Topics:
Animal Nutrition, Animal Refresher
Formula for Nutritive Ratio
The formula $\frac{TDN - DCP}{DCP}$ represents:
- Nutritive ratio — Correct Answer
- Net Protein utilization
- PER
- None
Explanation:
Correct Answer: Nutritive Ratio
The formula (TDN − DCP) / DCP defines the Nutritive Ratio (NR). It expresses the ratio of non-protein energy to digestible protein in a ration, indicating whether a diet is "wide" (energy-rich) or "narrow" (protein-rich).
Important Nutritional Formulas
| Formula | Name | Interpretation |
|---|---|---|
| (TDN − DCP) / DCP | Nutritive Ratio (NR) | Wide NR = more energy; Narrow NR = more protein |
| (DCP + DTP) / 2 | Protein Equivalent | Average of digestible crude and true protein |
| Retained N / Intake N × 100 | Net Protein Utilization (NPU) | % of dietary N actually retained |
| Weight gain / Protein consumed | PER (Protein Efficiency Ratio) | g weight gain per g protein |
Nutritive Ratio — Practical Values
- NR of 1:6 (narrow) → protein-rich diet; suitable for high-production dairy cows.
- NR of 1:10 (wide) → energy-rich; suitable for maintenance/fattening.
- Average concentrate NR: 1:5 to 1:7.
- Average roughage NR: 1:8 to 1:15 (wider = less protein).
Why Other Options Are Wrong
- Net Protein Utilization → formula is Retained N / Intake N × 100; not TDN/DCP-based.
- PER (Protein Efficiency Ratio) → weight gain per gram protein consumed; unrelated to TDN.
- None → Nutritive Ratio is the correct name for this formula.
📚 About this Topic — Animal Nutrition
This multiple choice question is from Animal Nutrition, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Nutrition to strengthen your preparation.
