Nationwide, equine (or more accurately described, horse) practitioners are receiving requests to provide professional services to donkey and mule owners. This trend is expected to continue. Many veterinarians are reluctant to respond to some of these requests because they don’t understand the differences among horses, mules and often, the different sizes of donkeys.

Each veterinarian must realize he or she has been well-trained to treat all members of the equine species. The diseases and conditions affecting these animals are the same. Certainly, there are variations in how each species may demonstrate clinical signs, but not in managing or treating the condition.

One of the most critical points is to realize that mules and donkeys have a markedly better tolerance for pain than do most horses. This is particularly significant in evaluating the musculoskeletal and gastrointestinal systems. Failure to recognize this can lead to an erroneous or delayed diagnosis, the results of which can sometimes be disastrous.

Everyone has heard the old tales about what donkeys and mules do or don’t do, and about why they are or are not better than horses. Like most information we receive, some is correct, some is incorrect and some is not presented in the correct context. As an example, let’s consider lameness in mules. They reportedly have fewer lamenesses than do horses. This view has been around for decades. It may or may not be true.

Before the 1960s, mules were working animals from draft-type mares and sired by draft- type jacks. They were doing the job draft horses did, and in some cases, were perhaps doing it better or more economically. They performed, generally, in a reasonably straight line or loose turn and at a walk and trot. Rarely were they ever required to work at greater speeds. Most of today’s mules are produced from our saddle-type performance mares and sired by smaller, more refined jacks. We are asking the mules to duplicate the maneuvers of our racehorses, roping horses, reining horses, driving horses, cutting horses and others. We have changed our expectations of our mules as well as their pedigree. Our observations suggest that we are infusing all our lameness dispositions into our mules and following up with the appropriate training programs to insure the development of the same lamenesses seen in horses. The idea that mules are less likely to become lame is at least in part because of the fact that many of the lamenesses will be much more advanced in the mule before the animals demonstrate sufficient lameness to be presented for examination and treatment.

Early impressions also suggest that as we begin to develop large donkeys for recreational use, we will begin to see the same problems that we see in performance horses. The following are some brief points worth filing in a little-used corner of the mind to be resurrected as needed when faced with mules and donkeys as patients. They are not all- inclusive, but represent the more often asked questions and errors of commission.

  • Restraint of mules (and to a lesser degree, donkeys) often requires a two-phased approach. One is to keep the patient in the area where you wish to work, and the other is to distract the patient from the procedure being performed. The use of stocks, chutes, snubbing posts and swinging gates or panels are very helpful and may be supplemented with the twitch, war bridle or other restraint. The foreleg strap and the scotch hobble are often very useful. Proper use of the foreleg or elbow strap is one of our most useful techniques.
  • With mules it is very important that you get it right the first time. Unsuccessful attempts to restrain a mule are positive rewards for bad behavior that rapidly become a learned skill.
  • Hoof testers seem to be less discriminating in the examination of mules and donkeys than in horses.
  • A limited number of nerve blocks are allowed in a lameness exam. The attending veterinarian must use them wisely.
  • If apparent lacerations or lesions over the flexure surface of the joints are found in donkeys, consider that they may be jack sores. This syndrome is not a well-defined condition, but it usually starts as a linear ulceration with a bad odor. Many veterinarians and current literature may call them summer sores. That is not always the case, and there is no effective treatment currently known.
  • Severe respiratory distress in donkeys is a cause for immediate and aggressive diagnostics and treatment, especially if in a herd. Donkeys often have severe secondary bacterial infections after or along with equine influenza virus. This is not so with mules.
  • Any donkey off feed for three to four days or more should be checked for hyperlipemia or hyperlipidemia.
  • Chronic non-healing coronary band lesions in donkeys look like a gravel eruption. This is a syndrome of donkeys that may persist for years and may become frequent. Keep the toes trimmed short. Check for sole-penetrating wounds since they may require removal.
  • Radiographic anatomy of the donkey digit is not the same as the horse. The mule is minimally different, if at all.
  • Donkey growth plates radiographically close later than those of the horse. Currently, information is not yet known regarding the mule closure times.
  • Donkeys and mules are more susceptible to equine sarcoids than are horses.
  • Consider fat pones and large neck crests to be permanent.
  • Laminitis in donkeys often occurs in all four feet or often in rear feet only. Laminitis of rear feet will more likely lead to euthanasia than if in front. Support laminitis in contralateral foot in the rear due to abscesses or injury is very common and is often missed by the owner and the attending veterinarian.
  • Endoscopic anatomy of the donkey is not identical to the horse with a tendency for dorsal collapse of the pharynx. The mule anatomy is not yet well-established.
  • Entropion (ophthalmologic condition) is very common in large draft Jack stock.
  • Donkeys can serve as hosts for lungworms.
  • Stringhalt and upward fixation of the patella is more common in donkeys and mules than in horses.

Contributed By: Tex Taylor, DVM, and Nora Matthews, DVM (AAEP)