Topics:
Animal Nutrition, Animal Refresher
Nutritional Value of Straw
DCP content of straw is practically ______ while the TDN is about ______.
- 0% and 40%
- Nil and 40% — Correct Answer
- 0% and 50%
- Nil and 50%
Explanation:
Correct Answer: Nil and 40%
Cereal straws are heavily lignified mature crop residues with extremely low nutritive value. DCP (Digestible Crude Protein) of straw is practically Nil (0%) and TDN (Total Digestible Nutrients) is approximately 40%.
Nutritional Composition of Common Roughages
| Roughage Type | CP% | DCP% | TDN% | Digestibility% |
|---|---|---|---|---|
| Normal straw (wheat) | 3–4% | 0% (Nil) | ~40% | ~46% |
| Urea-treated straw | ~8% | 4–5% | ~50% | ~70% |
| Lucerne hay | ~18% | ~14% | ~55% | ~65% |
Why Straw Has Zero DCP
- Straw has very high crude fibre and lignin content, making most protein indigestible.
- Lignin binds to protein and reduces its digestibility to near zero.
- Straw is also deficient in all minerals but rich in silica.
- Urea treatment can raise DCP to 4–5% by improving rumen fermentation.
Why Other Options Are Wrong
- 0% and 40% → technically same meaning as "Nil and 40%" but the textbook uses "Nil" for DCP to emphasize the virtual absence of digestible protein.
- 0% and 50% → 50% TDN is for urea-treated straw, not untreated straw.
- Nil and 50% → DCP is correct but TDN of 50% applies to improved straw.
📚 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.
