Better Detection of Pain in Donkeys to Improve Their Well-Being

People say donkeys are stubborn, but veterinarians prefer to describe them as stoic. In fact, they are very good at hiding their pain, which contributes to delays in detecting the diseases they suffer from—illnesses that are often treated only at a late stage, when their health has already deteriorated significantly. For the first time, researchers have developed tests capable of objectively assessing different types of pain in donkeys—a major breakthrough for the medical care and equine welfare.   Pain can be difficult to assess objectively in animals. This is particularly true for animals whose status as prey compels them to conceal their symptoms from their peers and potential predators to avoid becoming a target. Donkeys are no exception. Often described as stubborn by their owners, they are instead characterized as stoic by veterinarians and ethologists. Indeed, donkeys are known for their ability to mask signs of pain, even more so than horses. For this reason, the objective assessment of pain in donkeys proves to be complex. Yet it is vitally important for establishing an early diagnosis, ensuring effective monitoring of the therapeutic response, and thereby improving overall well-being. Since 2006, studies have sought to assess pain in horses, notably using an equine pain score, but donkeys are too often overlooked, and no validated scale exists for this equine species. However, while donkeys exhibit unique behavioral and physiological characteristics and vulnerabilities, they also share many similarities with horses. The researchers therefore assumed that the methods and scales designed and validated for horses could be used as a starting point to develop useful and valid pain scales for donkeys. They incorporated donkey-specific elements to develop 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). These scales were tested on 264 adult donkeys (12 with colic, 25 with orthopedic pain, 18 with cranial pain, 24 with postoperative pain, and 185 control cases). The results show that both the Equus-Donkey-Compass and Equus-Donkey-FAP tests can effectively and objectively assess various types of acute pain in donkeys, although there are differences depending on the type of pain. The Equus-Donkey-Compass test is particularly effective at detecting orthopedic pain and colic (88% and 83%, respectively), but less so for cranial and postoperative pain (17% and 21%, respectively). In contrast, the Equus-Donkey-FAP has good sensitivity for colic and cranial pain (75% and 78%, respectively), but moderate sensitivity for orthopedic and postoperative pain (40% and 50%, respectively). It is now possible to reliably and objectively assess pain in donkeys in the field. This is a major advance that will enable better care for donkeys, but above all will allow for prevention and early intervention in these animals, which show so little sign of discomfort, while ensuring effective monitoring of treatments. Thus, these tools are proving to be essential for the care and health monitoring of donkeys.