An obese Miniature Horse is a health risk! Fat can also prevent a Miniature mare from getting pregnant. Your risk of dystocia increases dramatically if your mare is carrying excess weight; the fat actually takes up the foal's space. If you have an obese Miniature, you need to take the weight off VERY SLOWLY!

Hyperlipidemia occurs often enough in miniature horses and donkeys that it is a disease miniature horse lovers need to be aware of. Maintaining a miniature's weight is sometimes kind of tricky. They usually are not too hard to keep weight on....it is the reverse, in that it is hard to keep them from getting too fat. You have to be very careful about how you take the fat off, for taking fat off too fast can cause hyperlipidemia (or hyperlipemia).

Hyperlipemia often develops as a secondary reaction to a systemic disease that has caused anorexia and depression. It is most often seen in the winter and spring.

Anytime a horse stops eating for any reason (such as stress, after foaling, illness), the stored fat begins to breakdown. The fat stores are released into the blood stream due to the body's assumption that it is starving. This released fat circulates via the blood and circulates into the liver. Once in the liver, you will see signs of liver failure. Often death is the result due to acute hepatic rupture. This often-fatal disease acts VERY QUICKLY, so be vigilant anytime your miniature stops eating. Call your vet!! Hyperlipidemia is diagnosed via a blood test. We just had a dear friend lose her Miniature Donkey from this condition. She was around the clock supplementing her long-eared friend, but lost her after much effort. Your only hope is to diagnose early. Karo Syrup can be some quick nutrition to pump in when you suspect this is occurring.

If you have a mare who has recently foaled and is losing weight too quickly, watch for  Hyperlipidemia.

Symptoms include depression, anorexia, decreased water intake, diarrhea, hanging of the head, lethargic....If you see these signs and your minis is not wiling to eat, call your vet and have them draw blood. The results of a horses with this disease will have lowered blood glucose levels and elevated triglycerides. Other lipids (nonesterified fatty acids and very low-density lipoproteins) in the blood may also be increased. Your vet will probably attempt to increase the glucose levels with nutritional supplementation (Insulin and Glucose). IV fluids are usually necessary. Heparin is often given to decrease the fat already in the blood by.

Here is an article that explains it in detail:

http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/22818.htm

http://wwwchem.csustan.edu/chem4400/SJBR/99boyce.htm