Pigs are highly intelligent, sentient animals with well-developed pain perception systems. Yet pain recognition and management in commercial pig production lags behind companion animal medicine—systematic improvement in this area represents a major animal welfare opportunity.
Pigs possess the neurobiological substrates for pain perception equivalent to other mammals: nociceptors, ascending pain pathways, and brain structures involved in pain processing and emotional response. Behavioural and physiological evidence of pain in pigs is extensive—cortisol elevation, altered gait, reduced feeding, social withdrawal, and facial expressions of pain all demonstrate pain experience following noxious stimuli. Pigs are not physiologically indifferent to pain.
Pigs tend to suppress pain behaviour in social situations—an evolutionary response that prevents predators or dominant conspecifics from identifying vulnerability. This means stockpeople observing group-housed pigs may not recognise individual pain signs until disease is advanced. Individual observation of separated pigs, trained stockperson pain recognition, and systematic use of validated pain assessment tools (Piglet Grimace Scale, Porcine Grimace Scale) improve detection rates.
Conditions causing significant pain in commercial pig production include: lameness (osteochondrosis, joint infections, foot lesions); tail and ear biting injuries; farrowing-related injuries (dystocia, prolapse); dental development issues in older animals; and post-operative pain following castration, herniotomy, and other procedures. Routine procedures historically performed without analgesia now have clear pain-relief protocols supported by scientific evidence and welfare regulation.
NSAIDs are the primary analgesic class in pig practice: meloxicam has good evidence for post-castration and post-farrowing pain relief; flunixin meglumine and ketoprofen are alternatives. Long-acting NSAIDs reduce administration frequency in production settings. Local anaesthesia (lidocaine) is used for castration, herniotomy, and some dental procedures. Opioids are licensed for pigs in some countries. Pre-emptive analgesia—administered before the painful procedure—is more effective than reactive treatment.
EU law requires pain relief for castration of piglets older than 7 days; some national regulations impose earlier age cutoffs or require anaesthesia for all ages. Despite regulations, compliance monitoring is challenging. Welfare certification schemes increasingly audit pain relief protocols for routine procedures. Veterinary engagement in developing farm-specific pain management protocols is the most effective route to systematic implementation.