Feeding Donkeys: Consider Their Thriftiness to Achieve Optimal Body Condition

Among members of the genus Equus—horses, donkeys, zebras—perhaps none stores and mobilizes energy as efficiently as donkeys. Genetically hardwired to survive in harsh conditions, donkeys thrive when nutritional resources are limited. These days, though, donkeys often live in tandem with horses and ponies, frequently consuming the same feedstuffs, sometimes in identical quantities. When caretakers fail to consider the thriftiness of donkeys—their ease in maintaining appropriate weight—problems may surface.

Donkeys are incredibly efficient at digesting fiber that would be considered unsuitable for many horses and ponies, such as middling hay and straw. According to one study, donkeys have similar digestive efficiency as cattle and much greater efficiency than ponies when fed oat straw. Because of this efficiency, when donkeys are nutritionally managed in the same way as horses and ponies, they may become obese, predisposing them to metabolic problems, including insulin dysregulation and laminitis.

Given their thriftiness, here are some nutritional guidelines that will help keep donkeys in optimal body condition and out of harm’s way.

• Choose feedstuffs with minimal energy values so donkeys can satisfy their natural desire to chew without excessive energy intake. Low- to mid-quality grass hay may be most appropriate forage for donkeys. This hay is often characterized by slight discoloration (yellowing or browning), overmaturity of plant species, and some weeds. Extreme stemminess should be avoided. As with horses and ponies, moldy or dusty hay should be rejected outright for donkeys.
• While some horsemen would be uneasy feeding barley or wheat straw, many donkeys do well on it, though donkeys prefer hay to straw. Concerns regarding increased colic or gastric ulcer risk with feeding straw were not substantiated in studies. Some caretakers feed a mix of 75% hay and 25% straw, and many donkeys can maintain appropriate body condition on this blend.
• For sedentary donkeys—those that do no work and are not used as breeding animals—nutritionists suggest 1.5-1.7% of their body weight daily in dry matter intake. In spring, summer, and autumn, many donkeys maintain their weight when fed at the lower end of this spectrum; in winter, donkeys may hold their condition better when fed at the upper end of the scale. For example, a 400-lb (180-kg) donkey at maintenance would require about 7 lb (3.4 kg) of suitable forage to maintain condition. Keep in mind that individuality plays a role in determining energy requirements; some donkeys will need slightly less or more for optimal condition.
• Mature female donkeys, called jennies, in late pregnancy (ninth month and onward) and lactation have an uptick in energy needs, often requiring more forage or an increase in forage quality.
• A low-calorie vitamin and mineral supplement is appropriate for most donkeys, especially if they are not allowed to graze fresh pasture. A donkey fed entirely dried forages (straw, hay, or forage pellets and cubes) may be at risk of vitamin E deficiency. Breeding jennies and young donkeys are excellent candidates for balancer pellets, which typically have a high-quality source of protein, which is necessary for fetal growth and development as well as tissue accretion in weanlings and yearlings.
• Donkeys that regularly engage in work may have elevated energy requirements. Like jennies in late pregnancy and lactation, these donkeys might require more forage or higher quality forage to maintain appropriate body condition.
• Do not feed donkeys concentrates intended for horses, especially those that contain cereal grains and other high-energy ingredients, as these are too calorically dense. As mentioned previously, balancer pellets formulated for horses are acceptable for donkeys, but be sure to work with the manufacturer or a nutritionist to calculate the appropriate feeding rate.
• Despite their reputation for hardiness and the ability to go long stretches without water, donkeys should always have access to fresh, clean water.

Other nutrition-related notes about donkeys:

• Condition scoring. Monitoring weight and body condition score are an essential part of managing donkeys. Because donkeys have a different body shape, including more angular conformation, body condition score charts or systems specifically for donkeys have been created. These scales consider the distinctive way that donkeys lay down fat, including significant accumulations on the crest as well as lumpy deposits on the neck, shoulders, back, and croup, called “fat pads.” Body condition scoring charts designed for use in horses and ponies should not be used for donkeys. In the same vein, formulas and tapes used to estimate body weight in horses and ponies are not reliable for donkeys.
• Crest and fat pad considerations. When a crest becomes so laden with fat, supporting structures that keep the crest upright will tear, causing the crest to fall to one side. This condition is called “fallen crest” or “broken crest.” Once this occurs, the crest never returns to its original position, even if dietary and management practices are changed to promote weight loss or increased fitness. Further, longstanding fat pads on other regions of the body may become calcified and hard to the touch. Fallen crests and calcified fat pads should be ignored when body condition scoring, as they are often artifacts and not indicative of current body condition. A neck scoring system for donkeys has been devised and can be used alongside body condition scoring.
• Because donkeys are herd animals, many will not eat despite hunger without being in the company of another donkey, horse, or pony. A peculiar trait among donkeys, especially those that are ill, is “sham eating” in which the animal appears to take forage or feed into the mouth and swallow but does not actually do so. In group-feeding situations with horses and mules, donkeys often end up at the bottom of the pecking order. Observe the herd to make sure donkeys receive sufficient feed. If dominant animals continue to push donkeys from feed or forage sources, donkeys should be fed separately.
• Dental problems. As with horses, dental disease is common among donkeys, especially aged animals, and causes difficulty chewing long-stem forages. Common findings include malocclusions and displaced or missing teeth. Eventually, dental disease compromises health through oral pain, weight loss, colic, and other complications. Because donkeys are not usually ridden or asked to carry a bit, dental anomalies often go unobserved until secondary problems arise. Annual dental exams by a professional help stave off problems.
• Hoof care. Like horses, donkeys should be seen regularly by a farrier that understands the conformation of their hooves, which differs from that of horses and ponies. Hooves that are allowed to grow long may be prone to coffin bone remodeling. Donkeys are frequently diagnosed with hoof abscesses, and they should be treated in the same manner as horses. Laminitis is a common concern in donkeys and typically rooted in endocrinopathy, such as donkey metabolic syndrome or pituitary pars intermedia dysfunction.

In sum, donkeys should not be fed like horses and ponies, as their nutritional requirements are significantly different. Of utmost importance is the knowledge that donkeys often flourish on clean forage—free of dust and mold—that might not otherwise be used for horses and ponies. Free-choice access to forage often provides too many calories, so providing an appropriate amount of forage in a slow-feed system that extends feeding time is a wise choice. For optimal health, a vitamin and mineral supplement should be used, but horse feeds containing cereal grains and other energy-dense ingredients are rarely suitable for donkeys. Above all, remember that every donkey should be treated as an individual and fed accordingly, just as horses and ponies are.

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