Dr. Tania Cubitt
Donkeys are members of the equine family along with horses, ponies, zebras, and mules. It is commonly assumed they can be fed a diet similar to that of horses, but in a lower quantity. However, donkeys have unique evolutionary traits that make them anatomically and behaviourally distinct.
Donkeys are highly adaptable feeders. If given the opportunity, they will consume a variety of different grasses and shrubs to obtain sufficient nutrients. It is generally accepted that the donkey can exist with less food than a horse. Their efficient utilization of food makes donkeys easy keepers, but don’t let the term misguide you. It is important to take care in determining when and how much to feed as obesity is a major concern in modern domesticated donkeys.
Forage studies have shown that donkeys voluntarily consume much less forage compared to horses – 1.5 percent of body weight (BW) for donkeys compared to 3.1 percent of BW for horses. The donkeys’ heightened ability to digest low quality forage has been likened to that of a goat. Their pasture should not be lush and nutrient dense. Low quality pasture grasses are adequate.
There is limited information about protein requirements for donkeys, but researchers have suggested that they are very efficient in the utilization of dietary protein. It has also been suggested that donkeys have a 20 percent lower digestible energy requirement than horses. Good grass hay is adequate. Legume hay such as lucerne is not recommended for the same reason that lush pasture is not good for donkeys – the digestibility is very high as is the energy and nutrient content. Donkeys are prone to obesity and will develop laminitis if they are given access to lush pastures such as those in the spring and fall.
Donkeys that are pregnant or lactating may need their diets supplemented with concentrated feeds to meet their additional nutrient requirements. Photo: Flickr
While grass and hay are often sufficient in supplying the maintenance requirements for most donkeys, additional supplementation in the form of concentrate feeds may be needed when they cannot eat sufficient forage to meet nutrient requirements. Donkeys that are working heavily, pregnant, lactating, growing, or senior need concentrate feeding, and the amount should be determined by their BW and physiological state of the donkey.
The donkey is able to continue eating for several days when deprived of drinking water. It has been suggested that donkeys have the ability to conserve internal water stores and avoid thirst by reducing sweating for temperature control and reducing the amount of water lost in manure. Donkeys have the lowest water requirements of all domestic animals with the exception of camels. Under hot conditions of 30 to 38 degrees C (85 to 100 degrees F), donkeys consume water at a rate of approximately nine percent of BW per day. Under cooler conditions, donkeys consume water at a rate of four to five percent of their BW per day.
Obesity is the biggest challenge facing most non-working donkeys kept where food sources are abundant and of good quality. Emaciation is very common in most areas where donkeys are used heavily for work and food is scarce and of poor quality.
Body condition scoring of donkeys is similar to condition scoring horses using the Henneke Body Condition Scoring System where 1 is emaciated and 9 is obese. Donkeys tend to accumulate fat on the neck, on either side of the chest wall giving a saddlebag appearance, and around the buttocks. Several studies in horses and ponies have clearly shown that regional fat deposited on the neck of the animal indicated a higher risk for developing metabolic challenges such as insulin resistance and laminitis. Donkeys frequently accumulate fat on their necks and are at high risk of insulin resistance and laminitis.
Donkeys have the lowest water requirements of all domestic animals with the exception of camels, and can continue eating for several days without drinking.Photo: iStock/Wyanitt
Practical Feeding Strategies
Donkeys that are not doing any work should be able to meet all of their nutrient requirements from good grass hay fed at a rate of 1.5 percent of BW. If the donkey is overweight, this amount should be decreased to 1.25 percent of BW. In severe cases, with the guidance of a veterinarian or nutritionist, this can be reduced to 1 percent of BW. Working, lactating or growing animals may need additional concentrate. Due to the donkeys’ increased ability to metabolize energy and protein it is important that we do not feed concentrates that are high in these nutrients.
When feeding donkeys, consult your veterinarian or equine nutritionist. Most major feed companies have an equine nutritionist on staff to help determine the best overall diet.
This article was originally published in the October 2015 issue of Canadian Horse Journal.
Main article photo: Hay and grass are often sufficient to supply the nutritional requirements for donkeys, and they also have the ability to digest lower quality forage than that suitable for horses. Photo: Thinkstock/DenBoma