The USDA points out that dehorning can open the frontal sinus, resulting in infection and haemorrhaging, and that neither dehorning nor tipping should be performed at the feedlot. NCBA guidelines note that tipping can be done with little impact on the well-being of individual animals, but they do not recommend against either dehorning or tipping at the feedlot.
Relatively skilled labour and specific equipment and techniques are required for all horn removal procedures. Costs per calf vary according to time and place, the method used, the age of calves and the number to be dehorned, as there are fixed costs as well as variable costs. A publication by the Agricultural Extension Service at the University of Tennessee estimates the total cost at $5 (R35) per head, the handling component of which can be reduced by combining dehorning with other procedures. According to the Cooperative Research Service at North Carolina University, producers can expect a premium of at least $5 per head for dehorned weaner calves.
Next week’s article will focus on the dehorning process. |fw