Early pain experiences in dairy calves on pain sensitivity later in life

In humans, early painful experiences can increase pain sensitivity later in life, but little is known regarding this phenomenon in cattle. This study assessed if a painful event early in life affects later pain sensitivity in 40-d-old calves. Holstein calves (n = 26) were randomly assigned to control or treatment conditions, blocked within sex and birth weight. At 9.5 ± 1.8 d old, treatment calves had 1 horn bud disbudded using caustic paste, whereas control calves had 1 horn sham disbudded; in both cases, multimodal pain control was provided. All calves had the contralateral horn bud disbudded using a hot iron 4 wk later, again with multimodal pain control. Mechanical nociceptive responses were assessed weekly using an algometer applied adjacent to both horn buds and on the rump, beginning 3 d before the first disbudding and ending 30 d after the second disbudding. Following the second disbudding, both groups of calves showed evidence of increased sensitivity (i.e., algometer pressure declined 3.69 ± 0.60 √N to 2.13 ± 0.70 √N) on the contralateral bud, but there was no difference between the control group and the treatment groups. An interaction between treatment and time, likely driven by treatment differences, was found on the rump when tested 5 h after the second disbudding event. These responses are not consistent with the hypothesis that an early pain experience results in increased sensitivity to later painful experiences.

Comparative Study of the Healing Process of Disbudding Wounds in Calves Using Bepanthene® or an Antibiotic Spray

The process of disbudding female calves is a common procedure in many dairy farms, avoiding injuries caused by horns and reducing feed bunk space requirements. The most common method for disbudding calves is by the use of a cautery iron, responsible for destroying the horn-generating tissue. After the procedure, wounds may be treated with an antibiotic-based spray. Nowadays, antimicrobial resistance is a worldwide concern in both human and veterinary medicine, highlighting the need to invest in the monitoring of antimicrobial use and in the development of alternative treatments in favour of One Health. The goal of this study is to promote a reduction in the use of antibiotics in farm animals by investigating an alternative treatment for disbudding wounds. Bepanthene® (dexpanthenol, a derivative of pantothenic acid, a component of the B vitamin complex) is a plausible option, since it is widely used in human medicine for the treatment of skin irritations and burns. The comparison of the healing process of disbudding wounds treated with Bepanthene® or a chlortetracycline-based spray was achieved through the presentation of a randomly-ordered sequence of images of the lesions to a panel of convenience-selected and blinded-to-treatment evaluators, composed of seven veterinarian practitioners, five veterinary medicine students, and five human medical field nurses. In order to classify the lesions, the panel applied an adapted format of a validated healing scale (Bates-Jensen Wound Assessment Tool), incorporating seven parameters of evaluation, culminating in the values used for statistical analyses. In the practitioners' evaluation, a statistically significant effect for the factors of time and treatment in favour of Bepanthene® was found for the parameters "Edges", "Necrotic Tissue Type", and "Skin Colour Surrounding Wound", indicating that Bepanthene® is superior to the spray when considering these parameters of healing. The assessment by the veterinary students showed a significant effect for the factors of time and treatment for the parameters "Necrotic Tissue Type", in favour of the Bepanthene®, and "Granulation Tissue", in favour of the antibiotic spray, demonstrating no clear benefit for either treatment. Lastly, the evaluation performed by nurses showed a significant effect for the factors of time and treatment, in favour of the Bepanthene®, for the parameters "Necrotic Tissue Type" and "Skin Colour Surrounding Wound", leading to the conclusion that Bepanthene® is associated with better and faster healing when compared to the spray. Overall, these findings lead us to suggest that Bepanthene® presents a better healing index compared to a chlortetracycline-based spray, allowing it to be safely used as a substitute to an antimicrobial agent.

Pain pathophysiology and pharmacology of cattle: how improved understanding can enhance pain prevention, mitigation, and welfare

Globally, humans rely on cattle for food production; however, there is rising societal concern surrounding the welfare of farm animals. From a young age, cattle raised for dairy and beef production experience pain caused by routine management procedures and common disease conditions. The fundamental mechanisms, nociceptive pathways, and central nervous system structures required for pain perception are highly conserved among mammalian species. However, there are limitations to a comparative approach to pain assessment due to interspecies differences in the expression of pain. The stoicism of prey species may impede pain identification and lead to the assumption that cattle lack pain sensitivity. This highlights the importance of establishing validated bovine-specific indicators of pain-a prerequisite for evidence-based pain assessment and mitigation. Our first objective is to provide an overview of pain pathophysiology to illustrate the importance of targeted analgesia in livestock medicine and the negative welfare outcomes associated with unmitigated pain. This is followed by a review of available analgesics, the regulations governing their use, and barriers to implementation of on-farm pain management. We then investigate the current research undertaken to evaluate the pain response in cattle-a critical aspect of the drug approval process. With an emphasis on emerging research in animal cognition and pain pathology, we conclude by discussing the significant influence that pain has on cattle welfare and areas where further research and modified practices are indicated.

Cold therapy and pain relief after hot-iron disbudding in dairy calves

Even when pain control is implemented, calves may experience pain for days after hot-iron disbudding. Whether calves seek pain relief post-disbudding offers a novel approach to assessing pain in these animals. By employing an approach-aversion paradigm, we explored the ability of cold therapy to provide immediate pain relief in disbudded calves. Calves were habituated to the manual placement of a cool or ambient pack on their forehead for a short duration simultaneous to milk reward consumption, prior to disbudding. Calves were then disbudded under local anaesthesia (procaine) and analgesia (meloxicam), and responses to the packs were observed over subsequent days. Individual calves were consistently exposed to either cool or ambient packs in different halves of a two-sided experimental pen, allowing for the testing of approach-aversion and conditioned place preference. We found calves approached milk rewards quicker and maintained contact for longer when receiving cold therapy compared to the ambient control. However, calves did not display any conditioned preference for the pen where they received the cool pack. These results add to the growing evidence of lasting pain following disbudding procedures and suggests that cold therapy provides some form of pain relief post-disbudding. Future studies should seek other ways to use cold therapy post-disbudding to reduce aversiveness and human involvement.

The history and future of the cornual nerve block for calf disbudding

Disbudding damages the germinal horn bud cells and prevents subsequent horn growth in young calves. Hot-iron cautery or caustic paste are the most common disbudding techniques and are unequivocally painful procedures. An important technique in controlling the acute pain experienced during disbudding is the cornual nerve block (CNB) that uses a local anesthetic agent and targets a branch of the trigeminal cranial nerve, the zygomaticotemporal nerve, as it travels along the temporal groove of the skull. Though CNB have been used since 1932, practitioners have reported variability in achieving full desensitization of the horn bud region since its inception. This failure may have led to the establishment of variations in the CNB technique, without consensus on a reliable and repeatable approach. Reasons for CNB failures may include technical errors by the practitioner, such as an injection into subcutaneous or deep muscle bodies; biologically important path variations in the zygomaticotemporal nerve and its cornual branches; and secondary innervation of the horn bud region, particularly the cornual branches of the infratrochlear nerve. Further investigation into documenting and understanding CNB failure and alternatives, such as regional perfusion, is warranted.

Pilot testing an ethanol cornual nerve block as a long-term analgesic for calf disbudding

Disbudding prevents horn growth in calves through thermal or chemical cauterization and causes damage that is painful for weeks following the procedure. Current pain management strategies are only effective from 1 to 2 h (local anesthetic) to 1 to 3 d (nonsteroidal anti-inflammatory drugs). A potential practical solution for addressing longer-term pain may be to administer ethanol as a cornual nerve block. When administered at a high concentration, ethanol damages the functionality of peripheral nerves, promoting localized long-lasting analgesia. It is also thought to be painful, thus ethanol may be combined with lidocaine, as a mixed solution or administered beforehand. We tested the use of an ethanol cornual nerve block for anesthesia around the horn bud in 2 pilot studies. We used different concentrations and amounts of ethanol (100% and 70%) in combination with different ratios of lidocaine in our attempt to identify an effective block. In pilot 1, 14 nondisbudded calves were administered 2 to 4 mL of 100% ethanol below the bony ridge on each side of the head to block the cornual nerve at 3 to 10 d of age (n = 28 horn buds) and observed for 5 wk. The duration of loss of sensation was evaluated using pinprick tests 10 min, 1, 3, and 7 d after the block, and then weekly thereafter until 35 d or full sensation had returned. Pinprick tests consisted of lightly pressing a needle in 10 evenly spaced locations around the base of the horn bud (0 responses = no sensation, 1-5 responses = partial sensation, 6-10 responses = full sensation). Pilot 2 looked at the 24 h after the injection and consisted of 9 nondisbudded calves (5 mL of 2:1, 70% ethanol and 2% lidocaine per horn bud) and 6 disbudded individuals (5 mL of 100% ethanol, 70% ethanol, or 2% lidocaine per horn bud). All treatments were administered at the calf level. Anesthesia was checked 10 min after the injection and 4 or 16 h later. In pilot 1, on the day of the ethanol injection (0 d), there was no sensation in 85% of horn buds. Sensation began to return as early as 1 d after blocking, with only 50%, 21%, and 3% of horn buds having no sensation at 1, 7, and 35 d, respectively. Partial sensation was present in 25%, 17%, and 10% of horn buds at these time points. In pilot 2, 27.8% of horn buds in the nondisbudded group had no sensation, whereas 33.3% had partial sensation 10 min after the injection. In the disbudded calves 10 min after the injection, 100% of horn buds from the 100% ethanol group had partial sensation and 100% of horn buds administered 70% ethanol had full sensation. Four or sixteen hours later, 100% of horn buds had full sensation. Together, in these pilot studies, ethanol provided inconsistent anesthesia when used for a cornual nerve block.

Pain Relief Interventions in Australian Livestock Husbandry: A Review of Animal Welfare and Pain Duration

In veterinary medicine and livestock production, ensuring good animal husbandry is vital for the physical and emotional wellbeing of animals under our care. Pain poses challenges for assessment and mitigation, especially in species unable to express pain overtly. This review examines current pain mitigation interventions in routine husbandry, focuses on the duration of pain after procedures and implications for animal welfare. Pain behaviours have been observed for days or weeks after regular husbandry procedures, and many studies have noted pain-related behaviour persisting until study finalisation, suggesting potential undocumented pain beyond study completion. Current products registered in Australia for pain mitigation in livestock primarily target immediate pain associated with procedures. The future of pain relief in livestock demands longer-acting solutions to address post-procedural pain adequately. Providing pain relief for at least 72 h post surgery is recommended, but current products require retreatment intervals to achieve this, posing practical challenges, especially in livestock. Methods of pain relief provision, such as voluntary consumption of medicated feed, transdermal medication delivery and long-acting formulations offer potential solutions for prolonged pain relief, with research ongoing in these areas. There is a need for further research and development of longer-acting pain relief to ensure optimal welfare of livestock.

The effects of pain following disbudding on calf memory

Studies have found evidence of pain in the hours following hot-iron disbudding, but little is known about longer-lasting pain following this procedure. Work on humans and rats has shown that lasting pain can have negative effects on the formation and recall of memories. The objective of this study was to assess whether lasting pain following disbudding affects learning and memory in calves. A modified hole-board apparatus was used to assess how quickly calves were able to learn the locations of 4 bottles containing milk dispersed among 11 locations with empty bottles. At 14 d of age and after 6 d of training on this task, calves (n = 30) were randomly assigned to 3 treatments: disbudding with analgesic on the day of the procedure, disbudding with analgesic throughout the study, and sham disbudding. All calves were sedated, given a lidocaine cornual local block and a single injection of an nonsteroidal anti-inflammatory drugs. Starting on the day after their disbudding treatment, calves were tested daily using the modified hole-board apparatus. After 12 d of testing, the locations of the 4 milk-containing bottles were switched, and calves then relearned the locations of the rewarded bottles over the next 6 daily test sessions. We found general working memory (i.e., short-term memory) and reference memory (i.e., long-term memory) increased over the 12 d of testing, declined when locations were switched on d 13, and then again increased over the final 6 d of testing. We did not find an effect of treatment on any measure, perhaps because there was no lasting pain or because effects were too minor to detect using this test of spatial memory.

Wound healing and pain sensitivity following caustic paste disbudding in dairy calves

Caustic paste disbudding is increasing in popularity on commercial dairy farms in the United States, but little research has explored the pain and welfare implications beyond the acute period of this procedure. In contrast, researchers have reported it takes 7 to 9 wk, on average, for hot-iron disbudding wounds to re-epithelialize in dairy calves. Our objective was to describe wound healing and sensitivity following caustic paste disbudding. Jersey and Holstein female calves were disbudded using caustic paste (H. W. Naylor Company Inc.) at 3 d of age (n = 18), and control calves received a sham procedure (n = 15). Before disbudding, calves received a local block and a nonsteroidal anti-inflammatory drug. Calves ≥34 kg and <34 kg at birth had 0.3 or 0.25 mL of paste applied per unshaved horn bud, respectively. Following disbudding, wounds were scored 2×/wk for the presence or absence of 8 tissue categories, including the final stages: new epithelium and fully healed. Control calves were removed from the experiment after 6 wk to be hot-iron disbudded. Mechanical nociceptive threshold (MNT) measures were collected weekly to evaluate wound sensitivity until calves were removed from the study or healed. Wounds were slow to re-epithelialize (16.2 ± 5.7 wk, mean ± SD; range: 6.2-32.5 wk) and contract to be considered fully healed (18.8 ± 6 wk, mean ± SD; range: 8.7-34.1 wk). Compared with non-disbudded controls, paste calves exhibited lower MNT values for all 6 wk (mean ± SE; control: 1.46 ± 0.16; paste: 1.18 ± 0.12 N). These data indicate that wounds from caustic paste disbudding are more sensitive than undamaged tissue for at least 6 wk and take twice as long to heal compared with cautery methods described in the literature. In conclusion, caustic paste disbudding wounds took 18.8 wk to fully heal and were more sensitive than intact horn buds for 6 wk. Future work should examine whether aspects of paste application (e.g., amount used, time rubbed in, calf age, pain mitigation) could improve healing time and sensitivity.

Behavioral changes in the first 3 weeks after disbudding in dairy calves

Hot-iron disbudding, the practice of cauterizing horn bud tissue to prevent horn growth in dairy calves, results in behavioral changes indicative of pain in the first few days after the procedure. However, few studies have quantified behavioral changes in the following weeks, while the burn wounds are still healing. Female Holstein calves were disbudded with a heated iron and pain relief (5.5 mL lidocaine cornual nerve block and 1 mg/kg oral meloxicam) at 4 to 10 d of age (n = 19) or not disbudded (n = 19). Calves wore ear tag accelerometers that reported the dominant behavior being performed at 1-min intervals from 3 to 21 d after disbudding. Compared with age-matched controls, disbudded calves tended to spend more time inactive throughout the observation period, ruminated less in the first 3 to 11 d after disbudding, and sucked more from a milk bottle beginning 5 d after disbudding until the end of the 21-d observation period. In addition to the accelerometer data, live observations of sleeping (using a behavioral proxy), lying, and ruminating were collected using instantaneous sampling at 5-min intervals for 24-h periods 3, 10, and 17 d after disbudding. Disbudded calves slept with their head down more on all live observation days and spent more time lying on the 17th d after disbudding, but ruminating did not differ compared with controls, in contrast to the accelerometer results. More time spent inactive, sleeping, and lying, and less time spent ruminating (as indicated by the accelerometer) can be interpreted as attempts to reduce painful stimulation of the disbudding wounds and allocate energy to healing. It is unclear whether the greater amount of sucking in the disbudded calves is nutritive (milk present) or non-nutritive (milk absent), as the algorithm did not distinguish the type of sucking, and further research is needed to explore the factors underlying this effect. We conclude that disbudding alters daily behavior patterns for at least 3 wk, far beyond the duration of recommended pain medication, raising additional welfare concerns about the procedure.

Development and application of a novel approach to scoring ear tag wounds in dairy calves

Application of ear tags in cattle is a common husbandry practice for identification purposes. Although it is known that ear tag application causes damage, little is known about the duration and process of wound healing associated with this procedure. Our objective was to develop a detailed scoring system and use it to quantify wound healing in dairy calves with plastic identification tags. Calves (n = 33) were ear tagged at 2 d of age, and wound photos were taken weekly until 9 to 22 wk of age. This approach generated 10 to 22 observations per calf that were analyzed using a novel wound scoring system. We developed this system to score the presence or absence of external tissue types related to piercing trauma or mechanical irritation along the top of the tag (impressions, crust, and desquamation) and around the piercing (exudate, crust, tissue growth, and desquamation). Ears were scored as "piercing only" when tissue around the ear tag was intact. We found that impressions, crust, tissue growth, and desquamation were still seen in many calves by 12 wk of age. This suggests that extrinsic factors, such as mechanical disturbance and irritation, may have contributed to prolonged wound healing. Indeed, impressions along the top of tag, likely caused by rubbing against the ear, were observed for nearly the full duration of the study. Further research is warranted to understand ways to improve the ear-tagging process.

Randomised Control Trial Investigating the Efficacy of Meloxicam and Sodium Salicylate Non-Steroidal Anti-Inflammatory Drugs for Calf Cautery Disbudding

Disbudding calves using hot iron cautery is a routine management procedure to destroy the germinal cells around the horn bud in calves. It is recommended that NSAIDs are used in conjunction with local anaesthesia to reduce pain in calves during and after the procedure. In this study, two treatment groups were examined; calves in the positive control MEL group received subcutaneous meloxicam, and SAL calves received sodium salicylate orally for three days, both in addition to a local anaesthesia. Tri-axis accelerometers were attached to the calves, and DLWG (Daily Live Weight Gain) was measured. There was no significant difference between the treatment groups with regard to DLWG (p = 0.52), MI (motion index (p = 0.66)), lying bouts (p = 0.96) or lying times (p = 0.54). Given these findings, sodium salicylate may offer a lower-cost option for farmers when given at licensed doses compared to meloxicam, as well as providing a reduced-stress method of NSAID administration via an oral route. In addition, this study identified significant differences in activity in the time periods before and after disbudding, with MI (p < 0.01), lying bouts (p = 0.002) and lying times (p < 0.001) indicating changes in behaviour which extended to five days post disbudding.

Welfare of calves

This Scientific Opinion addresses a European Commission request on the welfare of calves as part of the Farm to Fork strategy. EFSA was asked to provide a description of common husbandry systems and related welfare consequences, as well as measures to prevent or mitigate the hazards leading to them. In addition, recommendations on three specific issues were requested: welfare of calves reared for white veal (space, group housing, requirements of iron and fibre); risk of limited cow–calf contact; and animal‐based measures (ABMs) to monitor on‐farm welfare in slaughterhouses. The methodology developed by EFSA to address similar requests was followed. Fifteen highly relevant welfare consequences were identified, with respiratory disorders, inability to perform exploratory or foraging behaviour, gastroenteric disorders and group stress being the most frequent across husbandry systems. Recommendations to improve the welfare of calves include increasing space allowance, keeping calves in stable groups from an early age, ensuring good colostrum management and increasing the amounts of milk fed to dairy calves. In addition, calves should be provided with deformable lying surfaces, water via an open surface and long‐cut roughage in racks. Regarding specific recommendations for veal systems, calves should be kept in small groups (2–7 animals) within the first week of life, provided with ~ 20 m²/calf and fed on average 1 kg neutral detergent fibre (NDF) per day, preferably using long‐cut hay. Recommendations on cow–calf contact include keeping the calf with the dam for a minimum of 1 day post‐partum. Longer contact should progressively be implemented, but research is needed to guide this implementation in practice. The ABMs body condition, carcass condemnations, abomasal lesions, lung lesions, carcass colour and bursa swelling may be collected in slaughterhouses to monitor on‐farm welfare but should be complemented with behavioural ABMs collected on farm.

Literature Review on Technological Applications to Monitor and Evaluate Calves' Health and Welfare

Precision livestock farming (PLF) research is rapidly increasing and has improved farmers' quality of life, animal welfare, and production efficiency. PLF research in dairy calves is still relatively recent but has grown in the last few years. Automatic milk feeding systems (AMFS) and 3D accelerometers have been the most extensively used technologies in dairy calves. However, other technologies have been emerging in dairy calves' research, such as infrared thermography (IRT), 3D cameras, ruminal bolus, and sound analysis systems, which have not been properly validated and reviewed in the scientific literature. Thus, with this review, we aimed to analyse the state-of-the-art of technological applications in calves, focusing on dairy calves. Most of the research is focused on technology to detect and predict calves' health problems and monitor pain indicators. Feeding and lying behaviours have sometimes been associated with health and welfare levels. However, a consensus opinion is still unclear since other factors, such as milk allowance, can affect these behaviours differently. Research that employed a multi-technology approach showed better results than research focusing on only a single technique. Integrating and automating different technologies with machine learning algorithms can offer more scientific knowledge and potentially help the farmers improve calves' health, performance, and welfare, if commercial applications are available, which, from the authors' knowledge, are not at the moment.

Clinical efficacy of an ultrasound-guided bilateral rectus sheath block for umbilical hernia repair in calves: A prospective randomized trial

Introduction

Surgical umbilical hernia repair is a frequent procedure in newborn calves, requiring mandatory pain management. This study aimed to develop an ultrasound-guided rectus sheath block (RSB) and to evaluate its clinical efficacy in calves undergoing umbilical herniorrhaphy under general field anesthesia.

Methods

Gross and ultrasound anatomy of the ventral abdomen and the diffusion of a new methylene blue solution after injection within the rectus sheath were described in seven fresh calf cadavers. Then, fourteen calves undergoing elective herniorrhaphy were randomly assigned to receive either bilateral ultrasound-guided RSB with 0.3 mL/kg of bupivacaine 0.25% and 0.15 µg/kg of dexmedetomidine or 0.3 mL/kg of 0.9% NaCl (control). Intraoperative data included cardiopulmonary variables and anesthetic requirements. Postoperative data included pain scores, sedation scores and peri-incisional mechanical threshold assessed by force algometry at specific time points after anesthetic recovery. Treatments were compared using Wilcoxon rank-sum, Student's t-test, and Cox proportional hazard model as appropriate. Mixed effect linear models on rank, with random effect calf; fixed effects time, treatment, and their interaction were used to compare pain scores and mechanical thresholds over time. Significance was set at p = 0.05.

Results and Discussion

Calves receiving RSB recorded lower pain scores between 45 - 120 minutes (p < 0.05) and at 240 min after recovery (p = 0.02). And they recorded higher mechanical thresholds between 45 and 120 min after surgery (p < 0.05). Ultrasound-guided RSB provided effective perioperative analgesia in calves undergoing herniorrhaphy under field conditions.

A nationwide survey on producer and veterinarian perceptions of the painfulness of procedures and disease states in dairy and beef cattle

Failure to adequately manage pain in cattle causes suffering and is thus a welfare concern for the livestock industry. The objectives of this study were to summarize caregiver perceptions of the painfulness of various procedures and disease conditions in cattle. This survey also assessed factors that impact the perception of painfulness and determined relationships between pain perception and mitigation in producers and veterinarians in the United States beef and dairy cattle industries. An online survey was distributed via organization listservs and social media groups representing beef and dairy veterinarians and producers. The survey included questions about respondent demographics and pain perception and frequency of pain mitigation use for a variety of common husbandry procedures and disease conditions in cattle less than 2 months, 2-12 months, and greater than 12 months of age. Descriptive statistics were generated, and ordinal logistic regressions were used to assess the relationship between perceived pain level, frequency of pain mitigation use, and respondent demographic factors (e.g., gender, age, and role). There was a relatively low percentage of respondents that identified there was "no pain" associated with the listed procedures and conditions. Across the majority of procedures and conditions and cattle age categories, men perceived procedures to be less painful than women (P < 0.05). Veterinarians and producer-veterinarians perceived procedures to be more painful than producers (P < 0.05) for the majority of procedures and conditions. There were some differences identified between respondent age groups in pain perception but the trends were not consistent across procedures and conditions. There was a significant positive linear trend, with greater perceived pain associated with greater likelihood of providing local and systemic analgesia for all procedures and conditions across all cattle age categories (P ≤ 0.02). Perception of pain is complex and multifactorial, and it influences the likelihood to treat pain in cattle. This research highlighted the importance of understanding how these factors may play a role in increasing the use of pain mitigation within the beef and dairy industries.

Histopathological findings in a pilot study of dairy calves disbudded with hot cauterization or caustic paste

We describe the histological tissue damage and compare the healing process in 16 dairy calves disbudded at a mean age of 6 days by cauterization or alkaline caustic paste application. Biopsies were taken 2 days (T2) and 2 weeks (T14) after disbudding from sedated calves treated with local anaesthetic and non-steroidal anti-inflammatory drugs. At T2, the cauterized horn buds generally had eosinophilic coagulative necrosis of the epidermis and superficial dermis, bordered basally by a neutrophilic demarcation zone. Lateral to the direct heat contact area, dermal blood vessels were thrombosed, with wall damage and perivascular neutrophils. In the caustic paste-treated horn buds, the epidermis and dermis had diffuse full-thickness liquefactive necrosis directly under the paste contact area. The necrosis spread laterally in the dermis beyond the area of paste contact and was bordered by a neutrophilic infiltrate. At T14, the cauterized horn buds had epidermal to superficial dermal ulceration and crusting, dermal neutrophilic infiltration and granulation tissue formation. In contrast, most of the caustic paste-treated horn buds consisted of a superficial dermal crust or predominantly necrotic tissue fragments. The remaining viable areas had histiocytic inflammation with peripheral neutrophils and early granulation tissue formation. Caustic paste disbudding caused poorly demarcated lesions that were more severe and extensive and took longer to heal than those due to cautery. Cauterization induced a more intense acute reaction adjacent to the primary lesion compared with caustic paste.

Effect of flunixin meglumine on pain-related behaviours following cautery disbudding in dairy goat kids

The aim of this research was to evaluate the physiological and behavioural parameters in Saanen goat kids treated with flunixin meglumine compared with no analgesic treatment after cautery disbudding using a device fueled by propane gas. At 7 days of age, 30 goat kids were randomly allocated to three groups: Sham (Sh) control, (i.e., simulating disbudding); Disbudding (Di), using thermal cauterization; Disbudding + Flunixin (DiFl), thermal cauterization + flunixin meglumine (2.2 mg/kg body weight, 15 min before treatment). Each kid was video-recorded for 30 min before and after treatment to evaluate the frequency of head shaking, head scratching, body shaking, grooming, head rubbing, jumping, running, and bleating. Blood samples were taken 30 min after disbudding to evaluate serum cortisol concentrations and white blood cell count. Heart rate (HR) and respiratory rate (RR) were measured using a stethoscope. Liveweight of goat kids was recorded at birth, -24 h and 7 days after treatment, and at 25 days of age. The mean frequency of head shaking and head scratching was higher (p = 0.0001) after disbudding in Di (37.5 ± 47.8 and 33.32 ± 31.2) group compared to Sh (3.42 ± 3.58 and 2.2 ± 1.8) and DiFl, (4.02 ± 2.76 and 4.42 ± 3.72) groups. The frequency of jumping was higher (p = 0.022) for Di (3.74 ± 2.24) than that of DiFl (0.39 ± 0.92). The remaining behaviours did not show differences (p > 0.05). HR and RR were higher (HR: p < 0.0048; RR: p < 0.035) in group Di (HR: 156 ± 13.6; RR: 66 ± 14.8) than in Sh (HR: 138 ± 8.48; RR: 55.6 ± 5.4) and in DiFl (HR: 136 ± 6.38; RR: 52.8 ± 4.13). No differences were detected between live weight, serum cortisol and white blood cell count data (p > 0.05). Results show that flunixin meglumine was effective at reducing pain-related behaviours when given at the time of disbudding.

Pharmacokinetics and efficacy of a novel long-acting bupivacaine formulation for cornual nerve block in calves

Local anesthetics are commonly used in farm animals to provide analgesia for painful procedures but can cause adverse effects at high systemic concentrations. The pharmacokinetics and efficacy of a long-acting sucrose acetate isobutyrate (SAIB) bupivacaine formulation following cornual nerve block in calves were compared to lidocaine. Fourteen calves were randomly assigned to one of the treatment groups (i) 5% Bupivacaine-SAIB (BUP-SAIB), n = 7; or (ii) 2% lidocaine (LID), n = 7. Cornual nerve block was performed, and duration of effective analgesia was evaluated by nociceptive threshold testing using a hand-held pressure algometer. Blood samples were collected at various time points and plasma concentrations were analyzed by HPLC. Pharmacokinetic parameters were calculated using a non-compartmental model. The mechanical nociceptive thresholds showed that the novel formulation could desensitize the skin around the horn bud for 18.77 ± 8.88 h (range 8-36 h), compared to 0.79 ± 0.34 h (range 0.5-1.5 h) with lidocaine. The mean maximum plasma concentration (Cmax) of bupivacaine was 152.03 (SD 37.34) ng/mL and its Tmax was 0.39 (SD 0.13) h. The half-life of elimination was 32.79 ± 11.00 h and the rate of clearance was 0.12 ± 0.03 L h-1. No toxicity signs were seen after treatment in either group. The novel formulation produced long-lasting analgesia of several times greater duration than that produced by lidocaine. This study showed that the safety and efficacy of the SAIB formulation justifies further studies in a larger population of animals.

Heat abatement during the pre-weaning period: effects on lying behavior and disbudding-related responses of male Holstein calves

Strategies to abate heat stress are seldom adopted for pre-weaned dairy calves and little is known about their effects on behavior and pain sensitivity of youngstock. Our objectives were to determine the effects of heat stress abatement on lying behavior and disbudding-related pain sensitivity, wound healing, and change in intake. Male Holstein calves (n = 60; 0 to 68 d of age) were assigned randomly at birth (d 0) to 1 of 3 treatments: hutch outdoors with 50% of its area covered with plywood (control = 20), hutch in a barn with no cooling (SH = 21), and hutch in a barn with ceiling fans (SHF = 19). Calves were fitted with lying-behavior loggers on the hind leg from d 1 to 68. On d 32 ± 8 (±SD), we disbudded calves using hot iron, 30 min after cornual nerves were blocked with lidocaine. Immediately before (0 h), and at 1, 2, and 3 h after disbudding, we evaluated calves for mechanical nociceptive threshold (MNT) and head (ear flick, head shake, head rubbing) and somatic (tail flicking, foot stamping, restlessness) behaviors. On d 1, 3, 7, and 14 after disbudding, we evaluated the MNT and, on d 7 and 14, we evaluated wound healing (1 = crust, 5 = exudate). We calculated the relative change in milk solids and starter intake from d 0 to 6 relative to disbudding compared with the average of the 72 h preceding the procedure. The lying time was 0.6 h/d greater for the SHF treatment compared with the SH treatment. The control treatment resulted in 3.2 and 4.1 more lying bouts per day than the SH and SHF treatments, respectively; consequently, the control treatment resulted in lying-bout duration 7.7 and 10.9 min/event shorter than the SH and SHF treatments, respectively. We did not detect an effect of treatment on the number of disbudding-related head and somatic behaviors and MNT. The odds of calves having abnormal wound was 3.5 and 3.2 times greater for the control treatment compared with the SH and SHF treatments, respectively. We did not detect an effect of treatment on the relative change in intake of milk solids and starter. Heat abatement improves the welfare of pre-weaned dairy calves and may hasten healing.

Air Quality, Management Practices and Calf Health in Italian Dairy Cattle Farms

Simple Summary

Calf mortality is an important factor of economic loss in dairy operations. Among the factors which can affect calf health, air quality in calf housing has rarely been studied. In the present research, the relations among air quality in the calf pens, management practices, microclimatic conditions and calf health and mortality were studied in 25 Italian dairy cattle farms. Microbial air quality in the calf pens was found to be related to temperature and humidity, design and position of the pen, some management practices and calf health and mortality. Maintaining dry bedding and controlling microclimatic conditions in the calf pen can be useful practices to promote good air microbiological quality in the calf pen, improving calf health and reducing mortality.

Abstract

Among factors that can affect calf health, microbial quality of the pen air is poorly studied. In 25 Italian dairy farms, data concerning air quality in the calf pens, hygiene of pens and equipment, microclimatic conditions, calf health and management were collected during the winter season (January-March 2020 and December-March 2021). The average air Standard Plate Count (SPC) of 85 pens was 4.51 (SD = 0.52) log₁₀ cfu/m³ whereas the average air ammonia concentration was 0.66 (SD = 0.53) ppm. Positive correlations were found between average Temperature Humidity Index (THI) in the pen and air SPC, night maximum THI and air SPC and between SPC and yeast, mould and ammonia concentration in the pen air. The concentrations of E. coli, Enterobacteriaceae and yeasts in the pen air were higher and calf cough increased as the renewal interval of bedding material became longer. High bedding dry matter and low THI were associated with low air SPC, good calf health scores and low mortality. Maintaining low bedding humidity and controlling microclimatic conditions can contribute to enhancing air microbiological quality in the pen and reduce calf diseases and mortality.

Indication of social buffering in disbudded calves

Most dairy calves are housed individually in early ontogeny but social housing has positive effects on calf welfare including an advantage of social buffering, i.e., when negative effects of stress are mitigated through social support of conspecific. The effects of social buffering has not yet been examined in relation to disbudding; a painful husbandry procedure commonly performed on young dairy calves. The objective of this study was to investigate the effect of pair versus individual housing on calves’ behavioral reaction to disbudding. In total 52 female calves were randomly allocated either to individual (n = 16) or pair housing (n = 36, 18 focal). Calves were hot-iron disbudded with a local anesthetic and their spontaneous behavior in home pens was recorded for 24 h pre- and post-disbudding. Eating forage, ruminating, resting, exploration, play, self-grooming, and pain-related behaviors were quantified during eight 20 min intervals during the 24 h periods pre- as well as post-disbudding. In pair-housed (PAIR) calves social resting, active and passive allo-grooming were additionally recorded. The differences between individually housed (INDI, n = 10) and PAIR calves (n = 12) were tested by general linear models. The changes in pre- and post-disbudding behaviors in all calves as well as in social behaviors of PAIR calves were tested by paired t-test. We found that head shaking (t =  − 3.46, P = 0.0024), head rubbing (t = 4.96, P < 0.0001) and self-grooming (t = 2.11, P = 0.04) increased in all calves after disbudding. Eating forage increased only in PAIR calves (t = 2.50, P = 0.030) which also resulted in a difference between treatments with PAIR calves fed more often than INDI calves (F_1,18 = 12.96, P = 0.002). Differences in eating forage may be an indication of improved ability of PAIR calves to recover from disbudding. No other significant differences were detected between treatment groups which might have been caused by our limited sample. Our results provide the first evidence that housing treatment affects calves’ reactions to disbudding, with possible indication of social buffering.

Alternative Practices in Organic Dairy Production and Effects on Animal Behavior, Health, and Welfare

The number of organic dairy farms has increased because of the increased growth of the organic market, higher organic milk price, and because some consumers prefer to purchase products from less intensive production systems. Best management practices are expected from organic dairy farms to ensure animal health and milk production. Organic dairy producers typically transition from conventional systems to avoid chemicals and pesticides, enhance economic viability, improve the environment, and increase soil fertility. Organic dairy producers respect and promote a natural environment for their animals, is also an important component of animal welfare. Organic producers have few options to mitigate pain in dairy calves. In the United States, therapies to mitigate pain for disbudded organic dairy calves are regulated by the US National Organic Program. Organic producers regularly use naturally derived alternatives for the treatment of health disorders of dairy calves, heifers, and cows. Alternative natural products may provide an option to mitigate pain in organic dairy calves. Despite the reluctance to implement pain alleviation methods, some organic farmers have expressed interest in or currently implement plant-based alternatives. Efficacy studies of alternative remedies for organic livestock are needed to verify that their use improves animal welfare. Non-effective practices represent a major challenge for organic dairy animal welfare. The relationship between humans and animals may be jeopardized during milking because first-lactation cows may exhibit adverse behaviors during the milking process, such as kicking and stomping. The periparturient period is particularly challenging for first-lactation cows. Adverse behaviors may jeopardize animal welfare and reduce safety for humans because stressed heifers may kick off the milking unit, kick at milkers, and display other unwanted behaviors in the milking parlor. This may reduce milking efficiency, overall production, and ultimately reduce the profitability of the dairy farm. Positive animal welfare is a challenging balancing act between the three overlapping ethic concerns. Identifying animal welfare deficits in organic livestock production is the first step in capitalizing on these opportunities to improve welfare.

Graduate Student Literature Review: Role of pain mitigation on the welfare of dairy calves undergoing disbudding

This review synthesizes research findings on the pain and welfare of dairy calves undergoing disbudding procedures. We describe disbudding practices in North America as well as the use and perceptions of pain control for these procedures. Governing bodies across Canada and the United States, including each country's veterinary medical association and nationwide initiatives such as proAction and Farmers Assuring Responsible Management (FARM), recommend or require the use of a local anesthetic, a nonsteroidal anti-inflammatory drug (NSAID), and a sedative for disbudding procedures. Although the use of pain relief for disbudding has increased over the past decade or so, some in the dairy industry still do not believe that pain control for disbudding is necessary. As a painful procedure, disbudding has numerous welfare impacts on the calf both during and following the procedure that can be categorized under all 3 principles of animal welfare: natural living, biological functioning, and affective state. The use of pain control for disbudding; namely, a local anesthetic and NSAID, can improve welfare outcomes such as procedure-induced pain behavior, cortisol concentrations, mechanical nociceptive threshold, emotional states, and so on, compared with no pain control for the procedure. Although extensive research exists on pain control practices for disbudding, this review identified further gaps in knowledge and areas for future research. Mechanical nociceptive threshold can be evaluated around the disbudding wounds and is a reliable test in older calves; however, this outcome in very young calves after caustic paste disbudding has been reported to be inconclusive compared with that in older calves. As well, research evaluating xylazine sedation for disbudding has reported both potentially positive and negative results that are difficult to interpret or base suggestions on for the use of this drug. Finally, wounds caused by disbudding take a long time to heal (up to 13 wk) and have increased sensitivity for the entire healing process. Therefore, future research should aim to (1) determine accurate behavioral tests for calves under 1 wk of age undergoing disbudding to better understand their experience, (2) further attempt to understand the effects of xylazine sedation for disbudding and potential impacts of providing this medication, and (3) determine more ways to reduce the healing time and pain experienced by the calf after disbudding procedures.

The Neuroimmune Interface and Chronic Pain Through the Lens of Production Animals

Communication between the central nervous system (CNS) and the immune system has gained much attention for its fundamental role in the development of chronic and pathological pain in humans and rodent models. Following peripheral nerve injury, neuroimmune signaling within the CNS plays an important role in the pathophysiological changes in pain sensitivity that lead to chronic pain. In production animals, routine husbandry procedures such as tail docking and castration, often involve some degree of inflammation and peripheral nerve injury and consequently may lead to chronic pain. Our understanding of chronic pain in animals is limited by the difficulty in measuring this pathological pain state. In light of this, we have reviewed the current understanding of chronic pain in production animals. We discuss our ability to measure pain and the implications this has on animal welfare and production outcomes. Further research into the neuroimmune interface in production animals will improve our fundamental understanding of chronic pain and better inform human clinical pain management and animal husbandry practices and interventions.

Effect of plane of nutrition and analgesic drug treatment on wound healing and pain following cautery disbudding in preweaning dairy calves

The objective of this study was to determine the effect of a biologically normal plane of nutrition compared with a limited plane on the primary outcome wound healing, and one dose of nonsteroidal anti-inflammatory drug (NSAID) compared with 2 on the secondary outcomes: lying behavior, haptoglobin concentrations, and mechanical nociceptive threshold (MNT) in calves disbudded via cautery iron. Eighty female Holstein calves were enrolled at birth, individually housed, and fed via a Calf Rail system (Förster Technik). A 2 × 2 factorial design was used to assess the effect of plane of nutrition and an additional NSAID. Calves were randomly assigned to a biologically normal plane of nutrition (BN; offered up to 15 L/d) or a limited plane (LP; offered up to 6 L/d) and to receive one or 2 doses of meloxicam. All calves received a lidocaine cornual nerve block and a subcutaneous injection of meloxicam 15 min before cautery disbudding at 18 to 25 d of age, and half the calves received an additional injection of meloxicam (0.5 mg/kg) 3 d after disbudding. Tissue type present, wound diameter, and wound depth were evaluated 2 times per week for 7 to 8 wk as measures of wound healing, lying behavior was recorded beginning 1 to 2 wk before disbudding until 7 to 8 wk after as a behavioral indicator of pain, haptoglobin concentrations were measured once per day for 7 d after disbudding, and MNT was evaluated 2 times/wk for 3 wk. Survival analyses were analyzed using Cox regression models (wound healing) and continuous data were analyzed using mixed-effect linear regression models. Only 12% of horn buds were completely healed by 7 to 8 wk after disbudding and 54% had re-epithelized at this time. At any time, wounds from BN calves were more likely to have had re-epithelization occur compared with wounds from LP calves (hazard ratio: 1.93, 95% CI: 1.18-3.14). Wounds from calves that received only one dose of NSAID were more likely to have re-epithelization occur, compared with wounds from calves given 2 doses (hazard ratio: 1.87, 95% CI: 1.15-3.05). Wounds from BN calves had smaller diameters and depths over time beginning on wk 3 compared with LP calves. Wounds from calves that received an additional NSAID had larger diameters and depths over time beginning on wk 4 and 3 respectively, compared with calves that only received one dose of NSAID. Calves that received an extra NSAID tended to be less sensitive 7, 10, and 17 d after disbudding compared with calves that only received one dose and spent less time lying in the week after disbudding. Calves on the BN milk program were more active compared with LP calves with lower lying times, fewer lying bouts per day, and longer average lying bouts. Our results indicate that a BN milk feeding program for calves can result in faster healing times and more activity, and that providing an extra NSAID 3 d after disbudding appears to slow the healing process but may result in less pain experienced by the calf 1 to 2 wk after the procedure. This study is also among the first to demonstrate that after the complete removal of the horn bud, wounds can take more than 8 weeks to re-epithelize and fully heal.

Comparison of lidocaine alone or in combination with a local nerve block of ethanol, bupivacaine liposome suspension, or oral meloxicam to extend analgesia after scoop dehorning in Holstein calves

The American Veterinary Medical Association recommends the use of practices that reduce or eliminate pain and discomfort associated with dehorning. Identification of an effective, long-acting local anesthetic that is practical for producers to implement and reduces pain from dehorning would benefit animal welfare. Thirty-two Holstein bulls and heifers were enrolled. The objective of this study was to compare the efficacy and duration of activity of bupivacaine liposome suspension (BUP; n = 8), ethanol (ETH; n = 8), or meloxicam (LID + MEL; n = 8) co-administered with lidocaine compared with lidocaine only (LID; n = 8), and to quantify their effect on pain biomarkers and behaviors after scoop dehorning with cauterization in approximately 20-wk-old calves. Outcome variables collected included infrared thermography (IRT), mechanical nociceptive threshold (MNT), visual analog scale (VAS) scoring, and blood sampling for serum cortisol and prostaglandin E₂ metabolites (PGEM). There was evidence of a sex effect for MNT, with bulls demonstrating a higher threshold (13.74 kgf) compared with heifers (12.12 kgf). There was a treatment by time interaction for cortisol concentrations (ng/mL). At 2 h, the BUP group had higher cortisol values (17.32 ng/mL) than the LID + MEL group (3.10 ng/mL). Heifers also had higher mean cortisol values (13.88 ng/mL) compared with bulls (6.96 ng/mL). There was a treatment by time interaction for PGEM concentration. Calves in the LID + MEL group had lower PGEM values at 4 and 8 h (10.23 and 9.12 pg/mL) than at -24, 0, and 0.5 h (20.38, 27.27, and 22.59 pg/mL, respectively). At 4 h, the LID + MEL group had lower PGEM concentrations (10.23 pg/mL) than the ETH group (27.08 pg/mL). At 8 h, the LID + MEL group had lower PGEM concentrations (9.12 pg/mL) than both the ETH and BUP groups (24.80 and 20.52 pg/mL). Thus, LID + MEL reduced cortisol and prostaglandin metabolite concentrations more effectively than ETH + LID or BUP + LID administered as a local infiltration and cornual block, respectively, before scoop dehorning followed by cauterization. The treatments administered in the present study did not seem to extend the duration of analgesia beyond the currently recommended multimodal approach, including local anesthesia and systemic analgesia such as lidocaine and meloxicam. Evidence from the current study suggests that sex influences pain biomarkers such as nociceptive threshold and cortisol concentration, with males having a higher nociceptive threshold and lower cortisol responses.

Evaluation of Horn Bud Wound Healing Following Cautery Disbudding of Dairy Calves With and Without the Use of Oxytetracycline Aerosol Spray

Oxytetracycline is commonly applied as a topical agent to burn lesions post cautery disbudding of calves. Judicial use of antibiotics dictates that they should only be used where necessary to reduce the development of resistance in target bacteria. The objective of this study, therefore, was to evaluate the efficacy of topical oxytetracycline spray on wound healing post cautery disbudding of dairy calves over a 6-week period. Dairy calves were disbudded by veterinarians, technicians, or veterinary surgeons, using a standard cautery disbudding protocol. Oxytetracycline spray was randomly applied to the right or left horn bud of each animal (OXY), while the other horn bud received no antibiotic spray (NA). The outcomes measured were wound diameter (WD) and lesion score (LS), either normal healing (NH) or abnormal healing (AH). These assessments were conducted every 14 days following disbudding, until 42 days. A total of 360 animals completed the study. There was a difference in wound diameter and lesion score on day 14 post disbudding between the two groups. Cautery lesions sprayed with oxytetracycline (OXY) were 0.5 ± 0.15 mm smaller than NA lesions (P = 0.001), and there were fewer abnormal healing lesions for OXY compared to the NA (2.5 vs. 11%, respectively; P ≤ 0.001). There were no differences at day 28 and day 42 post disbudding, and on day 42, 34% of wounds had healed in both groups.

In summary, the authors were unable to demonstrate a difference in healing between the groups using the described methods.

Early Life Painful Procedures: Long-Term Consequences and Implications for Farm Animal Welfare

Farm animals routinely undergo painful husbandry procedures early in life, including disbudding and castration in calves and goat kids, tail docking and castration in piglets and lambs, and beak trimming in chicks. In rodents, inflammatory events soon after birth, when physiological systems are developing and sensitive to perturbation, can profoundly alter phenotypic outcomes later in life. This review summarizes the current state of research on long-term phenotypic consequences of neonatal painful procedures in rodents and farm animals, and discusses the implications for farm animal welfare. Rodents exposed to early life inflammation show a hypo-/hyper-responsive profile to pain-, fear-, and anxiety-inducing stimuli, manifesting as an initial attenuation in responses that transitions into hyperresponsivity with increasing age or cumulative stress. Neonatal inflammation also predisposes rodents to cognitive, social, and reproductive deficits, and there is some evidence that adverse effects may be passed to offspring. The outcomes of neonatal inflammation are modulated by injury etiology, age at the time of injury and time of testing, sex, pain management, and rearing environment. Equivalent research examining long-term phenotypic consequences of early life painful procedures in farm animals is greatly lacking, despite obvious implications for welfare and performance. Improved understanding of how these procedures shape phenotypes will inform efforts to mitigate negative outcomes through reduction, replacement, and refinement of current practices.

Effect of bupivacaine liposome suspension administered as a cornual nerve block on indicators of pain and distress during and after cautery dehorning in dairy calves

Dehorning is performed on a high percentage of dairies worldwide. Concern about the negative effect of dehorning on animal welfare has contributed to the development of new guidelines that require the use of pain management at the time of disbudding in the United States. However, livestock producers are limited in how to address this requirement due to a lack of (1) approved analgesic drugs, (2) analgesic options that control pain for an extended duration, and (3) analgesic formulations that are practical for producers to administer. The objective of this study was to evaluate the effectiveness of bupivacaine liposome suspension, a novel, long-acting, local anesthetic formulation administered as a nerve block at dehorning, compared with current industry standard analgesic approaches using lidocaine nerve blocks alone or in combination with the nonsteroidal anti-inflammatory drug meloxicam. Fifty male Holstein calves, 10 to 14 wk of age, were enrolled and randomly assigned to 1 of 5 treatment groups before cautery dehorning as follows: (1) bupivacaine liposome suspension block, oral placebo (BUP); (2) lidocaine block, oral placebo (LID); (3) lidocaine block, oral meloxicam (1 mg/kg of body weight; LID + MEL); (4) saline block, oral placebo (CON); and (5) saline block, oral placebo, sham dehorn (SHAM). Biomarkers were collected from 0 to 120 h postdehorning and included infrared thermography, mechanical nociceptive threshold (MNT), pressure mat gait analysis, chute defense and behavior scoring, and blood sampling for serum cortisol and prostaglandin E₂ metabolites. Responses were analyzed using repeated measures with calf nested in treatment designated as a random effect, and treatment, time, and their interaction designated as fixed effects. At 2 h postdehorning, the BUP group had a higher MNT compared with the CON group. Furthermore, at 24 h postdehorning, the BUP group had a higher MNT compared with the LID group. Gait distance differed significantly between treatment groups; the CON, LID, and LID + MEL groups had an increased gait distance relative to the SHAM group. The CON group exhibited a higher chute defense behavior score during the dehorning procedure compared with all other treatments. Furthermore, the CON group exhibited more ear flicks than the BUP and LID + MEL groups postdehorning. At 4 h and 24 h after dehorning, the LID + MEL group had a lower average prostaglandin E₂ metabolites concentration compared with all other treatment groups. These data showed that administration of bupivacaine liposome suspension as a cornual nerve block at the time of dehorning was as effective at controlling pain as a multimodal approach of lidocaine and meloxicam.

Disbudding and dehorning practices for preweaned dairy calves by farmers in Wisconsin, USA

Many dairy farmers in North America disbud or dehorn their cattle to improve human and animal safety. The Farmers Assuring Responsible Management (FARM v. 4.0) program requires that disbudding be performed before 8 wk of age with pain-control medication. The objective of this observational cross-sectional study was to quantify disbudding and dehorning practices of Wisconsin dairy producers to target future extension programming. Responses from 217 Wisconsin dairy producers and calf raisers were collected via digital surveys distributed at extension events and through industry contacts. Of the 217 respondents, 188 performed on-farm disbudding themselves. Most respondents (61%) used caustic paste as their primary method, which was most commonly applied on the day the calf was born (53%). Hot iron was used by 32% of respondents, and surgical methods (gouge, scoop, or wire saw) were used by 6% of respondents. Hot-iron disbudding was most commonly performed at 4 to 8 wk of age (41%) and 1 to 4 wk of age (33%), whereas surgical methods were most commonly performed at 8 wk or older (73%). Pain-control medication was used by 43% of respondents. Specifically, 35% used an anti-inflammatory, and 21% used a local nerve block. Veterinary involvement in creating the disbudding protocol was associated with increased odds of using pain control. Respondents with a target weaning age of ≥10 wk had greater odds of complying with FARM disbudding requirements and were also more likely to use polled genetics. Respondents aged 18 to 34 and respondents with >60 calves were more likely to have made changes to their disbudding or dehorning protocol in the last decade. Although use of pain control was higher than in previous US studies, full adoption of pain management requires further extension efforts. Veterinarians appeared influential on adoption of pain control, and their involvement may encourage adoption of pain management. Further research should investigate how the implementation of new FARM v. 4.0 standards will change the disbudding and dehorning practices of American dairy producers.

Dairy calves show behavioural responses to hot iron disbudding after local anaesthesia with procaine

BACKGROUND

The efficacy of procaine as anaesthetic for disbudding of calves is largely unknown. Likewise, information about effect of interval from local anaesthesia to disbudding and the size of the hot iron used is missing.

METHODS

A total of 167 dairy calves were disbudded after cornual nerve block with procaine. Time from administration of anaesthetic to disbudding varied, and calves were disbudded using two different sizes of hot iron. The calves' behavioural responses to disbudding were recorded based on (1) getting up, (2) kicking, and (3) lifting head. Using logistic regression, the associations between calves showing at least one of these three behaviours and interval from administration of anaesthetic to disbudding and size of the hot iron were evaluated.

RESULTS

Overall, 42% of calves showed at least one of the three behaviours, even though they had received a cornual nerve block prior to disbudding. Using the large hot iron was associated with a 2.3 times higher odds of the calf reacting behaviourally compared to the small iron. Interval from administration of anaesthetic to disbudding was not significantly associated with the odds of behavioural responses.

CONCLUSION

Approximately 40% of calves disbudded after cornual nerve block with procaine showed signs of inadequate local anaesthesia. This was especially problematic when hot irons with larger tips were used.

Evaluation of a carbon dioxide laser scalpel for disbudding Holstein calves: A pilot study

Cautery hot-iron disbudding is a painful routine husbandry practice performed on many dairy farms and calf rearing facilities. Refinements to eliminate or reduce the pain associated with disbudding are desired. Carbon dioxide (CO₂) laser scalpels cut and ablate tissue using high-power light energy. The objective of this study was to test the utility of a CO₂ laser scalpel in bovine disbudding and to compare healing and pain measures with those of cautery hot-iron disbudding. Twelve Holstein bull calves (6-39 d of age) were enrolled in the study. Calves were randomly assigned into groups that were disbudded with a CO₂ laser scalpel (n = 6) or cautery hot iron (n = 6). Calves were sedated with xylazine for the procedure and were given oral meloxicam and a local anesthetic block for analgesia. Outcome measures were maximum surface temperature by infrared thermography, mechanical nociception threshold (MNT) tests, and digital images for wound healing. The infrared thermography and MNT measures were collected before disbudding and out to 72 h postprocedure. Images for wound healing were collected before disbudding and at 6, 24, and 72 h and 7, 14, 28, and 42 d postdisbudding. Overall maximum surface temperatures were not different between groups (35.3 ± 0.3°C vs. 36.0 ± 0.3°C for laser and hot iron, respectively). No differences in overall MNT measures were noted between the laser calves (2.28 ± 0.19) and the hot-iron calves (2.42 ± 0.19 kg of force). All 6 calves in the laser group were completely healed by d 42, whereas only 4 out of 6 hot-iron calves were fully healed. These results suggest that disbudding calves using a CO₂ laser scalpel may be painful based on the outcomes measured. Further research that focuses on pain associated with time points beyond those used in this study and that performs the procedure in unsedated calves is needed to fully evaluate its utility.

An Investigation into the Perceptions of Veterinarians towards Perioperative Pain Management in Calves

Simple Summary

Despite developments in animal welfare science regarding perioperative pain management in calves (Bos taurus), there are concerns that current knowledge has not been adopted in practice. Given that the perceptions of veterinarians have implications for how the welfare needs of calves are assessed and managed in practice, this study sought to quantify veterinary perceptions towards perioperative pain management in calves, including barriers to its use and whether demographic differences may influence those perceptions. A nationwide survey was electronically distributed to veterinarians registered with the Veterinary Council of New Zealand. Veterinarians largely associated multimodal pain management with the greatest reduction in perioperative pain. Most veterinarians also perceived that postprocedural pain persists beyond 24 h for disbudding and castration and did not support the use of differential treatment based on developmental age. Despite this, certain barriers were identified for their potential to inhibit the use of pain management on-farm. While demographic differences were found to influence veterinary perceptions towards perioperative pain management, the findings revealed considerable support among veterinarians for improving pain mitigation in calves. Given the opportunity, veterinarians in New Zealand would likely support strengthening the minimum provisions afforded to calves in practice and policy.

Abstract

While veterinarians are instrumental to the welfare of calves (Bos taurus), limited knowledge exists concerning veterinary perceptions towards perioperative pain management in calves. As a part of a larger, nationwide study investigating the perceptions of veterinarians towards calf welfare, the current work sought to quantify veterinary perceptions towards perioperative pain management, including barriers to its use, and investigate demographic influences affecting those perceptions. An electronic mixed-methods survey was completed by 104 veterinarians registered with the Veterinary Council of New Zealand. The current work revealed that most veterinarians considered a multimodal approach as the most effective method for ameliorating perioperative pain in calves, rejected the practice of differential treatment based on developmental age, and perceived that postprocedural pain persists beyond 24 h for the majority of procedures included in the survey. Despite this, veterinarians identified certain barriers that may inhibit the provision of pain mitigation on-farm, including costs, inadequate recognition of pain, and ingrained farming practices. Certain demographic effects were found to influence perceptions towards perioperative pain management, including gender, the number of years since graduation, and species emphasis. Nevertheless, the current work demonstrated considerable support among veterinarians to improve pain management protocols during routine husbandry procedures. The asymmetries that exist between the current minimum provisions of perioperative pain management and veterinary perspectives suggest that substantive improvements are necessary in order to reconcile New Zealand’s existing regulatory regime with developments in scientific knowledge.

Horn bud size of dairy-bred and suckler-bred calves at time of disbudding

BACKGROUND

Hot-iron disbudding is a common management procedure to prevent horn growth in calves. The study objective was to examine effect of age, breed and sex on horn bud size of dairy-bred and suckler-bred calves at time of disbudding.

RESULTS

The left and right horn bud size (diameter and height in mm) of 279 calves, including dairy-bred Holstein-Friesian (Male (M) = 88) and 191 suckler-bred (86 Charolais, CH; (M = 39, Female (F) = 47), 67 Limousin, LM; (M = 32, F = 35) and 38 Simmental, SI; (M = 22, F = 16) sired)) was measured using a digital calliper at time of disbudding. Calves were retrospectively assigned to two age categories at time of disbudding: 1), 14 to 28 days (d) old and 2), 29 to 60 d old. Holstein-Friesian M calves had a greater horn bud diameter (16.97 v.14.45 mm) and height (7.79 v. 5.00 mm) compared to suckler-bred M calves (P < 0.01), with no difference (P > 0.05) among the suckler-bred calves. Suckler-bred M calves had a greater horn bud diameter (14.46 vs 13.29 mm) and height (5.01 vs 3.88 mm) compared to suckler-bred F calves (P < 0.05). The slopes of the lines of best fit show that horn bud diameter and height increased with age (P < 0.05) for HF, SI male and CH female calves while there was no relationship with age (P > 0.05) for CH and LM male calves, or for SI and LM female calves. Linear regression of age with diameter and with height for each breed and sex showed high variability in the data as indicated by R-squared values ranging from 0.003-0.41 indicating that in the case of the diameter and the height, the weight of the fitting effect was poor.

CONCLUSIONS

Calf age is not a good predictor of horn bud size and recommendations for the disbudding of calves should be based on horn bud size and not on age. The implications of these findings are that calves should be disbudded while horn development is still at the bud stage and when the bud is large enough to be easily palpable/visible, but not so large that disbudding could lead to severe tissue trauma.

Methods for Pain Assessment in Calves and Their Use for the Evaluation of Pain during Different Procedures-A Review

The evaluation and assessment of the level of pain calves are experiencing is important, as the experience of pain (e.g., due to routine husbandry procedures) severely affects the welfare of calves. Studies about the recognition of pain in calves, and especially pain management during and after common procedures, such as castration, dehorning, and disbudding, have been published. This narrative review discusses and summarizes the existing literature about methods for pain assessment in calves. First, it deals with the definition of pain and the challenges associated with the recognition of pain in calves. Then it proceeds to outline the different options and methods for subjective and objective pain assessment in calves, as described in the literature. Research data show that there are several tools suitable for the assessment of pain in calves, at least for research purposes. Finally, it concludes that for research purposes, various variables for the assessment of pain in calves are used in combination. However, there is no variable which can be used solely for the exclusive assessment of pain in calves. Also, further research is needed to describe biomarkers or variables which are easily accessible in the field practice.

Injury alters motivational trade-offs in calves during the healing period

Injury can produce long-lasting motivational changes that may alter decisions made under risk. Our objective was to determine whether a routine painful husbandry procedure, hot-iron disbudding, affects how calves trade off risk avoidance against a competing motivation (i.e., feeding), and whether this response depends on time since injury. We used a startle test to evaluate this trade-off in calves disbudded 0 or 21 days previously and non-injured control calves. For 3 days, calves were individually habituated to the testing arena in which they received a 0.5 L milk meal via a rubber teat. On the 4^th day, upon approaching the milk reward, the calf was startled by a sudden noise. We assessed the duration and magnitude of the calf’s startle response, their latency to return to the milk bottle, and duration spent suckling after startling. No treatment differences were observed in the duration and magnitude of the startle response or in the probability of returning to the bottle after startling. However, among those who did return, disbudded calves spent longer suckling, indicating they accepted more risk in order to feed compared to controls. In addition, calves with 21-day-old injuries tended to return to the bottle faster compared to newly disbudded calves and controls. We suggest that hot-iron disbudding increases calves’ motivation to suckle, as they were more likely to prioritize this behaviour over risk avoidance compared to control calves. This effect was most evident 21 days after disbudding, indicating that injury can produce long-term changes in motivational state.

Mechanical Nociceptive Threshold, Tissue Alterations and Horn Growth in Calves after Injection of Isoeugenol or Clove Oil under the Horn Bud

Disbudding of calves is a common, painful intervention. Due to cytotoxic and anesthetic properties, the injection of clove oil or its component isoeugenol may be less detrimental to animal welfare. We investigated mechanical nociceptive threshold (MNT), possible tissue alterations and horn growth for up to 12 weeks after injection of 1.5 mL clove oil (CLOV), isoeugenol (ISO) or saline (CON) or after hot-iron disbudding (BURN; with local anesthesia and sedation, n = 10/treatment). MNT was measured using von Frey filaments and a pressure algometer at four locations around the horn bud. There was a treatment*time point interaction (linear mixed model, p < 0.05). MNT decreased most strongly and for the longest time for BURN in most calves at least for 3 weeks. For ISO, the decrease was less distinct and most calves' values returned to baseline after 1-2 weeks. MNT in CLOV was intermediate, with decreased values up to 3 weeks in some animals. 12 weeks after the treatment, horn growth was prevented in about 50% of the horns in CLOV and ISO. Tissue alterations such as swellings of the eyelids often occurred in CLOV, but less so in ISO. Our results suggest that injection of isoeugenol causes less pain and thus seems to be beneficial compared to hot-iron disbudding, while clove oil was not advantageous. Regarding the effectiveness of isoeugenol to prevent horn growth, more studies are needed.

Producer and Veterinarian Perspectives towards Pain Management Practices in the US Cattle Industry

Simple Summary

A key aspect to improve animal welfare is to reduce pain experienced by the animal. However, pain management practices have not been widely adopted in the United States (US) cattle industry. Furthermore, for a veterinarian or producer to relieve pain in cattle, analgesics must be provided in an extra-label drug manner. Currently, research describing pain mitigation strategies used by cattle producers and the study of barriers to implement those strategies from a producer or veterinarian perspective is limited. Understanding challenges faced by these stakeholders is key in improving on-farm pain management strategies. Therefore, the objectives of this study were to explore producer and veterinarian perspectives on pain. Albeit analgesia use increased in the past ten years for some producers and the majority of veterinarians, administering analgesics for pain management on US cattle farms remains a challenge. From a producer perspective, drug cost, availability and logistics for administration. From a veterinarian perspective, lack of Food and Drug Administration (FDA) products hinders the support of on-farm protocols requiring extra-label drug use. Future steps to improve analgesic use on-farm include identifying and approving drugs that demonstrate efficacy for managing pain and disseminating educational resources to support stakeholders in both the implementation and drug withdrawal process.

Abstract

Producers and veterinarians are considered responsible for improving animal welfare, as they are responsible for implementing practices that directly impact the animal’s well-being. Most husbandry procedures performed in cattle do not include pain mitigation, and understanding challenges faced by these stakeholders to use analgesics is key in improving on-farm pain management strategies. Therefore, the objectives of this study were to explore producer and veterinarian perspectives on pain management practices by (1) exploring inquires received by Food Animal Residue Avoidance Databank (FARAD) regarding analgesic use in cattle and (2) using a survey instrument to identify factors that impact pain management implementation in the US cattle industry. Albeit analgesia use increased in the past ten years for some producers and the majority of veterinarians, administering analgesics for pain management on US cattle farms remains a challenge. From a producer perspective, drug cost, availability and logistics for administration. From a veterinarian perspective, lack of Food and Drug Administration (FDA) products hinders the support of on-farm protocols requiring extra-label drug use. Future steps to improve analgesic use on-farm include identifying and approving drugs that demonstrate efficacy for managing pain in cattle and disseminating educational resources to support stakeholders in both the implementation and drug withdrawal process.

Negative play contagion in calves

Play is a strong outwardly directed, emotional behaviour and can contagiously spread between individuals. It has been suggested that high-playing animals could 'seed' play in others, spreading positive affective states. Despite the current interest in play contagion there has been no previous attempt to measure the strength of the play contagion effect. The calf (Bos taurus) is ideal for testing the strength of play contagion as play in calves is strongly related to energy intake from milk. We manipulated play in calves through their milk allowances and housed the calves in uniform groups all on the same milk allowance (high = UHigh or low = ULow) or in mixed groups with calves in the same group receiving either a high (= MHigh) or low (= MLow) milk allowance. We measured locomotor play using accelerometers on two consecutive days when calves were four and eight weeks old, in order to study play contagion over a protracted developmental window. We anticipated that differences in the level of play contagion between treatment groups would result in difference in the play levels observed in the MLow and ULow individuals. Contrary to our expectations we found that spontaneous play was suppressed in the high-milk calves housed in mixed groups (MHigh), in comparison to calves housed with group mates all receiving high-milk (UHigh). These results are the first to quantify a negative play contagion effect, particularly in a situation of long-term contact, and may suggest that negative contagion has a stronger effect on play behaviour than positive contagion.

Dairy Calf Welfare and Factors Associated with Diarrhea and Respiratory Disease Among Chilean Dairy Farms

Simple Summary

Since 2013, a Chilean law regulates the welfare of farm animals. Despite advances in scientific knowledge and legislation, many farms use management practices that can be detrimental to animals. The objectives of this study were to describe common management practices that may affect the welfare status of unweaned dairy calves and identify factors associated with diarrhea and respiratory disease. We visited 29 dairy farms and collected information on management practices, environment, and animal health. Management practices identified as risk factors for poor calf welfare were: reliance on the mother to provide colostrum, use of restrictive milk feeding (<4 L/day), disbudding performed with no pain control, and lack of appropriate euthanasia protocols. Factors associated with diarrhea were: frequency of bed cleaning, calf cleanliness score, type of milk, and herd size. Factors associated with respiratory disease were: calf cleanliness score, pen space allowance, and colostrum quality evaluation. Showing critical points that impact the health and welfare of dairy calves facilitates the implementation of improvement strategies.

Abstract

This study aimed to describe management practices that may compromise the welfare of unweaned dairy calves on 29 dairy farms in Chile, and identify factors associated with diarrhea and respiratory disease (n = 700 calves). Evaluations were divided into protocol-, facility-, and animal-based measurements. Calf diarrhea and respiratory disease data were analyzed using logistic regression models. Management practices identified as risk factors for poor calf welfare were: relying on the mother to provide colostrum (48.0% of the farms); using restrictive milk feeding (65.5%), and unpasteurized waste milk (51.7%); giving water after 30 days of age (17.2%); disbudding without analgesia (89.6%) or anesthesia (79.3%); lacking euthanasia protocols (61.5%). Factors significantly (p < 0.05) associated with increased odds of diarrhea were: cleaning the calves’ bed once a week and 2–3 times a week compared with every day, using milk replacer and untreated waste milk compared with treated waste milk (pasteurized or acidified), animals scored dirty in the calf cleanliness score compared with clean animals, and greater herd size. Factors significantly associated with increased odds of respiratory disease were: less pen space allowance (<1.8 m²), farms that did not check colostrum quality, and animals that scored dirty and moderately dirty compared with clean calves. These results suggest the need to improve specific management practices associated with reduced welfare and health in dairy calves in Chile.

Behavioral changes in calves 11 days after cautery disbudding: Effect of local anesthesia

Hot-iron disbudding results in painful burn wounds that take weeks to heal. Spontaneous behaviors indicative of pain are apparent in the immediate hours after disbudding, but whether they occur later in the healing process is unknown. To evaluate whether ongoing pain was present around the time the necrotic tissue loosens from the scalp, we tested the effect of administration of local anesthetic 11 d after the procedure. Disbudded female Holstein and Jersey calves (n = 24) were randomly assigned to receive an injection of local anesthetic (lidocaine) or saline at the cornual nerve on both sides of the head. We recorded the frequency of 8 behaviors for 75 min: head shakes, head rubs, head scratches, ear flicks, tail flicks, bucks/jumps/kicks, grooming, and transitions between standing and lying. Calves treated with lidocaine shook their heads less and tended to flick their ears less than calves administered saline, consistent with the effects of pain relief previously reported in the immediate hours after disbudding. These calves also rubbed their head against the sides of the pen more often, suggesting lidocaine suppressed wound protective behavior. Head shaking and head scratching became more common in the last 25 min compared with the first 50 min in calves treated with lidocaine, consistent with the return of sensation to the disbudding wounds. No treatment differences in the other behaviors were observed. These results suggest that calves experience ongoing pain 11 d after hot-iron disbudding, adding to a growing body of evidence that pain persists for weeks after the procedure.

Comparison of two topical treatments on wound healing 7 days after disbudding of calves using thermocautery

Aims To compare wound healing 7 days after cautery disbudding of dairy calves treated immediately after disbudding with a traditional antimicrobial spray (OXY) or with a topical anaesthetic gel containing cetrimide, adrenaline and two local anaesthetics, lignocaine and bupivacaine (TA). Method Eighty-one female dairy calves between 6-8 weeks of age were disbudded using a standard cautery disbudding protocol (sedation, cornual block, and analgesia), with complete removal of the horn bud. After disbudding, the wound on the right and left horn buds within each animal were randomly allocated to receive either OXY or TA. One week after disbudding, wounds were visually assessed for the presence of exudate, necrotic tissue, crust, or granulation tissue which were each assigned a grade from 1-3, where 1 = no evidence, 2 = moderate presence; and 3 = marked presence. Results At 7 days after disbudding, the prevalence of wounds with exudate or necrotic tissue was very low, and independent of treatment. The odds of a disbudding wound treated with TA being scored as having granulation tissue and was 5.2 (95% CI = 1.72-15.7) times that of a wound treated with OXY. Conversely, the odds of wounds treated with TA being scored as having crusts was 0.18 (95% CI = 0.06-0.57) that of a wound treated with OXY. No sign of infection was seen in any calves. Conclusion and clinical relevance The greater prevalence of granulation tissue and reduction in crusting in disbudding wounds treated with topical anaesthetic gel compared to those treated with the antimicrobial spray suggests that use of the topical anaesthetic gel may speed wound healing compared to using antimicrobial spray. This should be further tested in a larger study undertaken over a longer period.

Randomized control trial assessing the efficacy of pain control strategies for caustic paste disbudding in dairy calves younger than 9 days of age

Disbudding is a common procedure practiced in the dairy industry and is known to cause pain when performed without pain control. Dairy producers who disbud calves with caustic paste are less likely to provide pain control than those using cautery. Little research has been conducted on pain control for caustic paste disbudding and no studies have specifically examined calves under 9 d of age. The objective of this study was to evaluate the efficacy of local anesthesia and nonsteroidal anti-inflammatory drug analgesia on indicators of pain and inflammation in dairy calves disbudded using caustic paste. One hundred forty Holstein heifer calves 1 to 9 d of age were enrolled in 28 blocks and randomly allocated to 1 of 5 treatments: sham control (SH); positive control (POS); lidocaine cornual nerve block (LC); meloxicam (MEL); and lidocaine cornual nerve block plus meloxicam (LCM). We measured outcomes including serum cortisol and haptoglobin, pressure sensitivity, and lying behavior. Data were analyzed using mixed linear regression models with treatment as a fixed effect, baseline values as a covariate, and trial block as a random effect. Compared with the POS group, the LCM group had reduced serum cortisol at 15, 30, 45, and 60 min post-disbudding; cortisol values were not different between LC, LCM, and SH calves at these time points. At 60, 90, 120, and 180 min post-disbudding, LCM calves had reduced cortisol compared with LC calves, whereas, values did not differ between LCM and SH calves at these time points. At 3 to 4 d post-disbudding, the LCM group tended to have reduced haptoglobin, but no differences were found between groups at 180 min and 7 d post-disbudding. At 60, 90, and 120 min post-disbudding, LC and LCM treated calves had decreased pressure sensitivity compared with other groups. No differences were seen in pressure sensitivity between groups at 180 min, 3 to 4 or 7 d post-disbudding. No differences in lying behavior were found between treatment groups on any of the 7 d following disbudding. These findings demonstrate that the combination of a local anesthetic with a nonsteroidal anti-inflammatory drug is beneficial for reducing indicators of pain and inflammation in young calves disbudded with caustic paste.

The effect of early burn injury on sensitivity to future painful stimuli in dairy heifers

Animals that experience painful procedures as neonates are more sensitive to pain later in life. We evaluated whether disbudding with a heated iron at 3 (n = 12), 35 (n = 9), or 56 (n = 20) d of age affected heifers’ pain responses to vaccine injections at 11 mo of age. Heifers responded to the injection procedure with struggling and changes in eye temperature and heart rate variability compared to a sham procedure the day before, and still had a heightened response 6 d later, regardless of disbudding age. However, some heart rate variability indices suggested increased sympathetic dominance in heifers disbudded at 35 d, compared to the other 2 age groups, independent of the injection procedure. We also found that heifers disbudded at 3 or 35 d had a higher mean heart rate after the injection procedure compared to those disbudded at 56 d. We conclude that: (1) heifers find injections aversive; and (2) there is some evidence that disbudding age influences autonomic nervous system activity later in life.

Acute cortisol and behavior of dairy goat kids administered local anesthesia, topical anesthesia or systemic analgesia prior to cautery disbudding

Cautery disbudding of goat kids causes thermal burns and tissue destruction, which results in acute and post-operative pain and negatively affects animal welfare. The objectives of this study were to evaluate acute cortisol concentrations and behavioral responses associated with (1) injecting a lidocaine ring block prior to cautery disbudding and comparing this to saline injections and (2) pain mitigation strategies (lidocaine ring block, topical eutectic mixture of local anesthetics (EMLA) cream, oral meloxicam) on cautery disbudded dairy goat kids. Sixty doe kids were allocated to one of six treatments: (1) disbudding without pain relief (DB), (2) a ring block using 1% lidocaine (DBLA) 20 min before disbudding, (3) saline injection (DBSA) 20 min before disbudding, (4) oral meloxicam 60 min before disbudding (DBMEL), (5) EMLA cream rubbed into the buds 60 min before disbudding (DBEM) and (6) handled but not disbudded (HAND). Blood was sampled pre- (-20 and -5 min) and post-treatment (15 and 30 min) to assess plasma cortisol concentrations and behavior during treatment was recorded using video cameras to assess rump movements, tail shakes and vocalizations (values presented as number/treatment). DBLA and DBSA kids showed elevated cortisol above baseline 5 min pre-disbudding (after injections) (P ≤ 0.01), which was no different to cortisol 15 min post-disbudding (P > 0.05). Rump movements and tail shakes of DBLA (5.5 ± 0.8 and 6.9 ± 1.2) and DBSA kids (5.6 ± 0.8 and 7.2 ± 1.2) were no different to those of DB kids (P > 0.10). Cortisol was elevated from baseline for 30 min post-disbudding for DBEM kids and DBMEL kids (P ≤ 0.05). Rump movements, tail shakes and vocalizations of DBEM (5.7 ± 0.8, 6.3 ± 1.2 and 11.1 ± 1.6) and DBMEL kids (5.3 ± 0.8, 8.0 ± 1.2 and 9.1 ± 1.6) were no different to those of DB kids (P > 0.05). HAND kids showed no change in cortisol over time (P > 0.10) and performed fewer rump movements, tail shakes and vocalizations than all treatments (P ≤ 0.01). In conclusion, lidocaine injection using a ring block appears to cause more pain than handling alone and may not reduce pain associated with cautery disbudding; therefore, a lidocaine ring block may not be a useful pain mitigation strategy for disbudding dairy goat kids. There was no evidence that meloxicam reduced acute pain and EMLA cream may have intensified the pain associated with disbudding. Further research on efficacious pain mitigation strategies for cautery disbudding of dairy goat kids is required.

Conditioned place preference reveals ongoing pain in calves 3 weeks after disbudding

Hot-iron disbudding, a routine procedure that prevents horn bud growth through cauterization, is painful for calves. The resulting burns remain sensitive to touch for weeks, but it is unknown whether calves experience ongoing, non-evoked pain. We evaluated conditioned place preference for analgesia in 44 calves disbudded or sham-disbudded 6 hours (Day 0) or 20 days (Day 20) before testing (n = 11/treatment). Calves were conditioned to associate the effects of a lidocaine cornual nerve block with the location and pattern of a visual stimulus, and a control injection of saline with the contrasting stimulus. On Day 0, disbudded calves tended to prefer the lidocaine-paired stimulus over the saline-paired one, suggesting that they found analgesia rewarding. On Day 20, sham calves avoided the lidocaine-paired stimulus, consistent with humans’ experience of this drug being painful. Disbudded calves on Day 20 did not show this aversion, suggesting that they traded off the short-term pain of the lidocaine with the longer-term analgesia provided. Day 0 sham calves did not avoid the lidocaine-paired stimulus, likely because they received less than half the dose of Day 20 calves during conditioning. Thus, higher doses of lidocaine are aversive to uninjured animals, but disbudded calves are willing to engage in this cost. We conclude that calves experience ongoing pain 3 weeks after disbudding, raising additional welfare concerns about this procedure.