Dehorning and disbudding are common management practices. Disbudding is a form of dehorning performed on calves while horn development is minimal. (J10.44.w2)

• Methods of disbudding include:
  • Scoop: two interlocking semicircular blades, about 45 mm diameter, attached to handles are used. These are placed in the "open" position around each horn bud, and operated by separating the handles at the same time as pushing down on the calf's head. This has a shallow cutting action which amputates the horn bud, adjacent skin, and some of the underlying bone. (J10.44.w2)
  • Cautery (gas  heated iron): a gas-heated disbudding iron is applied over each horn bud for about 3-5 seconds. (J10.44.w2)
  • Cautery (electrically heated iron): an electrically heated iron is held on each horn bud for the appropriate length of time (depending on the instrument used), e.g. about 35 seconds (J295.83.w2); 2-3 minutes (J295.68.w1); 15 seconds (J35.158.w2)
  • Caustic: a caustic preparation (potassium hydroxide) is rubbed onto each horn bud using a caustic stick. (J288.43.w1)
• Methods of dehorning include scoop, saw, guillotine shears or embryotomy wire. (J24.76.w2)

• --

• This is carried out to reduce the risk of injury to other animals and to humans, particularly during yarding operations and transport, as well as to decrease disruption by aggressive cows, for example at feeding stations. (J4.221.w4, J10.45.w2, J24.58.w1, J295.68.w1, J295.72.w1)
• Dehorning reduces bruising of carcasses. (J24.58.w1)
• Dehorning reduces the amount of feeder space required, makes it easier to move cattle through chutes and prevents cattle getting their horns caught in fences. (J234.11.w2)

However:

• Until relatively recently, cattle were often maintained with horns. Certain rare breeds of cattle, such as Longhorns, are still maintained horned, at least for breeding animals. Extensive rather than intensive management is preferred for horned cattle and for those with long horns some adaptations are required, for example in crush design. (V.w62)
• N.B. disbudding or dehorning is not needed in naturally polled animals. Breeding for polled animals would remove the requirement for this procedure. (D154)

• Dehorning, by whatever method, involves destruction of tissue and "it is apparent that calves experience stress and pain."
• "Dehorning by amputation involves tissue destruction and causes pain and distress." (P61.60.w1)
• "We are confident that all methods of dehorning and disbudding cause pain, with an initial response to the actual act of amputation or cautery, followed by a more protracted phase due to inflammation-related pain." (J10.45.w1)
• When adult cattle are dehorned without provision of local anaesthesia they vocalise and struggle more than do cattle which are just being restrained; their responses suggest that the procedure is painful. (P61.53.w1)
• Dehorning is a surgical procedure which is routine, but is nevertheless painful and requires analgesia. (P61.62.w1)
• Hot-iron dehorning of calves "causes a pronounced behavioural response such that significant physical restraint is required to carry out the procedure." (J295.83.w2)
• "All methods of disbudding involve tissue damage and presumably afferent nerve discharge from nociceptors. The noxious stimulation caused by disbudding is assumed to cause distress." (J10.44.w2)

Cortisol responses:

• Plasma cortisol, an indicator of stress, rises in response to dehorning. (J295.68.w1)
  • Application of an electrical dehorner to each horn stump of eight-week-old calves resulted in a significantly (P<0.01) elevated plasma cortisol level at 5,15,30 and 60 minutes after dehorning; cortisol levels were significantly (P <0.01) higher than (about four times higher than) levels in control calves subjected to restraint and venipuncture but not to dehorning. (J295.68.w1)
  • A study compared scoop and cautery disbudding with one another and looked at the effect of local anaesthesia (3 mL 2% lidocaine, 20 minutes prior to disbudding). Overall the study indicated that cautery disbudding caused less distress than scoop dehorning, although both methods of dehorning caused distress. (J10.44.w2)
    • Scoop dehorning resulted in a marked rise in mean cortisol levels; levels then fell to a plateau which was sustained for at least five hours after dehorning. (J10.44.w2)
    • Scoop dehorning following application of local anaesthesia resulted in a small initial cortisol rise similar to that seen with local anaesthesia administration alone, returning to pretreatment levels by 30 minutes but followed by a significant, protracted rise in cortisol, returning to levels seen in those given local anaesthetic without disbudding by 7.5 hours after disbudding; it was noted that one calf showed little rise in cortisol throughout. The administration of local anaesthetic resulted in a significantly lower cortisol level than scoop dehorning without local anaesthesia for the period 15 to 60 minutes after dehorning but levels at 2.5 to 8 hours were generally higher in the local anaesthetic treated group and this was significant (P<0.05) at 3.5 hours after dehorning. Prior administration of local anaesthesia also reduced escape attempts during the disbudding procedure. (J10.44.w2)
    • Cautery dehorning resulted in an initial peak of plasma cortisol of about 18 ng/mL at 15 to 30 minutes after dehorning and levels were greater than those seen in control handled calves for one hour after treatment. (J10.44.w2)
    • Calves dehorned by cautery or by scoop dehorning did not have significantly different cortisol levels in response to the dehorning. (J10.44.w2)
    • Cautery dehorning following application of local anaesthesia resulted in a transient rise in mean plasma cortisol (about 12 ng/mL), returning to normal by 60 minutes (a marked transient rise was seen in one individual). Mean plasma cortisol levels over the sampling period were not significantly different from those of control calves or those given local anaesthesia alone, nor were they significantly different from those seen in calves disbudded by cautery without local anaesthesia. Fewer escape behaviours occurred in response to the cautery than in those calves not given local anaesthetic. Judged solely from cortisol responses, benefits of local anaesthesia prior to cautery appeared to be marginal. (J10.44.w2)
    • The integrated cortisol response in the first two hours was significantly greater for calves subject to scoop dehorning than for those dehorned by cautery with or without local anaesthesia and those dehorned by scoop following local anaesthesia. The integrated cortisol response after two hours was significantly higher for scoop dehorned calves given local anaesthesia than for those dehorned by cautery with or without local anaesthetic, control handled calves and those given local anaesthetic without dehorning. For the entire 9.5 hours after dehorning there was no significant difference between calves disbudded by scoop or cautery. (J10.44.w2).
  • "We are confident that all methods of dehorning and disbudding cause pain, with an initial response to the actual act of amputation or cautery, followed by a more protracted phase due to inflammation-related pain." (J10.45.w1 - [comment on interpretations of J10.44.w2])
  • Both deep and shallow scoop dehorning resulted in pain as indicated by marked rises in plasma cortisol level (mean 28-29 ng/mL, p <0.001) followed by a fall to (still raised) plateau values, sustained to about 4.5 hours after dehorning, returning to normal by about 7 to 8 hours after dehorning. Integrated cortisol responses were also significantly higher than those found after handling (control animals). (J10.45.w2)
  • Responses to amputation dehorning by four methods (scoop, saw, guillotine shears or embryotomy wire), found that all four methods resulted in similar rises in plasma cortisol concentration and that these rises had similar durations. Maximum concentrations (89 - 119 nmol/L) occurred at 0.5 to 1.0 hours after dehorning, before declining quickly to plateau values (still raised) for a further 1.5 to three hours, with decreasing cortisol secretion after  this time and a return to pre-dehorning levels by six hours after dehorning. Cortisol levels at 36 hours were not raised, suggesting that chronic distress from dehorning may be minimal. (J24.76.w2)
  • Plasma cortisol concentration responses of calves to scoop dehorning, and the effects of local anaesthetic and NSAID (ketoprofen) on the cortisol response, suggest that the initial cortisol response is related to the activation of damaged nerves at and shortly after horn amputation whereas the second phase (plateau then decline) is largely inflammatory. (J21.64.w1)
  • Calves subjected to disbudding by hot-iron showed an increase in blood cortisol concentration after dehorning compared with control sham-disbudded calves (statistically significant for the first 30 minutes and raised, but not statistically significantly, for the next 30 minutes); this rise was eliminated by provision of local analgesia before the procedure. (J35.158.w2)
  • Calves of four to six weeks old subjected to hot iron dehorning without analgesia showed significant (P<0.05)  rises in plasma ACTH and cortisol compared to calves provided with local anaesthetic prior to dehorning. Peak cortisol concentrations occurred at 20 minutes after dehorning and levels were significantly elevated from five to 90 minutes after dehorning. (J288.62.w1)
  • Scoop dehorning of calves of 10 weeks of age produced cortisol levels which rose markedly, peaked at 40 minutes after dehorning, declined to a high plateau by 90 minutes, remained at about this level to 150 minutes then declined gradually, returning to original levels by 420 minutes; the concentration was significantly higher than that seen in control handles calves from 40 to 210 minutes. Provision of local anaesthesia (5 mL of 2% lidocaine into each cornual nerve 20 minutes before dehorning) reduced the peak, which was reached at 30 minutes, to a level intermediate between that of control handled calves and that of those dehorned without analgesia (control value 23 nmol/L, dehorned 84 nmol/L, with local anaesthetic 53 nmol/L) after which the levels decreased, returning to pre-treatment values by 90 minutes. The concentration was significantly lower than that of calves not given local anaesthetic for the periods 40 to 90 and 150 to 300 minutes, although values in calves given local anaesthetic were still significantly higher than those seen in control handled calves from 150 to 300 minutes: this rise was attributed to delayed onset of pain as the local anaesthetic wears off. (J24.80.w2)
  • In calves disbudded at three to four weeks old, using two different electrical instruments, one requiring one to two minutes of contact at 538°C, the other only 10s at a higher temperature (816°C), and treating one horn bud on each occasion, two days apart, cortisol responses were found to be similar whichever instrument was used, peaking at 15 minutes after dehorning with an increase four- to fivefold above baseline (compared to a twofold rise with control handling), and remaining elevated for one hour. (J295.77.w1)
  • In calves disbudded by application of a caustic agent (potassium hydroxide) at four weeks old or by heat cauterisation at eight weeks old, behavioural and cortisol responses indicated pain which was considered to be "intense but brief", and was decreased by use of local anaesthesia; higher cortisol responses in the chemically disbudded calves suggested that this method was more painful than heat cautery.. Plasma cortisol levels rose following caustic disbudding being significantly raised at one hour after the procedure, returning to basal levels by four to 24 hours; levels returned to basal levels sooner in calves given local anaesthesia (4 mL of 2% lidocaine injected midway between the horn bud and the lateral canthus of the eye fifteen minutes before disbudding). In heat cauterised calves cortisol levels also rose; at 24 hours the cortisol level was significantly lower in calves given local anaesthesia than in those not given analgesia. (J288.43.w1)

Behavioural signs:

• Calves showed behavioural signs such as head jerking and leg movements during hot-iron disbudding, as well as head shaking, ear flicking and kicking of the hind legs in the hours after the procedure. (J35.158.w2)
• There was a longer period before calves resume ruminating following hot-iron disbudding without analgesia than in calves disbudded with analgesia provided, or sham-disbudded. Frequency of rumination was also decreased following disbudding without analgesia. (J35.158.w2)
• Female Friesian calves of three to four months old subjected to scoop dehorning without analgesia, showed higher incidence of tail shaking (P<0.05), ear flicking (not statistically significant) and lying behaviour (P<0.01) and decreased incidence of grazing and rumination (P<0.01) when watched at two hours after dehorning, compared to control calves in which the horn buds had been handled. (J10.47.w2)
• Calves of four to six weeks old subjected to hot iron dehorning without analgesia, showed a number of behavioural signs of pain both during and in an observation period of four hours after dehorning. Signs seen during dehorning included tail wagging, head moving, tripping, forcing ahead and rearing and all except forcing ahead were seen significantly more (P<0.01) than in calves given local anaesthetic prior to dehorning and were also more than following sham dehorning (pressure but no heat). In the period following dehorning, backwards locomotion was noted in the first hour (not seen in calves given local analgesia), calves totally avoided head pushing against other calves during the four hours of observation and also showed more head shaking (p<0.05 compared to those given local anaesthesia) in the first hour and continuing in the next three hours; feeding behaviour was also clearly reduced in the first two hours after dehorning (significant reduction p<0.05 compared to those given local anaesthetic) in the second hour). (J288.62.w1)
• Analysis of the behaviour of calves of about six weeks old in the eight hours following amputation dehorning with or without local anaesthetic, found that behaviour was significantly changed but that there were few differences in behaviours shown by calves which had or had not received local anaesthetic (5mL of 2% lidocaine around each cornual nerve) prior to dehorning. It was suggested that the behavioural modifications seen may have been due to bleeding and associated irritation rather than pain per se, or that irritation due to the bleeding "sufficient to override any additional behavioural changes stimulated by the pain of dehorning." It was also considered possible "that the behaviours monitored and methods used were not sufficient to identify subtle changes in calf behaviour." (P61.60.w1)
• In calves disbudded by application of a caustic agent (potassium hydroxide) at four weeks old, or by heat cauterisation at eight weeks old, behavioural and cortisol responses indicated pain which was considered to be "intense but brief", and was decreased by use of local anaesthesia; higher cortisol responses in the chemically disbudded calves suggested that this method was more painful than heat cautery. The intensity of immediate reactions during application of the dehorning procedure was similar with both methods. Local anaesthesia (4 mL of 2% lidocaine injected midway between the horn bud and the lateral canthus of the eye fifteen minutes before disbudding)  significantly (P<0.001) reduced the intensity of reactions during application of both methods of disbudding. It was noted that 60% of calves given local anaesthetic showed no discernable signs of pain during the disbudding procedure whereas the other 40% tried to escape the procedure, suggesting that anaesthesia was not complete in these animals. No differences were observed in the time spent standing versus lying during the 24 hours before or after disbudding, but frequencies of other behaviours such as self grooming, rubbing, social behaviours, lying down and then standing up, scratching and head shaking were significantly altered (P<0.001) following either method of disbudding, whether or not local anaesthetic had been given; there was a non-significant trend towards less grooming and rubbing and more head shaking in heat cauterised calves which had been given local anaesthesia compared to those which had not. The frequency of behaviours such as lying down-standing up was highest in the first two hours and decreased to return to normal frequencies within three to four hours. (J288.43.w1)

Heart rate:

• Calves subjected to disbudding by hot-iron showed an elevated heart rate for about 213 minutes after dehorning; this rise was eliminated by provision of local analgesia before the procedure. (J35.158.w2)

Catecholamines:

• Scoop dehorning of calves of 10 weeks of age produced a rise in plasma noradrenaline concentration, peaking at 30 minutes and significantly higher than that of control handles calves from 10 to 50 minutes after the procedure; levels were similar in calves given local anaesthesia (5 mL of 2% lidocaine into each cornual nerve 20 minutes before dehorning) to those seen in calves dehorned without local anaesthetic. Plasma adrenaline levels peaked at five minutes after the procedure and the peak was significantly higher in dehorned calves (with or without local anaesthetic) than in control handled calves. (J24.80.w2)

Reduction in liveweight gain:

• Brahman crossbred cattle subjected to dehorning at ages approximately four months to adult (average age 30 months) showed significantly reduced (P<0.05) bodyweight gains over the first two weeks following dehorning in 16 of 24 treatment groups (compared to controls left horned) and in 50% of groups over the first six weeks following dehorning, but no differences were noted by one year after dehorning. it was noted that wounds had healed by four weeks after dehorning in animals of up to yearling age, but that in adults healing of the frontal sinuses took at least six weeks. (J24.58.w1)

• Assessment of Pain in Ruminants

• Practical considerations in pain prevention include whether the method to be used:
  • Is safe for the person carrying out the procedure;
  • Can be carried out rapidly and efficiently;
  • Can be carried out under normal farm conditions, including in inclement weather;
  • Requires additional personnel;
  • Requires special training;
  • May potentially cause additional harm to the animal.
  (P61.53.w1)

Breeding for polled cattle:

The Farm Animal Welfare Council (FAWC) has recommended that "genetic selection for polled animals should be further investigated and breeding programmes initiated." Noting that this trait is found in some breeds such as Herefords but is rarely found in Holstein/Fresians, FAWC suggested that selective use of genetic engineering might allow transfer of the "polled" gene without adverse effect on other attributes of dairy cattle breeds. (D154) 

Age considerations: 

• It has been suggested that "for welfare reasons" dehorning should be carried out as early as possible. Healing of the frontal sinuses following dehorning takes longer in adults than in younger animals. (J24.58.w1)

Use of least painful methods:

• Disbudding by cautery is probably less painful than disbudding by other methods such as scoop disbudding. There is no evidence that any one method of dehorning (of older animals) is more or less painful than other methods. 
  • A study which compared scoop and cautery disbudding in calves of six weeks old considered that overall the study indicated that cautery disbudding caused less distress than scoop dehorning, although both methods of dehorning caused distress. The noxious input from cautery appeared to be of lesser magnitude and shorter duration than that seen with scoop dehorning. This may be due to the fact that cautery causes third degree burns which would destroy nociceptors at the application site, thus reducing perception of pain in this area. (J10.44.w2)
  • A study which compared standard (deep) scoop dehorning with shallow scoop dehorning of 15-week-old calves found that there was no significant difference in the cortisol response, and by inference in the pain caused, between the two methods. (J10.45.w2)
  • A study which compared four methods of amputation dehorning (scoop, saw, guillotine shears or embryotomy wire) found that there was no significant difference in the maximum cortisol response, and by inference in the pain caused, between the four methods. The only significant difference in cortisol responses was that with the guillotine, cortisol values at 2.0 and 2.5 hours were lower than with the other three methods. All four methods resulted in initial cortisol peaks similar to those found following injection of ACTH, i.e. maximum cortisol secretion.  (J24.76.w2)
  • The Farm Animal Welfare Council (FAWC) suggests that "the pain and stress which can be caused by chemical cauterisation means tha the method should not be used." (D154)
  • The Farm Animal Welfare Council (FAWC) has recommended that "Dehorning [as distinct from disbudding] must be carried out only by a veterinary surgeon and then only when deemed necessary. It should not be a routine procedure. (D154) 

Use of local analgesics:

• Use of local anaesthetics prior to disbudding or dehorning prevents pain sensation at the time of the disbudding or dehorning. However, behavioural evidence as well as plasma cortisol measurements indicate that pain is felt once the local anaesthetic wears off. Even if an additional dose of long-acting local anaesthetic is given while the first dose is still in effect, pain appears to develop after the period of action of the second local anaesthetic.
  • It has been suggested for many years that local anaesthesia prior to dehorning may prevent pain and the elevation in plasma cortisol seen when calves are dehorned. (J295.68.w1)
  • Sufficient time must be allowed to elapse after administration of local anaesthetics before disbudding or dehorning is initiated. (W550.Dec04.w2)
  • Local anaesthetic alone, whether short-acting (lidocaine) or long-acting (bupivacaine) is effective in alleviating pain in calves during dehorning and for its period of action thereafter (about two hours for lidocaine, four hours for bupivacaine). However a delayed cortisol response is seen after the period of action of the local anaesthetic so that the overall cortisol response may not be reduced. (J24.76.w3)
  • Injection of 5 mL 2% lidocaine with 1:100,000 adrenaline at a depth of 0.5-1.0 cm over the corneal nerve five minutes prior to electrical dehorning of Holstein heifer calves did not significantly reduce the cortisol rise seen following dehorning. Injection of local anaesthetic alone (i.e. without dehorning) was found to cause a significant rise in plasma cortisol levels. (J295.72.w1)
  • Injection of local anaesthetic (3 mL 2% lidocaine) 20 minutes prior to restraint as for dehorning, resulted in a small increase in plasma cortisol (about 9 nm/mL 15 minutes after treatment), similar to that seen from control calves restrained and handled around the horn buds. Local anaesthesia was successfully achieved as shown by pricking with a needle around the base of each horn. The local anaesthetic apparently abolished the initial pain of disbudding both in calves disbudded by cautery and in those disbudded by scoop dehorning, with fewer escape behaviours seen during either disbudding procedure when local anaesthesia was used, a significant reduction in initial cortisol responses to scoop dehorning and a marginal (not statistically significant) reduction in initial cortisol levels in calves disbudded by cautery, compared to those not given local anaesthesia. However, in those disbudded by scoop, cortisol levels rose significantly after a delay of about two hours; such a rise did not occur in calves disbudded by cautery. (J10.44.w2)
  • A study of acute cortisol response of five- to six-month-old Friesian calves, found that in calves treated with local anaesthetic 30 minutes prior to scoop dehorning, the cortisol response to dehorning, in the first three hours after dehorning, was practically abolished by prior administration of local anaesthetic. However, as indicated by needle-prick testing of the skin around the horns of control calves (given local anaesthetic but not dehorned), sensation began to return to the horn bud area at about 2.5-3.0 hours; cortisol levels in the dehorned calves rose after three hours to levels similar to those seen in calves not given local anaesthetic, and then declined in a similar manner to calves not given local anaesthetic. It was considered that the local anaesthetic was effective at minimising noxious input during the period for which it was active. (J24.76.w2)
  • A study of acute cortisol response of 5-6 month old Friesian calves found that local anaesthesia in combination with cautery appeared to be most effective in reducing pain as indicated by the cortisol response: calves given local anaesthetic 0.5 hours before scoop dehorning, with the wounds cauterised immediately after dehorning, showed a significant but small peak in plasma cortisol (27.0 nmol/l, at 0.25 hours); mean cortisol concentrations in these animals then fell rapidly, and remained at pretreatment values for most of the time from one to nine hours post dehorning, except for a small transient increase (P <0.05) at three hours. Cortisol values were similar to those seen in control calves given local anaesthesia and handling only, throughout the observation period. (J24.76.w2)
  • A study of acute cortisol response of 3-4 month-old female Friesian calves found that local anaesthesia with bupivacaine (6 mL of 0.25% bupivacaine hydrochloride injected around each corneal nerve, midway along the lateral edge of the frontal bone crest) resulted in local anaesthetic action (as indicated by needle-prick test of the skin adjacent to the horn buds) for approximately four hours and that injection of a second dose of bupivacaine at four hours extended the period of local anaesthesia to 7-8 hours. However, a delayed cortisol rise was seen following the period of action of the local anaesthetic. (J24.76.w3)
    • Following local anaesthesia with bupivacaine twenty minutes prior to amputation, the initial plasma cortisol rise in response to dehorning was abolished and the mean cortisol concentration in the first four hours after dehorning was not significantly different from that of those given local anaesthesia but not dehorned, however, a "significant and protracted" increase in mean cortisol concentration was seen 4.33 hours after dehorning and levels did not return to those seen in calves given local anaesthetic only (but not dehorned) until 8.33 hours nor to those of control (handled only) calves until 9.33 hours. (J24.76.w3)
    • Following local anaesthesia with bupivacaine immediately prior to amputation, the initial plasma cortisol rise in response to dehorning was abolished and the mean cortisol concentration in the first four hours after dehorning was not significantly different from that of those given local anaesthesia but not dehorned although levels were different from those of control "handled only" calves at 0.66 hours. A significant and protracted increase in mean cortisol concentration was seen starting at 4.83 hours after dehorning and levels did not return to those seen in calves given local anaesthetic only (but not dehorned) or control (handled only) calves until 8.33 hours. It was noted that at 7.33 hours the mean plasma cortisol concentration was significantly greater than that seen in calves scoop dehorned without local anaesthetic. (J24.76.w3)
    • Following local anaesthesia with bupivacaine immediately prior to amputation, and again at four hours after dehorning, the initial plasma cortisol rise in response to dehorning was abolished and the mean cortisol concentration in the first four hours after dehorning was not significantly different from that of those given local anaesthesia but not dehorned, or from that of control "handled only" calves, except at 3.83, 8.33 and 9.33 hours. However, mean cortisol concentrations at 8.33 and 9.33 hours were significantly higher than those seen in calves scoop dehorned without local anaesthetic. (J24.76.w3)
    • The study found that a single injection of bupivacaine (long-acting local anaesthetic) twenty minutes prior to dehorning effectively alleviated the pain-induced distress caused by scoop dehorning in calves, and abolished the immediate behavioural responses to dehorning, but it did not significantly reduce the overall cortisol response, because a delayed cortisol increase occurred as the local anaesthetic wore off. Although injection immediately prior to dehorning had a similar effect on plasma cortisol, it was not certain whether the cortisol response was sufficiently rapid to reflect pain in the first few minutes after dehorning, and immediate behavioural responses to dehorning were not abolished, therefore it was still recommended that local anaesthesia be given a while before dehorning to ensure that it has time to act. (J24.76.w3)
    • The delayed cortisol response seen in dehorned calves as the local anaesthetic wore off may be due to habituation to the noxious sensory input in calves not given analgesia, or a failure to inactivate an early stress-induced endogenous analgesia, or due to local anaesthesia indirectly enhancing inflammatory pain in dehorned calves, possibly because the cortisol which would normally be released in response to the noxious input is a potent anti-inflammatory substance, therefore absence of cortisol could result in unimpeded progress of inflammatory reactions in the wounds from horn amputation.  (J24.76.w3)
  • Local anaesthetic (lidocaine 2%) given prior to scoop dehorning, plus bupivacaine (6 mL of 0.25% bupivacaine hydrochloride) given at two hours after dehorning, the combination being designed to provide local analgesia for five hours, reduced plasma cortisol levels to control levels for the first five hours after dehorning. However, cortisol levels then increased and remained above control levels over the next five hours; after this time they were not different from control levels over the remainder of the period to 24 hours after dehorning. (J21.73.w2)
  • Local anaesthetic (cornual block with 2% lidocaine), given prior to hot-iron disbudding of four- to six-week old calves,  significantly (P<0.05) reduced the frequency and intensity of head jerking during disbudding and the frequency and intensity of leg movements during disbudding (P<0.01). It also prevented the rise in heart rate, increase in plasma cortisol concentration, delayed return to rumination and decrease in frequency of rumination seen after disbudding without use of analgesia. (J35.158.w2)
  • Female Friesian calves of 3-4 months old given local anaesthesia (cornual block with 6 mL of 2% lidocaine around each corneal nerve 20 minutes prior to dehorning) showed behavioural signs in the hours and days after dehorning which were intermediate between those of control calves (horn buds handled) and those subjected to dehorning without analgesia "but not always statistically different from either". Some behaviours (lying and ear flicking at four and six hours) were significantly (p<0.05) different from those seen in control calves not dehorned. Overall it was noted that the behaviour was similar to that of calves dehorned without any pain relief. (J10.47.w2)
  • Calves of four to six weeks old provided with local anaesthesia (cornual block with lidocaine plus local deposition of lidocaine caudal and medial to the horn bud) before hot dehorning showed marked and generally significant behavioural signs of pain both during and in an observation period of four hours after dehorning compared to calves not given analgesia. subjected to hot iron dehorning without analgesia, and also showed significant differences in ACTH and cortisol responses. (J288.62.w1). 
    • Behavioural signs seen during dehorning included tail wagging, head moving, tripping, forcing ahead and rearing; all except forcing ahead were seen significantly less (P<0.01) than in calves given not given local anaesthetic. (J288.62.w1)
    • In the period following dehorning, no backwards locomotion was noted in the first hour (this was seen in calves not given local analgesia), and calves did not (unlike control calves not given local analgesia) avoid head pushing against other calves during the four hours of observation. Analgesic-treated calves also showed less head shaking (p<0.05 compared to control calves not given local analgesia) in the first hour and continuing in the next three hours. Feeding behaviour was not reduced in calves given local anaesthetic, although it was in control calves not given local analgesia for the first two hours after dehorning (significant reduction in the second hour  p<0.05 compared to those given local anaesthetic). (J288.62.w1)
    • Calves not given analgesia showed significant (P<0.05) rises in plasma ACTH and cortisol compared to those provided with local anaesthetic prior to dehorning. Peak cortisol concentrations occurred at 20 minutes after dehorning and levels were significantly elevated from five to 90 minutes after dehorning. It was also recorded that administration of the local anaesthetic did not result in rises in plasma ACTH or cortisol, whereas small (compared to the rises seen on dehorning) rises did occur when similar volumes of saline were injected. (J288.62.w1)

Use of NSAIDs

• The Farm Animal Welfare Council (FAWC) suggests that if dehorning has to be carried out then, in addition to local anaesthesia, analgesics should be given. (D154)
• Administration of ketoprofen to calves has been shown to reduce pain associated with dehorning although effects have not always been seen when the NSAID was administered but local anaesthetic was not used:
  • Intravenous ketoprofen alone (without concurrent administration of local anaesthetic) 20 minutes prior to scoop dehorning, only slightly reduced the initial cortisol response peak but completely abolished the plateau phase of the cortisol response, with plasma cortisol concentrations similar to those of control calves from 1.83 hours after dehorning to 9.5 hours when the trial ended. (J21.64.w1)
  • Intravenous administration of the NSAID ketoprofen 20 minutes prior to scoop dehorning, together with administration of local anaesthetic (lidocaine or bupivacaine) to the corneal nerves 20 minutes prior to dehorning, effectively eliminated the cortisol response to dehorning and by inference, the pain and distress of dehorning. (J21.64.w1)
  • Following scoop dehorning under local anaesthetic (2% lidocaine 15 minutes prior to dehorning plus bupivacaine two hours after dehorning), ketoprofen (3-3.75 mg/kg intravenously, given 15 minutes before dehorning) significantly reduced the delayed plasma cortisol response seen from five hours to 10 hours after dehorning in calves treated with the local anaesthetics alone. The maximum plasma cortisol rise above control levels was 65 (+/- 17) nmol/L in calves given ketoprofen, compared with 128 (+/- 32) nmol/L in calves not given the ketoprofen. (J21.73.w2)
  • In three-week-old calves the cortisol response to scoop dehorning were minimised by the administration of ketoprofen (3 mg/kg intravenously) 15 minutes before dehorning plus administration of local anaesthesia (2% lidocaine injected around the cornual nerve 15 minutes prior to dehorning); plasma cortisol concentrations in calves given these treatments did not differ significantly from those of control (non-dehorned) calves for at least eight hours after dehorning. (J10.51.w1)
  • When ketoprofen (3 mg/kg liquid ketoprofen (10% Anafen, Rhone Merieux Inc., USA) was given orally in milk at two hours before, two hours after and seven hours after dehorning) in addition to xylazine sedation (0.2 mg/kg intravenously) and local anaesthetic (2% lidocaine around the cornual nerve and the horn base), pain related behaviours, which otherwise developed and peaked six hours after dehorning by cautery, were greatly reduced. The incidence of head-shaking was significantly reduced for 12 hours and that of ear flicking for 24 hours after dehorning. Incidence of head rubbing was low but was reduced by ketoprofen, and ketoprofen-treated calves also tended to gain more weight in the 24 hours after dehorning (1.2 +/- 0.4kg, versus 0.2 +/-0.4 kg for those not given ketoprofen). (J295.83.w2)
  • Administration of ketoprofen (3 mL 10% Ketofen) to female Friesian calves of 3-4 months old 20 minutes before they were subjected to scoop dehorning appeared to only partially reduce pain, with significantly depressed grazing and ruminating (P<0.05) and significantly elevated tail shaking (P<0.05) at two hours, compared to control calves not dehorned or those provided with ketoprofen plus local analgesia. Overall it was noted that the behaviour was similar to that of calves dehorned without any pain relief. (J10.47.w2)
• Administration of phenylbutazone did not effectively relieve the pain of dehorning:
  • Following scoop dehorning under local anaesthetic (2% lidocaine 15 minutes prior to dehorning plus bupivacaine two hours after dehorning), phenylbutazone (4.0-5.3 mg/kg intravenously, given 15 minutes before dehorning) did not affect the delayed plasma cortisol response seen from five hours to 10 hours after dehorning in calves treated with the local anaesthetics alone. (J21.73.w2)

Use of alpha 2 agonists:

• Administration of the sedative xylazine has some pain relieving effect on calves subjected to dehorning.
  • Xylazine(0.1 mg/kg) given intravenously 20 minutes prior to scoop dehorning significantly reduced the peak cortisol response seen after dehorning but did not eliminate it. When xylazine was given in combination with local anaesthesia the peak cortisol response was virtually eliminated, however whether given with or without local anaesthesia, cortisol responses increased significantly above control levels at about t 3 hours after dehorning and remained elevated for at least the next five hours. (J10.51.w1)
  • Administration of xylazine (0.2 mg/kg intravenously) to calves of four to eight weeks old eliminated responses to injection of local anaesthetic agent into the cornual nerve area and as a ring block around the horn base. (J295.83.w2)
  • Administration of xylazine 0.2 mg/kg and butorphanol 0.1 mg/kg by intramuscular injection twenty minutes prior to dehorning only slightly reduced the number (not statistically significant) and intensity (P<0.05) of head jerks during dehorning. Deep sedation of the calves prevented analysis of behavioural responses in the hours following dehorning. Since the sedatives are known to reduce heart rate (and this effect was seen) it was not possible to use heart rate as an indicator of analgesic effect. (J35.158.w2)

Use of cautery:

• It has been observed that dehorning by cautery produces a cortisol response of lesser magnitude and shorter duration than the response caused by amputation dehorning (scoop dehorning). It has been suggested that this difference may be due to the fact that cautery causes third degree burns which would destroy nociceptors at the application site, thus reducing perception of pain in this area. (J10.44.w2) Further to this finding it has been suggested that cauterising the wound caused by amputation dehorning may reduce pain and cortisol response. (J24.76.w1)
  • A study of acute cortisol response of 5-6 month old Friesian calves after scoop dehorning followed by cautery of the wound, found that cortisol values were numerically lower than those seen with scoop dehorning alone, with the difference being statistically significant at 0.5, 2.5 and 3 hours after dehorning, but not at other times. It was considered that cautery had a small effect in reducing pain caused by scoop dehorning. (J24.76.w2)
• Dehorning by cautery has been shown to produce both physiological (raised plasma cortisol) and behavioural signs indicating pain. (J288.62.w1)

Combined techniques:

• Combination of local anaesthesia and administration of an effective NSAID has been shown to eliminate behavioural signs of pain and the acute cortisol response to dehorning and therefore, by inference, to eliminate the pain associated with dehorning:
  • In three-week-old calves, the cortisol response to scoop dehorning were minimised by the administration of ketoprofen (3 mg/kg intravenously) 15 minutes before dehorning plus administration of local anaesthesia (2% lidocaine injected around the cornual nerve 15 minutes prior to dehorning); plasma cortisol concentrations in calves given these treatments did not differ significantly from those of control (non-dehorned) calves for at least eight hours after dehorning. (J10.51.w1)
  • Following scoop dehorning under local anaesthetic (2% lidocaine 15 minutes prior to dehorning plus bupivacaine two hours after dehorning), ketoprofen (3-3.75 mg/kg intravenously, given 15 minutes before dehorning) significantly reduced the delayed plasma cortisol response seen from five hours to 10 hours after dehorning in calves treated with the local anaesthetics alone. The maximum plasma cortisol rise above control levels was 65 (+/- 17) nmol/L in calves given ketoprofen, compared with 128 (+/- 32) nmol/L in calves not given the ketoprofen. (J21.73.w2)
  • Intravenous administration of the NSAID ketoprofen 20 minutes prior to scoop dehorning, together with administration of local anaesthetic (lidocaine or bupivacaine) to the corneal nerves 20 minutes prior to dehorning, effectively eliminated the cortisol response to dehorning and by inference, the pain and distress of dehorning. (J21.64.w1)
  • Combined local anaesthesia and systemic analgesia with ketoprofen was effective in alleviating pain associated with scoop dehorning in calves. Administration of ketoprofen (3 mL 10% Ketofen) plus local anaesthetic (cornual block with 6 mL of 2% lidocaine around each corneal nerve 20 minutes prior to dehorning) to female Friesian calves of three- to four-months-old, 20 minutes before they were subjected to scoop dehorning, markedly reduced the differences in behaviours (lying, grazing or ruminating, tail shaking incidence and ear flicking incidence) seen following scoop dehorning, compared with control calves. At two hours after dehorning, the behaviour of calves given both types of analgesic were "very similar to those of calves which had not been dehorned." The combined treatment had a significantly greater effect in reducing pain related behaviours than either local anaesthesia or ketoprofen alone, indicating superior analgesia resulting from the combined treatment. (J10.47.w2)
• Combination of alpha-2 agonist sedation, local anaesthesia and administration of an effective NSAID has been shown to eliminate both cortisol and behavioural responses to dehorning. Administration of the sedative (xylazine) eliminated responses to injection of local anaesthetic:
  • Use of xylazine sedation, local anaesthesia and administration of an effective NSAID (e.g. ketoprofen) has been recommended to minimise responses to pain both during and following dehorning of calves. (J295.83.w2)
    • When ketoprofen (3 mg/kg liquid ketoprofen (10% Anafen, Rhone Merieux Inc., USA) was given orally in milk at two hours before, two hours after and seven hours after dehorning) in addition to xylazine sedation (0.2 mg/kg intravenously) and local anaesthetic (2% lidocaine around the cornual nerve and the horn base), pain related behaviours, which otherwise developed and peaked six hours after dehorning by cautery, were greatly reduced. The incidence of head-shaking was significantly reduced for 12 hours and that of ear flicking for 24 hours after dehorning. Incidence of head rubbing was low but was reduced by ketoprofen and ketoprofen-treated calves also tended to gain more weight in the 24 hours after dehorning (1.2 +/- 0.4kg, versus 0.2 +/-0.4 kg for those not given ketoprofen). (J295.83.w2)
    • Administration of xylazine (0.2 mg/kg intravenously) to calves of four to eight weeks old eliminated responses to injection of local anaesthetic agent into the cornual nerve area and as a ring block around the horn base. 
• Combination of local anaesthesia and cautery (for scoop dehorning) substantially reduced or effectively eliminated cortisol responses to scoop dehorning, but may not eliminate behavioural responses:
  • A study of acute cortisol response of 5-6 month old Friesian calves found that cautery in combination with local anaesthesia appeared to be effective in reducing pain as indicated by the cortisol response. Calves treated with local anaesthetic 30 minutes prior to scoop dehorning AND with the wounds cauterised showed a significant but small peak in plasma cortisol (27.0 nmol/l, at 0.25 hours); mean cortisol concentrations in these animals then fell rapidly, and remained at pretreatment values for most of the time from one to nine hours post dehorning, except for a small transient increase (P <0.05) at three hours. Cortisol values were similar to those seen in control calves given local anaesthesia and handling only, throughout the observation period.  (J24.76.w2)
  • A study found that in Friesian calves of three to four months old, local anaesthetic prior to scoop dehorning and re-administered to provide local anaesthetic action for five hours, and cautery of the scoop dehorning wounds, substantially reduced the cortisol response in at least the first 24 hours after dehorning. (J24.80.w1)
  • Local anaesthetic (lidocaine 2%) given prior to scoop dehorning, plus bupivacaine (6 mL of 0.25% bupivacaine hydrochloride) given at two hours after dehorning, the combination being designed to provide local analgesia for five hours, reduced plasma cortisol levels to control levels for the first five hours after dehorning. In calves treated in this manner, with an additional treatment in which scoop dehorning was followed by cautery, the delayed cortisol response (seen after five hours in calves in which the wounds were not cauterised) was abolished they were not different from control levels over the remainder of the period to 24 hours after dehorning. (J21.73.w2)
  • However a study of calves disbudded by an electrically-heated hot-iron disbudder found that pain related behaviours such as head shaking and ear flicking occurred in calves from about three hours after dehorning, despite administration of both xylazine and local anaesthetic (lidocaine) prior to the disbudding. These behaviours were significantly reduced by administration of a NSAID (ketoprofen), indicating that they were indeed pain related. (J295.83.w2)
• Combination of local anaesthesia and sedation:
  • Administration of xylazine 0.2 mg/kg and butorphanol 0.1 mg/kg by intramuscular injection twenty minutes prior to dehorning as well as injection of local anaesthetic, did reduce head jerk frequency and intensity (differences were not statistically significant) and significantly (P<0.05) reduced leg movement frequency and intensity during hot-iron disbudding. This treatment also reduced the plasma cortisol rise seen with hot-iron disbudding (P<0.01). (J35.158.w2)

• Cornual Block in Cattle
• Prevention of Pain Associated with Routine and Clinical Surgical Procedures in Ruminants
• Groups of Analgesic Drugs
• Routes of Drug Administration in Ruminants
• Understanding Pharmacokinetics for Pain Management in Ruminants

• Attitudes towards pain in animals;
• Tradition;
• Failure to recognise pain;
• Failure to recognise the importance of the adverse effects of pain;
• Concern about removing possible protective effects of pain [this concern is generally excessive];
• Concern that providing pain relief may itself stress the animal and have a negative impact on it;
• Concern that treating pain may interfere with diagnosis;
• Lack of information about analgesics;
• Concern about toxicity and side-effects of analgesics;
• Concerns about the safety and legislative controls associated with some analgesics such as opiates;
• Economic and practical considerations.

Attitudes towards pain in animals - beliefs regarding neonates and young animals not feeling pain:

• "It is a widespread opinion that in neonate and young animals the nociceptive system has not yet developed completely. From a biological point of view, there are no reasons for such a speculation, in particular in precocial animals such as cattle." (J288.62.w1) 

• Reasons for Failure to Provide Pain Relief