Question

Generally, the calcium: phosphorus ratio in animal diets shall be

• A. 10:1
• B. 2:1
• C. 15:1
• D. 9:1

Hint:

Remember the standard animal diet rule of thumb: Keep the Ca:P ratio around 2:1, except for laying poultry where it is elevated to roughly 10:1 for eggshell formation.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Calcium (Ca) and Phosphorus (P) are essential macro-minerals required for skeletal integrity and metabolic function.
In addition to their absolute dietary quantities, maintaining a proper balance between these two minerals is critical to avoid absorption interference.

Step 3: Detailed Explanation:
For most domestic livestock, the ideal dietary Ca:P ratio is between 1:1 and 2:1.
A ratio of 2:1 closely mimics the natural physiological composition of bone tissue (hydroxyapatite).
Extremely high ratios (such as 10:1 or 15:1) can inhibit the absorption of phosphorus, leading to reproductive inefficiency, rickets, and pica.
An exception to this rule is laying hens, which require a high Ca:P ratio (around 10:1) to support calcium deposition for eggshell production.

Step 4: Final Answer
Generally, the standard recommended Ca:P ratio in animal diets is 2:1.