Validation of a Composite Pain Scale for Use with Horses Experiencing Acute Colic Pain

Abstract

Pain recognition and management in horses has become more important in recent years. Interest in the animal’s welfare has increased. Horses are prey animals, and therefore will not easily show their pain. This study attempted to create and validate to objectively score and interpret pain in horses with acute colic. We have used an adapted Composite Pain Scale (CPS) system previously developed and tested by others on horses with orthopedic or post-operative somatic pain. Eight horses with acute colic were scored using the colic CPS and these scores were compared to 18 healthy pain free horses (farrier clients and recipient mares). Two observers scored the animals, and scores were compared between observer 1 and observer 2 in order to determine the CPS’s reliability. Videos of all horses were scored by other veterinarians using a Visual Analogue Scale (VAS) after which these scores were compared to the scores given using the CPS. Animals not experiencing any pain were shown to score low, whereas horses with acute colic pain scored significantly higher on the CPS. Pain scores for colic patients decreased over time during their stay at the clinic. Scoring based on the CPS was significantly more reliable between observers than scoring performed with the VAS. This study found that the CPS system could become a reliable method to use in the objective assessment of pain in horses with acute colic, and therefore benefit clinicians as well as owners and caretakers.