Although they can be expressive, donkeys and mules don’t always show such obvious signs of pain as horses do, said Amy McLean, PhD, equid lecturer at the University of California, Davis, during the 2021 American Association of Equine Practitioners’ convention, held Dec. 4-8 in Nashville, Tennessee. And while donkeys “tend to make friends” with humans fairly well, mules can be particularly aggressive with unknown people—including well-meaning veterinarians—so knowing warning signs the mule might express can make for a better and safer veterinary visit.

“You need to get in and get out, and make it safe,” McLean said.

Such a plan starts with talking to the mule or donkey before approaching, said McLean. “With those oversized ears, “they can hear up to 3 or 4 miles away, and they don’t like surprises,” she says. “So don’t surprise them. Say hello, and introduce yourself.”

Approach the animal’s head first, offer a treat, and watch carefully for signs he or she has accepted your presence—like forward-facing ears, McLean said.

Both equids are highly intelligent, she explained. Mules in particular might bite or kick, even striking people standing by their shoulders. “A horse might kick you, but a mule aims to kick you, so remember that when you approach them,” she said.

“Extend your hand to the nose, then work your way up to his forehead, then go to the neck,” McLean said. “Proceed when you’re allowed to proceed.” Laid-back ears or a rear-leaning stance—suggesting the animal is preparing to kick out—indicate he isn’t ready for you to proceed.

Appropriately dosed sedatives can help make evaluations safer, she said, but that means getting the sedative into the animal. Physical restraint methods such as a nose twitch, a blindfold, or a thick, soft rope used as a Scotch hobble to hold up one leg can be useful in preventing accidents without harming or traumatizing the patient.

Avoid using training techniques on mules and donkeys that you’d use with horses in an attempt to gain patient compliance. “No. Instead, think smart…. Be smarter than the patient,” she said.

The physical examination should begin before approaching the donkey or mule, with the veterinarian observing the animal’s behavior, said McLean. Despite their reputation for being stoic, both mules and donkeys will seem expressive if the veterinarian knows what to look for and is attentive.

“They will tell us a lot if we just take the time to notice,” she said.

Signs of general discomfort in a donkey or mule ­can include an unusual stance, headshaking, and tail-swishing, McLean said. Mules in particular tend to swish their tails repeatedly when they’re in pain but also when they’re discontent with a situation or a person. In addition to their physical agility and ear mobility, this represents yet one more “catlike feature” in these equids, she said.

“I think mules and cats had a conversation,” said McLean. “They like to swish their tail when they’re mad.”

Donkeys and mules can also have expressive faces, said McLean. She and her team recently developed a scoring mechanism based on facial features such as a fixed stare, clenched jaw, tightened orbitals around the eyes, and dilated nostrils.

Aside from these general pain signs, donkeys and mules can give more specific signs indicating localized pain. For example, head tilt, yawning, and food packing—keeping a wad of food in the jaw—can suggest dental pain, while foot lifting or pointing could indicate foot discomfort.

Like horses, colicky donkeys and mules typically turn to look at their flanks, but they might be more subtle about it, she said. They also tend to refuse to move. But, unlike horses, donkeys and mules will withstand much higher levels of intestinal pain before lying down.

While these skilled observations are worthwhile, McLean said she hopes to see technology as a helpful tool for picking up on the subtle cues donkeys and mules give about their pain levels and moods. Recent technologies such as thermography and smart halters in association with pain or distress are already proving useful, for example.

Veterinarians can also look for other general signs of pain in their case history conversations with the owner, McLean said. For example, donkeys tend to “sham eat”—meaning they look like they’re eating but aren’t taking in any food—if they’re uncomfortable. However, not all owners notice the donkey isn’t actually eating.

Hospitalized donkeys and mules are at particular risk of sham eating or refusing to eat, probably due to stress and/or feed changes. “They’re such survivalists, they can live in a lot of these different places on limited forage (and) work very hard, but then they become very selective eaters when they come to a vet clinic,” McLean said. They also tend to refuse water if it does not taste the same as what they’re used to, she added.

Making feed and water tastier by adding flavorings or offering alfalfa hay can help in hospital settings, she said.

As for veterinary handling during breeding, keep in mind that “jacks (intact males) can tend to be either very shy breeders, or they can be the other extreme and be very aggressive,” McLean said. They need a very calm environment with very few people around but, even then, veterinarians should come prepared with restraint equipment such as a stud chain. “You may even consider having a muzzle on the jack,” she said, adding that they might bite.

Take-Home Message

Overall, from the time of arrival until the time of departure, veterinarians should aim to make donkey and mule exams and treatment as positive as possible for the animals, McLean insisted. That’s not only important for that particular visit, but for all future visits with these “really incredible” animals.