Obesity in Donkeys – Why is it a big deal?

Possibly the most significant threat to the health and longevity of donkeys in the US is obesity. We love our long-eared friends and sometimes we dote on them too much with delicious, high-quality treats that donkeys are not equipped to metabolize.

My donkey’s fat? But he barely eats anything!

Donkeys are adapted to live in semi-arid environments, like the deserts of Nevada and Arizona. Because of this, their metabolism is significantly different than that of horses – think of them as the world’s easiest keepers. Donkeys are incredibly efficient at digesting tough fibrous plants and have a much lower energy requirement than horses. To put it in perspective, ponies and horses need 2-2.5% of their body weight in dry matter daily, whereas donkeys only need 1.3-1.8%.

The high fiber, low energy diet that donkeys have evolved to eat can be mimicked by feeding mainly straw (wheat, oat, or barley) along with a forage balancer to avoid micronutrient deficiencies. As an aside, you want to stay away from rice straw – for some reason it is the one type of forage that donkeys seem to have absolutely no interest in eating. If the only option is hay, it is recommended to soak the hay for at least an hour before feeding to your donkeys to remove most of the simple sugars.

So my donkey’s fat – what’s the big deal?

Adipose tissue – or fat – is not just a cosmetic issue. It is a very active tissue that produces inflammatory molecules that circulate throughout the bloodstream and can propagate multiple disease states, including metabolic syndrome and laminitis. Another life-threatening sequela of obesity is the increased risk of developing fatty liver. Fatty liver occurs when an obese animal goes through a period of anorexia – this could be a simple as a bout of gas colic that results in your donkey not eating his whole breakfast. When the body doesn’t get its normal amount of energy through food, it rapidly mobilizes and breaks down adipose tissue to use for energy instead. The resulting fat molecules (triglycerides) get filtered through the liver and overwhelm it, resulting in a liver that is clogged with fat. This can lead to liver failure, as well as damage to and failure of other organ systems. Donkeys are especially predisposed to this process, which is a major reason why we always recommend a call to your veterinarian for any donkey that goes off food, even if they don’t seem to be in overt distress.

Okay I’m convinced, my donkey’s fat – now what?

As discussed above, sudden reductions in feed intake can lead to life-threatening disease, so having a conversation with your veterinarian about safely putting your donkey on a diet is paramount. It may even be necessary to test the levels of triglycerides in the blood as a monitoring tool while your donkey loses weight. As with all our equine friends, a slow systematic approach to dietary change is the best way to reduce risk.

How to Keep Donkeys and Mules Healthy

Donkeys and mules are readily recognizable by their distinguished large ears. These equids frequently have the reputation of requiring less veterinary attention. Although they are certainly more stoic (and perhaps smarter!) than horses, they still need—and deserve—the same preventative veterinary care and routine farrier work.

Image by Marzena P. from Pixabay

The long-eared can fall into a few categories, so here are the basic definitions:

Donkey: Like the horse, the donkey is in the Equidae family. The donkey is derived from the African wild ass and was likely domesticated about 5000-6000 years ago in Africa. Male donkeys are called jacks, female donkeys are called jennys.

Mule: mare/jack cross. Mules are sterile.

Hinny: stallion/jenny cross. Hinnys are sterile.

Image by Ralphs_Fotos from Pixabay

Donkeys and mules are thrifty, able to work hard and survive in barren conditions. Donkeys in particular are adapted to digest fiber of poor nutritional quality and they have lower daily intake requirements to maintain body weight. This heartiness is especially problematic in our non-working donkeys, as they tend to be easy keepers prone to obesity and related conditions, such as laminitis.

The stoicism of the donkey also means that health issues are frequently not observed as quickly as in horses. Donkeys can become extremely ill when health conditions cause them to stop eating, leading to high levels of fat mobilization within the bloodstream, or hyperlipidemia. Hyperlipidemia can be fatal unless treated aggressively. Signs of illness or pain in a donkey can be easily overlooked. Typically, the first sign of a problem is decreased water or food intake, but signs can also be as subtle as less interest in the surrounding environment and decreased social behavior with other donkeys. In addition, donkeys and mules can suffer from all the same ailments as horses, including colic, respiratory disease, hoof abscesses, and gastric ulcers.

Image by Christine Sponchia from Pixabay

Other considerations

While they have the reputation for being stubborn, frequently this behavior is due to a donkey taking time to assess a new situation. Donkeys are less likely to panic than horses, and more likely to protest- fight instead of flight! They also form strong bonds with other donkeys, so for travel or hospitalization, a donkey companion is a great way to minimize additional stress.

free day womens burro race” by ken ratcliff is licensed under CC BY 2.0.

Recommended veterinary care for donkeys and mules includes the recommended yearly core vaccinations (rabies, tetanus, eastern and western encephalitis, and West Nile) as well as routine veterinary dental care and targeted deworming. Although most donkeys in our community are non-athletes, many Colorado donkeys participate in burro racing, the official sport of Colorado! This is a great way to bond with your donkey and help keep him fit. Whether your donkey or mule is a backyard companion or burro racing champion, don’t forget to ensure he has access to the same care as your horses!