Miniature horses are increasingly common across the land. In fact, the American Miniature Horse Association is one of the fastest growing horse groups in the nation (www.amha.org).
You may spot minis as mascots at show barns, trimming the grass in suburban neighborhoods, in their own show barns and even acting as seeing-eye guides for people with visual handicaps (www.guidehorse.com). Our own miniature horse came home at age three in the back of our minivan - how fitting!
When you ask mini horse owners about health concerns, a couple of topics come up immediately. Weight problems (as in obesity, rarely being too thin), problems with teeth or bites, liver disease and some orthopedic problems are quickly brought up. Dwarfism can show up in any equine breed, but it's also more common in minis. Download a PDF of this article.
WEIGHT ISSUES. Weight, particularly obesity, is huge. Those elegant show minis are kept on strict diets and given regular and full workouts virtually every day. A dry lot is the free-exercise area of choice.
But minis are still horses and therefore need fiber and forage for a healthy intestinal tract. So, you do need to feed some hay. Figure about 1% of body weight, so a 200-lb. mini will get 2 lbs. of hay. You can substitute in some beet pulp for some hay, but all horses need roughage and forage.
Pasture in limited amounts, along with carefully controlled amounts of hay, provides plenty of good nutrition for the average mini. No need to spend money on grain! An overweight mini is stressing many body systems. You want your mini fit and trim.
You also need to exercise your mini. Left to his own devices, your mini will happily stroll the pasture stuffing in grass as fast as he can all day. Try to establish a daily routine of longeing, driving or even hand walking your mini.
To feed your mini properly, you need an accurate weight. Most minis weigh around 200 pounds. If your feed store has a large walk-on scale, you may be able to take your mini there. The weight tapes commonly used for regular horses are even less accurate for minis. Fortunately, Kentucky Equine Research has developed equations for using weight tape measurements to come up with accurate numbers.eight-tape measurements to come up with accurate numbers (see below).
KER's WEIGHT TAPE EQUATION. To measure girth, place the tape just behind the front legs and over 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. If there is a question as to the exact location of the withers, allow the horse to lower his head and neck as if to graze and measure to the highest point in front of the saddle area. 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. Use the measurements (in inches) in one or more of the following equations:
1. (Girth x 9.36) + (length x 5.01) - 348.53 = body weight in pounds.
2. (Girth x 11.68) + (height x 2.85) - 357.26 = body weight in pounds.
3. (Girth x 13.18) - 326.07 = body weight in pounds.
Visit Kentucky Equine Research at www.ker.com for more information.
WEIGHTY ITEM: MEDS. Having an accurate weight on your mini is important for other reasons as well. Figuring out the correct dose of dewormer or any medication or supplement depends on having the right weight. And, since they're smaller, you don't have as much leeway as you do with a regular-size horse.
When it comes to vaccinations, mini horses are in a bit of a muddle. They're equines and should receive the basic horse core vaccines as outlined in the American Association of Equine Practitioners (AAEP) guidelines: Tetanus, rabies, Eastern and Western influenza for sure and also often West Nile virus. But here's the kicker: There is limited data on the use of any equine vaccines in miniature horses. So technically, your veterinarian is working "off label."
Realistically, your mini horse needs protection from these diseases. By law, he may be required to have a rabies vaccination. So you don't have much of a choice.
Some veterinarians feel the prime change to make is to cut the dose slightly for minis due to the size difference. Others give the full dose as stated on the vaccine insertions. Discuss this with your vet.
MORE HEALTH ISSUES. Liver problems aren't common in most horses but can rear their ugly heads in minis. Hyperlipemia (fats in the bloodstream) and hepatic lipidosis (fatty liver disease) often go hand in hand in overweight minis, especially if they get stressed.
In hyperlipemia, a mini mobilizes fat stored in the body to use for energy. At some point, the amount of fat being mobilized becomes too much for the liver to process and fats are released into the blood.
The first sign of this disease is often going off feed. This can also be the first sign of colic, so call your vet immediately.
This is a rare case where grain feeding is encouraged. You want carbohydrate-rich foods to provide an easy-to-digest energy source while the liver works on the excess fats. Rich hay or top-notch pasture will also help. For minis who don't eat, IV nutrition may be required.
Once treatment is underway, you need to determine what stressed your mini and remove the cause.
Hepatic lipidosis is the next step along the way with this problem. The fats in the liver interfere with normal liver functions. Your miniature horse may stop eating, colic, look jaundiced or yellow when you check his eyes or gums, develop swelling of his legs or show neurologic signs such as behavior changes or even a coma.
Many minis will die despite care with intravenous nutrients, insulin to slow down fat movement, and heparin to help move fats out of the bloodstream. We can't stress enough that it's important to react immediately if you feel your mini is showing any signs of this illness.
MINI DENTAL WORK. Miniatures are prone to having abnormal bites, which means the incisors don't meet in front, they are mismatched. In a "sow mouth," the upper jaw is shorter than the bottom jaw. In a "parrot mouth," the upper jaw is longer than the bottom. These malformations can lead to changes in the wear of the teeth further back in the mouth, such as the premolars and molars.
Miniatures often need more frequent floatings than regular horses, including every year for the first four years of his life. This is especially true for foals and young minis, where enamel or transverse ridges may cause the jaw to lock and develop abnormally.
A knowledgeable veterinarian may correct young minis with bites that are "off" with the use of wires. Those horses should not be shown in conformation classes or bred, however, as the genetic defect will be passed on even if the mini now looks normal.
Finally, miniatures are more likely to retain parts of their baby teeth. These "caps" can interfere with normal chewing but can usually be removed with care and mild sedation.
CONFORMATION ISSUES. Orthopedic problems can show up in minis. Foals with severe dwarfism characteristics tend to have more orthopedic problems. Mini foals may be born with tendon and ligament laxity or tightness. With laxity, the joints will need support until the soft tissues firm up. With tightness, there will be contracture, requiring gentle stretching of the affected areas. Since mini foals grow so rapidly, it's critical that you call your vet as soon as you suspect a leg deformity.
Angular limb deformities such as toeing out or in can be caused by bone growth disturbances or lax tendons and ligaments. These conditions can usually be helped by bandaging, splinting or adding supports to the hoof or limb to change angles. If your mini foal needs some of this care, be prepared for frequent vet visits and bandage changes. The rapid growth means splints can easily become too tight. You don't want secondary sores or infections to deal with in addition to the primary problem.
Miniature horses are more likely to have problems with their patellas (knee caps) than the average horse. The patella can get "locked" and leave your mini with his rear leg extended and unable to flex at the hock or stifle. Generally, this will fix itself in a short time, but it will keep recurring. Surgery and exercise to build up muscles around the area can help.
Minis are also prone to patella luxation where the knee cap slides to the outside instead of staying straight in the groove down the stifle joint. While this can be a traumatic injury, it is most commonly seen in mini foals shortly after birth. The foal will have trouble standing or moving and will keep his stifle flexed. You can feel the abnormal "bump" on the outside of the stifle joint. Luckily minis are small enough that surgery can often repair the problem.
BOTTOM LINE. Most minis are hardy little horses who go through life with minimal problems. And they are attractive and fun! Keep your mini at a reasonable weight, fit and active. As always, prevention is better than treatment.
Article by Contributing Veterinary Editor Deb Eldredge DVM, who owns a mini driving horse.