Topics:
Animal Nutrition, Animal Refresher
Nitrogen Percentage in Urea
Nitrogen content of urea is ______ %.
- 46.6 — Correct Answer
- 18
- 40
- None
Explanation:
Correct Answer: 46.6%
The nitrogen content of pure urea [CO(NH₂)₂] is 46.6%. This is calculated from molecular weights: N = 2 × 14 = 28; molecular weight of urea = 60; N% = 28/60 × 100 = 46.6%.
Nitrogen Content of Common NPN Sources
| NPN Source | N% (approx.) | Crude Protein Equivalent |
|---|---|---|
| Urea [CO(NH₂)₂] | 46.6% | 46.6 × 6.25 = 291% |
| DAP (Diammonium phosphate) | 18% | — |
| Ammonium sulfate | 21% | — |
| Biuret | ~40% | — |
Key Facts About Urea in Ruminant Nutrition
- Urea is 100% rumen-degradable → rapidly converted to NH₃ by urease enzyme.
- 1 kg urea replaces approximately 2.8 kg crude protein from natural sources.
- Urea is fed only to ruminants ≥6 months old (functional rumen required).
- Urea has no energy value and is deficient in all minerals.
Why Other Options Are Wrong
- 18% → nitrogen content of DAP (Diammonium Phosphate), not urea.
- 40% → approximate N% of biuret; not urea.
- None → 46.6% is the correct value for pure urea.
📚 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.
