The effect of breed, sex and oral meloxicam administration on pain biomarkers following hot-iron branding in Hereford and Angus calves

Self-Administration of Meloxicam via Medicated Molasses Lick Blocks May Improve Welfare of Castrated Calves

The self-administration of meloxicam via medicated feed is a novel concept that could enable non-invasive, pre-emptive and long-term analgesia. Forty Bos taurus male calves were randomly allocated to four treatment groups: no castration (PC), surgical castration (NC), surgical castration with subcutaneous meloxicam (M), and surgical castration with medicated lick blocks (ML). Data collection occurred at various timepoints over 13 days following treatment. Plasma concentration of meloxicam was greater in ML compared to M calves at all timepoints except day 1 (p < 0.001); however, variation between ML individuals was high (standard deviation = 1.68). There was no effect of treatment on scrotal diameter or scrotal temperature. Wound morphology scores were improved in ML compared to NC calves. Eating observations were greater in ML calves immediately post-castration, followed by M calves at 3 h post-castration (p < 0.001). ML calves were observed locomoting more (p = 0.0032) and lying less (p < 0.001) than PC calves. These findings indicate that meloxicam-medicated lick blocks may provide a practical option for a longer duration of pain mitigation for surgically castrated calves. Conclusions are limited by the complexities of assessing pain in cattle, and further research into the toxicity effects of continued administration of meloxicam is recommended.

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.

Kinetics of Inflammatory Mediators in the Immune Response to Burn Injury: Systematic Review and Meta-Analysis of Animal Studies

Burns are often accompanied by a dysfunctional immune response, which can lead to systemic inflammation, shock, and excessive scarring. The objective of this study was to provide insight into inflammatory pathways associated with burn-related complications. Because detailed information on the various inflammatory mediators is scattered over individual studies, we systematically reviewed animal experimental data for all reported inflammatory mediators. Meta-analyses of 352 studies revealed a strong increase in cytokines, chemokines, and growth factors, particularly 19 mediators in blood and 12 in burn tissue. Temporal kinetics showed long-lasting surges of proinflammatory cytokines in blood and burn tissue. Significant time-dependent effects were seen for IL-1β, IL-6, TGF-β1, and CCL2. The response of anti-inflammatory mediators was limited. Burn technique had a profound impact on systemic response levels. Large burn size and scalds further increased systemic, but not local inflammation. Animal characteristics greatly affected inflammation, for example, IL-1β, IL-6, and TNF-α levels were highest in young, male rats. Time-dependent effects and dissimilarities in response demonstrate the importance of appropriate study design. Collectively, this review presents a general overview of the burn-induced immune response exposing inflammatory pathways that could be targeted through immunotherapy for burn patients and provides guidance for experimental set-ups to advance burn research.

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.

Limited Effects of Pain Control Treatments on Behaviour and Weight Gain of Pure and Crossbred Nellore Heifer Calves When Subjected to Hot-Iron Branding

Hot-iron branding is still commonly performed in cattle farming in tropical countries, and possibly has negative consequences for animal welfare and weight gain. This study examined the behavioural and weight gain responses of pure and crossbred Nellore heifer calves subjected to hot-iron branding on the cheek, without and with use of anaesthesia and analgesia. Ninety-two heifer calves, around 120 days old, were studied prospectively when subjected to hot-iron branding on the cheek (a statutory procedure in Brazil following brucellosis vaccination). Four randomly selected groups of calves were allocated to four treatments: no pain control (CO); subcutaneous anaesthetic local block (LA); intramuscular analgesia (meloxicam) (LT); and local anaesthesia plus meloxicam (LL). Behaviour, flight speed and body weight were evaluated before, during, and five (5-d) and 60 days (60-d) after branding. For these parameters, the only difference observed was higher tension in the CO group 5-d post-branding, suggesting a short-term negative effect of branding without pain control. The limited effects of the pain control treatments suggest interference in pain assessment by other factors, such as expression of fear and stress. Despite the lack of differences observed in behaviour and production parameters, facial hot-iron branding is an obvious welfare issue and, due to the additional handling involved, adoption of a simple pain relief protocol is not sufficient to minimise the welfare impact.

Pain in the hours following surgical and rubber ring castration in dairy calves: Evidence from conditioned place avoidance

Male cattle reared for beef are typically castrated. Male calves born on dairy farms are increasingly reared for beef, so a better understanding of how to humanely perform this procedure in dairy systems is now required. We studied the short-term affective responses of dairy calves to castration using a conditioned place aversion paradigm. Young Holstein bulls (16 d old, n = 30) were castrated by either rubber ring (n = 15) or surgery (n = 15), and then kept in a visually distinctive recovery pen for 6 h after the procedure. Calves acted as their own control and were sham castrated and allowed to recover for 6 h in another visually distinctive pen. During both castration and sham procedures, calves received a sedative (xylazine, 0.2 mg/kg), local anesthetic (lidocaine, 5 mL), and a nonsteroidal anti-inflammatory (meloxicam, 0.5 mg/kg). After exposure to both treatments (castration and sham), calves were tested for place aversion by providing free access to the 2 pens where they experienced the different treatments. Calves were tested for aversion 48, 72, and 96 h after their last treatment. We recorded how much time they spent in each pen and where they chose to rest. We did not find differences in time spent resting or resting location, suggesting that calves did not form a more negative memory of castration in comparison to the sham procedure. The lack of treatment effects may be due to features of our testing paradigm, including effective multimodal pain control during the 6-h conditioning period and limiting testing to the first days after the procedure.

Frequency of disagreements between producers and veterinarians about pain management in cattle

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Cattle producers and veterinarians engage in conversations about pain mitigation.

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Differences in opinion are infrequent and do not appear to affect their relationships.

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Both producers and veterinarians rely on personal experiences to identify pain in cattle.

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There is an opportunity to develop educational programs regarding pain management decisions.

Pain management is a key element of ensuring animal welfare. Although the opinions of both producers and veterinarians affect decisions about the use of pain mitigation on cattle operations, little is known about how they communicate about this topic. Given the importance of a veterinary-client-patient relationship for developing pain mitigation protocols, understanding the communication between veterinarians and producers is key to the implementation of robust, industry-wide pain management protocols. The objectives of this survey were to understand how producers and veterinarians may respond to disagreements about pain mitigation and to determine where respondents obtain their knowledge about pain recognition and treatment. Results presented herein are part of a larger study previously described. An online survey was distributed to 6 cattle industry groups. Surveys that were >80% complete were included for analysis (n = 1,066). Approximately half of the respondents identified as producers (497, 46.6%) and half as veterinarians (569, 53.4%). The majority of producers believed that disagreements about the use of pain management in cattle never affected their relationship with their veterinarians (349, 70.2%). The veterinarian respondents indicated more disagreements, although the frequency was relatively low, with 43.9% (250) indicated having a disagreement less than once a year. Most producers and veterinarians indicated they were either “extremely unlikely” or “somewhat unlikely” to dissolve the relationship completely if disagreements about pain management arose (veterinarians: 398/569, 70%; producers: 294/497, 59.1%). Veterinarians and producers reported gaining their knowledge about pain recognition from a variety of sources including personal experience and continuing education opportunities. Disagreements about pain mitigation occurred infrequently; however, this could be due to few discussions about pain management in general. These results indicated that there is opportunity for veterinarians to engage with their producers in more discussions about pain management.