Antlers, unique to male deer species (apart from reindeer), exhibit remarkable characteristics such as the ability to develop a branched architecture and undergo annual regeneration from the base [1]. Unlike permanent horns, antlers are temporary structures that serve various purposes, including consumption and transportation to meat processing plants [2]. Velvet antlers have been consumed for centuries in Asian countries like China and Korea [1]. In commercial deer farming, yearling stags raised for venison production are typically transported to processing plants after their antlers are removed during their first year of growth [3].

Antler removal is considered a significant surgical procedure [4]. It is recommended that antlers be removed before autumn and should not exceed a length of 110 mm prior to transportation [4]. To ensure animal welfare, proper analgesia is required during antler removal, either by veterinarians or farmers under veterinary supervision, following the Velveting Code of Practice and recommendations outlined by the Ministry of Primary Industries of New Zealand in 2016. Currently, the industry standard involves using a lidocaine ring block applied around the base of each antler [5]. Lidocaine's onset is rapid, but its duration of action is relatively short (60 to 90 min) [6], leading to potential post-procedural pain [7]. An alternative method for antler removal involves the use of NaturOTM rings, which are sturdy rubber rings applied around the base of the pedicle [8]. These rings offer local desensitization and help control bleeding. However, this application is limited to yearling deer that require antler removal before slaughter [3].

To date, the only pain management technique developed for antler removal in deer is the local ring block, utilizing lidocaine with a duration of action of only 90 min or bupivacaine with a duration of 4 to 7 h, depending on the formulation [9]. Furthermore, there have been reports of postoperative infections at the site of antler removal in deer inspected at slaughter plants [10], [11]. These factors highlight the need for improved wound management and pain relief strategies for open wounds associated with antler removal.

Collagen, known for its exceptional biocompatibility and biodegradability, serves as an ideal vehicle for drug delivery [12], [13]. Collagen is abundant in animal tissues such as bovine hide, fish skin, and porcine gastrointestinal tract. They are all commonly used sources for extracting collagen. [14]. Extracted collagens can be repurposed into various forms such as pads, gels, or sprays [15], [16], which have shown potential in promoting hemostasis, tissue scaffolding, wound healing, and drug delivery [17], [18]. Incorporating nanoparticles into collagen fibers can enhance their tensile strength, mechanical stability under varying pH and temperature conditions, and prolong their retention in tissues, inhibiting absorption and thereby slowing the degradation of collagen hydrogels [19].

In summary, this study aims to develop collagen-based formulations incorporating local anesthetics to improve wound management and alleviate pain after antler removal in red deer. The study involved the preparation of collagen nanocomposites, in vitro testing of drug release rates, pharmacokinetic analysis of total drug release in red deer, and evaluation of the analgesic efficacy of collagen nanocomposite pads. The experiments conducted included the formulation of novel collagen nano-composites with local anesthetics, assessment of drug release rates using In vitro Drug Release Test (IVDRT), pharmacokinetic analysis of drug release in red deer post-velvet removal, and evaluation of the analgesic effectiveness of collagen nanocomposite pads after antler removal.