Topics:
Animal Nutrition, Animal Refresher
Examples of Highly Degradable (Low Bypass) Protein
Which of the following is example of a very low bypass protein?
- Urea & casein — Correct Answer
- Maize, feather meal, blood meal
- Soybean meal
- None
Explanation:
Correct Answer: Urea and Casein
Low bypass (high rumen-degradable) proteins are those that are rapidly and almost completely hydrolyzed by rumen microorganisms. Urea (100% degradable — no protein structure, just NPN) and Casein (milk protein — highly soluble, ~90–95% degraded in rumen) are the classic examples.
Bypass Protein Spectrum
| Feed | Rumen Degradability | Classification |
|---|---|---|
| Urea | 100% | Completely degradable (NPN) |
| Casein | ~90–95% | Very low bypass |
| Soybean meal | ~65–70% | Moderate bypass |
| Maize (Zein protein) | ~40–50% | Higher bypass |
| Feather meal | ~20–30% | High natural bypass |
| Blood meal | ~20% | High natural bypass |
Why Low Bypass is Important
- Highly degradable proteins provide NH₃ for microbial protein synthesis in the rumen.
- But if NH₃ production exceeds microbial utilization → wasted N and potential toxicity.
- High-producing cows need bypass protein to meet their post-ruminal amino acid requirements.
Why Other Options Are Wrong
- Maize, feather meal, blood meal → these are HIGH bypass proteins, not low bypass.
- Soybean meal → moderate bypass (~30–35%); not as low as urea/casein.
- None → Urea and Casein are the definitive examples of low/no bypass protein.
📚 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.
