Feed a Miniature Horse as A Horse - with some caveats!

By Juliet M. Getty, Ph.D.

Miniature horses are adorable. They not only make great pets, but offer ample showing opportunities including halter, jumping, driving, and trails. Because of their small stature, they also make excellent therapy horses for ill or disabled adults and children.

Some controversy still exists as to whether or not a mini is a horse or a pony; however, the vast majority of experts agree that a miniature horse retains the horse phenotype and its metabolic characteristics. They are scaled down versions of their full-sized friends with the same nutritional requirements. Ponies, on the other hand, descended from horses living in harsh, cold climates where they adapted to low-quality, sparse forages. Their genetic nature is to gain and maintain weight easily, making it difficult to adapt to the plentiful, highly nutritious diets typically fed to horses.

Basic principles of feeding horses

The foundation of any horse’s diet is a steady, unending flow of forage.[i] Since hay has lost the nutrients that live pasture once had, a comprehensive supplement or fortified feed and a source of omega 3s are needed to fill in nutritional gaps. Protein quality is best maintained by feeding a variety of protein sources, rather than only one type of forage. A balanced, varied, and nutritious diet protects the horse’s ability to naturally fight off disease, produce and repair tissues, and prevent degenerative diseases. And equally important, a calm, stress-free environment[ii] should be maintained to prevent the damaging hormonal response that can lead to ulcers, colic, allergies, metabolic syndrome, and even laminitis and equine Cushing’s disease.

The same rules apply for the miniature horse, but there are several considerations unique to these animals that we must not overlook. In fact, by ignoring the distinctive needs of the miniature horse, the well-intentioned owner can create serious health problems. To help you avoid potential difficulties, let’s review the guidelines for a healthy miniature horse.

Minis gain weight easily and tend to be overfed 

Miniature horses are easy keepers; they tend to hold on to body weight and have a genetic propensity toward insulin resistance. On top of this, they are often overfed. Guessing their weight when portioning out feeds can result in feeding far too many calories. 

Knowing your mini’s weight is not only important for calculating feed and supplement amounts, it is also necessary for administering medications and dewormers. Since weight tapes are not accurate for the miniature horse, you’ll want to calculate his weight using one or the average of these formulas:[iii]

1. Body weight (pounds) = (Girth in inches X 9.36) + (length in inches X 5.01) - 348.53 
2. Body weight (pounds) = (Girth in inches X 11.68) + (height in inches X 2.85) - 357.26
3. Body weight (pounds) = (Girth in inches X 13.18) - 326.07

Instructions: To measure the girth, place the tape just behind the front legs and over the base of the withers. Pull the tape snug, but not tight enough to depress the flesh. For height, stand the horse squarely on level ground or pavement and measure the vertical distance from the ground to the top of the withers. The tape should be kept perpendicular to the ground, not laid against the horse. Length is measured from the middle of the horse's chest, along the side, and around to a point under the center of the tail.

Metric conversions:

• To convert centimeters to inches, divide by 2.54.
• To convert pounds to kg, divide by 2.2.

Diets should be low in sugar and starch

Your mini should be fed a diet that has less than 10% combined sugar and starch. If at all possible, test your hay[iv] to determine its nutrient content. Here are additional feeding considerations:

• Many minis cannot consume pasture because of their tendency to develop regional fat deposits (due to insulin resistance). This puts them at risk of developing laminitis. If your mini is of good body condition and gets plenty of exercise, he can likely enjoy some pasture grazing. Familiarize yourself with the factors that increase the sugar/starch content of grasses.[v]
• Athletic minis who are exercised regularly can be fed concentrated feeds as long as they are low in sugar and starch. Avoid any feed that contains cereal grains (oats, corn, rice, wheat, barley, etc.) or added sugar (typically from molasses).
• If your horse is not active and is a bit chubby, all he needs is forage along with necessary supplementation, salt, and fresh water.
• Allow your mini to tell you how much hay and/or pasture he needs to maintain a healthy body condition. When forage is provided free-choice, minis will self-regulate their intake and typically consume 1.5 to 2 percent of their body weight for maintenance. Cart animals, animals being shown, and lactating mares have higher caloric demands and will naturally consume 3% to 3.5% of their body weight in forage.
• Alfalfa can be fed to boost overall protein quality, keeping in mind that alfalfa is high in calories. However, alfalfa hay, cubes, or pellets are low in sugar and starch and make excellent carriers for supplements. Limit intake to 10 to 20% of the total hay ration.

Make movement a part of your mini’s daily life. Movement inhibits weight gain; exercise not only burns calories, but it makes the cells more receptive to insulin, allowing the body to burn fat. It also reduces stress and its impact on overall health.

Consider slow feeders. Your horse’s digestive health, oxidative stress level, and hormonal balance depend on a steady flow of forage. Slow feeders allow your mini to graze on forage 24/7 but at a slower pace. They come in many varieties;[vi] place several throughout your horse’s living area to encourage normal movement. Allow time for your mini to adjust to this new feeding method by placing some hay on the ground alongside the feeder until he is totally accustomed to it.

Stress is especially dangerous for minis

Stress produces a hormonal response that is capable of destroying your mini’s health. It damages the immune function, contributes to digestive disorders, promotes weight gain, increases laminitis risk, and creates oxidative damage to the hypothalamic portion of the brain, potentially leading to equine Cushing’s disease as well as leptin resistance.

Any factor that increases stress, whether mental or physical, should be carefully monitored. Illness, pain, hectic travel and performance schedules, stall confinement, lack of a buddy, or forage-restriction can disproportionately stress minis to the point that they stop eating.

When the mini stops eating, he is at a high risk of developing hyperlipemia. This life-threatening condition is the most significant difference between large horses and their miniature counterparts. When the mini loses his appetite, his blood glucose level plummets. The pancreas responds by releasing the hormone glucagon which pulls glucose out of liver glycogen, causing insulin to rise. But if the mini is overweight and insulin resistant, glucose cannot adequately enter the tissues. In an effort to meet energy needs, fatty tissues are broken down. In fact, fat enters the bloodstream at such remarkable levels that the liver becomes overwhelmed. The consequence is a fatty liver, interfering with normal liver function. The mini may show signs of incoordination, abdominal pain, diarrhea, jaundice, and seizures. Ultimately liver failure can threaten the mini’s life. Prompt veterinary attention is critical. Rapid intervention, typically by administering a source of glucose (such as corn syrup), should be implemented while waiting for your veterinarian to arrive. Intravenous glucose coupled with insulin therapy is often necessary.

Minis have unique dental issues

Interestingly, minis have the same number and size of teeth as full-sized horses. Since their heads are considerably smaller, this potentially leads to overcrowded teeth and malocclusions. If ignored, your mini can experience sinus infections and facial distortions, as well as difficulty chewing, predisposing him to choke and colic. Even if your mini is just a pasture pet and appears well-nourished, it doesn’t mean that his teeth are fine. It is imperative that minis receive yearly dental exams.

Minis are especially prone to developing impaction colic from three sources:

• Fecaliths. These rock-like stones develop in the small colon (the last section of the colon before the rectum). They consist of manure combined with coarse hay and hair consumed when horses groom each other. They obstruct normal digestive flow and cause gas accumulation. Minis grazing on pasture have a lower incidence of fecaliths than those receiving hay as their predominant forage source. The lack of movement imposed by stall confinement increases the risk of acquiring these stones.  
• Enteroliths. These stones can develop anywhere along the hindgut. They typically form from high alfalfa diets (more than 50% of the hay ration as alfalfa). The high protein, magnesium, and phosphorus content of alfalfa adhere to an ingested foreign object (such as a scrap of wire) to form stones. Enteroliths are most often passed, especially when the horse has opportunity to walk around and there is a steady flow of forage to allow the cecum to evacuate properly.
• Sand. Minis tend to scavenge their surroundings. If placed on a dry lot with little hay, they will eat sand as they “vacuum” the ground for any tasty morsel. When sand settles in the hindgut, it inflames the cecum and colon linings, leading to diarrhea. As the sand slowly accumulates, it can eventually lead to an impaction. Movement, combined with a steady flow of forage and free access to water, will encourage sand to be eliminated in the manure.

Bottom line

Minis have the same digestive system as full-sized horses, but because of their small size and unique breed needs, they require a steady flow of forage, appropriate feeds, plenty of exercise, freedom to graze, and reduced stress, along with regular dental care.

[i] For more on feeding forage free-choice, please refer to Dr. Getty’s Resource Library on "Free-Choice Forage Feeding Concepts."

[ii] Please read, “Restricting Forage is Incredibly Stressful,” by Juliet M. Getty.  

[iii] Developed by Joe Pagan, PhD, president of Kentucky Equine Research (KER)

[iv] For information on interpreting your hay analysis report: “Do You Need to Analyze Your Hay?” by Juliet M. Getty.

[v] Read, “Testing Your Pasture – For Peace of Mind,” by Juliet M. Getty  

[vi] A variety of Slow Feeders is available at Dr. Getty’s Free Shipping Store. 

For Permission to Reprint

For permission to reprint this article, in part or in its entirety, please contact Dr. Juliet Getty directly at Gettyequinenutrition@gmail.com.