Mule Care & Management Guide: Characteristics, Health & Nutrition | Mad Barn (2024)

Mules are an equid hybrid produced by crossing a female horse and a male donkey. Enthusiasts claim mules combine the best of both species, offering the strength, endurance, and patience of the donkey with the speed, agility, and aesthetics of the horse.

Mules are often praised for their hardiness, intelligence, and lesser need for maintenance compared to horses, making them a popular choice for a variety of tasks, from farm work to trail riding. These equids are still used as working animals around the world.

While mules share traits with horses and donkeys, they also have unique characteristics. Although there is limited research available on the welfare and management of mules, new studies have found significant differences between these hybrids and horses.

With their growing popularity as recreational mounts and pets in North America, it is important for owners and handlers to understand these differences. This profile will discuss the history, characteristics, health problems and nutritional needs of mules. Keep reading to learn more about feeding and caring for these equids.

What is a Mule?

A mule is a hybrid animal resulting from the crossbreeding of two different species within the Equidae family: a male donkey and a female horse. This crossbreeding results in offspring with a blend of traits from both parents.

Mules typically exhibit physical and behavioral characteristics inherited from both donkeys and horses. They often have the body shape and size of a horse, with long, strong limbs and a muscular build, but also inherit the donkey’s hardier, more resilient nature.

Mules have longer ears than horses, a trait characteristic of donkeys, and their coats, tail, and mane may also resemble that of a donkey. They are also less prone to many of the genetic diseases that horses are susceptible to and often have a longer lifespan.

Equids and Hybrids

The term “equid” can refer to any animal that belongs to the Equidae family. Equus is the only surviving genus in this small taxonomic family. This genus consists of three subgenuses. ^[6]

• Horses: Includes the domesticated horse (Equus caballus) and the Przewalski’s horse (Equus ferus przewalskii).
• Asses: Includes the African wild ass and domesticated donkey (Equus africanus), the Asiatic wild ass (Equus hemionus), and the Tibetan wild ass (Equus kiang).
• Zebras: Includes the Plains zebra (Equus quagga), the Grevy’s zebra (Equus grevyi), and the Mountain zebra (Equus zebra).

Crossbreeding different species in the Equidae family produces equid hybrids. Most hybrids are sterile and cannot produce offspring.

Types of Equid Hybrids

Hybrid names describe the species and sex of the parents.

• Mule: Male horse and female donkey parents
• Hinny: Male donkey and female horse parents
• Zorse: Typically male zebra and female horse
• Zonkey: Typically male zebra and female donkey

Can Mules Reproduce?

Mules are sterile and cannot reproduce due to chromosomal differences between horses and donkeys.

Horses have 64 chromosomes in their genetic material, while donkeys have 62. When a horse and a donkey mate, their mule offspring will have an intermediate chromosome count of 63 chromosomes, which generally leads to sterility.

This odd number of chromosomes disrupts meiosis, the process of cell division that produces reproductive cells, such as sperm or eggs. During meiosis, chromosomes pair up and then separate into new cells to ensure that each reproductive cell gets a complete set of chromosomes.

However, the uneven number of chromosomes in mules leads to cells that do not have the proper number of chromosomes. As a result, most mules end up with reproductive cells that are not viable, rendering them infertile.

Mule History

Humans have bred domesticated mules as beasts of burden for thousands of years. Crossbreeding donkeys and horses remained popular throughout history thanks to the mule’s practical talents.

Origin

Mules are the oldest known and most common equid hybrid. The mule name specifically refers to the offspring of a male donkey (Equus asinus) and a female horse (Equus caballus). A hinny is a less common hybrid produced by crossing a male horse and a female donkey.

Research suggests domestic horses originated in the Eurasian steppes, while domestic donkeys originated in East Africa. Genomic studies revealed humans domesticated donkeys approximately 3,000 years before horses. ^[1]

Other genomic studies identified mules dating from the Iron Age, which spans approximately from 1200 BC to 600 AD. These hybrids are also portrayed in ancient Egyptian iconography, suggesting Egyptians bred mules before 1000 BC. ^[2]

Historic Use

Mules are typically sterile and not suitable for breeding. As a result, these equids are only used for work. In several ancient civilizations, mules gained a reputation as robust, low-maintenance working animals. Egyptian iconography depicted mules pulling chariots and plows. ^[1]

For centuries, militaries used mules as pack animals. Archeologists identified remains of mules at Roman military forts dating as far back as 160 AD. ^[3]

Settlers in the Americas also used sure-footed mules to carry supplies over mountainous terrain and pull heavy loads in large teams. The American mining industry famously used 20 mule teams to pull wagon loads of borax out of Death Valley, California. ^[4]

While mule populations declined in industrialized countries in the twentieth century, some communities still rely on mules for their livelihood. Over 12 million mules live in developing countries, where they are still primarily used as working animals. ^[5]

Mule Characteristics

Mules aren’t just horses with long ears. They are well known for their hybrid vigor, a phenomenon where crossbred animals exhibit improved physical and physiological characteristics, resulting in greater strength and endurance.

These equids also have unique psychological traits that are distinct from their parentage.

Conformation

Mules vary significantly in size. Miniature mules produced by crossing mini horses and donkeys can stand under 12 hands. But mules with a draft horse mother can exceed 18 hands at the withers.

Many conformational traits can also vary depending on the breed of the horse parent. However, most mules have longer ears and heavier heads than horses. Mules typically have narrower hooves than horses, but morphology studies found mules had similar bone sizes to horses. ^[7]

Colours

Mules can come in any coat colour found in horses or donkeys. Most mules have the light points and mealy colouring found around the muzzle, belly, and eyes of donkeys. These hybrids also often have primitive markings.

Donkeys have sparse manes and tails, but most mules inherit full tails from their horse parents. Their coat hairs are coarser than horse coat hairs. ^[8]

Temperament

Mules have a reputation for being stubborn. Some studies found mules performed better on cognitive tests than other equids, suggesting mules have above-average intelligence. This intelligence allows mules to learn both desirable and undesirable behaviours quickly. ^[9]

These hybrids are more aggressive than horses towards unknown people. While they can develop good relationships with their owners, new caretakers should take extra precautions when handling mules.

Mules typically have more stoic personalities than horses. Their stoicism and resilience can make detecting early signs of pain or health problems more challenging.

Although mules are sterile, most veterinarians recommend owners castrate their male mules to make them safer to handle.

Disciplines

Most mules are working animals. However, these hybrids are quickly gaining popularity with recreational horse owners in North America. Many mules and donkeys are companion animals and pets, but owners can also train mules to ride.

Mules can excel in many different disciplines with good training. Their suitability for particular jobs varies depending on their breeding. Some riders even compete with their mules in low-level eventing and show jumping.

These equids are brave, sure-footed trail mounts. Some trail riders also use mules as pack horses to carry supplies on overnight adventures. Their strength and stamina are also well-suited to endurance riding and pulling wagons and carriages.

Mule Health Profile

Mules are generally considered to have improved health and vitality compared to horses or donkeys. These resilient animals are less susceptible to many common equine diseases and require less management overall.

However, some health problems occur at a higher frequency in mules, varying depending on their use. But with proper care and management, these equids can live significantly longer than most horses.

Genetics

Several horse breeds carry mutations linked to genetic diseases, but there are few genetic diseases found in donkeys and mules.

Like most hybrid animals, mules have a low risk of hereditary diseases. ^[10] This is a result of greater genetic diversity, which reduces the likelihood of inheriting certain genetic disorders common in purebred animals.

A distinctive aspect of mule genetics is their odd number of chromosomes, which makes them infertile. Mules have 63 chromosomes, an odd number that cannot be divided evenly during meiosis to form viable reproductive cells. In comparison, horses have 64 chromosomes and donkeys have 62. ^[10]

Health Problems

While mules are generally hardy, they can experience different health problems depending on their management and work. Studies have identified a high frequency of gait abnormalities, limb deformities, poor body condition, and body lesions in working mules. ^[11]

Donkeys and mules are more susceptible to sarcoids, a type of cancerous skin tumour. They are also predisposed to other skin conditions and ectoparasites due to their coarse coat hair. ^[12]

Mules affected by colic often display milder clinical signs than horses. As a result, gastrointestinal disorders in mules are frequently undiagnosed until they become severe and potentially life-threatening. ^[13]

With proper care and management, some mules can achieve remarkably long lifespans, living into their forties. However, these aged equids can develop health problems commonly found in senior horses, including:

• Dental issues
• Swayback (Lordosis)
• Osteoarthritis
• Pituitary Pars Intermedia Dysfunction (PPID)

Care and Management

Mules require the same basic care as horses. However, there are some special considerations to keep in mind when designing a management program for these equids.

Understanding the different behaviours and needs of these animals will help ensure both handler safety and mule health. Work with a team experienced with mules or donkeys to develop a preventative wellness plan that includes:

• Veterinary Exams: Schedule regular wellness appointments with your veterinarian twice yearly to check your mule for signs of health problems. Since mules are typically more stoic than horses, it can be more challenging for owners to identify issues early.
• Vaccinations: Mules are susceptible to many of the same infectious diseases that affect horses. Following a veterinarian-recommended vaccination program can protect your mule from these diseases. ^[14]
• Deworming: Parasites such as lungworms are significant concerns for mules. Work with your veterinarian to develop an effective deworming schedule to protect your mule from these parasites.
• Dental Care: Studies show mules have slightly different tooth morphology than horses. Schedule routine dental exams with an experienced dentist to monitor for signs of problems, which are more common in older mules. ^[15]
• Farrier Care: Mules typically have good hoof quality and rarely need shoes. However, they still need regular trimming. These equids have a narrower hoof shape and can be difficult to handle, so work with a farrier with mule experience.

Donkeys and mules have different reactions to medications, anesthesia, and painkillers compared to horses. For instance, donkeys metabolize common NSAIDs more rapidly. Always consult a veterinarian before giving any medication to a mule. ^[16]

Mules typically don’t fare well with extended stall confinement. Maximizing their turnout time and allowing them to live outdoors with other equines is beneficial for their wellbeing.

Research shows that donkeys do not grow winter coats. Mules may also require extra protection from blankets and shelter to stay warm in colder, wet climates. ^[8]

Daily grooming helps keep your mule’s skin and coat healthy. Regular handling and good training from a young age also support desirable behaviour in mules.

Nutrition Program

Mules have unique nutritional needs that differ from those of their parent species. Like all equids, they thrive on a forage-based diet, but mules typically have a more efficient metabolism compared to horses.

Weight Maintenance

Most mules are easy keepers, meaning they require less food to maintain a healthy weight compared to horses. These hybrids inherit their ability to efficiently digest energy and protein from their donkey parent. ^[17]

Because mules easily gain weight, regular monitoring and dietary adjustments are necessary to prevent obesity. These equids are also predisposed to equine metabolic syndrome, which is associated with a higher risk of laminitis. ^[18] To reduce the risk of laminitis, mules should avoid grain-based concentrates in their diet.

A cresty neck is a sign of obesity in mules. You can use the Henneke body condition scoring system to assess your mule’s condition and determine if dietary changes are necessary.

Sample Diet

The following sample diet is intended for a mature 410 kg (900 lb) mule with normal body condition at maintenance (not exercising).

The optimal feeding program for a mule is a a balanced, forage-based diet with high fiber and low levels of hydrolyzable carbohydrates (HC).

While mules have lower protein and energy requirements compared to horses, they still have the same requirements for vitamins, minerals, and other essential nutrients. Feeding a balanced vitamin and mineral supplement in addition to forage can help you meet your mule’s nutritional requirements.

Mad Barn’s Omneity is a comprehensive vitamin and mineral supplement that provides all of the key nutrients required to support hoof health, performance, skin and coat quality and overall well-being in mules. Omniety is formulated without grains or added sugars, making it ideal for balacing your mule’s diet while avoiding excess calories.

Forage

Forage should be the foundation of every mule, donkey, and horse’s diet. Equids are grazing animals whose digestive systems have evolved to support a continuous intake of high-fiber roughage.

However, some forages will be too nutrient-dense for mules when fed free choice. Providing hay in a slow feeder is often necessary to safely restrict forage intake.

Mules should eat approximately 1.5 to 2% of their body weight in forage daily. Choose high-fibre, low-sugar grass hay to ensure you can feed enough volume without adding too much energy to the diet.

Straw is commonly used as a low-calorie alternative to satisfy forage requirements in donkeys and mules, who are more efficient than horses at digesting this fibrous forage. Alfalfa and high-quality grass hays are usually not suitable for mules.

Unrestricted access to lush pastures can contribute to obesity and laminitis in these equids. To mitigate these risks, consider using a grazing muzzle or turning your mule out on a dry lot instead. ^[18]

Feeding Recommendations

Mules in light work should not be fed grains or commercial concentrates. Even in small amounts, cereal grains can provide more energy than most mules require, and their high starch content can heighten the risk of digestive and metabolic issues. ^[17]

While mules typically do not require fat supplements for energy, incorporating fat sources in their diet can be beneficial for skin, coat, and joint health. For mules without pasture access, omega-3 fatty acids are particularly beneficial.

Research suggests that environmental adaptations have made donkeys more tolerant of water loss than horses. However, all mules should still have free access to clean water to support adequate hydration.

Providing salt as a source of sodium can also trigger thirst and increase water intake. Avoid salt licks, and instead feed your mule plain loose salt to ensure they get enough sodium. ^[17]

Nutritional Supplements

Balancing your mule’s overall diet and preventing nutrient deficiencies is the first priority when developing a feeding program. Once the diet is balanced, some mules benefit from additional supplements to support their overall health and well-being.

• W-3 Oil is a fat supplement enriched with vitamin E and the omega-3 fatty acid DHA. These nutrients support joint health, antioxidant status, exercise care, skin and coat quality as well as the immune system.
• MSM is a natural joint supplement that can help maintain healthy connective tissues in mules. Senior mules can greatly benefit from joint support to maintain their mobility and comfort as they age.
• Optimum Digestive Health is a probiotic and prebiotic supplement that support hindgut health, nutrient absorption, and immune function in mules. Formulated with a unique blend of yeast, enzymes, and nucleotides, this supplement is ideal for protecting your mule’s digestive system.
• Spirulina is a nutrient-dense blue-green algae that is a popular supplement for horses. It is also beneficial for mules to support skin and coat condition, the respiratory system and immune function..

Have questions about what to feed your mule? Submit their diet online for a free evaluation, and consult with our experienced equine nutritionists for help with formulating a balanced diet.