Farm Animal Welfare

Pig Pain Recognition Grimace Scale Applications

The porcine grimace scale provides an objective behavioural tool for assessing acute pain in pigs that can guide treatment decisions.

Key Facts

The porcine grimace scale assesses orbital tightening, nose-cheek flattening, and ear position
Studies show good correlation between grimace scale scores and known pain states
The scale enables consistent pain assessment without requiring physiological sampling
Training farm staff in grimace scale use improves pain recognition
Grimace scales have been validated for surgical, disease-related, and chronic pain in pigs

Welfare Considerations

Pain recognition in pigs has historically relied on subjective assessment by individual observers with variable accuracy. The grimace scale provides an objective, reproducible tool that can be used by trained farm staff to detect pain and guide treatment decisions. Widespread adoption of grimace scale assessment would improve pain recognition and prompt more consistent analgesic treatment.

What You Can Do

Support training programmes teaching the porcine grimace scale to farm staff
Advocate for pain assessment requirements in pig welfare standards
Share grimace scale resources with veterinary professionals working with pigs