Role of Topical Anaesthesia in Pain Management of Farm Animals, a Changing Paradigm

SIMPLE SUMMARY: Improved on-farm animal welfare is increasingly expected by consumers of livestock products, yet motivating farmers to adopt practice changes is challenging, with many presuming increased regulations are required. Husbandry procedures are routinely conducted in livestock production globally, mostly without analgesia, despite recognition they cause pain. Similarly, debilitating transboundary viral infections, including foot-and-mouth disease (FMD), occur in numerous countries, with affected animals often treated with antimicrobial preparations and infrequently with pain relief, despite obvious suffering. A commercially available, farmer-applied spray-on topical anaesthetic formulation (TAF), containing two topical anaesthetics, an antiseptic and adrenalin in a gel matrix (Tri-Solfen(®), Medical Ethics, Australia), provides almost instant pain relief when applied to wounds and lesions incurred during husbandry procedures and FMD infections, respectively, with field trials demonstrating that pain and suffering are markedly reduced. Additional benefits occur when the TAF is used with a non-steroidal anti-inflammatory drug (NSAID), with parenteral and oral applications increasingly available. As the TAF hastens healing rates, improves animal demeanour and provides antisepsis, the requirement for antimicrobials to manage risk of secondary bacterial infections is diminished, offering antimicrobial-resistance (AMR) stewardship. As pain management improves recovery rates, it enhances farmer animal health and welfare attitudes and increases livestock productivity and efficiency. ABSTRACT: Field evidence indicates that livestock producers are motivated by access to products that readily deliver pain management during husbandry interventions and, more recently, viral epidermal infectious diseases, including FMD. There has been impressive adoption in Australia of a farmer-applied spray-on topical anaesthetic wound formulation (TAF; Tri-Solfen(®), Medical Ethics, Australia), initially for managing pain of the breech modification ‘mulesing’ procedure that reduces susceptibility of sheep to flystrike. Over 120 million lambs have now received pain relief and cattle producers have commenced using the TAF for a range of husbandry procedures. This product has demonstrated efficacy for surgical castration and tail docking of lambs, surgical castration and dehorning of calves, surgical castration of piglets, debridement of lesions of the hoof for lame cattle and, importantly, treatment of clinical FMD lesions, including decubitus ulcerations occurring from prolonged recumbency. Multimodal use of an NSAID for improved pain management is advocated, particularly meloxicam, available by prescription from veterinarians for injection and as an oral formulation (Ilium Buccalgesic(®), Troy Laboratories, Australia), with current work assessing the potential for prolonged delivery in molasses blocks. Increased use of TAF with NSAIDs significantly reduces pain and suffering in livestock, with enhanced healing of FMD lesions, reduced viral loads from Orf infections in lambs and diminished necessity of ‘antibiotic cover’, assisting antimicrobial-resistance (AMR) stewardship.