Effect of local anaesthetic combined with wound cauterisation on the cortisol response to dehorning in calves

The Effect of Topical Anaesthesia on the Cortisol Responses of Calves Undergoing Dehorning

Simple Summary

Dehorning in cattle involves the manual removal of horns which causes acute pain. Although the long-term solution to removing horns is to breed polled cattle, limitations include the complex inheritance for polled Brahman cattle, and negative interactions with productivity in dairy cattle. Best practice pain relief in the form of a local nerve block, a sedative and a non-steroidal anti-inflammatory drug prior to the procedure usually requires a veterinarian and may be impractical for some cattle production systems. Improved livestock welfare requires a practical and cost-effective pain relief strategy for dehorning that can be readily adopted commercially. We evaluated a modified topical local anaesthetic wound formulation that can be applied by farmers immediately following dehorning. While previous studies have demonstrated a reduction in wound sensitivity, there was no effect on cortisol concentrations. It is likely that the cortisol response reflects a combination of factors including the stress of handling, the initial pain of the dehorning procedure and haemorrhage.

Abstract

Dehorning causes pain and distress to cattle, and there is a need to provide effective and practical analgesia to improve animal welfare. We conducted an experiment to determine the effect of a modified post-operative topical wound management formulation containing two local anaesthetics (TA) on the plasma cortisol concentration (PCC) of scoop-dehorned calves. Two months old Holstein-Friesian heifer calves (n = 30) were randomly allocated to sham dehorning control (CON), scoop dehorning (D), or scoop dehorning with immediate post-operative application of the TA (DTA). Blood samples were obtained via jugular venepuncture prior to sham or actual dehorning, and 40 min, 1.5, 4 and 24 h later. PCC changed significantly over time (p < 0.01). There was a trend for lower PCC in DTA calves compared to D calves (p = 0.09), with the PCC area under the curve lowest in CON calves as compared to D and DTA calves (p = 0.02). Cortisol concentrations were similar between D and DTA at all time points. The TA did not reduce cortisol concentrations up to 24 h following treatment and the cortisol response likely reflects the pain induced by the procedure, the effect of handling and restraint, and haemorrhaging which limited adherence of the TA actives. A multimodal analgesic approach, as assessed through multiple pain indicators, should be the focus of future work.

The effects of firocoxib on cautery disbudding pain and stress responses in preweaned dairy calves

Perioperative analgesic effects of oral firocoxib following cautery disbudding were investigated in preweaned calves. Twenty Holstein calves approximately 4 to 6wk old received a single oral dose of firocoxib, a nonsteroidal antiinflammatory, at 0.5mg/kg (n=10) or placebo (n=10) in a randomized controlled clinical trial. Responses, including ocular temperature determined by infrared thermography, pressure algometry measuring mechanical nociception threshold, and heart rate, were evaluated at 2, 4, 7, 8, and 24h after cornual nerve block and cautery disbudding. Blood samples were collected over 96h and analyzed for plasma cortisol and substance P concentrations by RIA. Additionally, ex vivo prostaglandin E2 concentrations were determined over a 72-h study period using an enzyme immunoassay. Data were analyzed using a linear mixed effects model with repeated measures. An inhibition of ex vivo prostaglandin E2 synthesis was observed from 12 to 48h following disbudding in calves treated with firocoxib. Cautery disbudding was associated with an increased nociception for the duration of sampling (24h). During the initial 24-h period following disbudding, no difference in response between treatment groups was noted. Following 24h, mean cortisol concentrations diverged between the 2 study groups with placebo-treated calves having increased cortisol concentrations at approximately 48h after disbudding. Furthermore, the overall integrated cortisol response as calculated as area under the effect curve tended to be reduced in firocoxib-treated calves. The prolonged effects of cautery dehorning require further investigation. Moreover, the effect of firocoxib on cortisol reduction observed in this study requires additional exploration.

The pharmacokinetics and effects of meloxicam, gabapentin, and flunixin in postweaning dairy calves following dehorning with local anesthesia

Approved analgesic compounds in cattle are not currently available in the United States due to the lack of validated pain assessment methods and marker residue depletion studies. In this study, we compared the pharmacokinetic parameters and effect of preemptive analgesics administered to calves subjected to dehorning with local anesthesia. Holstein steers were randomly assigned to receive one of the following treatments per os (PO) or intravenously (IV) (n = 8/group): meloxicam (1 mg/kg PO), gabapentin (15 mg/kg PO), meloxicam (1 mg/kg), and gabapentin (15 mg/kg) PO, flunixin (2.2 mg/kg IV), or a placebo. Plasma drug, haptoglobin, substance P (SP) concentrations, serum cortisol concentrations, ocular thermography, mechanical nociceptive threshold (MNT), and average daily gain (ADG) were evaluated. Data were analyzed using mixed-effects models and noncompartmental pharmacokinetic analysis. Meloxicam, gabapentin, and meloxicam with gabapentin at the present doses did not reduce cortisol concentrations. Analgesic-treated calves had significantly lower plasma SP concentrations and improved ADG compared with controls. Flunixin calves had reduced circulating cortisol compared with controls. Meloxicam-treated calves showed an increase in MNT at two horn bud sites compared with the other treatments. Analgesics improved ADG and reduced biomarkers of pain, but effects differed by compound and route of administration.

Validation of the acute electroencephalographic responses of calves to noxious stimulus with scoop dehorning

AIM

To validate use of the electroencephalogram (EEG) and a minimal anaesthesia model for assessment of noxious sensory input caused by scoop dehorning of calves.

METHODS

Twenty Friesian heifers weighing 125-178 kg were maintained under light general anaesthesia using halothane and an established protocol (minimal anaesthesia model). They were then dehorned using a scoop dehorner either with (DH+LA) or without (DH) a lignocaine ring block, and changes in the EEG and electrocardiogram (ECG) recorded. Median frequency (F50), 95% spectral edge frequency (F95) and total power (Ptot) were derived from the EEG data.

RESULTS

There were significant increases in the F50 (p<0.01) and F95 (p<0.01), and a decrease in Ptot (p<0.01) following dehorning in the DH group, but there were no changes in the DH+LA group. Transient bradycardia in the first 75 sec following dehorning was recorded in the DH group compared with both pre-treatment values in the same group and with the DH+LA group (p<0.001). Tachycardia was evident by 15 min after dehorning in the DH but not the DH+LA group.

CONCLUSIONS

The results validate use of the EEG and a minimal anaesthesia model for assessment of noxious sensory inputs in cattle.

The effect of different combinations of lignocaine, ketoprofen, xylazine and tolazoline on the acute cortisol response to dehorning in calves

AIMS

The aims of this study were (a) to evaluate the effect of xylazine and tolazoline, with and without lignocaine, on the cortisol response of calves following amputation dehorning and (b) to assess the effect of a non-steroidal anti-inflammatory drug (ketoprofen) and local anaesthesia on the cortisol response of calves to amputation dehorning.

METHODS

Plasma cortisol concentrations were measured in 100 dehorned or non-dehorned 3-month-old calves over an 8-h period following five different sedative/analgesic or control treatments. Sedative/analgesic treatments were: control (no anaesthesia); local anaesthesia and ketoprofen; local anaesthesia and xylazine; local anaesthesia, xylazine and tolazoline; and xylazine only. Within each sedative/analgesic treatment group, half the calves (n=10 per group) were amputation dehorned and half were not dehorned.

RESULTS

The change in plasma cortisol concentrations in calves dehorned after being given ketoprofen and local anaesthesia did not differ significantly from that of non-dehorned control calves for at least 8 h. In contrast, the cortisol response of dehorned calves not given analgesic drugs peaked 30 min after dehorning and lasted >4 h. Xylazine injected before dehorning significantly reduced but did not eliminate the peak of the cortisol response. When both xylazine and local anaesthesia were administered before dehorning the peak in the cortisol response was virtually eliminated. In the dehorned calves that received xylazine with or without local anaesthesia, cortisol concentration increased significantly 3 h after dehorning and did not return to baseline until at least 5 h later. When tolazoline was administered shortly after xylazine, it caused a marked cortisol response, higher than the response to any other treatment.

CONCLUSIONS

Combining ketoprofen and local anaesthesia minimised the cortisol response, and by inference the pain-induced distress, following amputation dehorning in calves. Xylazine reduced the initial cortisol response to dehorning but not as much as when local anaesthesia was also given. The increase in cortisol concentration from 3-8 h after dehorning in calves given xylazine alone or in combination with local anaesthesia suggests that calves experienced pain-induced distress during this time and that xylazine had no long-term analgesic effect. Tolazoline, used to reverse the sedative effects of xylazine, caused a marked cortisol response in calves via a mechanism which remains unclear.

Welfare of farmed deer in New Zealand. 2. Velvet antler removal

This paper reviews published data on welfare aspects of stag restraint and velvet antler removal, and prevention of antler growth. Several studies of physical restraint and handling demonstrate behavioural and physiological changes both during and after velvet antler removal. Interpretations vary as to whether the act of velvet antler removal imposes a welfare cost additional to that of handling and restraint alone. Chemical restraint presents immediate and delayed welfare risks to the animal. Surgical removal of velvet antler can be achieved without acute pain using a high dose rate of local anaesthetic applied as a ring block, rather than as regional nerve blocks, provided the wait time is adequate. However, there is evidence of less than optimum reproducibility. Lignocaine hydrochloride produces rapid analgesia of short duration, whilst bupivacaine has a delayed onset, but longer duration of analgesia. Mepivacaine has a rapid onset and intermediate duration of analgesia. Mixtures of long and short-acting local anaesthetics provide rapid onset and long duration of analgesia. Present methods for electronic analgesia are aversive and not sufficiently effective. The efficacy and possible aversiveness of compression techniques for inducing analgesia of antlers are currently under evaluation. Post-operative pain and the need for its control have been insufficiently researched. Post-operative sequelae are uncommon, but include clostridial infection. Antler growth in most stags can be prevented by rubber-band application to the growing pedicle, although behavioural changes after ring application suggest this practice may be painful. The procedures used for velvet antler removal, and whether practices are acceptable on the balance of welfare costs and benefits, should be reviewed on an ongoing basis as science, using an increasing range of techniques and measures, provides more data about the welfare implications of this practice.

Behavioural responses of calves to amputation dehorning with and without local anaesthesia

OBJECTIVE

To assess the pain elicited by amputation dehorning and evaluate the effect of local anaesthesia by using changes in calf behaviour.

METHODS

The behaviour of 6-month-old Friesian calves (n = 60), subjected to control handling, dehorned or dehorned after local anaesthesia treatment, was monitored in this study. The proportion of calves displaying particular behaviours was recorded using instantaneous scan sampling during the first 10 h and between 26 and 29 h after treatment.

RESULTS

The three behaviours of tail flicking, head shaking and ear flicking displayed similar features with time according to treatment and appeared to occur in an inverse relation to rumination. Dehorned calves were highly restless for the first 6 h after treatment. A significantly greater proportion of them displayed tail flicking, head shaking and ear flicking than the control calves, which, by contrast, stood still and ruminated (P < 0.05). The behaviour of calves given local anaesthetic prior to dehorning was similar to that of the control calves for the first 2 h. Thereafter the proportion of calves displaying tail flicking, head shaking and ear flicking increased, rumination decreased, and the behaviour was similar to that of the dehorned calves.

CONCLUSIONS

These results suggest that dehorning is a painful experience that lasts about 6 h and that local anaesthetic alleviates that pain during its period of action. It is recommended that local anaesthetic be administered when conducting amputation dehorning.

Dehorning and disbudding distress and its alleviation in calves

Dehorning and disbudding are routine painful procedures carried out on cattle to facilitate management. The pain caused by these procedures and its alleviation may be evaluated by monitoring behaviour and physiological responses, and by measuring their effects on weight gain. The cortisol response to cautery disbudding is significantly smaller than that to amputation dehorning which infers that the latter is more painful. Amputation dehorning stimulates a defined cortisol response with a rapid rise to a peak value within 30 min followed by a decline to a plateau which then declines to pre-treatment values after about 8 h. A cornual nerve blockade using lignocaine virtually eliminates the escape behaviour seen during disbudding and dehorning and reduces the plasma cortisol response to dehorning for about 2 h. Thereafter there is an increase in the plasma cortisol concentration, a delayed response, which lasts for about 6 h. A cornual nerve blockade, using lignocaine combined with cauterizing the wound caused by amputation dehorning, virtually eliminates the cortisol response as does combining a lignocaine blockade with the non-steroidal anti-inflammatory drug (NSAID) ketoprofen. When xylazine is combined with a cornual nerve blockade using lignocaine before dehorning, the cortisol response is virtually eliminated for about 3 h. When this regime is used before cautery disbudding and includes a NSAID given before and after disbudding the behaviour of calves so treated suggests that pain may be alleviated for 24 h. Cautery disbudding is preferable to amputation dehorning, but for optimal pain relief xylazine sedation, local anaesthesia and a NSAID should be used with both procedures.

Routine surgical procedures in dairy cattle under field conditions: Abomasal surgery, dehorning, and tail docking

This article discusses the different methods used for the correction of left displaced abomasum. The advantages, disadvantages, and success rates of each technique are reviewed. The most common complications are described, and the economics of repeat surgery after a failed left displaced abomasum repair are examined. This article also addresses the need for anesthesia when dehorning and tail docking dairy cattle. The justifications for routine use of these two procedures are discussed, mainly from an animal welfare standpoint.

Cortisol responses to dehorning of calves given a 5-h local anaesthetic regimen plus phenylbutazone, ketoprofen, or adrenocorticotropic hormone prior to dehorning

The purpose of this work was to assess whether the non-steroidal anti-inflammatory drugs (NSAIDs) phenylbutazone and ketoprofen, and an adrenocorticotropic hormone (ACTH) induced cortisol surge, reduce the cortisol response which occurs when the local anaesthetic wears off in calves following dehorning. There were four control groups and one dehorned group; also four groups were given local anaesthetic lasting 5h and were dehorned without or with phenylbutazone, ketoprofen or an ACTH injection, one group was injected with ACTH twice (at 0 and 6h) and another received ACTH and 6h later was dehorned. Blood samples were taken before and after dehorning and plasma cortisol concentrations were determined by radio-immunoassay. Dehorning increased the mean plasma cortisol concentrations [max 137 (11)nmoll(-1)] above control values [38 (5)nmoll(-1)] for about 7h, whereas local anaesthesia maintained concentrations at control values until about 5h after dehorning, and then they became elevated until about 10h. The maximum rise in mean concentration which occurred when the local anaesthetic wore off [128 (32)nmoll(-1)] was not affected when phenylbutazone was given before dehorning [141 (28)nmoll(-1)], but was reduced significantly when ketoprofen [65 (17)nmoll(-1)] or ACTH [61 (19)nmoll(-1)] were injected before or at the time of dehorning, respectively. Marked cortisol responses to ACTH injected at 0 and 6h were similar, but the early part of the cortisol response to dehorning 6h after an ACTH injection was reduced. It is suggested that the delayed cortisol response, which began 5h after dehorning, arose both from ketoprofen-sensitive and cortisol-sensitive sensory input as well as from other factors. Phenylbutazone did not affect the sensory input from the amputation wounds in the present calves.