Progress in pain management to improve small ruminant farm welfare

Abstract

Pain management to improve the welfare of livestock during aversive husbandry interventions is increasingly expected of global farming systems, although few products are available for use by farmers to achieve this. An exception is the ‘spray-on’ topical anaesthetic (TS) formulation containing lignocaine and bupivicaine (Tri-Solfen®; Bayer Animal Health, Pymble, NSW, Australia) originally developed for the mulesing operation in sheep in Australia, where breech skin is removed to create a ‘bare area' that significantly decreases the risk of myiasis from Lucilia cuprina. Over 40 million Merino lambs have now received pain management and some flocks have continued mulesing to manage life-time risk of blowfly strike until ‘wrinkle’ phenotypes are removed through genetic improvements. This innovation enabled investigations of TS spray for pain from other procedures in lambs and kids (and calves), including surgical castration, tail-docking, disbudding, ear-tagging and shearing wounds. Our observations suggest that practical pain management during surgical interventions should commence with inhibition of nociception and that TS is far more efficacious than previously considered. For multi-modal pain management, ameliorating wound sensitisation by the use of nonsteroidal anti-inflammatory drugs (NSAID’s) is increasingly available and may also have a role, particularly when cautery is used (eg tail docking and disbudding). Further modification of pain through centrally-acting drugs altering physiology and cognition, such as low dose xylazine, is also possible but requires closer veterinary supervision than is available in most extensive farming systems. We note that Tri-Solfen® use by farmers has improved welfare attitudes on many farms and the approach has potential application for global livestock industries.