Nutritional Considerations for Donkeys

Believe it or not, as an independent equine nutritionist, I have a lot of donkey clients too!! Oftentimes these guys may get overlooked when it comes to nutrition, but they need balanced diets too. Most of the donkeys I see are extremely overweight due to being fed in a similar fashion to horses. Even though feed restriction may be required, a forage-only diet is not going to meet their requirements. Vitamins and minerals are still required!  

Evolutionally, donkeys are related to horses as they are both part of the Equus Family, but if you have ever interacted with a donkey you will quickly realize that they are behaviourally distinct from horses, this translates into their physiology as well. Donkeys evolved in hot and barren areas, this has led to them being highly adaptable feeders, they will consume a variety of grasses in order to meet their nutritional requirements. Therefore, the feeding strategy they use differs! They use a selective feeding strategy that targets high quality bites when foraging over a mixed pasture or rangeland area. However, when they are fed a homogenous hay, the donkeys will maximize intake as an alternative feeding strategy. Another interesting physiological difference that relates to nutrition is that the donkey is able to manage temporary water deprivation more effectively than horses and are able to rehydrate quickly.

Differing Nutritional Requirements

Since it has been established that donkeys can utilize more mature, less digestible, woodier plant material than compared to horses, it is accepted that they need less feed than a horse. This ability to be “thriftier” is attributed to their higher capacity to sort feed, lower water intake and their more developed system to recycle blood urea which makes their protein requirement lower.

Unfortunately, the research on donkey nutrition is extremely limited. In the NRC, there are guidelines for digestible energy intake, protein, calcium, and phosphorus. But due to the limited research, other mineral guidelines have yet to be established for donkeys. Despite a lack of clear guidelines, donkeys do still require vitamins and minerals in their diet.

The first step in evaluating your donkey’s nutritional status should be to body condition score them and estimate their weight. If you own a donkey, it is important to know that they have their own unique body condition scoring system as well as a different formula for calculating weight. If you are curious about this I am happy to provide you with these guidelines.

Common Issues

Despite most of the donkeys I see in Ontario, Canada being overweight, it is estimated that about 95% of the world’s donkey population is working. There are about 44 million donkeys worldwide! The work these donkeys do will differ depending on geographical location, but some common roles include: pack transport, pulling carts, farm tillage, drawing water and milling. In industrialized countries they are typically kept for recreation, breeding, shows or companionship. The practical recommendations in this article will focus on the recreational donkey population.

Practical Diets for Recreational Donkeys

When donkeys are being fed forage with a high nutritional value it should be restricted according to body condition. It is largely recommended that donkeys consume straw as part of their daily ration. This mimics the type of forage they have evolved to consume and allows them to eat to appetite without consuming too many calories. There are a few different kinds of straw that are popular:

• Oat straw: generally, has a higher nutritional value, therefore is higher in caloric value.
• Barley straw: typically has a lower nutritional value than oat straw. Recommended as the best all-round type of straw for donkeys.
• Wheat straw: very fibrous and has lower energy values. Not recommended for older donkeys who may have dentition issues.

Monitoring body condition and feeding forage in accordance with that is important, but as previously mentioned, vitamins and minerals are required as well. For donkeys, I recommend seeking out a ration balancer that is concentrated and does not provide significant protein or energy. Generally, these ration balancers will have a very low feeding rate. As an example, one of the products I commonly recommend for donkeys only about 3 oz per day to balance the typical ration.

If you have a donkey and are wondering if their diet is balanced and low enough in digestible energy to optimally support them, please don’t hesitate to reach out.

By: Madeline Boast, MSc. Equine Nutrition

References:

Duncan, J., & Hadrill, D. (2008). The professional handbook of the donkey. The professional handbook of the donkey., (Ed. 4).

Martin-Rosset, W. (2018). Donkey nutrition and feeding: Nutrient requirements and recommended allowances—A review and prospect. Journal of equine veterinary science, 65, 75-85.

Mueller, P. J., Jones, M. T., Rawson, R. E., Van Soest, P. J., & Hintz, H. F. (1994). Effect of increasing work rate on metabolic responses of the donkey (Equus asinus). Journal of Applied Physiology, 77(3), 1431-1438.

National Research Council. Nutrient Requirements of Horses. (2007). National Academy Press, Washington, D.C.