Metabolic Bone Disease


What is Metabolic Bone Disease?

Nutritional Metabolic Bone Disease (MBD) is a serious disease that occurs in opossums. It results in severe crippling and eventually death. It affects the skeletal system, making it weak and causing pain that prevents the animal from being able to move properly.  

What Causes it?

MBD is most commonly caused by feeding opossums an improper diet. Usually this means either not having the proper calcium to phosphorus (Ca:P) ratio or feeding too much protein or too many fruits. It’s critical to give opossums a 1.5:1 Ca:P ratio, and to ensure the rest of their food is balanced and nutritionally complete. If the opossum does not have a balanced diet then nutritional MBD may result.

Low calcium in the diet results in low calcium levels in the blood. When this happens, the parathyroid gland produces parathyroid hormone (PTH) to prevent the calcium levels from falling to low. One of the ways it does this is by taking calcium from the skeletal system, which results in the weakening of the bones. This weakening causes many of the symptoms associated with MBD.


Early on, there may be a loss of grip in the hands or feet, tremors, twitching, lethargy, uncoordinated gait, and a decreased appetite. They will be in pain. Their movement may become shaky. The opossum may have difficulty walking and climbing. It may develop a hunched back and start walking more gingerly, or crawl/drag its limbs. The legs may start to bow or appear chubby. The bones are demineralizing, making them fragile. Because of this, skeletal deformities may be visible.

As the disease gets worse, the opossum may be incapable of eating or drinking. Changes in the skull result in an incapacitation of the mouth. The tongue may stick out from the side of the mouth. Other organ systems may become affected as the disease progresses. How quickly the disease develops depends on the severity of the calcium deficiency and the overall health and age of the opossum.


If MBD is caught early enough then it can be treated and may be reversible. A balanced diet with enough calcium and the correct Ca:P ratio is the best treatment for MBD. Calcium-rich foods such as low or non-fat yogurt, kale, cabbage, collard greens, or bok choy are good to supplement the staple diet. Calcium supplements can also be used in some cases, but it’s important to make sure you aren’t over-supplementing.

In general, it’s best to use a staple pellet diet and supplement with high-calcium vegetables and/or a calcium supplement and occasional protein sources. Always offer meat with the bones as an extra source of calcium. Exotic Nutrition’s Insectivore-Fare is a good option for a staple diet, as it’s low protein (20%) and easy to supplement with calcium-rich foods. 

Make sure the opossum also receives some indirect exposure to sunlight for Vitamin D. Vitamin D is essential for calcium metabolism. Exposure to direct sunlight is not recommended because there is a high risk for overheating and sunburn. Rather, keep them under the shade of a tree or use a fluorescent tube reptile light (the type that doesn’t get hot) over some sort of mesh to simulate a shaded effect at times when the weather is too extreme to take them outdoors. 


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Please Note: Exotic Nutrition is not in a position to provide specific health and care guidelines on an individual basis. Please visit our animal info tabs or consider purchasing a care guide book for additional information. If you have a health or pet emergency issue, please notify your veterinarian or a specialized technician.


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