Dehorning is the removal of a cow or calf’s horn in order to reduce the incidence of bruising and potential injury to animals or people. When carried out on calves under 2 months of age, before the horns have attached to the skull, the procedure is termed ‘disbudding’.
Disbudding and dehorning are usually performed by farmers or contractors without the use of anaesthetic or pain relief and result in significant acute pain. Dehorning involves using special equipment to cut through the bone and horn tissue – this is more painful than disbudding. If the calf is not effectively restrained, the procedure is even more stressful for the animal. Studies have also shown that calves not provided with pain relief compared to those who have, have reduced appetite for up to two weeks after the procedure, indicating ongoing pain is also experienced.
The RSPCA strongly supports the breeding of poll animals (animals without horns) to avoid having to perform the procedure. Where disbudding and dehorning is performed, the RSPCA believes that all animals must be given an anaesthetic and pain relief. The RSPCA believes that appropriate pain prevention and pain relief must be given for any invasive procedure.
The Australian Animal Welfare Standards and Guidelines for Cattle disappointingly don’t require pain relief to be provided unless an animal is over 6 months of age or, if at first mustering, over 12 months of age. These Standards will eventually become legal requirements across Australia, however, it is clear that, from a pain prevention and pain relief perspective, they are completely inadequate.
The dairy industry is encouraging the use of local anaesthetic and pain relief and for the disbudding procedure to be done before calves reach 2 months of age. The dairy industry recommends disbudding using heat cauterisation (also known as hot iron or thermal disbudding) as soon as the horn bud appears in preference to dehorning older calves. However, based on a 2014 farmer survey, 22% of dairy farmers continue to dehorn their calves at 2-6 months of age, with an alarming 10% of farmers dehorning calves older than 6 months of age. A 2016 survey found that 64% of farms are using professional disbudding/dehorning services and that pain relief was provided to calves on 23% of farms. The dairy industry is not promoting the use of poll breeds to eliminate the need to disbud calves, which is the most cost effective and humane solution. The 2016 survey reports that only 9% of dairy farms are using polled genetics.
Beef cattle farmers (mainly in northern Australia where the predominant cattle breeds are horned) rarely disbud young calves but instead dehorn older calves at 6-12 months of age. However, the beef industry strongly encourages the use of polled breeds to avoid the need to dehorn and a poll gene marker test now makes it easier to identify breeding animals which will consistently produce polled offspring. This should increase the number of polled animals thereby reducing the number requiring dehorning.
A recent study  found no detrimental effects of polledness on important production and reproduction traits in a number of beef cattle breeds used in northern and southern Australia, including birth weight, mature cow weight, carcase weight, retail beef yield, intramuscular fat, milk yield, scrotal size and days to calving. A decision to continue to breed beef cattle that require painful dehorning is completely unjustified.
 Randhawa IAS, Porto-Neto LR, McGowan MR et al (2019) Production and polledness: Genetic correlations between target traits in beef cattle. Paper presented at Association for the Advancement of Animal Breeding and Genetics 23rd Conference, University of New England, Armidale, NSW, 27 October – 1 November 2019.