composite pain scale

Assessment of chronic pain is very important for monitoring and improving welfare and quality of life in donkeys. Freedom from disease and pain is one of the ‘five freedoms’ underlying animal welfare. The aim of the current study was to develop a pain scale for assessment of chronic pain in donkeys (Donkey Chronic Pain Scale; DCPS), including behavioural and facial expression-related parameters. The scale was applied to 77 donkeys (38 donkeys diagnosed with chronic health problems by means of clinical examination and additional diagnostic procedures and 39 healthy control animals). Animals were assessed twice daily for three consecutive days by two observers that were not masked to the condition of the animals but were unaware of the analgesic treatment regimens. Both composite, facial expression-based and combined DCPS pain scales showed excellent inter-observer reliability (Cronbach’s alpha = 0.98, 0.96 and 0.98 respectively; P < 0.001). Individual composite and facial expression-based pain scores and the resulting combined DCPS showed significant differences between donkeys with chronic conditions and control donkeys at all time points (P < 0.001). A DCPS cut-off of 6 showed good sensitivity and specificity (92% and 82.5% respectively) for presence of a chronic painful condition. Facial expression-related parameters separately showed low sensitivity. In conclusion, it is possible to use a composite pain scale for assessment of chronic pain in donkeys, based on behavioural and facial expression-based parameters. Further studies are needed to validate this pain scale before it can be used in veterinary practice.

Objective pain assessment in donkeys is of vital importance for improving welfare in a species that is considered stoic. This study presents the construction and testing of two pain scales, the Equine Utrecht University Scale for Donkey Composite Pain Assessment (EQUUS-DONKEY-COMPASS) and the Equine Utrecht University Scale for Donkey Facial Assessment of Pain (EQUUS-DONKEY-FAP), in donkeys with acute pain. A cohort follow-up study using 264 adult donkeys (n = 12 acute colic, n = 25 acute orthopaedic pain, n = 18 acute head-related pain, n = 24 postoperative pain, and n = 185 controls) was performed. Both pain scales showed differences between donkeys with different types of pain and their control animals (p < 0.001). The EQUUS-DONKEY-COMPASS and EQUUS-DONKEY-FAP showed high inter-observer reliability (Cronbach’s alpha = 0.97 and 0.94, respectively, both p < 0.001). Sensitivity of the EQUUS-DONKEY-COMPASS was good for colic and orthopaedic pain (83% and 88%, respectively), but poor for head-related and postoperative pain (17% and 21%, respectively). Sensitivity of the EQUUS-DONKEY-FAP was good for colic and head-related pain (75% and 78%, respectively), but moderate for orthopaedic and postoperative pain (40% and 50%, respectively). Specificity was good for all types of pain with both scales (91%–99%). Different types of acute pain in donkeys can be validly assessed by either a composite or a facial expression-based pain scale.