What is the proper calcium:phosphorus ratio in an adult animal?

• A. Between 1:1 to 2:1
• B. 3:1
• C. 0.5:1
• D. 1:3

Answer: (A)

Calcium and phosphorus must be kept in balance for proper bone health and metabolic function. For an adult animal, a calcium to phosphorus ratio around 1:1 to 2:1 is appropriate, providing enough calcium for bone mineralization without tipping so far toward calcium that phosphorus absorption or bone remodeling is impaired.

Why this range works: calcium supports bone formation and many physiological processes, while phosphorus is essential for energy metabolism and cellular functions. If phosphorus is too high relative to calcium (ratios like 0.5:1 or 1:3), bone mineralization can suffer and parathyroid-driven bone resorption may occur. If calcium is excessively high relative to phosphorus (like 3:1), the balance can hinder proper phosphorus utilization and bone health as well.

So the best choice is the range that keeps calcium and phosphorus in a near-equal to moderately calcium-rich relationship, 1:1 to 2:1, aligning with adult needs.