Tips on caring for ‘long ears’
October 16, 2013
Part one of two…
A sturdy little donkey grazes happily in a roadside pasture, ears flopping and tail swishing. His belly is round, his feet solid. His thick, coarse coat appears as if it could protect him from even the nastiest weather. Considering this typical image of a donkey in good health, it's no wonder some people believe mules and donkeys to be so very durable, compared with horses, that they are immune to many equine diseases or conditions. This, however, is a myth.
"Donkeys and mules (offspring of a male donkey and a mare) are not immune, just more resistant," says Robert M. Miller, DVM, an equine veterinarian from Thousand Oaks, CA, who has owned and treated donkeys and mules for decades. "They are injured less often, less prone to colic, and less apt to develop common equine illness, with a handful of exceptions."
Despite their reputation for hardiness, donkeys and mules require the same basic care approaches that horses do, such as teeth floating, hoof maintenance, routine vaccinations and deworming. What's more, they are even prone to health issues unique to their kind.
Common Health Issues
Veterinarians must take into consideration certain physical and metabolic differences when treating these animals. For instance, donkeys and some mules have smaller nostrils and nasal passages than do same-sized horses, which can be a limiting factor when veterinarians need to pass a nasogastric (stomach) tube to treat issues such as choke or colic. Since they were originally desert animals, their thick hair lacks the insulating undercoat that horses possess, leaving them vulnerable to bronchitis and pneumonia if it gets cold and wet. And donkey skin is typically thicker than that of horses – so when administering medications or fluids intravenously, the veterinarian frequently uses a different needle angle (to go deeper) when inserting it into the vein.
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Also due to their history as desert dwellers, donkeys can survive longer in certain climates than horses. Due to this durability, their fluid balances and drug metabolism are different than in horses. Donkeys metabolize some drugs faster than horses, which affects anesthetic duration.
So, keeping in mind some of these differences, let's take a look at specific conditions these long-eared equids might face:
The late Tex Taylor, DVM, who taught at Texas A&M University, observed that respiratory diseases are more prevalent in donkeys than in mules or horses. Taylor was widely recognized in the veterinary community as a donkey and mule expert, and in the late 1990s he published a handout to help practitioners understand and treat these
In the handout he wrote that veterinarians often see severe outbreaks of viral respiratory infections in donkey herds, and young animals might die in spite of treatment. He recommended conducting transtracheal washes for culture and sensitivity tests at first indication of disease. He also said it's important to put young animals on steroids (such as dexamethasone) – sometimes at higher dosages and for longer durations than would be recommended for horses – to reduce fluid formation in the lungs. He recommended checking affected donkeys' temperature, pulse, and respiration values twice daily. Taylor instructed veterinarians to treat any donkey with an elevated temperature or nasal discharge, or if the animal goes off feed or appears depressed.
Occasionally, veterinarians have linked equine influenza virus to these outbreaks, but usually it's neither a common strain nor one included in influenza vaccines. Taylor reported that older animals usually show milder influenza signs similar to those horses display (e.g., fever, cough, and nasal discharge).
This disease usually results from rapid reduction of nutrients in the diet. "Stress can also precipitate this, such as the stress of foaling, transportation, or being without food," says Sybil Sewell, co-founder of the Canadian Donkey and Mule Association and Alberta Donkey and Mule Club, in Leslieville, Alberta. "It particularly affects obese donkeys. The excess fat in the body is broken down and mobilized into the bloodstream too quickly and causes liver and organ damage, with high mortality rates."
Another medical condition more common in mules and donkeys than in horses is what's known as jack sores, or summer sores (habronemiasis). Flies carry and deposit Draschia and Habronema stomach worm larvae that can cause granulomas when they infect small wounds or other moist areas of the animal's body, such as the conjunctiva of the eye.
"Better deworming drugs like ivermectin (which kills the tiny larvae in these sores) have reduced the incidence of this problem," says Miller.
Lungworms (Dictyocaulus arnfieldi) are also more common in donkeys than in horses and cause coughing and signs of lung irritation similar to heaves. Unless donkeys are dewormed routinely, they might harbor these parasites and pass them to horses housed in the same pastures (via worms passed in manure and ingested during grazing). Taylor suggested fecal sampling and deworming affected donkeys with ivermectin twice a year to reduce the threat of lungworms.
Donkeys and mules also seem more susceptible to sarcoids (noncancerous skin tumors). "Horse sarcoids are usually not difficult to clear up with modern treatments," says Carl Lind, DVM, of Bishop Veterinary Hospital, in Bishop, CA, "Mule or donkey sarcoids, by contrast, tend to recur or spread from the initial location." (See TheHorse.com/19898 for common sarcoid treatment suggestions.)
"Another problem donkeys have more often than horses is lice – maybe because of the longer hair coat," says Sewell. "A new animal to the herd may spread lice to the others if not isolated and treated. You may not realize the animal has lice because they are hidden in the long hair. This can be easily controlled with delousing powders, but if neglected lice can quickly cause serious hair loss."
Donkeys, with their longer hair, are also more susceptible to rain rot than horses. "If there's a lot of rain in the fall and no shelter, donkeys may get this skin problem," Sewell says. "Clumps of hair fall out, and bald patches develop." F
Please watch next week's paper for part two.