Pig Pain Recognition: Closing the Assessment Gap on Farm

Why pain recognition in pigs is challenging and what assessment tools help farmers and vets identify and treat suffering more effectively.

Key Facts

Pigs conceal pain as a prey-species survival behaviour, making clinical assessment challenging even for experienced observers
The Pig Grimace Scale — developed from analogues in rodent and rabbit pain research — provides a validated facial expression tool
Lameness is the most common observable indicator of pain in pigs, yet significant lameness is often under-treated on farm
Tail biting injuries cause chronic pain that persists long after visible wound healing — nerve damage is common
NSAIDs (meloxicam) are licensed for pigs and significantly improve welfare outcomes when used appropriately for post-surgical and injury pain
A 2023 study found over 40% of slaughtered pigs in the UK had healed but previously untreated lameness lesions at post-mortem

Welfare Considerations

The pain recognition gap in pig farming is a structural welfare problem driven by several converging factors: pigs mask pain behaviours; large herd sizes make individual animal observation brief; stockpersons have limited training in pain indicators; and economic pressures discourage the cost of treatment in animals close to slaughter weight. The result is that a significant proportion of farmed pigs carry pain burdens that are detectable by trained observers but go untreated. Addressing this requires systematic training, validated assessment tools integrated into routine health checks and clear protocols for NSAID administration without requiring a vet on-site for every individual treatment decision.

What You Can Do

Familiarise yourself or your stockpersons with the Pig Grimace Scale and lameness scoring systems through AHDB training materials
Establish a standing medicine protocol with your vet for NSAID use in clearly defined pain scenarios without requiring individual prescriptions
Record and review lameness incidence monthly — set targets for reduction and track progress
Investigate the root cause of any lameness cluster — flooring, nutrition, overstocking and infectious disease are the primary drivers
Report tail biting injuries to stockpersons immediately and remove injured pigs to recovery pens with analgesic treatment
Advocate within your supply chain for pain management standards to be included in assurance scheme audit criteria