What causes mbd in squirrels

What is Metabolic Bone Disease (MBD) in Squirrels?

Metabolic bone disease (MBD) is a common and serious skeletal disorder affecting many captive wild animals, including squirrels. It's not a single disease but rather a group of conditions that result from nutritional deficiencies or imbalances, leading to weakened bones. These bones become soft, brittle, and deformed, making them susceptible to fractures even from minor stresses.

Causes of MBD in Squirrels

The primary culprits behind MBD in squirrels are related to their diet and environmental factors:

Nutritional Imbalances

Squirrels in the wild have a varied diet that typically provides the necessary nutrients for strong bone development. However, squirrels kept as pets or those relying on human handouts often receive diets that are severely lacking in essential minerals and vitamins.

Calcium Deficiency

Calcium is a critical building block for bones and teeth. A diet low in calcium forces the squirrel's body to draw calcium from its bones to maintain essential bodily functions, leading to demineralization and weakening.

Phosphorus Excess or Imbalance

While phosphorus is also essential for bone health, an excessive amount relative to calcium can be detrimental. The crucial factor is the calcium-to-phosphorus ratio. A healthy ratio is vital for proper calcium absorption and utilization. In many unbalanced diets fed to squirrels, the phosphorus content is too high, or the calcium content is too low, disrupting this ratio and preventing calcium from being effectively incorporated into the bones.

Vitamin D Deficiency

Vitamin D plays a pivotal role in calcium absorption from the digestive tract and its regulation in the body. Without sufficient vitamin D, even if calcium is present in the diet, the squirrel cannot absorb it effectively. Vitamin D can be synthesized by the skin when exposed to ultraviolet B (UVB) radiation from sunlight. Squirrels kept indoors or in environments with limited sun exposure are at high risk of vitamin D deficiency.

Inadequate Diet Composition

Many foods offered to squirrels, especially those from human sources, lack the complete nutritional profile required for bone health. For instance:

• Processed Foods: Human snacks, bread, and sugary items are nutritionally poor and can displace more beneficial foods in a squirrel's diet.
• Seed-Heavy Diets: While seeds are a natural part of a squirrel's diet, relying solely on them can lead to imbalances, particularly a low calcium-to-phosphorus ratio.
• Lack of Variety: A diverse diet including nuts, seeds, fruits, vegetables, and occasional insects or fungi is ideal for wild squirrels. Captive squirrels need a carefully formulated diet mimicking this variety.

Environmental Factors

Limited Sunlight Exposure: As mentioned, UVB rays are necessary for vitamin D synthesis. Squirrels housed indoors or in shaded enclosures may not get enough sunlight, even if they are in a sunny climate.

Symptoms of MBD in Squirrels

Recognizing the signs of MBD is crucial for prompt veterinary care. Symptoms can include:

• Lethargy and weakness
• Lameness or difficulty moving
• Swollen limbs or joints
• Tremors or twitching
• Spontaneous fractures (bones breaking easily)
• Deformed limbs or spine
• Loss of appetite
• Constipation (due to low calcium affecting muscle function)

Prevention and Treatment

Preventing MBD involves providing a balanced diet rich in calcium and vitamin D, with an appropriate calcium-to-phosphorus ratio. This often requires consulting with a wildlife veterinarian or a specialist in exotic animal nutrition. Supplementation with calcium and vitamin D may be necessary, but it must be done carefully under veterinary guidance to avoid other health issues like kidney stones. Ensuring adequate UVB exposure, either through natural sunlight or specialized lighting, is also important for captive squirrels.