A yearling doe presents with lethargy, bowed thoracic limbs, muscle tremors, and softened ribs. The most likely culprit?

A yearling doe presents with lethargy, bowed thoracic limbs, muscle tremors, and softened ribs. The most likely culprit?

• A. Calcium deficiency
• B. Vitamin D deficiency
• C. Phosphorus deficiency
• D. Selenium deficiency

Answer: (B)

Growing animals rely on vitamin D to absorb calcium and phosphate, which is essential for proper bone mineralization. When vitamin D is lacking, calcium and phosphate uptake drops, leading to poorly mineralized bones. In a young, rapidly growing animal, this shows up as rickets: the growth plates don’t mineralize well, bones become soft, and the limbs can bow while the ribs may appear softened. Lethargy and tremors can accompany the low calcium levels that accompany vitamin D deficiency, reflecting systemic weakness. Among the deficiencies listed, inadequate vitamin D best explains the combination of skeletal deformities (bowed limbs and softened ribs) with general weakness in a yearling. Selenium deficiency mainly causes muscle problems without the characteristic bone deformities, while phosphorus deficiency disrupts mineralization but doesn’t produce the classic rickets pattern as cleanly as vitamin D deficiency.

Growing animals rely on vitamin D to absorb calcium and phosphate, which is essential for proper bone mineralization. When vitamin D is lacking, calcium and phosphate uptake drops, leading to poorly mineralized bones. In a young, rapidly growing animal, this shows up as rickets: the growth plates don’t mineralize well, bones become soft, and the limbs can bow while the ribs may appear softened. Lethargy and tremors can accompany the low calcium levels that accompany vitamin D deficiency, reflecting systemic weakness. Among the deficiencies listed, inadequate vitamin D best explains the combination of skeletal deformities (bowed limbs and softened ribs) with general weakness in a yearling. Selenium deficiency mainly causes muscle problems without the characteristic bone deformities, while phosphorus deficiency disrupts mineralization but doesn’t produce the classic rickets pattern as cleanly as vitamin D deficiency.