Pig Pain Assessment: Tools and Indicators for Recognizing Suffering

Recognizing pain in pigs is essential for welfare management but challenging because pigs often suppress pain expression. Validated assessment tools and knowledge of behavioral indicators improve pain detection.

Key Facts

Pigs show pain through postural changes, facial expressions, behavioral alterations, and physiological parameters
The Pig Grimace Scale (PGS) provides a validated tool for acute pain assessment based on facial muscle tension, orbital tightening, and ear position
Behavioral indicators of pain include hunched posture, reluctance to move, altered gait, reduced feed intake, and social withdrawal
Pigs with chronic pain often show subtle signs including decreased positive behavioral indicators rather than obvious pain behaviors
Physiological indicators include elevated cortisol, heart rate, and acute-phase proteins - useful for research but impractical for routine assessment
Pain assessment must be integrated into daily stockperson rounds - pigs observed infrequently are likely to have pain missed
Post-operative and post-procedural pain is commonly under-treated in farm pigs compared to companion animals
The Welfare Quality protocol provides a farm-level pain assessment framework that includes lameness scoring and injury assessment

Welfare Considerations

Pain recognition in pigs represents a critical welfare skill gap. Stockpeople who cannot identify pain in their animals cannot respond to it, leading to prolonged, preventable suffering. Pigs' tendency to suppress obvious pain expressions means that subtle behavioral and postural changes must be actively sought. The development of validated pig pain scales and the growing emphasis on pain recognition training for stockpeople represent important welfare advances. The welfare argument is straightforward: pain that is recognized can be treated; pain that is missed results in unnecessary suffering. Investment in stockperson training on pain recognition is among the most cost-effective welfare interventions available to pig producers, improving welfare outcomes across all health events that cause pain.

What You Can Do

Train all stockpeople in pig pain recognition using validated tools like the Pig Grimace Scale
Conduct daily welfare observations of all pigs in your care, specifically looking for behavioral and postural pain indicators
Establish clear protocols for responding to identified pain - who administers treatment, which treatments are stocked and approved
Use NSAIDs (meloxicam) for procedural pain management - castration, tail docking, and dental procedures all cause pain
Monitor recovery from illness and surgery using behavioral indicators - persistence of abnormal posture or behavior indicates inadequate pain management
Implement record-keeping for pain events and treatments to identify patterns and evaluate intervention effectiveness
Consult your vet about a pain management protocol that is stocked, trained, and ready for use on your farm
Recognize that treating pain in farm animals is both an ethical obligation and often economically rational - animals in pain grow poorly