Metabolic Bone Disease in Brown Bears

What is it?

Metabolic bone disease is a skeletal disorder that mainly affects young brown bears raised in captivity or orphaned bears fed inadequate diets.

It results from a prolonged imbalance of calcium, phosphorus, and vitamin D in the diet. The bones become fragile, deformed, or fractured more easily.

This disease is rare in bears living wild in their natural habitat, where the diet is varied and balanced.

Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Causes and risk factors

The main cause is an unbalanced diet during growth, particularly a lack of calcium relative to phosphorus, or insufficient vitamin D.

This most often occurs in orphaned cubs fed poorly formulated milk replacers, or captive bears receiving a diet too high in meat and lacking mineral supplements.

Lack of exposure to natural light can worsen vitamin D deficiency in some captive individuals.

Young growing bears are most vulnerable, as their mineral requirements are high.

Orphaned cubs rescued at a very young age and fed poorly balanced homemade preparations are at particular risk.

Captive housing with a low-diversity diet, high in muscle or meat without supplementation, also increases the risk.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

Treatment

Management centers primarily on gradually correcting the diet under veterinary supervision, with appropriate mineral and vitamin supplements.

Complete rest and limited physical activity are recommended until the bones heal.

In cases involving fractures or severe deformities, surgical or orthopedic intervention may be necessary.

Prevention

Possible complications

Without correction, the disease may progress to multiple fractures, permanent skeletal deformities, and chronic lameness.

In severe cases, the animal's mobility can be permanently compromised, which poses a major challenge for an animal intended for release into the wild.

When to see a veterinarian

Prognosis

The prognosis is generally good if the disease is detected early and the diet is corrected promptly, as young bones have good remodeling capacity.

However, if the disease is diagnosed late or after significant deformities have developed, permanent orthopedic sequelae may persist.

Frequently asked questions

References

AVMA — American Veterinary Medical Association

WSAVA — World Small Animal Veterinary Association

Content reviewed by the TunisieVet editorial team · Updated 30 August 2026