Chronic pain might be displayed as anxiety or depression. It may be more difficult to assess behaviorally than acute pain. Types of pain respond differently. The treating veterinarian chooses the appropriate drug to match the pain the horse communicates. Because horses express pain through their behavior, the horse owner observes each animal to detect its condition.
Horses do vary in their pain thresholds, or how they tolerate pain.
Like a person, a horse might feel pain without demonstrating evidence of it. Humans and animals can suppress pain by affecting nerve fibers. Rubbing or scratching an area near an injury can lessen pain. Released from the pituitary gland during exertion or other stress, these hormones reduce the sensation of pain. Pain experienced by the equine athlete can be acute or reflect chronic inflammatory tissue injury.