Chemical analgesia for velvet antler removal in deer

Minimizing pain in deer antler removal: Local anaesthetics in ZnO nanoparticle based collagen dressings as a promising solution

Antler removal in deer is a common practice for various purposes, including meat production and traditional medicine. However, the current industry practice using lidocaine as a local anesthetic has limitations, such as short duration of action and the potential for postoperative infections. In this study, we investigated the performance of a ZnO collagen nanocomposites loaded with local anesthetics to improve wound management and alleviate pain associated with antler removal in red deer. The research involved the preparation of collagen nanocomposites with local anesthetics and testing the drug release rates using in vitro drug release tests. Pharmacokinetic analysis was performed to evaluate the total drug release from the collagen matrix in red deer after velvet removal. Additionally, the analgesic efficacy of these collagen nanocomposite dressings was assessed after antler removal in red deer. Functionalized ZnO nanoparticles were incorporated into collagen fibers to enhance their mechanical stability and prolong drug release. The developed collagen nanocomposites aimed to slowly release local anesthetics and promote wound healing. The findings of this research could have significant implications for improving the pain management and wound healing associated with antler removal in deer. The results obtained from the in vitro drug release tests, pharmacokinetic analysis, and analgesic efficacy evaluations provide valuable insights into the understanding and development of novel approaches for antler removal procedures in red deer. The findings contribute to the advancement of knowledge in this field and lay the foundation for future implementation of improved techniques and protocols for antler removal.

Analgesic efficacy of articaine hydrochloride for velvet antler removal in red deer (Cervus elaphus) and analysis of drug residues in the harvested velvet antlers

AIMS

To investigate the analgesic efficacy of articaine hydrochloride for antler removal in red deer (Cervus elaphus) following S/C administration as a ring block, and to quantify the residue concentrations of articaine compared to lignocaine in the harvested antlers.

METHODS

Articaine hydrochloride (40 mg/mL) was administered to 10 male red deer as a ring block around the base of each antler at 1 mL/cm of pedicle circumference. Analgesia was evaluated by determining the response to a saw cut test every 1-minute, until no response was observed. Behaviour during and following removal of antlers was also recorded. Twenty commercially harvested velvet antlers were also collected following S/C administration of 2% lignocaine hydrochloride. A liquid chromatography-mass spectrometry (LC-MS) method for quantification of residues of articaine and lignocaine in velvet antlers was developed and validated.

RESULTS

In red deer administered 4% articaine hydrochloride as a ring block, the median interval to analgesia was 4 (min 3, max 5) minutes and no deer showed withdrawal responses during antler removal. There were no signs of toxicity or adverse effects up to 2 hours after administration. The sample preparation method developed for the LC-MS was simple and had acceptable extraction recoveries of articaine and lignocaine from the velvet antlers. The lower limits of quantification of lignocaine and articaine were 5 and 50 ng/g, respectively. Mean concentrations of articaine in antlers following ring block with 4% articaine hydrochloride were 1.50 (SD 1.09) mg/kg, and of lignocaine following ring block with 2% lignocaine hydrochloride were 0.66 (SD 0.71) mg/kg.

CONCLUSIONS AND CLINICAL RELEVANCE

A ring block with 4% articaine hydrochloride at a dose of 1 mL/cm of pedicle circumference provided effective analgesia for velvet antler removal in red deer. The LC-MS method developed and validated to quantify articaine and lignocaine was simple and sensitive. Based on these results, articaine hydrochloride appears to be an effective alternative to lignocaine hydrochloride for velvet antler removal. However, further studies to evaluate the safety and residue concentrations of articaine and articainic acid are required before it can be recommended for use in deer.Abbreviations: DMA: 2,6-dimethylaniline; LC-MS: Liquid chromatography-mass spectrometry; MEGX: Monoethylglycinexylidide; MRL: Maximum residue level.

Sika deer antler as a novel model to investigate dental implant healing: A pilot experimental study

Dental implants are important tools for restoring the loss of teeth. The rapid growth and periodic regeneration of antlers make Sika deer a good and less invasive alternative model for studying bone remodelling in mammals. We developed a special loading device for antlers and analysed the bone reaction around unloaded implants and under immediate loading conditions until osseointegration occurred. In micro-computed tomography images, the density of antler tissue around the implants increased as the loading time increased. This finding was histologically confirmed by the good osseointegration observed in unloaded and loaded specimens. Antler tissue displays a similar healing process to human bone. The use of an antler model is a promising alternative for implant studies that does not require animal sacrifice.

Sedation and chemical restraint of deer

This review examines the properties of chemical immobilising agents of use or potential use in deer for velvet antler removal. The alpha-2-adrenergic agonist, xylazine, is the most commonly used agent for chemical restraint of stags for this purpose in New Zealand. This compound is often combined with an opioid or ketamine to enhance its effectiveness. Concerns about the carcinogenic potential of a xylazine metabolite have led to a call by the deer industry to limit the use of this drug and stimulated enquiry into alternatives. The potent pure opioid agonists, fentanyl, carfentanil and etorphine, are less effective than xylazine when used alone, and their use presents greater risk to operators and animals and is subject to more stringent legal restrictions. Newer alpha-2-adrenergic agonists, detomidine and medetomidine, are more potent than xylazine and unlikely to result in carcinogenic metabolites. Availability of specific alpha-2-adrenergic antagonists further enhances the usefulness of these drugs. The dissociative agent, ketamine, has proven useful for immobilisation of various domestic and wildlife species and captive species of deer but undesirable side effects and the low concentration, relative to the effective dose, of currently available formulations limit its usefulness. Combination of a dissociative agent with an alpha-2-adrenergic agent reduces the required dose of both and enhances their efficacy. A commercially available combination of the dissociative anaesthetic agent, tiletamine, and the benzodiazepine, zolazepam, is more potent than ketamine and induction times are faster. This combination can be manipulated to varying concentrations by dissolution with alpha-2-adrenergic agents. A long-acting neuroleptic agent, zuclopenthixol, has recently been investigated for calming deer and may be an alternative to classical sedative-immobilising agents. Most chemical immobilisation agents used alone or in combination produce respiratory depression and supplemental oxygen has been recommended. All would likely result in some form of chemical residues in velvet antler.