Q. I recently acquired a rescue donkey. I’ve had horses for a long time, but I understand donkeys have different nutritional needs. I getting a lot of mixed advice about the ideal forages for donkeys. Can you provide some clarity?

A. Donkeys can be such a joy to own, and while like horses they are part of the genus Equus, they have unique nutritional needs. Donkeys evolved in the hot, arid climates of Africa and Asia, where forage options are poor most of the year. Thus, they survived browsing highly fibrous plant materials. Much of the forage grown for horses is, therefore, too lush to safely make up the majority of the donkey’s diet.

In fact, donkeys given access to pasture most of the year will not need much hay, even in the winter. And pastures should be grazed very carefully. Ideally, most of your donkey’s diet should be made up of straw, with grazing as a supplemental nutrient source. The Donkey Sanctuary, a world-leading authority in donkey care and management, recommends barley straw as the preferred type of straw, as it is high in fiber and low in sugar. It also most closely resembles the type of food a donkey would consume in the wild.

You can feed other types of straw, such as oat and wheat, but oat straw is more nutritious than barley straw, so it is best used for feeding underweight and old donkeys. Wheat straw is best suited to donkeys with good dental health, as it is very fibrous and lower in calories. Any straw fed to donkeys should be clean and dust- and mold-free, which can be challenging to find in the United States where straw is rarely grown with feeding in mind.

If feeding hay to donkeys, ensure it is grass hay (no alfalfa) and as mature as possible. Late-cut grass hay that horse owners might not desire can be ideal for donkeys when straw is not an option. If looking at an analysis to determine whether a specific hay would be good for a donkey, look at the levels of fiber, sugars, protein, and calories.

Donkeys’ crude protein requirement is somewhere in the range of 3.8% and 7.4% of the diet compared to 8% to 12% for mature horses. Donkeys have the ability to recycle nitrogen, so they do not need to consume the same levels of nitrogen in their diet as horses. This is why it is inappropriate to feed alfalfa, which has very high protein levels, to donkeys. 

By feeding donkeys lower-calorie hay, you can keep more hay in front of them, which helps reduce boredom and promote gastrointestinal health. It is, however, challenging to find a grass hay with a calorie content in the recommended range (they are typically over 0.8 Mcals per pound). Straw is often between 0.73 and 0.85 Mcals per pound.

Neutral detergent fiber (NDF) and acid detergent fiber (ADF) are measures of structural carbohydrates. If I were to select forages for horses, I would look for hays with an NDF range of 40% to 65% and an ADF of 30% to 40%. Horses typically will not eat forages with an NDF over 65% or an ADF over 45%. However, these are the forages that are ideal for donkeys. Therefore, a very stemmy, mature timothy hay (assuming the sugar content is not too high) might be a good option. Try to find forages with an NDF content in the low 70% range.

Nonstructural carbohydrates (e.g., sugar and starch) should be less than 12%, similar to forages for horses and ponies with metabolic issues. Donkeys can develop insulin dysregulation, and often the higher the sugar, the higher the calorie content. Once donkeys get fat, it can be very difficult to remove weight, and they are not only at risk of laminitis but also hyperlipidemia—both of which can lead to death. Therefore, I can’t stressed enough the importance of careful weight management for donkey well-being.

With careful forage selection, you can maintain your donkey at a healthy weight while maximizing forage intake, maintaining gastrointestinal health, and staving off boredom.