Pain recognition in animals requires specialized tools and training. Advances in veterinary pain assessment are transforming how practitioners identify and treat pain across species, improving welfare outcomes.
The development of validated pain assessment tools represents one of the most significant advances in applied animal welfare science. Without reliable ways to recognize pain, veterinarians and farmers undertreat suffering. The Grimace Scale exploits the universal mammalian tendency to alter facial muscle tension during pain — measurements of orbital tightening, cheek flattening, ear position, and nose shape can objectively quantify pain intensity. These tools transform pain management from guesswork to evidence-based practice. Implementation requires training and standardization, and progress has been faster in laboratory animal and companion animal contexts than in farm animal practice. Automated systems using computer vision and machine learning now allow continuous monitoring of large numbers of animals for pain indicators — a potential game-changer for intensive farming welfare monitoring. Regulatory adoption of validated pain scales as part of veterinary and farm welfare inspection protocols would accelerate their use.